text: /* vi:set ts=8 sts=4 sw=4 noet:
   *
   * VIM - Vi IMproved	by Bram Moolenaar
   *
   * Do ":help uganda"  in Vim to read copying and usage conditions.
   * Do ":help credits" in Vim to see a list of people who contributed.
   * See README.txt for an overview of the Vim source code.
   */
  
  /*
   * vim9compile.c: :def and dealing with instructions
   */
  
  #define USING_FLOAT_STUFF
  #include "vim.h"
  
  #if defined(FEAT_EVAL) || defined(PROTO)
  
  #ifdef VMS
  # include <float.h>
  #endif
  
  #define DEFINE_VIM9_GLOBALS
  #include "vim9.h"
  
  // values for ctx_skip
  typedef enum {
      SKIP_NOT,		// condition is a constant, produce code
      SKIP_YES,		// condition is a constant, do NOT produce code
      SKIP_UNKNOWN	// condition is not a constant, produce code
  } skip_T;
  
  /*
   * Chain of jump instructions where the end label needs to be set.
   */
  typedef struct endlabel_S endlabel_T;
  struct endlabel_S {
      endlabel_T	*el_next;	    // chain end_label locations
      int		el_end_label;	    // instruction idx where to set end
  };
  
  /*
   * info specific for the scope of :if / elseif / else
   */
  typedef struct {
      int		is_seen_else;
      int		is_had_return;	    // every block ends in :return
      int		is_if_label;	    // instruction idx at IF or ELSEIF
      endlabel_T	*is_end_label;	    // instructions to set end label
  } ifscope_T;
  
  /*
   * info specific for the scope of :while
   */
  typedef struct {
      int		ws_top_label;	    // instruction idx at WHILE
      endlabel_T	*ws_end_label;	    // instructions to set end
  } whilescope_T;
  
  /*
   * info specific for the scope of :for
   */
  typedef struct {
      int		fs_top_label;	    // instruction idx at FOR
      endlabel_T	*fs_end_label;	    // break instructions
  } forscope_T;
  
  /*
   * info specific for the scope of :try
   */
  typedef struct {
      int		ts_try_label;	    // instruction idx at TRY
      endlabel_T	*ts_end_label;	    // jump to :finally or :endtry
      int		ts_catch_label;	    // instruction idx of last CATCH
      int		ts_caught_all;	    // "catch" without argument encountered
  } tryscope_T;
  
  typedef enum {
      NO_SCOPE,
      IF_SCOPE,
      WHILE_SCOPE,
      FOR_SCOPE,
      TRY_SCOPE,
      BLOCK_SCOPE
  } scopetype_T;
  
  /*
   * Info for one scope, pointed to by "ctx_scope".
   */
  typedef struct scope_S scope_T;
  struct scope_S {
      scope_T	*se_outer;	    // scope containing this one
      scopetype_T se_type;
      int		se_local_count;	    // ctx_locals.ga_len before scope
      skip_T	se_skip_save;	    // ctx_skip before the block
      union {
  	ifscope_T	se_if;
  	whilescope_T	se_while;
  	forscope_T	se_for;
  	tryscope_T	se_try;
      } se_u;
  };
  
  /*
   * Entry for "ctx_locals".  Used for arguments and local variables.
   */
  typedef struct {
      char_u	*lv_name;
      type_T	*lv_type;
      int		lv_idx;		// index of the variable on the stack
      int		lv_from_outer;	// nesting level, using ctx_outer scope
      int		lv_const;	// when TRUE cannot be assigned to
      int		lv_arg;		// when TRUE this is an argument
  } lvar_T;
  
  /*
   * Context for compiling lines of Vim script.
   * Stores info about the local variables and condition stack.
   */
  struct cctx_S {
      ufunc_T	*ctx_ufunc;	    // current function
      int		ctx_lnum;	    // line number in current function
      char_u	*ctx_line_start;    // start of current line or NULL
      garray_T	ctx_instr;	    // generated instructions
  
      garray_T	ctx_locals;	    // currently visible local variables
      int		ctx_locals_count;   // total number of local variables
  
      int		ctx_has_closure;    // set to one if a closures was created in
  				    // the function
  
      garray_T	ctx_imports;	    // imported items
  
      skip_T	ctx_skip;
      scope_T	*ctx_scope;	    // current scope, NULL at toplevel
      int		ctx_had_return;	    // last seen statement was "return"
  
      cctx_T	*ctx_outer;	    // outer scope for lambda or nested
  				    // function
      int		ctx_outer_used;	    // var in ctx_outer was used
  
      garray_T	ctx_type_stack;	    // type of each item on the stack
      garray_T	*ctx_type_list;	    // list of pointers to allocated types
  
      int		ctx_has_cmdmod;	    // ISN_CMDMOD was generated
  };
  
  static void delete_def_function_contents(dfunc_T *dfunc, int mark_deleted);
  
  /*
   * Lookup variable "name" in the local scope and return it in "lvar".
   * "lvar->lv_from_outer" is incremented accordingly.
   * If "lvar" is NULL only check if the variable can be found.
   * Return FAIL if not found.
   */
      static int
  lookup_local(char_u *name, size_t len, lvar_T *lvar, cctx_T *cctx)
  {
      int	    idx;
      lvar_T  *lvp;
  
      if (len == 0)
  	return FAIL;
  
      // Find local in current function scope.
      for (idx = 0; idx < cctx->ctx_locals.ga_len; ++idx)
      {
  	lvp = ((lvar_T *)cctx->ctx_locals.ga_data) + idx;
  	if (STRNCMP(name, lvp->lv_name, len) == 0
  					       && STRLEN(lvp->lv_name) == len)
  	{
  	    if (lvar != NULL)
  	    {
  		*lvar = *lvp;
  		lvar->lv_from_outer = 0;
  	    }
  	    return OK;
  	}
      }
  
      // Find local in outer function scope.
      if (cctx->ctx_outer != NULL)
      {
  	if (lookup_local(name, len, lvar, cctx->ctx_outer) == OK)
  	{
  	    if (lvar != NULL)
  	    {
  		cctx->ctx_outer_used = TRUE;
  		++lvar->lv_from_outer;
  	    }
  	    return OK;
  	}
      }
  
      return FAIL;
  }
  
  /*
   * Lookup an argument in the current function and an enclosing function.
   * Returns the argument index in "idxp"
   * Returns the argument type in "type"
   * Sets "gen_load_outer" to TRUE if found in outer scope.
   * Returns OK when found, FAIL otherwise.
   */
      static int
  arg_exists(
  	char_u	*name,
  	size_t	len,
  	int	*idxp,
  	type_T	**type,
  	int	*gen_load_outer,
  	cctx_T	*cctx)
  {
      int	    idx;
      char_u  *va_name;
  
      if (len == 0)
  	return FAIL;
      for (idx = 0; idx < cctx->ctx_ufunc->uf_args.ga_len; ++idx)
      {
  	char_u *arg = FUNCARG(cctx->ctx_ufunc, idx);
  
  	if (STRNCMP(name, arg, len) == 0 && arg[len] == NUL)
  	{
  	    if (idxp != NULL)
  	    {
  		// Arguments are located above the frame pointer.  One further
  		// if there is a vararg argument
  		*idxp = idx - (cctx->ctx_ufunc->uf_args.ga_len
  							    + STACK_FRAME_SIZE)
  			      + (cctx->ctx_ufunc->uf_va_name != NULL ? -1 : 0);
  
  		if (cctx->ctx_ufunc->uf_arg_types != NULL)
  		    *type = cctx->ctx_ufunc->uf_arg_types[idx];
  		else
  		    *type = &t_any;
  	    }
  	    return OK;
  	}
      }
  
      va_name = cctx->ctx_ufunc->uf_va_name;
      if (va_name != NULL
  		    && STRNCMP(name, va_name, len) == 0 && va_name[len] == NUL)
      {
  	if (idxp != NULL)
  	{
  	    // varargs is always the last argument
  	    *idxp = -STACK_FRAME_SIZE - 1;
  	    *type = cctx->ctx_ufunc->uf_va_type;
  	}
  	return OK;
      }
  
      if (cctx->ctx_outer != NULL)
      {
  	// Lookup the name for an argument of the outer function.
  	if (arg_exists(name, len, idxp, type, gen_load_outer, cctx->ctx_outer)
  									 == OK)
  	{
  	    ++*gen_load_outer;
  	    return OK;
  	}
      }
  
      return FAIL;
  }
  
  /*
   * Lookup a script-local variable in the current script, possibly defined in a
   * block that contains the function "cctx->ctx_ufunc".
   * "cctx" is NULL at the script level.
   * if "len" is <= 0 "name" must be NUL terminated.
   * Return NULL when not found.
   */
      static sallvar_T *
  find_script_var(char_u *name, size_t len, cctx_T *cctx)
  {
      scriptitem_T    *si = SCRIPT_ITEM(current_sctx.sc_sid);
      hashitem_T	    *hi;
      int		    cc;
      sallvar_T	    *sav;
      ufunc_T	    *ufunc;
  
      // Find the list of all script variables with the right name.
      if (len > 0)
      {
  	cc = name[len];
  	name[len] = NUL;
      }
      hi = hash_find(&si->sn_all_vars.dv_hashtab, name);
      if (len > 0)
  	name[len] = cc;
      if (HASHITEM_EMPTY(hi))
  	return NULL;
  
      sav = HI2SAV(hi);
      if (sav->sav_block_id == 0 || cctx == NULL)
  	// variable defined in the script scope or not in a function.
  	return sav;
  
      // Go over the variables with this name and find one that was visible
      // from the function.
      ufunc = cctx->ctx_ufunc;
      while (sav != NULL)
      {
  	int idx;
  
  	// Go over the blocks that this function was defined in.  If the
  	// variable block ID matches it was visible to the function.
  	for (idx = 0; idx < ufunc->uf_block_depth; ++idx)
  	    if (ufunc->uf_block_ids[idx] == sav->sav_block_id)
  		return sav;
  	sav = sav->sav_next;
      }
  
      return NULL;
  }
  
  /*
   * Return TRUE if the script context is Vim9 script.
   */
      static int
  script_is_vim9()
  {
      return SCRIPT_ITEM(current_sctx.sc_sid)->sn_version == SCRIPT_VERSION_VIM9;
  }
  
  /*
   * Lookup a variable (without s: prefix) in the current script.
   * If "vim9script" is TRUE the script must be Vim9 script.  Used for "var"
   * without "s:".
   * "cctx" is NULL at the script level.
   * Returns OK or FAIL.
   */
      static int
  script_var_exists(char_u *name, size_t len, int vim9script, cctx_T *cctx)
  {
      int		    is_vim9_script;
  
      if (current_sctx.sc_sid <= 0)
  	return FAIL;
      is_vim9_script = script_is_vim9();
      if (vim9script && !is_vim9_script)
  	return FAIL;
      if (is_vim9_script)
      {
  	// Check script variables that were visible where the function was
  	// defined.
  	if (find_script_var(name, len, cctx) != NULL)
  	    return OK;
      }
      else
      {
  	hashtab_T	*ht = &SCRIPT_VARS(current_sctx.sc_sid);
  	dictitem_T	*di;
  	int		cc;
  
  	// Check script variables that are currently visible
  	cc = name[len];
  	name[len] = NUL;
  	di = find_var_in_ht(ht, 0, name, TRUE);
  	name[len] = cc;
  	if (di != NULL)
  	    return OK;
      }
  
      return FAIL;
  }
  
  /*
   * Check if "p[len]" is already defined, either in script "import_sid" or in
   * compilation context "cctx".  "cctx" is NULL at the script level.
   * Does not check the global namespace.
   * Return FAIL and give an error if it defined.
   */
      int
  check_defined(char_u *p, size_t len, cctx_T *cctx)
  {
      int		c = p[len];
      ufunc_T	*ufunc = NULL;
  
      p[len] = NUL;
      if (script_var_exists(p, len, FALSE, cctx) == OK
  	    || (cctx != NULL
  		&& (lookup_local(p, len, NULL, cctx) == OK
  		    || arg_exists(p, len, NULL, NULL, NULL, cctx) == OK))
  	    || find_imported(p, len, cctx) != NULL
  	    || (ufunc = find_func_even_dead(p, FALSE, cctx)) != NULL)
      {
  	// A local or script-local function can shadow a global function.
  	if (ufunc == NULL || !func_is_global(ufunc)
  		|| (p[0] == 'g' && p[1] == ':'))
  	{
  	    p[len] = c;
  	    semsg(_(e_name_already_defined_str), p);
  	    return FAIL;
  	}
      }
      p[len] = c;
      return OK;
  }
  
  
  /////////////////////////////////////////////////////////////////////
  // Following generate_ functions expect the caller to call ga_grow().
  
  #define RETURN_NULL_IF_SKIP(cctx) if (cctx->ctx_skip == SKIP_YES) return NULL
  #define RETURN_OK_IF_SKIP(cctx) if (cctx->ctx_skip == SKIP_YES) return OK
  
  /*
   * Generate an instruction without arguments.
   * Returns a pointer to the new instruction, NULL if failed.
   */
      static isn_T *
  generate_instr(cctx_T *cctx, isntype_T isn_type)
  {
      garray_T	*instr = &cctx->ctx_instr;
      isn_T	*isn;
  
      RETURN_NULL_IF_SKIP(cctx);
      if (ga_grow(instr, 1) == FAIL)
  	return NULL;
      isn = ((isn_T *)instr->ga_data) + instr->ga_len;
      isn->isn_type = isn_type;
      isn->isn_lnum = cctx->ctx_lnum + 1;
      ++instr->ga_len;
  
      return isn;
  }
  
  /*
   * Generate an instruction without arguments.
   * "drop" will be removed from the stack.
   * Returns a pointer to the new instruction, NULL if failed.
   */
      static isn_T *
  generate_instr_drop(cctx_T *cctx, isntype_T isn_type, int drop)
  {
      garray_T	*stack = &cctx->ctx_type_stack;
  
      RETURN_NULL_IF_SKIP(cctx);
      stack->ga_len -= drop;
      return generate_instr(cctx, isn_type);
  }
  
  /*
   * Generate instruction "isn_type" and put "type" on the type stack.
   */
      static isn_T *
  generate_instr_type(cctx_T *cctx, isntype_T isn_type, type_T *type)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
  
      if ((isn = generate_instr(cctx, isn_type)) == NULL)
  	return NULL;
  
      if (ga_grow(stack, 1) == FAIL)
  	return NULL;
      ((type_T **)stack->ga_data)[stack->ga_len] = type == NULL ? &t_any : type;
      ++stack->ga_len;
  
      return isn;
  }
  
  /*
   * If type at "offset" isn't already VAR_STRING then generate ISN_2STRING.
   * But only for simple types.
   */
      static int
  may_generate_2STRING(int offset, cctx_T *cctx)
  {
      isn_T	*isn;
      isntype_T	isntype = ISN_2STRING;
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	**type;
  
      RETURN_OK_IF_SKIP(cctx);
      type = ((type_T **)stack->ga_data) + stack->ga_len + offset;
      switch ((*type)->tt_type)
      {
  	// nothing to be done
  	case VAR_STRING: return OK;
  
  	// conversion possible
  	case VAR_SPECIAL:
  	case VAR_BOOL:
  	case VAR_NUMBER:
  	case VAR_FLOAT:
  			 break;
  
  	// conversion possible (with runtime check)
  	case VAR_ANY:
  	case VAR_UNKNOWN:
  			 isntype = ISN_2STRING_ANY;
  			 break;
  
  	// conversion not possible
  	case VAR_VOID:
  	case VAR_BLOB:
  	case VAR_FUNC:
  	case VAR_PARTIAL:
  	case VAR_LIST:
  	case VAR_DICT:
  	case VAR_JOB:
  	case VAR_CHANNEL:
  			 to_string_error((*type)->tt_type);
  			 return FAIL;
      }
  
      *type = &t_string;
      if ((isn = generate_instr(cctx, isntype)) == NULL)
  	return FAIL;
      isn->isn_arg.number = offset;
  
      return OK;
  }
  
      static int
  check_number_or_float(vartype_T type1, vartype_T type2, char_u *op)
  {
      if (!((type1 == VAR_NUMBER || type1 == VAR_FLOAT || type1 == VAR_ANY)
  	    && (type2 == VAR_NUMBER || type2 == VAR_FLOAT
  							 || type2 == VAR_ANY)))
      {
  	if (*op == '+')
  	    emsg(_(e_wrong_argument_type_for_plus));
  	else
  	    semsg(_(e_char_requires_number_or_float_arguments), *op);
  	return FAIL;
      }
      return OK;
  }
  
      static int
  generate_add_instr(
  	cctx_T *cctx,
  	vartype_T vartype,
  	type_T *type1,
  	type_T *type2)
  {
      garray_T	*stack = &cctx->ctx_type_stack;
      isn_T	*isn = generate_instr_drop(cctx,
  		      vartype == VAR_NUMBER ? ISN_OPNR
  		    : vartype == VAR_LIST ? ISN_ADDLIST
  		    : vartype == VAR_BLOB ? ISN_ADDBLOB
  #ifdef FEAT_FLOAT
  		    : vartype == VAR_FLOAT ? ISN_OPFLOAT
  #endif
  		    : ISN_OPANY, 1);
  
      if (vartype != VAR_LIST && vartype != VAR_BLOB
  	    && type1->tt_type != VAR_ANY
  	    && type2->tt_type != VAR_ANY
  	    && check_number_or_float(
  			type1->tt_type, type2->tt_type, (char_u *)"+") == FAIL)
  	return FAIL;
  
      if (isn != NULL)
  	isn->isn_arg.op.op_type = EXPR_ADD;
  
      // When concatenating two lists with different member types the member type
      // becomes "any".
      if (vartype == VAR_LIST
  	    && type1->tt_type == VAR_LIST && type2->tt_type == VAR_LIST
  	    && type1->tt_member != type2->tt_member)
  	(((type_T **)stack->ga_data)[stack->ga_len - 1]) = &t_list_any;
  
      return isn == NULL ? FAIL : OK;
  }
  
  /*
   * Get the type to use for an instruction for an operation on "type1" and
   * "type2".  If they are matching use a type-specific instruction. Otherwise
   * fall back to runtime type checking.
   */
      static vartype_T
  operator_type(type_T *type1, type_T *type2)
  {
      if (type1->tt_type == type2->tt_type
  	    && (type1->tt_type == VAR_NUMBER
  		|| type1->tt_type == VAR_LIST
  #ifdef FEAT_FLOAT
  		|| type1->tt_type == VAR_FLOAT
  #endif
  		|| type1->tt_type == VAR_BLOB))
  	return type1->tt_type;
      return VAR_ANY;
  }
  
  /*
   * Generate an instruction with two arguments.  The instruction depends on the
   * type of the arguments.
   */
      static int
  generate_two_op(cctx_T *cctx, char_u *op)
  {
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	*type1;
      type_T	*type2;
      vartype_T	vartype;
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
  
      // Get the known type of the two items on the stack.
      type1 = ((type_T **)stack->ga_data)[stack->ga_len - 2];
      type2 = ((type_T **)stack->ga_data)[stack->ga_len - 1];
      vartype = operator_type(type1, type2);
  
      switch (*op)
      {
  	case '+':
  		  if (generate_add_instr(cctx, vartype, type1, type2) == FAIL)
  		      return FAIL;
  		  break;
  
  	case '-':
  	case '*':
  	case '/': if (check_number_or_float(type1->tt_type, type2->tt_type,
  								   op) == FAIL)
  		      return FAIL;
  		  if (vartype == VAR_NUMBER)
  		      isn = generate_instr_drop(cctx, ISN_OPNR, 1);
  #ifdef FEAT_FLOAT
  		  else if (vartype == VAR_FLOAT)
  		      isn = generate_instr_drop(cctx, ISN_OPFLOAT, 1);
  #endif
  		  else
  		      isn = generate_instr_drop(cctx, ISN_OPANY, 1);
  		  if (isn != NULL)
  		      isn->isn_arg.op.op_type = *op == '*'
  				 ? EXPR_MULT : *op == '/'? EXPR_DIV : EXPR_SUB;
  		  break;
  
  	case '%': if ((type1->tt_type != VAR_ANY
  					       && type1->tt_type != VAR_NUMBER)
  			  || (type2->tt_type != VAR_ANY
  					      && type2->tt_type != VAR_NUMBER))
  		  {
  		      emsg(_(e_percent_requires_number_arguments));
  		      return FAIL;
  		  }
  		  isn = generate_instr_drop(cctx,
  			      vartype == VAR_NUMBER ? ISN_OPNR : ISN_OPANY, 1);
  		  if (isn != NULL)
  		      isn->isn_arg.op.op_type = EXPR_REM;
  		  break;
      }
  
      // correct type of result
      if (vartype == VAR_ANY)
      {
  	type_T *type = &t_any;
  
  #ifdef FEAT_FLOAT
  	// float+number and number+float results in float
  	if ((type1->tt_type == VAR_NUMBER || type1->tt_type == VAR_FLOAT)
  		&& (type2->tt_type == VAR_NUMBER || type2->tt_type == VAR_FLOAT))
  	    type = &t_float;
  #endif
  	((type_T **)stack->ga_data)[stack->ga_len - 1] = type;
      }
  
      return OK;
  }
  
  /*
   * Get the instruction to use for comparing "type1" with "type2"
   * Return ISN_DROP when failed.
   */
      static isntype_T
  get_compare_isn(exprtype_T exprtype, vartype_T type1, vartype_T type2)
  {
      isntype_T	isntype = ISN_DROP;
  
      if (type1 == VAR_UNKNOWN)
  	type1 = VAR_ANY;
      if (type2 == VAR_UNKNOWN)
  	type2 = VAR_ANY;
  
      if (type1 == type2)
      {
  	switch (type1)
  	{
  	    case VAR_BOOL: isntype = ISN_COMPAREBOOL; break;
  	    case VAR_SPECIAL: isntype = ISN_COMPARESPECIAL; break;
  	    case VAR_NUMBER: isntype = ISN_COMPARENR; break;
  	    case VAR_FLOAT: isntype = ISN_COMPAREFLOAT; break;
  	    case VAR_STRING: isntype = ISN_COMPARESTRING; break;
  	    case VAR_BLOB: isntype = ISN_COMPAREBLOB; break;
  	    case VAR_LIST: isntype = ISN_COMPARELIST; break;
  	    case VAR_DICT: isntype = ISN_COMPAREDICT; break;
  	    case VAR_FUNC: isntype = ISN_COMPAREFUNC; break;
  	    default: isntype = ISN_COMPAREANY; break;
  	}
      }
      else if (type1 == VAR_ANY || type2 == VAR_ANY
  	    || ((type1 == VAR_NUMBER || type1 == VAR_FLOAT)
  	      && (type2 == VAR_NUMBER || type2 ==VAR_FLOAT)))
  	isntype = ISN_COMPAREANY;
  
      if ((exprtype == EXPR_IS || exprtype == EXPR_ISNOT)
  	    && (isntype == ISN_COMPAREBOOL
  	    || isntype == ISN_COMPARESPECIAL
  	    || isntype == ISN_COMPARENR
  	    || isntype == ISN_COMPAREFLOAT))
      {
  	semsg(_(e_cannot_use_str_with_str),
  		exprtype == EXPR_IS ? "is" : "isnot" , vartype_name(type1));
  	return ISN_DROP;
      }
      if (isntype == ISN_DROP
  	    || ((exprtype != EXPR_EQUAL && exprtype != EXPR_NEQUAL
  		    && (type1 == VAR_BOOL || type1 == VAR_SPECIAL
  		       || type2 == VAR_BOOL || type2 == VAR_SPECIAL)))
  	    || ((exprtype != EXPR_EQUAL && exprtype != EXPR_NEQUAL
  				 && exprtype != EXPR_IS && exprtype != EXPR_ISNOT
  		    && (type1 == VAR_BLOB || type2 == VAR_BLOB
  			|| type1 == VAR_LIST || type2 == VAR_LIST))))
      {
  	semsg(_(e_cannot_compare_str_with_str),
  		vartype_name(type1), vartype_name(type2));
  	return ISN_DROP;
      }
      return isntype;
  }
  
      int
  check_compare_types(exprtype_T type, typval_T *tv1, typval_T *tv2)
  {
      if (get_compare_isn(type, tv1->v_type, tv2->v_type) == ISN_DROP)
  	return FAIL;
      return OK;
  }
  
  /*
   * Generate an ISN_COMPARE* instruction with a boolean result.
   */
      static int
  generate_COMPARE(cctx_T *cctx, exprtype_T exprtype, int ic)
  {
      isntype_T	isntype;
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
      vartype_T	type1;
      vartype_T	type2;
  
      RETURN_OK_IF_SKIP(cctx);
  
      // Get the known type of the two items on the stack.  If they are matching
      // use a type-specific instruction. Otherwise fall back to runtime type
      // checking.
      type1 = ((type_T **)stack->ga_data)[stack->ga_len - 2]->tt_type;
      type2 = ((type_T **)stack->ga_data)[stack->ga_len - 1]->tt_type;
      isntype = get_compare_isn(exprtype, type1, type2);
      if (isntype == ISN_DROP)
  	return FAIL;
  
      if ((isn = generate_instr(cctx, isntype)) == NULL)
  	return FAIL;
      isn->isn_arg.op.op_type = exprtype;
      isn->isn_arg.op.op_ic = ic;
  
      // takes two arguments, puts one bool back
      if (stack->ga_len >= 2)
      {
  	--stack->ga_len;
  	((type_T **)stack->ga_data)[stack->ga_len - 1] = &t_bool;
      }
  
      return OK;
  }
  
  /*
   * Generate an ISN_2BOOL instruction.
   */
      static int
  generate_2BOOL(cctx_T *cctx, int invert)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_2BOOL)) == NULL)
  	return FAIL;
      isn->isn_arg.number = invert;
  
      // type becomes bool
      ((type_T **)stack->ga_data)[stack->ga_len - 1] = &t_bool;
  
      return OK;
  }
  
  /*
   * Generate an ISN_COND2BOOL instruction.
   */
      static int
  generate_COND2BOOL(cctx_T *cctx)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_COND2BOOL)) == NULL)
  	return FAIL;
  
      // type becomes bool
      ((type_T **)stack->ga_data)[stack->ga_len - 1] = &t_bool;
  
      return OK;
  }
  
      static int
  generate_TYPECHECK(
  	cctx_T	    *cctx,
  	type_T	    *expected,
  	int	    offset)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_CHECKTYPE)) == NULL)
  	return FAIL;
      isn->isn_arg.type.ct_type = alloc_type(expected);
      isn->isn_arg.type.ct_off = offset;
  
      // type becomes expected
      ((type_T **)stack->ga_data)[stack->ga_len + offset] = expected;
  
      return OK;
  }
  
      static int
  generate_SETTYPE(
  	cctx_T	    *cctx,
  	type_T	    *expected)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_SETTYPE)) == NULL)
  	return FAIL;
      isn->isn_arg.type.ct_type = alloc_type(expected);
      return OK;
  }
  
  /*
   * Return TRUE if "actual" could be "expected" and a runtime typecheck is to be
   * used.  Return FALSE if the types will never match.
   */
      int
  use_typecheck(type_T *actual, type_T *expected)
  {
      if (actual->tt_type == VAR_ANY
  	    || actual->tt_type == VAR_UNKNOWN
  	    || (actual->tt_type == VAR_FUNC
  		&& (expected->tt_type == VAR_FUNC
  					   || expected->tt_type == VAR_PARTIAL)
  		&& (actual->tt_member == &t_any || actual->tt_argcount < 0)
  		&& ((actual->tt_member == &t_void)
  					 == (expected->tt_member == &t_void))))
  	return TRUE;
      if ((actual->tt_type == VAR_LIST || actual->tt_type == VAR_DICT)
  				       && actual->tt_type == expected->tt_type)
  	// This takes care of a nested list or dict.
  	return use_typecheck(actual->tt_member, expected->tt_member);
      return FALSE;
  }
  
  /*
   * Check that
   * - "actual" matches "expected" type or
   * - "actual" is a type that can be "expected" type: add a runtime check; or
   * - return FAIL.
   * If "actual_is_const" is TRUE then the type won't change at runtime, do not
   * generate a TYPECHECK.
   */
      int
  need_type(
  	type_T	*actual,
  	type_T	*expected,
  	int	offset,
  	int	arg_idx,
  	cctx_T	*cctx,
  	int	silent,
  	int	actual_is_const)
  {
      if (expected == &t_bool && actual != &t_bool
  					&& (actual->tt_flags & TTFLAG_BOOL_OK))
      {
  	// Using "0", "1" or the result of an expression with "&&" or "||" as a
  	// boolean is OK but requires a conversion.
  	generate_2BOOL(cctx, FALSE);
  	return OK;
      }
  
      if (check_type(expected, actual, FALSE, arg_idx) == OK)
  	return OK;
  
      // If the actual type can be the expected type add a runtime check.
      // If it's a constant a runtime check makes no sense.
      if (!actual_is_const && use_typecheck(actual, expected))
      {
  	generate_TYPECHECK(cctx, expected, offset);
  	return OK;
      }
  
      if (!silent)
  	arg_type_mismatch(expected, actual, arg_idx);
      return FAIL;
  }
  
  /*
   * Check that the top of the type stack has a type that can be used as a
   * condition.  Give an error and return FAIL if not.
   */
      static int
  bool_on_stack(cctx_T *cctx)
  {
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	*type;
  
      type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
      if (type == &t_bool)
  	return OK;
  
      if (type == &t_any || type == &t_number)
  	// Number 0 and 1 are OK to use as a bool.  "any" could also be a bool.
  	// This requires a runtime type check.
  	return generate_COND2BOOL(cctx);
  
      return need_type(type, &t_bool, -1, 0, cctx, FALSE, FALSE);
  }
  
  /*
   * Generate an ISN_PUSHNR instruction.
   */
      static int
  generate_PUSHNR(cctx_T *cctx, varnumber_T number)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_type(cctx, ISN_PUSHNR, &t_number)) == NULL)
  	return FAIL;
      isn->isn_arg.number = number;
  
      if (number == 0 || number == 1)
  	// A 0 or 1 number can also be used as a bool.
  	((type_T **)stack->ga_data)[stack->ga_len - 1] = &t_number_bool;
      return OK;
  }
  
  /*
   * Generate an ISN_PUSHBOOL instruction.
   */
      static int
  generate_PUSHBOOL(cctx_T *cctx, varnumber_T number)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_type(cctx, ISN_PUSHBOOL, &t_bool)) == NULL)
  	return FAIL;
      isn->isn_arg.number = number;
  
      return OK;
  }
  
  /*
   * Generate an ISN_PUSHSPEC instruction.
   */
      static int
  generate_PUSHSPEC(cctx_T *cctx, varnumber_T number)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_type(cctx, ISN_PUSHSPEC, &t_special)) == NULL)
  	return FAIL;
      isn->isn_arg.number = number;
  
      return OK;
  }
  
  #ifdef FEAT_FLOAT
  /*
   * Generate an ISN_PUSHF instruction.
   */
      static int
  generate_PUSHF(cctx_T *cctx, float_T fnumber)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_type(cctx, ISN_PUSHF, &t_float)) == NULL)
  	return FAIL;
      isn->isn_arg.fnumber = fnumber;
  
      return OK;
  }
  #endif
  
  /*
   * Generate an ISN_PUSHS instruction.
   * Consumes "str".
   */
      static int
  generate_PUSHS(cctx_T *cctx, char_u *str)
  {
      isn_T	*isn;
  
      if (cctx->ctx_skip == SKIP_YES)
      {
  	vim_free(str);
  	return OK;
      }
      if ((isn = generate_instr_type(cctx, ISN_PUSHS, &t_string)) == NULL)
  	return FAIL;
      isn->isn_arg.string = str;
  
      return OK;
  }
  
  /*
   * Generate an ISN_PUSHCHANNEL instruction.
   * Consumes "channel".
   */
      static int
  generate_PUSHCHANNEL(cctx_T *cctx, channel_T *channel)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_type(cctx, ISN_PUSHCHANNEL, &t_channel)) == NULL)
  	return FAIL;
      isn->isn_arg.channel = channel;
  
      return OK;
  }
  
  /*
   * Generate an ISN_PUSHJOB instruction.
   * Consumes "job".
   */
      static int
  generate_PUSHJOB(cctx_T *cctx, job_T *job)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_type(cctx, ISN_PUSHJOB, &t_channel)) == NULL)
  	return FAIL;
      isn->isn_arg.job = job;
  
      return OK;
  }
  
  /*
   * Generate an ISN_PUSHBLOB instruction.
   * Consumes "blob".
   */
      static int
  generate_PUSHBLOB(cctx_T *cctx, blob_T *blob)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_type(cctx, ISN_PUSHBLOB, &t_blob)) == NULL)
  	return FAIL;
      isn->isn_arg.blob = blob;
  
      return OK;
  }
  
  /*
   * Generate an ISN_PUSHFUNC instruction with name "name".
   * Consumes "name".
   */
      static int
  generate_PUSHFUNC(cctx_T *cctx, char_u *name, type_T *type)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_type(cctx, ISN_PUSHFUNC, type)) == NULL)
  	return FAIL;
      isn->isn_arg.string = name == NULL ? NULL : vim_strsave(name);
  
      return OK;
  }
  
  /*
   * Generate an ISN_GETITEM instruction with "index".
   */
      static int
  generate_GETITEM(cctx_T *cctx, int index)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	*type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
      type_T	*item_type = &t_any;
  
      RETURN_OK_IF_SKIP(cctx);
  
      if (type->tt_type != VAR_LIST)
      {
  	// cannot happen, caller has checked the type
  	emsg(_(e_listreq));
  	return FAIL;
      }
      item_type = type->tt_member;
      if ((isn = generate_instr(cctx, ISN_GETITEM)) == NULL)
  	return FAIL;
      isn->isn_arg.number = index;
  
      // add the item type to the type stack
      if (ga_grow(stack, 1) == FAIL)
  	return FAIL;
      ((type_T **)stack->ga_data)[stack->ga_len] = item_type;
      ++stack->ga_len;
      return OK;
  }
  
  /*
   * Generate an ISN_SLICE instruction with "count".
   */
      static int
  generate_SLICE(cctx_T *cctx, int count)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_SLICE)) == NULL)
  	return FAIL;
      isn->isn_arg.number = count;
      return OK;
  }
  
  /*
   * Generate an ISN_CHECKLEN instruction with "min_len".
   */
      static int
  generate_CHECKLEN(cctx_T *cctx, int min_len, int more_OK)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
  
      if ((isn = generate_instr(cctx, ISN_CHECKLEN)) == NULL)
  	return FAIL;
      isn->isn_arg.checklen.cl_min_len = min_len;
      isn->isn_arg.checklen.cl_more_OK = more_OK;
  
      return OK;
  }
  
  /*
   * Generate an ISN_STORE instruction.
   */
      static int
  generate_STORE(cctx_T *cctx, isntype_T isn_type, int idx, char_u *name)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_drop(cctx, isn_type, 1)) == NULL)
  	return FAIL;
      if (name != NULL)
  	isn->isn_arg.string = vim_strsave(name);
      else
  	isn->isn_arg.number = idx;
  
      return OK;
  }
  
  /*
   * Generate an ISN_STOREOUTER instruction.
   */
      static int
  generate_STOREOUTER(cctx_T *cctx, int idx, int level)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_drop(cctx, ISN_STOREOUTER, 1)) == NULL)
  	return FAIL;
      isn->isn_arg.outer.outer_idx = idx;
      isn->isn_arg.outer.outer_depth = level;
  
      return OK;
  }
  
  /*
   * Generate an ISN_STORENR instruction (short for ISN_PUSHNR + ISN_STORE)
   */
      static int
  generate_STORENR(cctx_T *cctx, int idx, varnumber_T value)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_STORENR)) == NULL)
  	return FAIL;
      isn->isn_arg.storenr.stnr_idx = idx;
      isn->isn_arg.storenr.stnr_val = value;
  
      return OK;
  }
  
  /*
   * Generate an ISN_STOREOPT instruction
   */
      static int
  generate_STOREOPT(cctx_T *cctx, char_u *name, int opt_flags)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_drop(cctx, ISN_STOREOPT, 1)) == NULL)
  	return FAIL;
      isn->isn_arg.storeopt.so_name = vim_strsave(name);
      isn->isn_arg.storeopt.so_flags = opt_flags;
  
      return OK;
  }
  
  /*
   * Generate an ISN_LOAD or similar instruction.
   */
      static int
  generate_LOAD(
  	cctx_T	    *cctx,
  	isntype_T   isn_type,
  	int	    idx,
  	char_u	    *name,
  	type_T	    *type)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_type(cctx, isn_type, type)) == NULL)
  	return FAIL;
      if (name != NULL)
  	isn->isn_arg.string = vim_strsave(name);
      else
  	isn->isn_arg.number = idx;
  
      return OK;
  }
  
  /*
   * Generate an ISN_LOADOUTER instruction
   */
      static int
  generate_LOADOUTER(
  	cctx_T	    *cctx,
  	int	    idx,
  	int	    nesting,
  	type_T	    *type)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_type(cctx, ISN_LOADOUTER, type)) == NULL)
  	return FAIL;
      isn->isn_arg.outer.outer_idx = idx;
      isn->isn_arg.outer.outer_depth = nesting;
  
      return OK;
  }
  
  /*
   * Generate an ISN_LOADV instruction for v:var.
   */
      static int
  generate_LOADV(
  	cctx_T	    *cctx,
  	char_u	    *name,
  	int	    error)
  {
      int	    di_flags;
      int	    vidx = find_vim_var(name, &di_flags);
      type_T  *type;
  
      RETURN_OK_IF_SKIP(cctx);
      if (vidx < 0)
      {
  	if (error)
  	    semsg(_(e_variable_not_found_str), name);
  	return FAIL;
      }
      type = typval2type_vimvar(get_vim_var_tv(vidx), cctx->ctx_type_list);
  
      return generate_LOAD(cctx, ISN_LOADV, vidx, NULL, type);
  }
  
  /*
   * Generate an ISN_UNLET instruction.
   */
      static int
  generate_UNLET(cctx_T *cctx, isntype_T isn_type, char_u *name, int forceit)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, isn_type)) == NULL)
  	return FAIL;
      isn->isn_arg.unlet.ul_name = vim_strsave(name);
      isn->isn_arg.unlet.ul_forceit = forceit;
  
      return OK;
  }
  
  /*
   * Generate an ISN_LOCKCONST instruction.
   */
      static int
  generate_LOCKCONST(cctx_T *cctx)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_LOCKCONST)) == NULL)
  	return FAIL;
      return OK;
  }
  
  /*
   * Generate an ISN_LOADS instruction.
   */
      static int
  generate_OLDSCRIPT(
  	cctx_T	    *cctx,
  	isntype_T   isn_type,
  	char_u	    *name,
  	int	    sid,
  	type_T	    *type)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if (isn_type == ISN_LOADS)
  	isn = generate_instr_type(cctx, isn_type, type);
      else
  	isn = generate_instr_drop(cctx, isn_type, 1);
      if (isn == NULL)
  	return FAIL;
      isn->isn_arg.loadstore.ls_name = vim_strsave(name);
      isn->isn_arg.loadstore.ls_sid = sid;
  
      return OK;
  }
  
  /*
   * Generate an ISN_LOADSCRIPT or ISN_STORESCRIPT instruction.
   */
      static int
  generate_VIM9SCRIPT(
  	cctx_T	    *cctx,
  	isntype_T   isn_type,
  	int	    sid,
  	int	    idx,
  	type_T	    *type)
  {
      isn_T	*isn;
      scriptref_T	*sref;
      scriptitem_T *si = SCRIPT_ITEM(sid);
  
      RETURN_OK_IF_SKIP(cctx);
      if (isn_type == ISN_LOADSCRIPT)
  	isn = generate_instr_type(cctx, isn_type, type);
      else
  	isn = generate_instr_drop(cctx, isn_type, 1);
      if (isn == NULL)
  	return FAIL;
  
      // This requires three arguments, which doesn't fit in an instruction, thus
      // we need to allocate a struct for this.
      sref = ALLOC_ONE(scriptref_T);
      if (sref == NULL)
  	return FAIL;
      isn->isn_arg.script.scriptref = sref;
      sref->sref_sid = sid;
      sref->sref_idx = idx;
      sref->sref_seq = si->sn_script_seq;
      sref->sref_type = type;
      return OK;
  }
  
  /*
   * Generate an ISN_NEWLIST instruction.
   */
      static int
  generate_NEWLIST(cctx_T *cctx, int count)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	*type;
      type_T	*member;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_NEWLIST)) == NULL)
  	return FAIL;
      isn->isn_arg.number = count;
  
      // get the member type from all the items on the stack.
      if (count == 0)
  	member = &t_void;
      else
  	member = get_member_type_from_stack(
  	    ((type_T **)stack->ga_data) + stack->ga_len, count, 1,
  							  cctx->ctx_type_list);
      type = get_list_type(member, cctx->ctx_type_list);
  
      // drop the value types
      stack->ga_len -= count;
  
      // add the list type to the type stack
      if (ga_grow(stack, 1) == FAIL)
  	return FAIL;
      ((type_T **)stack->ga_data)[stack->ga_len] = type;
      ++stack->ga_len;
  
      return OK;
  }
  
  /*
   * Generate an ISN_NEWDICT instruction.
   */
      static int
  generate_NEWDICT(cctx_T *cctx, int count)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	*type;
      type_T	*member;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_NEWDICT)) == NULL)
  	return FAIL;
      isn->isn_arg.number = count;
  
      if (count == 0)
  	member = &t_void;
      else
  	member = get_member_type_from_stack(
  	    ((type_T **)stack->ga_data) + stack->ga_len, count, 2,
  							  cctx->ctx_type_list);
      type = get_dict_type(member, cctx->ctx_type_list);
  
      // drop the key and value types
      stack->ga_len -= 2 * count;
  
      // add the dict type to the type stack
      if (ga_grow(stack, 1) == FAIL)
  	return FAIL;
      ((type_T **)stack->ga_data)[stack->ga_len] = type;
      ++stack->ga_len;
  
      return OK;
  }
  
  /*
   * Generate an ISN_FUNCREF instruction.
   */
      static int
  generate_FUNCREF(cctx_T *cctx, ufunc_T *ufunc)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_FUNCREF)) == NULL)
  	return FAIL;
      isn->isn_arg.funcref.fr_func = ufunc->uf_dfunc_idx;
      cctx->ctx_has_closure = 1;
  
      // if the referenced function is a closure, it may use items further up in
      // the nested context, including this one.
      if (ufunc->uf_flags & FC_CLOSURE)
  	cctx->ctx_ufunc->uf_flags |= FC_CLOSURE;
  
      if (ga_grow(stack, 1) == FAIL)
  	return FAIL;
      ((type_T **)stack->ga_data)[stack->ga_len] =
  	       ufunc->uf_func_type == NULL ? &t_func_any : ufunc->uf_func_type;
      ++stack->ga_len;
  
      return OK;
  }
  
  /*
   * Generate an ISN_NEWFUNC instruction.
   * "lambda_name" and "func_name" must be in allocated memory and will be
   * consumed.
   */
      static int
  generate_NEWFUNC(cctx_T *cctx, char_u *lambda_name, char_u *func_name)
  {
      isn_T	*isn;
  
      if (cctx->ctx_skip == SKIP_YES)
      {
  	vim_free(lambda_name);
  	vim_free(func_name);
  	return OK;
      }
      if ((isn = generate_instr(cctx, ISN_NEWFUNC)) == NULL)
      {
  	vim_free(lambda_name);
  	vim_free(func_name);
  	return FAIL;
      }
      isn->isn_arg.newfunc.nf_lambda = lambda_name;
      isn->isn_arg.newfunc.nf_global = func_name;
  
      return OK;
  }
  
  /*
   * Generate an ISN_DEF instruction: list functions
   */
      static int
  generate_DEF(cctx_T *cctx, char_u *name, size_t len)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_DEF)) == NULL)
  	return FAIL;
      if (len > 0)
      {
  	isn->isn_arg.string = vim_strnsave(name, len);
  	if (isn->isn_arg.string == NULL)
  	    return FAIL;
      }
      return OK;
  }
  
  /*
   * Generate an ISN_JUMP instruction.
   */
      static int
  generate_JUMP(cctx_T *cctx, jumpwhen_T when, int where)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_JUMP)) == NULL)
  	return FAIL;
      isn->isn_arg.jump.jump_when = when;
      isn->isn_arg.jump.jump_where = where;
  
      if (when != JUMP_ALWAYS && stack->ga_len > 0)
  	--stack->ga_len;
  
      return OK;
  }
  
      static int
  generate_FOR(cctx_T *cctx, int loop_idx)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_FOR)) == NULL)
  	return FAIL;
      isn->isn_arg.forloop.for_idx = loop_idx;
  
      if (ga_grow(stack, 1) == FAIL)
  	return FAIL;
      // type doesn't matter, will be stored next
      ((type_T **)stack->ga_data)[stack->ga_len] = &t_any;
      ++stack->ga_len;
  
      return OK;
  }
  
  /*
   * Generate an ISN_BCALL instruction.
   * "method_call" is TRUE for "value->method()"
   * Return FAIL if the number of arguments is wrong.
   */
      static int
  generate_BCALL(cctx_T *cctx, int func_idx, int argcount, int method_call)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
      int		argoff;
      type_T	**argtypes = NULL;
      type_T	*maptype = NULL;
  
      RETURN_OK_IF_SKIP(cctx);
      argoff = check_internal_func(func_idx, argcount);
      if (argoff < 0)
  	return FAIL;
  
      if (method_call && argoff > 1)
      {
  	if ((isn = generate_instr(cctx, ISN_SHUFFLE)) == NULL)
  	    return FAIL;
  	isn->isn_arg.shuffle.shfl_item = argcount;
  	isn->isn_arg.shuffle.shfl_up = argoff - 1;
      }
  
      if (argcount > 0)
      {
  	// Check the types of the arguments.
  	argtypes = ((type_T **)stack->ga_data) + stack->ga_len - argcount;
  	if (internal_func_check_arg_types(argtypes, func_idx, argcount,
  								 cctx) == FAIL)
  	    return FAIL;
  	if (internal_func_is_map(func_idx))
  	    maptype = *argtypes;
      }
  
      if ((isn = generate_instr(cctx, ISN_BCALL)) == NULL)
  	return FAIL;
      isn->isn_arg.bfunc.cbf_idx = func_idx;
      isn->isn_arg.bfunc.cbf_argcount = argcount;
  
      // Drop the argument types and push the return type.
      stack->ga_len -= argcount;
      if (ga_grow(stack, 1) == FAIL)
  	return FAIL;
      ((type_T **)stack->ga_data)[stack->ga_len] =
  			  internal_func_ret_type(func_idx, argcount, argtypes);
      ++stack->ga_len;
  
      if (maptype != NULL && maptype->tt_member != NULL
  					       && maptype->tt_member != &t_any)
  	// Check that map() didn't change the item types.
  	generate_TYPECHECK(cctx, maptype, -1);
  
      return OK;
  }
  
  /*
   * Generate an ISN_LISTAPPEND instruction.  Works like add().
   * Argument count is already checked.
   */
      static int
  generate_LISTAPPEND(cctx_T *cctx)
  {
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	*list_type;
      type_T	*item_type;
      type_T	*expected;
  
      // Caller already checked that list_type is a list.
      list_type = ((type_T **)stack->ga_data)[stack->ga_len - 2];
      item_type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
      expected = list_type->tt_member;
      if (need_type(item_type, expected, -1, 0, cctx, FALSE, FALSE) == FAIL)
  	return FAIL;
  
      if (generate_instr(cctx, ISN_LISTAPPEND) == NULL)
  	return FAIL;
  
      --stack->ga_len;	    // drop the argument
      return OK;
  }
  
  /*
   * Generate an ISN_BLOBAPPEND instruction.  Works like add().
   * Argument count is already checked.
   */
      static int
  generate_BLOBAPPEND(cctx_T *cctx)
  {
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	*item_type;
  
      // Caller already checked that blob_type is a blob.
      item_type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
      if (need_type(item_type, &t_number, -1, 0, cctx, FALSE, FALSE) == FAIL)
  	return FAIL;
  
      if (generate_instr(cctx, ISN_BLOBAPPEND) == NULL)
  	return FAIL;
  
      --stack->ga_len;	    // drop the argument
      return OK;
  }
  
  /*
   * Generate an ISN_DCALL or ISN_UCALL instruction.
   * Return FAIL if the number of arguments is wrong.
   */
      static int
  generate_CALL(cctx_T *cctx, ufunc_T *ufunc, int pushed_argcount)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
      int		regular_args = ufunc->uf_args.ga_len;
      int		argcount = pushed_argcount;
  
      RETURN_OK_IF_SKIP(cctx);
      if (argcount > regular_args && !has_varargs(ufunc))
      {
  	semsg(_(e_toomanyarg), printable_func_name(ufunc));
  	return FAIL;
      }
      if (argcount < regular_args - ufunc->uf_def_args.ga_len)
      {
  	semsg(_(e_toofewarg), printable_func_name(ufunc));
  	return FAIL;
      }
  
      if (ufunc->uf_def_status != UF_NOT_COMPILED)
      {
  	int		i;
  
  	for (i = 0; i < argcount; ++i)
  	{
  	    type_T *expected;
  	    type_T *actual;
  
  	    if (i < regular_args)
  	    {
  		if (ufunc->uf_arg_types == NULL)
  		    continue;
  		expected = ufunc->uf_arg_types[i];
  	    }
  	    else if (ufunc->uf_va_type == NULL || ufunc->uf_va_type == &t_any)
  		// possibly a lambda or "...: any"
  		expected = &t_any;
  	    else
  		expected = ufunc->uf_va_type->tt_member;
  	    actual = ((type_T **)stack->ga_data)[stack->ga_len - argcount + i];
  	    if (need_type(actual, expected, -argcount + i, 0, cctx,
  							  TRUE, FALSE) == FAIL)
  	    {
  		arg_type_mismatch(expected, actual, i + 1);
  		return FAIL;
  	    }
  	}
  	if (ufunc->uf_def_status == UF_TO_BE_COMPILED)
  	    if (compile_def_function(ufunc, ufunc->uf_ret_type == NULL, NULL)
  								       == FAIL)
  		return FAIL;
      }
  
      if ((isn = generate_instr(cctx,
  		    ufunc->uf_def_status != UF_NOT_COMPILED ? ISN_DCALL
  							 : ISN_UCALL)) == NULL)
  	return FAIL;
      if (isn->isn_type == ISN_DCALL)
      {
  	isn->isn_arg.dfunc.cdf_idx = ufunc->uf_dfunc_idx;
  	isn->isn_arg.dfunc.cdf_argcount = argcount;
      }
      else
      {
  	// A user function may be deleted and redefined later, can't use the
  	// ufunc pointer, need to look it up again at runtime.
  	isn->isn_arg.ufunc.cuf_name = vim_strsave(ufunc->uf_name);
  	isn->isn_arg.ufunc.cuf_argcount = argcount;
      }
  
      stack->ga_len -= argcount; // drop the arguments
      if (ga_grow(stack, 1) == FAIL)
  	return FAIL;
      // add return value
      ((type_T **)stack->ga_data)[stack->ga_len] = ufunc->uf_ret_type;
      ++stack->ga_len;
  
      return OK;
  }
  
  /*
   * Generate an ISN_UCALL instruction when the function isn't defined yet.
   */
      static int
  generate_UCALL(cctx_T *cctx, char_u *name, int argcount)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_UCALL)) == NULL)
  	return FAIL;
      isn->isn_arg.ufunc.cuf_name = vim_strsave(name);
      isn->isn_arg.ufunc.cuf_argcount = argcount;
  
      stack->ga_len -= argcount; // drop the arguments
      if (ga_grow(stack, 1) == FAIL)
  	return FAIL;
      // add return value
      ((type_T **)stack->ga_data)[stack->ga_len] = &t_any;
      ++stack->ga_len;
  
      return OK;
  }
  
  /*
   * Generate an ISN_PCALL instruction.
   * "type" is the type of the FuncRef.
   */
      static int
  generate_PCALL(
  	cctx_T	*cctx,
  	int	argcount,
  	char_u	*name,
  	type_T	*type,
  	int	at_top)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	*ret_type;
  
      RETURN_OK_IF_SKIP(cctx);
  
      if (type->tt_type == VAR_ANY)
  	ret_type = &t_any;
      else if (type->tt_type == VAR_FUNC || type->tt_type == VAR_PARTIAL)
      {
  	if (type->tt_argcount != -1)
  	{
  	    int	    varargs = (type->tt_flags & TTFLAG_VARARGS) ? 1 : 0;
  
  	    if (argcount < type->tt_min_argcount - varargs)
  	    {
  		semsg(_(e_toofewarg), name);
  		return FAIL;
  	    }
  	    if (!varargs && argcount > type->tt_argcount)
  	    {
  		semsg(_(e_toomanyarg), name);
  		return FAIL;
  	    }
  	    if (type->tt_args != NULL)
  	    {
  		int i;
  
  		for (i = 0; i < argcount; ++i)
  		{
  		    int	    offset = -argcount + i - 1;
  		    type_T *actual = ((type_T **)stack->ga_data)[
  						       stack->ga_len + offset];
  		    type_T *expected;
  
  		    if (varargs && i >= type->tt_argcount - 1)
  			expected = type->tt_args[
  					     type->tt_argcount - 1]->tt_member;
  		    else
  			expected = type->tt_args[i];
  		    if (need_type(actual, expected, offset, 0,
  						    cctx, TRUE, FALSE) == FAIL)
  		    {
  			arg_type_mismatch(expected, actual, i + 1);
  			return FAIL;
  		    }
  		}
  	    }
  	}
  	ret_type = type->tt_member;
      }
      else
      {
  	semsg(_(e_not_callable_type_str), name);
  	return FAIL;
      }
  
      if ((isn = generate_instr(cctx, ISN_PCALL)) == NULL)
  	return FAIL;
      isn->isn_arg.pfunc.cpf_top = at_top;
      isn->isn_arg.pfunc.cpf_argcount = argcount;
  
      stack->ga_len -= argcount; // drop the arguments
  
      // drop the funcref/partial, get back the return value
      ((type_T **)stack->ga_data)[stack->ga_len - 1] = ret_type;
  
      // If partial is above the arguments it must be cleared and replaced with
      // the return value.
      if (at_top && generate_instr(cctx, ISN_PCALL_END) == NULL)
  	return FAIL;
  
      return OK;
  }
  
  /*
   * Generate an ISN_STRINGMEMBER instruction.
   */
      static int
  generate_STRINGMEMBER(cctx_T *cctx, char_u *name, size_t len)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	*type;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_STRINGMEMBER)) == NULL)
  	return FAIL;
      isn->isn_arg.string = vim_strnsave(name, len);
  
      // check for dict type
      type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
      if (type->tt_type != VAR_DICT && type != &t_any)
      {
  	emsg(_(e_dictreq));
  	return FAIL;
      }
      // change dict type to dict member type
      if (type->tt_type == VAR_DICT)
      {
  	((type_T **)stack->ga_data)[stack->ga_len - 1] =
  		      type->tt_member == &t_unknown ? &t_any : type->tt_member;
      }
  
      return OK;
  }
  
  /*
   * Generate an ISN_ECHO instruction.
   */
      static int
  generate_ECHO(cctx_T *cctx, int with_white, int count)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr_drop(cctx, ISN_ECHO, count)) == NULL)
  	return FAIL;
      isn->isn_arg.echo.echo_with_white = with_white;
      isn->isn_arg.echo.echo_count = count;
  
      return OK;
  }
  
  /*
   * Generate an ISN_EXECUTE/ISN_ECHOMSG/ISN_ECHOERR instruction.
   */
      static int
  generate_MULT_EXPR(cctx_T *cctx, isntype_T isn_type, int count)
  {
      isn_T	*isn;
  
      if ((isn = generate_instr_drop(cctx, isn_type, count)) == NULL)
  	return FAIL;
      isn->isn_arg.number = count;
  
      return OK;
  }
  
  /*
   * Generate an ISN_PUT instruction.
   */
      static int
  generate_PUT(cctx_T *cctx, int regname, linenr_T lnum)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_PUT)) == NULL)
  	return FAIL;
      isn->isn_arg.put.put_regname = regname;
      isn->isn_arg.put.put_lnum = lnum;
      return OK;
  }
  
      static int
  generate_EXEC(cctx_T *cctx, char_u *line)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_EXEC)) == NULL)
  	return FAIL;
      isn->isn_arg.string = vim_strsave(line);
      return OK;
  }
  
      static int
  generate_EXECCONCAT(cctx_T *cctx, int count)
  {
      isn_T	*isn;
  
      if ((isn = generate_instr_drop(cctx, ISN_EXECCONCAT, count)) == NULL)
  	return FAIL;
      isn->isn_arg.number = count;
      return OK;
  }
  
  /*
   * Generate ISN_RANGE.  Consumes "range".  Return OK/FAIL.
   */
      static int
  generate_RANGE(cctx_T *cctx, char_u *range)
  {
      isn_T	*isn;
      garray_T	*stack = &cctx->ctx_type_stack;
  
      if ((isn = generate_instr(cctx, ISN_RANGE)) == NULL)
  	return FAIL;
      isn->isn_arg.string = range;
  
      if (ga_grow(stack, 1) == FAIL)
  	return FAIL;
      ((type_T **)stack->ga_data)[stack->ga_len] = &t_number;
      ++stack->ga_len;
      return OK;
  }
  
      static int
  generate_UNPACK(cctx_T *cctx, int var_count, int semicolon)
  {
      isn_T	*isn;
  
      RETURN_OK_IF_SKIP(cctx);
      if ((isn = generate_instr(cctx, ISN_UNPACK)) == NULL)
  	return FAIL;
      isn->isn_arg.unpack.unp_count = var_count;
      isn->isn_arg.unpack.unp_semicolon = semicolon;
      return OK;
  }
  
  /*
   * Generate an instruction for any command modifiers.
   */
      static int
  generate_cmdmods(cctx_T *cctx, cmdmod_T *cmod)
  {
      isn_T	*isn;
  
      if (cmod->cmod_flags != 0
  	    || cmod->cmod_split != 0
  	    || cmod->cmod_verbose != 0
  	    || cmod->cmod_tab != 0
  	    || cmod->cmod_filter_regmatch.regprog != NULL)
      {
  	cctx->ctx_has_cmdmod = TRUE;
  
  	if ((isn = generate_instr(cctx, ISN_CMDMOD)) == NULL)
  	    return FAIL;
  	isn->isn_arg.cmdmod.cf_cmdmod = ALLOC_ONE(cmdmod_T);
  	if (isn->isn_arg.cmdmod.cf_cmdmod == NULL)
  	    return FAIL;
  	mch_memmove(isn->isn_arg.cmdmod.cf_cmdmod, cmod, sizeof(cmdmod_T));
  	// filter program now belongs to the instruction
  	cmod->cmod_filter_regmatch.regprog = NULL;
      }
  
      return OK;
  }
  
      static int
  generate_undo_cmdmods(cctx_T *cctx)
  {
      if (cctx->ctx_has_cmdmod && generate_instr(cctx, ISN_CMDMOD_REV) == NULL)
  	return FAIL;
      cctx->ctx_has_cmdmod = FALSE;
      return OK;
  }
  
  /*
   * Reserve space for a local variable.
   * Return the variable or NULL if it failed.
   */
      static lvar_T *
  reserve_local(
  	cctx_T	*cctx,
  	char_u	*name,
  	size_t	len,
  	int	isConst,
  	type_T	*type)
  {
      lvar_T  *lvar;
  
      if (arg_exists(name, len, NULL, NULL, NULL, cctx) == OK)
      {
  	emsg_namelen(_(e_str_is_used_as_argument), name, (int)len);
  	return NULL;
      }
  
      if (ga_grow(&cctx->ctx_locals, 1) == FAIL)
  	return NULL;
      lvar = ((lvar_T *)cctx->ctx_locals.ga_data) + cctx->ctx_locals.ga_len++;
      CLEAR_POINTER(lvar);
  
      // Every local variable uses the next entry on the stack.  We could re-use
      // the last ones when leaving a scope, but then variables used in a closure
      // might get overwritten.  To keep things simple do not re-use stack
      // entries.  This is less efficient, but memory is cheap these days.
      lvar->lv_idx = cctx->ctx_locals_count++;
  
      lvar->lv_name = vim_strnsave(name, len == 0 ? STRLEN(name) : len);
      lvar->lv_const = isConst;
      lvar->lv_type = type;
  
      return lvar;
  }
  
  /*
   * Remove local variables above "new_top".
   */
      static void
  unwind_locals(cctx_T *cctx, int new_top)
  {
      if (cctx->ctx_locals.ga_len > new_top)
      {
  	int	idx;
  	lvar_T	*lvar;
  
  	for (idx = new_top; idx < cctx->ctx_locals.ga_len; ++idx)
  	{
  	    lvar = ((lvar_T *)cctx->ctx_locals.ga_data) + idx;
  	    vim_free(lvar->lv_name);
  	}
      }
      cctx->ctx_locals.ga_len = new_top;
  }
  
  /*
   * Free all local variables.
   */
      static void
  free_locals(cctx_T *cctx)
  {
      unwind_locals(cctx, 0);
      ga_clear(&cctx->ctx_locals);
  }
  
  /*
   * If "check_writable" is ASSIGN_CONST give an error if the variable was
   * defined with :final or :const, if "check_writable" is ASSIGN_FINAL give an
   * error if the variable was defined with :const.
   */
      static int
  check_item_writable(svar_T *sv, int check_writable, char_u *name)
  {
      if ((check_writable == ASSIGN_CONST && sv->sv_const != 0)
  	    || (check_writable == ASSIGN_FINAL
  					      && sv->sv_const == ASSIGN_CONST))
      {
  	semsg(_(e_readonlyvar), name);
  	return FAIL;
      }
      return OK;
  }
  
  /*
   * Find "name" in script-local items of script "sid".
   * Pass "check_writable" to check_item_writable().
   * Returns the index in "sn_var_vals" if found.
   * If found but not in "sn_var_vals" returns -1.
   * If not found or the variable is not writable returns -2.
   */
      int
  get_script_item_idx(int sid, char_u *name, int check_writable, cctx_T *cctx)
  {
      hashtab_T	    *ht;
      dictitem_T	    *di;
      scriptitem_T    *si = SCRIPT_ITEM(sid);
      svar_T	    *sv;
      int		    idx;
  
      if (!SCRIPT_ID_VALID(sid))
  	return -1;
      if (sid == current_sctx.sc_sid)
      {
  	sallvar_T *sav = find_script_var(name, 0, cctx);
  
  	if (sav == NULL)
  	    return -2;
  	idx = sav->sav_var_vals_idx;
  	sv = ((svar_T *)si->sn_var_vals.ga_data) + idx;
  	if (check_item_writable(sv, check_writable, name) == FAIL)
  	    return -2;
  	return idx;
      }
  
      // First look the name up in the hashtable.
      ht = &SCRIPT_VARS(sid);
      di = find_var_in_ht(ht, 0, name, TRUE);
      if (di == NULL)
  	return -2;
  
      // Now find the svar_T index in sn_var_vals.
      for (idx = 0; idx < si->sn_var_vals.ga_len; ++idx)
      {
  	sv = ((svar_T *)si->sn_var_vals.ga_data) + idx;
  	if (sv->sv_tv == &di->di_tv)
  	{
  	    if (check_item_writable(sv, check_writable, name) == FAIL)
  		return -2;
  	    return idx;
  	}
      }
      return -1;
  }
  
  /*
   * Find "name" in imported items of the current script or in "cctx" if not
   * NULL.
   */
      imported_T *
  find_imported(char_u *name, size_t len, cctx_T *cctx)
  {
      int		    idx;
  
      if (!SCRIPT_ID_VALID(current_sctx.sc_sid))
  	return NULL;
      if (cctx != NULL)
  	for (idx = 0; idx < cctx->ctx_imports.ga_len; ++idx)
  	{
  	    imported_T *import = ((imported_T *)cctx->ctx_imports.ga_data)
  									 + idx;
  
  	    if (len == 0 ? STRCMP(name, import->imp_name) == 0
  			 : STRLEN(import->imp_name) == len
  				  && STRNCMP(name, import->imp_name, len) == 0)
  		return import;
  	}
  
      return find_imported_in_script(name, len, current_sctx.sc_sid);
  }
  
      imported_T *
  find_imported_in_script(char_u *name, size_t len, int sid)
  {
      scriptitem_T    *si;
      int		    idx;
  
      if (!SCRIPT_ID_VALID(sid))
  	return NULL;
      si = SCRIPT_ITEM(sid);
      for (idx = 0; idx < si->sn_imports.ga_len; ++idx)
      {
  	imported_T *import = ((imported_T *)si->sn_imports.ga_data) + idx;
  
  	if (len == 0 ? STRCMP(name, import->imp_name) == 0
  		     : STRLEN(import->imp_name) == len
  				  && STRNCMP(name, import->imp_name, len) == 0)
  	    return import;
      }
      return NULL;
  }
  
  /*
   * Free all imported variables.
   */
      static void
  free_imported(cctx_T *cctx)
  {
      int idx;
  
      for (idx = 0; idx < cctx->ctx_imports.ga_len; ++idx)
      {
  	imported_T *import = ((imported_T *)cctx->ctx_imports.ga_data) + idx;
  
  	vim_free(import->imp_name);
      }
      ga_clear(&cctx->ctx_imports);
  }
  
  /*
   * Return a pointer to the next line that isn't empty or only contains a
   * comment. Skips over white space.
   * Returns NULL if there is none.
   */
      char_u *
  peek_next_line_from_context(cctx_T *cctx)
  {
      int lnum = cctx->ctx_lnum;
  
      while (++lnum < cctx->ctx_ufunc->uf_lines.ga_len)
      {
  	char_u *line = ((char_u **)cctx->ctx_ufunc->uf_lines.ga_data)[lnum];
  	char_u *p;
  
  	// ignore NULLs inserted for continuation lines
  	if (line != NULL)
  	{
  	    p = skipwhite(line);
  	    if (*p != NUL && !vim9_comment_start(p))
  		return p;
  	}
      }
      return NULL;
  }
  
  /*
   * Called when checking for a following operator at "arg".  When the rest of
   * the line is empty or only a comment, peek the next line.  If there is a next
   * line return a pointer to it and set "nextp".
   * Otherwise skip over white space.
   */
      static char_u *
  may_peek_next_line(cctx_T *cctx, char_u *arg, char_u **nextp)
  {
      char_u *p = skipwhite(arg);
  
      *nextp = NULL;
      if (*p == NUL || (VIM_ISWHITE(*arg) && vim9_comment_start(p)))
      {
  	*nextp = peek_next_line_from_context(cctx);
  	if (*nextp != NULL)
  	    return *nextp;
      }
      return p;
  }
  
  /*
   * Get the next line of the function from "cctx".
   * Skips over empty lines.  Skips over comment lines if "skip_comment" is TRUE.
   * Returns NULL when at the end.
   */
      char_u *
  next_line_from_context(cctx_T *cctx, int skip_comment)
  {
      char_u	*line;
  
      do
      {
  	++cctx->ctx_lnum;
  	if (cctx->ctx_lnum >= cctx->ctx_ufunc->uf_lines.ga_len)
  	{
  	    line = NULL;
  	    break;
  	}
  	line = ((char_u **)cctx->ctx_ufunc->uf_lines.ga_data)[cctx->ctx_lnum];
  	cctx->ctx_line_start = line;
  	SOURCING_LNUM = cctx->ctx_lnum + 1;
      } while (line == NULL || *skipwhite(line) == NUL
  		     || (skip_comment && vim9_comment_start(skipwhite(line))));
      return line;
  }
  
  /*
   * Skip over white space at "whitep" and assign to "*arg".
   * If "*arg" is at the end of the line, advance to the next line.
   * Also when "whitep" points to white space and "*arg" is on a "#".
   * Return FAIL if beyond the last line, "*arg" is unmodified then.
   */
      static int
  may_get_next_line(char_u *whitep, char_u **arg, cctx_T *cctx)
  {
      *arg = skipwhite(whitep);
      if (**arg == NUL || (VIM_ISWHITE(*whitep) && vim9_comment_start(*arg)))
      {
  	char_u *next = next_line_from_context(cctx, TRUE);
  
  	if (next == NULL)
  	    return FAIL;
  	*arg = skipwhite(next);
      }
      return OK;
  }
  
  /*
   * Idem, and give an error when failed.
   */
      static int
  may_get_next_line_error(char_u *whitep, char_u **arg, cctx_T *cctx)
  {
      if (may_get_next_line(whitep, arg, cctx) == FAIL)
      {
  	SOURCING_LNUM = cctx->ctx_lnum + 1;
  	emsg(_(e_line_incomplete));
  	return FAIL;
      }
      return OK;
  }
  
  
  // Structure passed between the compile_expr* functions to keep track of
  // constants that have been parsed but for which no code was produced yet.  If
  // possible expressions on these constants are applied at compile time.  If
  // that is not possible, the code to push the constants needs to be generated
  // before other instructions.
  // Using 50 should be more than enough of 5 levels of ().
  #define PPSIZE 50
  typedef struct {
      typval_T	pp_tv[PPSIZE];	// stack of ppconst constants
      int		pp_used;	// active entries in pp_tv[]
      int		pp_is_const;	// all generated code was constants, used for a
  				// list or dict with constant members
  } ppconst_T;
  
  static int compile_expr0_ext(char_u **arg,  cctx_T *cctx, int *is_const);
  static int compile_expr0(char_u **arg,  cctx_T *cctx);
  static int compile_expr1(char_u **arg,  cctx_T *cctx, ppconst_T *ppconst);
  
  /*
   * Generate a PUSH instruction for "tv".
   * "tv" will be consumed or cleared.
   * Nothing happens if "tv" is NULL or of type VAR_UNKNOWN;
   */
      static int
  generate_tv_PUSH(cctx_T *cctx, typval_T *tv)
  {
      if (tv != NULL)
      {
  	switch (tv->v_type)
  	{
  	    case VAR_UNKNOWN:
  		break;
  	    case VAR_BOOL:
  		generate_PUSHBOOL(cctx, tv->vval.v_number);
  		break;
  	    case VAR_SPECIAL:
  		generate_PUSHSPEC(cctx, tv->vval.v_number);
  		break;
  	    case VAR_NUMBER:
  		generate_PUSHNR(cctx, tv->vval.v_number);
  		break;
  #ifdef FEAT_FLOAT
  	    case VAR_FLOAT:
  		generate_PUSHF(cctx, tv->vval.v_float);
  		break;
  #endif
  	    case VAR_BLOB:
  		generate_PUSHBLOB(cctx, tv->vval.v_blob);
  		tv->vval.v_blob = NULL;
  		break;
  	    case VAR_STRING:
  		generate_PUSHS(cctx, tv->vval.v_string);
  		tv->vval.v_string = NULL;
  		break;
  	    default:
  		iemsg("constant type not supported");
  		clear_tv(tv);
  		return FAIL;
  	}
  	tv->v_type = VAR_UNKNOWN;
      }
      return OK;
  }
  
  /*
   * Generate code for any ppconst entries.
   */
      static int
  generate_ppconst(cctx_T *cctx, ppconst_T *ppconst)
  {
      int	    i;
      int	    ret = OK;
      int	    save_skip = cctx->ctx_skip;
  
      cctx->ctx_skip = SKIP_NOT;
      for (i = 0; i < ppconst->pp_used; ++i)
  	if (generate_tv_PUSH(cctx, &ppconst->pp_tv[i]) == FAIL)
  	    ret = FAIL;
      ppconst->pp_used = 0;
      cctx->ctx_skip = save_skip;
      return ret;
  }
  
  /*
   * Clear ppconst constants.  Used when failing.
   */
      static void
  clear_ppconst(ppconst_T *ppconst)
  {
      int	    i;
  
      for (i = 0; i < ppconst->pp_used; ++i)
  	clear_tv(&ppconst->pp_tv[i]);
      ppconst->pp_used = 0;
  }
  
  /*
   * Generate an instruction to load script-local variable "name", without the
   * leading "s:".
   * Also finds imported variables.
   */
      static int
  compile_load_scriptvar(
  	cctx_T *cctx,
  	char_u *name,	    // variable NUL terminated
  	char_u *start,	    // start of variable
  	char_u **end,	    // end of variable
  	int    error)	    // when TRUE may give error
  {
      scriptitem_T    *si;
      int		    idx;
      imported_T	    *import;
  
      if (!SCRIPT_ID_VALID(current_sctx.sc_sid))
  	return FAIL;
      si = SCRIPT_ITEM(current_sctx.sc_sid);
      idx = get_script_item_idx(current_sctx.sc_sid, name, 0, cctx);
      if (idx == -1 || si->sn_version != SCRIPT_VERSION_VIM9)
      {
  	// variable is not in sn_var_vals: old style script.
  	return generate_OLDSCRIPT(cctx, ISN_LOADS, name, current_sctx.sc_sid,
  								       &t_any);
      }
      if (idx >= 0)
      {
  	svar_T		*sv = ((svar_T *)si->sn_var_vals.ga_data) + idx;
  
  	generate_VIM9SCRIPT(cctx, ISN_LOADSCRIPT,
  					current_sctx.sc_sid, idx, sv->sv_type);
  	return OK;
      }
  
      import = find_imported(name, 0, cctx);
      if (import != NULL)
      {
  	if (import->imp_flags & IMP_FLAGS_STAR)
  	{
  	    char_u	*p = skipwhite(*end);
  	    char_u	*exp_name;
  	    int		cc;
  	    ufunc_T	*ufunc;
  	    type_T	*type;
  
  	    // Used "import * as Name", need to lookup the member.
  	    if (*p != '.')
  	    {
  		semsg(_(e_expected_dot_after_name_str), start);
  		return FAIL;
  	    }
  	    ++p;
  	    if (VIM_ISWHITE(*p))
  	    {
  		emsg(_(e_no_white_space_allowed_after_dot));
  		return FAIL;
  	    }
  
  	    // isolate one name
  	    exp_name = p;
  	    while (eval_isnamec(*p))
  		++p;
  	    cc = *p;
  	    *p = NUL;
  
  	    idx = find_exported(import->imp_sid, exp_name, &ufunc, &type, cctx);
  	    *p = cc;
  	    p = skipwhite(p);
  
  	    // TODO: what if it is a function?
  	    if (idx < 0)
  		return FAIL;
  	    *end = p;
  
  	    generate_VIM9SCRIPT(cctx, ISN_LOADSCRIPT,
  		    import->imp_sid,
  		    idx,
  		    type);
  	}
  	else if (import->imp_funcname != NULL)
  	    generate_PUSHFUNC(cctx, import->imp_funcname, import->imp_type);
  	else
  	    generate_VIM9SCRIPT(cctx, ISN_LOADSCRIPT,
  		    import->imp_sid,
  		    import->imp_var_vals_idx,
  		    import->imp_type);
  	return OK;
      }
  
      if (error)
  	semsg(_(e_item_not_found_str), name);
      return FAIL;
  }
  
      static int
  generate_funcref(cctx_T *cctx, char_u *name)
  {
      ufunc_T *ufunc = find_func(name, FALSE, cctx);
  
      if (ufunc == NULL)
  	return FAIL;
  
      // Need to compile any default values to get the argument types.
      if (ufunc->uf_def_status == UF_TO_BE_COMPILED)
  	if (compile_def_function(ufunc, TRUE, NULL) == FAIL)
  	    return FAIL;
      return generate_PUSHFUNC(cctx, ufunc->uf_name, ufunc->uf_func_type);
  }
  
  /*
   * Compile a variable name into a load instruction.
   * "end" points to just after the name.
   * "is_expr" is TRUE when evaluating an expression, might be a funcref.
   * When "error" is FALSE do not give an error when not found.
   */
      static int
  compile_load(
  	char_u **arg,
  	char_u *end_arg,
  	cctx_T	*cctx,
  	int	is_expr,
  	int	error)
  {
      type_T	*type;
      char_u	*name = NULL;
      char_u	*end = end_arg;
      int		res = FAIL;
      int		prev_called_emsg = called_emsg;
  
      if (*(*arg + 1) == ':')
      {
  	// load namespaced variable
  	if (end <= *arg + 2)
  	{
  	    isntype_T  isn_type;
  
  	    switch (**arg)
  	    {
  		case 'g': isn_type = ISN_LOADGDICT; break;
  		case 'w': isn_type = ISN_LOADWDICT; break;
  		case 't': isn_type = ISN_LOADTDICT; break;
  		case 'b': isn_type = ISN_LOADBDICT; break;
  		default:
  		    semsg(_(e_namespace_not_supported_str), *arg);
  		    goto theend;
  	    }
  	    if (generate_instr_type(cctx, isn_type, &t_dict_any) == NULL)
  		goto theend;
  	    res = OK;
  	}
  	else
  	{
  	    isntype_T  isn_type = ISN_DROP;
  
  	    name = vim_strnsave(*arg + 2, end - (*arg + 2));
  	    if (name == NULL)
  		return FAIL;
  
  	    switch (**arg)
  	    {
  		case 'v': res = generate_LOADV(cctx, name, error);
  			  break;
  		case 's': res = compile_load_scriptvar(cctx, name,
  							    NULL, NULL, error);
  			  break;
  		case 'g': if (vim_strchr(name, AUTOLOAD_CHAR) == NULL)
  			      isn_type = ISN_LOADG;
  			  else
  			  {
  			      isn_type = ISN_LOADAUTO;
  			      vim_free(name);
  			      name = vim_strnsave(*arg, end - *arg);
  			      if (name == NULL)
  				  return FAIL;
  			  }
  			  break;
  		case 'w': isn_type = ISN_LOADW; break;
  		case 't': isn_type = ISN_LOADT; break;
  		case 'b': isn_type = ISN_LOADB; break;
  		default:  // cannot happen, just in case
  			  semsg(_(e_namespace_not_supported_str), *arg);
  			  goto theend;
  	    }
  	    if (isn_type != ISN_DROP)
  	    {
  		// Global, Buffer-local, Window-local and Tabpage-local
  		// variables can be defined later, thus we don't check if it
  		// exists, give error at runtime.
  		res = generate_LOAD(cctx, isn_type, 0, name, &t_any);
  	    }
  	}
      }
      else
      {
  	size_t	    len = end - *arg;
  	int	    idx;
  	int	    gen_load = FALSE;
  	int	    gen_load_outer = 0;
  
  	name = vim_strnsave(*arg, end - *arg);
  	if (name == NULL)
  	    return FAIL;
  
  	if (arg_exists(*arg, len, &idx, &type, &gen_load_outer, cctx) == OK)
  	{
  	    if (gen_load_outer == 0)
  		gen_load = TRUE;
  	}
  	else
  	{
  	    lvar_T lvar;
  
  	    if (lookup_local(*arg, len, &lvar, cctx) == OK)
  	    {
  		type = lvar.lv_type;
  		idx = lvar.lv_idx;
  		if (lvar.lv_from_outer != 0)
  		    gen_load_outer = lvar.lv_from_outer;
  		else
  		    gen_load = TRUE;
  	    }
  	    else
  	    {
  		// "var" can be script-local even without using "s:" if it
  		// already exists in a Vim9 script or when it's imported.
  		if (script_var_exists(*arg, len, TRUE, cctx) == OK
  			|| find_imported(name, 0, cctx) != NULL)
  		   res = compile_load_scriptvar(cctx, name, *arg, &end, FALSE);
  
  		// When evaluating an expression and the name starts with an
  		// uppercase letter or "x:" it can be a user defined function.
  		// TODO: this is just guessing
  		if (res == FAIL && is_expr
  				   && (ASCII_ISUPPER(*name) || name[1] == ':'))
  		    res = generate_funcref(cctx, name);
  	    }
  	}
  	if (gen_load)
  	    res = generate_LOAD(cctx, ISN_LOAD, idx, NULL, type);
  	if (gen_load_outer > 0)
  	{
  	    res = generate_LOADOUTER(cctx, idx, gen_load_outer, type);
  	    cctx->ctx_outer_used = TRUE;
  	}
      }
  
      *arg = end;
  
  theend:
      if (res == FAIL && error && called_emsg == prev_called_emsg)
  	semsg(_(e_variable_not_found_str), name);
      vim_free(name);
      return res;
  }
  
  /*
   * Compile the argument expressions.
   * "arg" points to just after the "(" and is advanced to after the ")"
   */
      static int
  compile_arguments(char_u **arg, cctx_T *cctx, int *argcount)
  {
      char_u  *p = *arg;
      char_u  *whitep = *arg;
      int	    must_end = FALSE;
  
      for (;;)
      {
  	if (may_get_next_line(whitep, &p, cctx) == FAIL)
  	    goto failret;
  	if (*p == ')')
  	{
  	    *arg = p + 1;
  	    return OK;
  	}
  	if (must_end)
  	{
  	    semsg(_(e_missing_comma_before_argument_str), p);
  	    return FAIL;
  	}
  
  	if (compile_expr0(&p, cctx) == FAIL)
  	    return FAIL;
  	++*argcount;
  
  	if (*p != ',' && *skipwhite(p) == ',')
  	{
  	    semsg(_(e_no_white_space_allowed_before_str), ",");
  	    p = skipwhite(p);
  	}
  	if (*p == ',')
  	{
  	    ++p;
  	    if (*p != NUL && !VIM_ISWHITE(*p))
  		semsg(_(e_white_space_required_after_str), ",");
  	}
  	else
  	    must_end = TRUE;
  	whitep = p;
  	p = skipwhite(p);
      }
  failret:
      emsg(_(e_missing_close));
      return FAIL;
  }
  
  /*
   * Compile a function call:  name(arg1, arg2)
   * "arg" points to "name", "arg + varlen" to the "(".
   * "argcount_init" is 1 for "value->method()"
   * Instructions:
   *	EVAL arg1
   *	EVAL arg2
   *	BCALL / DCALL / UCALL
   */
      static int
  compile_call(
  	char_u	    **arg,
  	size_t	    varlen,
  	cctx_T	    *cctx,
  	ppconst_T   *ppconst,
  	int	    argcount_init)
  {
      char_u	*name = *arg;
      char_u	*p;
      int		argcount = argcount_init;
      char_u	namebuf[100];
      char_u	fname_buf[FLEN_FIXED + 1];
      char_u	*tofree = NULL;
      int		error = FCERR_NONE;
      ufunc_T	*ufunc = NULL;
      int		res = FAIL;
      int		is_autoload;
  
      // we can evaluate "has('name')" at compile time
      if (varlen == 3 && STRNCMP(*arg, "has", 3) == 0)
      {
  	char_u	    *s = skipwhite(*arg + varlen + 1);
  	typval_T    argvars[2];
  
  	argvars[0].v_type = VAR_UNKNOWN;
  	if (*s == '"')
  	    (void)eval_string(&s, &argvars[0], TRUE);
  	else if (*s == '\'')
  	    (void)eval_lit_string(&s, &argvars[0], TRUE);
  	s = skipwhite(s);
  	if (*s == ')' && argvars[0].v_type == VAR_STRING
  		&& !dynamic_feature(argvars[0].vval.v_string))
  	{
  	    typval_T	*tv = &ppconst->pp_tv[ppconst->pp_used];
  
  	    *arg = s + 1;
  	    argvars[1].v_type = VAR_UNKNOWN;
  	    tv->v_type = VAR_NUMBER;
  	    tv->vval.v_number = 0;
  	    f_has(argvars, tv);
  	    clear_tv(&argvars[0]);
  	    ++ppconst->pp_used;
  	    return OK;
  	}
  	clear_tv(&argvars[0]);
      }
  
      if (generate_ppconst(cctx, ppconst) == FAIL)
  	return FAIL;
  
      if (varlen >= sizeof(namebuf))
      {
  	semsg(_(e_name_too_long_str), name);
  	return FAIL;
      }
      vim_strncpy(namebuf, *arg, varlen);
      name = fname_trans_sid(namebuf, fname_buf, &tofree, &error);
  
      *arg = skipwhite(*arg + varlen + 1);
      if (compile_arguments(arg, cctx, &argcount) == FAIL)
  	goto theend;
  
      is_autoload = vim_strchr(name, AUTOLOAD_CHAR) != NULL;
      if (ASCII_ISLOWER(*name) && name[1] != ':' && !is_autoload)
      {
  	int	    idx;
  
  	// builtin function
  	idx = find_internal_func(name);
  	if (idx >= 0)
  	{
  	    if (STRCMP(name, "add") == 0 && argcount == 2)
  	    {
  		garray_T    *stack = &cctx->ctx_type_stack;
  		type_T	    *type = ((type_T **)stack->ga_data)[
  							    stack->ga_len - 2];
  
  		// add() can be compiled to instructions if we know the type
  		if (type->tt_type == VAR_LIST)
  		{
  		    // inline "add(list, item)" so that the type can be checked
  		    res = generate_LISTAPPEND(cctx);
  		    idx = -1;
  		}
  		else if (type->tt_type == VAR_BLOB)
  		{
  		    // inline "add(blob, nr)" so that the type can be checked
  		    res = generate_BLOBAPPEND(cctx);
  		    idx = -1;
  		}
  	    }
  
  	    if (idx >= 0)
  		res = generate_BCALL(cctx, idx, argcount, argcount_init == 1);
  	}
  	else
  	    semsg(_(e_unknownfunc), namebuf);
  	goto theend;
      }
  
      // An argument or local variable can be a function reference, this
      // overrules a function name.
      if (lookup_local(namebuf, varlen, NULL, cctx) == FAIL
  	    && arg_exists(namebuf, varlen, NULL, NULL, NULL, cctx) != OK)
      {
  	// If we can find the function by name generate the right call.
  	// Skip global functions here, a local funcref takes precedence.
  	ufunc = find_func(name, FALSE, cctx);
  	if (ufunc != NULL && !func_is_global(ufunc))
  	{
  	    res = generate_CALL(cctx, ufunc, argcount);
  	    goto theend;
  	}
      }
  
      // If the name is a variable, load it and use PCALL.
      // Not for g:Func(), we don't know if it is a variable or not.
      // Not for eome#Func(), it will be loaded later.
      p = namebuf;
      if (STRNCMP(namebuf, "g:", 2) != 0 && !is_autoload
  	    && compile_load(&p, namebuf + varlen, cctx, FALSE, FALSE) == OK)
      {
  	garray_T    *stack = &cctx->ctx_type_stack;
  	type_T	    *type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
  
  	res = generate_PCALL(cctx, argcount, namebuf, type, FALSE);
  	goto theend;
      }
  
      // If we can find a global function by name generate the right call.
      if (ufunc != NULL)
      {
  	res = generate_CALL(cctx, ufunc, argcount);
  	goto theend;
      }
  
      // A global function may be defined only later.  Need to figure out at
      // runtime.  Also handles a FuncRef at runtime.
      if (STRNCMP(namebuf, "g:", 2) == 0 || is_autoload)
  	res = generate_UCALL(cctx, name, argcount);
      else
  	semsg(_(e_unknownfunc), namebuf);
  
  theend:
      vim_free(tofree);
      return res;
  }
  
  // like NAMESPACE_CHAR but with 'a' and 'l'.
  #define VIM9_NAMESPACE_CHAR	(char_u *)"bgstvw"
  
  /*
   * Find the end of a variable or function name.  Unlike find_name_end() this
   * does not recognize magic braces.
   * When "use_namespace" is TRUE recognize "b:", "s:", etc.
   * Return a pointer to just after the name.  Equal to "arg" if there is no
   * valid name.
   */
      char_u *
  to_name_end(char_u *arg, int use_namespace)
  {
      char_u	*p;
  
      // Quick check for valid starting character.
      if (!eval_isnamec1(*arg))
  	return arg;
  
      for (p = arg + 1; *p != NUL && eval_isnamec(*p); MB_PTR_ADV(p))
  	// Include a namespace such as "s:var" and "v:var".  But "n:" is not
  	// and can be used in slice "[n:]".
  	if (*p == ':' && (p != arg + 1
  			     || !use_namespace
  			     || vim_strchr(VIM9_NAMESPACE_CHAR, *arg) == NULL))
  	    break;
      return p;
  }
  
  /*
   * Like to_name_end() but also skip over a list or dict constant.
   * This intentionally does not handle line continuation.
   */
      char_u *
  to_name_const_end(char_u *arg)
  {
      char_u	*p = to_name_end(arg, TRUE);
      typval_T	rettv;
  
      if (p == arg && *arg == '[')
      {
  
  	// Can be "[1, 2, 3]->Func()".
  	if (eval_list(&p, &rettv, NULL, FALSE) == FAIL)
  	    p = arg;
      }
      return p;
  }
  
  /*
   * parse a list: [expr, expr]
   * "*arg" points to the '['.
   * ppconst->pp_is_const is set if all items are a constant.
   */
      static int
  compile_list(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
  {
      char_u	*p = skipwhite(*arg + 1);
      char_u	*whitep = *arg + 1;
      int		count = 0;
      int		is_const;
      int		is_all_const = TRUE;	// reset when non-const encountered
  
      for (;;)
      {
  	if (may_get_next_line(whitep, &p, cctx) == FAIL)
  	{
  	    semsg(_(e_list_end), *arg);
  	    return FAIL;
  	}
  	if (*p == ',')
  	{
  	    semsg(_(e_no_white_space_allowed_before_str), ",");
  	    return FAIL;
  	}
  	if (*p == ']')
  	{
  	    ++p;
  	    break;
  	}
  	if (compile_expr0_ext(&p, cctx, &is_const) == FAIL)
  	    return FAIL;
  	if (!is_const)
  	    is_all_const = FALSE;
  	++count;
  	if (*p == ',')
  	{
  	    ++p;
  	    if (*p != ']' && !IS_WHITE_OR_NUL(*p))
  	    {
  		semsg(_(e_white_space_required_after_str), ",");
  		return FAIL;
  	    }
  	}
  	whitep = p;
  	p = skipwhite(p);
      }
      *arg = p;
  
      ppconst->pp_is_const = is_all_const;
      return generate_NEWLIST(cctx, count);
  }
  
  /*
   * Parse a lambda: "(arg, arg) => expr"
   * "*arg" points to the '{'.
   * Returns OK/FAIL when a lambda is recognized, NOTDONE if it's not a lambda.
   */
      static int
  compile_lambda(char_u **arg, cctx_T *cctx)
  {
      int		r;
      typval_T	rettv;
      ufunc_T	*ufunc;
      evalarg_T	evalarg;
  
      CLEAR_FIELD(evalarg);
      evalarg.eval_flags = EVAL_EVALUATE;
      evalarg.eval_cctx = cctx;
  
      // Get the funcref in "rettv".
      r = get_lambda_tv(arg, &rettv, TRUE, &evalarg);
      if (r != OK)
      {
  	clear_evalarg(&evalarg, NULL);
  	return r;
      }
  
      // "rettv" will now be a partial referencing the function.
      ufunc = rettv.vval.v_partial->pt_func;
      ++ufunc->uf_refcount;
      clear_tv(&rettv);
  
      // Compile the function into instructions.
      compile_def_function(ufunc, TRUE, cctx);
  
      clear_evalarg(&evalarg, NULL);
  
      if (ufunc->uf_def_status == UF_COMPILED)
      {
  	// The return type will now be known.
  	set_function_type(ufunc);
  
  	// The function reference count will be 1.  When the ISN_FUNCREF
  	// instruction is deleted the reference count is decremented and the
  	// function is freed.
  	return generate_FUNCREF(cctx, ufunc);
      }
  
      func_ptr_unref(ufunc);
      return FAIL;
  }
  
  /*
   * parse a dict: {key: val, [key]: val}
   * "*arg" points to the '{'.
   * ppconst->pp_is_const is set if all item values are a constant.
   */
      static int
  compile_dict(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
  {
      garray_T	*instr = &cctx->ctx_instr;
      garray_T	*stack = &cctx->ctx_type_stack;
      int		count = 0;
      dict_T	*d = dict_alloc();
      dictitem_T	*item;
      char_u	*whitep = *arg + 1;
      char_u	*p;
      int		is_const;
      int		is_all_const = TRUE;	// reset when non-const encountered
  
      if (d == NULL)
  	return FAIL;
      if (generate_ppconst(cctx, ppconst) == FAIL)
  	return FAIL;
      for (;;)
      {
  	char_u	    *key = NULL;
  
  	if (may_get_next_line(whitep, arg, cctx) == FAIL)
  	{
  	    *arg = NULL;
  	    goto failret;
  	}
  
  	if (**arg == '}')
  	    break;
  
  	if (**arg == '[')
  	{
  	    isn_T	*isn;
  
  	    // {[expr]: value} uses an evaluated key.
  	    *arg = skipwhite(*arg + 1);
  	    if (compile_expr0(arg, cctx) == FAIL)
  		return FAIL;
  	    isn = ((isn_T *)instr->ga_data) + instr->ga_len - 1;
  	    if (isn->isn_type == ISN_PUSHS)
  		key = isn->isn_arg.string;
  	    else
  	    {
  		type_T *keytype = ((type_T **)stack->ga_data)
  						       [stack->ga_len - 1];
  		if (need_type(keytype, &t_string, -1, 0, cctx,
  						     FALSE, FALSE) == FAIL)
  		    return FAIL;
  	    }
  	    *arg = skipwhite(*arg);
  	    if (**arg != ']')
  	    {
  		emsg(_(e_missing_matching_bracket_after_dict_key));
  		return FAIL;
  	    }
  	    ++*arg;
  	}
  	else
  	{
  	    // {"name": value},
  	    // {'name': value},
  	    // {name: value} use "name" as a literal key
  	    key = get_literal_key(arg);
  	    if (key == NULL)
  		return FAIL;
  	    if (generate_PUSHS(cctx, key) == FAIL)
  		return FAIL;
  	}
  
  	// Check for duplicate keys, if using string keys.
  	if (key != NULL)
  	{
  	    item = dict_find(d, key, -1);
  	    if (item != NULL)
  	    {
  		semsg(_(e_duplicate_key), key);
  		goto failret;
  	    }
  	    item = dictitem_alloc(key);
  	    if (item != NULL)
  	    {
  		item->di_tv.v_type = VAR_UNKNOWN;
  		item->di_tv.v_lock = 0;
  		if (dict_add(d, item) == FAIL)
  		    dictitem_free(item);
  	    }
  	}
  
  	if (**arg != ':')
  	{
  	    if (*skipwhite(*arg) == ':')
  		semsg(_(e_no_white_space_allowed_before_str), ":");
  	    else
  		semsg(_(e_missing_dict_colon), *arg);
  	    return FAIL;
  	}
  	whitep = *arg + 1;
  	if (!IS_WHITE_OR_NUL(*whitep))
  	{
  	    semsg(_(e_white_space_required_after_str), ":");
  	    return FAIL;
  	}
  
  	if (may_get_next_line(whitep, arg, cctx) == FAIL)
  	{
  	    *arg = NULL;
  	    goto failret;
  	}
  
  	if (compile_expr0_ext(arg, cctx, &is_const) == FAIL)
  	    return FAIL;
  	if (!is_const)
  	    is_all_const = FALSE;
  	++count;
  
  	whitep = *arg;
  	if (may_get_next_line(whitep, arg, cctx) == FAIL)
  	{
  	    *arg = NULL;
  	    goto failret;
  	}
  	if (**arg == '}')
  	    break;
  	if (**arg != ',')
  	{
  	    semsg(_(e_missing_dict_comma), *arg);
  	    goto failret;
  	}
  	if (IS_WHITE_OR_NUL(*whitep))
  	{
  	    semsg(_(e_no_white_space_allowed_before_str), ",");
  	    return FAIL;
  	}
  	whitep = *arg + 1;
  	if (!IS_WHITE_OR_NUL(*whitep))
  	{
  	    semsg(_(e_white_space_required_after_str), ",");
  	    return FAIL;
  	}
  	*arg = skipwhite(*arg + 1);
      }
  
      *arg = *arg + 1;
  
      // Allow for following comment, after at least one space.
      p = skipwhite(*arg);
      if (VIM_ISWHITE(**arg) && vim9_comment_start(p))
  	*arg += STRLEN(*arg);
  
      dict_unref(d);
      ppconst->pp_is_const = is_all_const;
      return generate_NEWDICT(cctx, count);
  
  failret:
      if (*arg == NULL)
      {
  	semsg(_(e_missing_dict_end), _("[end of lines]"));
  	*arg = (char_u *)"";
      }
      dict_unref(d);
      return FAIL;
  }
  
  /*
   * Compile "&option".
   */
      static int
  compile_get_option(char_u **arg, cctx_T *cctx)
  {
      typval_T	rettv;
      char_u	*start = *arg;
      int		ret;
  
      // parse the option and get the current value to get the type.
      rettv.v_type = VAR_UNKNOWN;
      ret = eval_option(arg, &rettv, TRUE);
      if (ret == OK)
      {
  	// include the '&' in the name, eval_option() expects it.
  	char_u	*name = vim_strnsave(start, *arg - start);
  	type_T	*type = rettv.v_type == VAR_BOOL ? &t_bool
  			  : rettv.v_type == VAR_NUMBER ? &t_number : &t_string;
  
  	ret = generate_LOAD(cctx, ISN_LOADOPT, 0, name, type);
  	vim_free(name);
      }
      clear_tv(&rettv);
  
      return ret;
  }
  
  /*
   * Compile "$VAR".
   */
      static int
  compile_get_env(char_u **arg, cctx_T *cctx)
  {
      char_u	*start = *arg;
      int		len;
      int		ret;
      char_u	*name;
  
      ++*arg;
      len = get_env_len(arg);
      if (len == 0)
      {
  	semsg(_(e_syntax_error_at_str), start - 1);
  	return FAIL;
      }
  
      // include the '$' in the name, eval_env_var() expects it.
      name = vim_strnsave(start, len + 1);
      ret = generate_LOAD(cctx, ISN_LOADENV, 0, name, &t_string);
      vim_free(name);
      return ret;
  }
  
  /*
   * Compile "@r".
   */
      static int
  compile_get_register(char_u **arg, cctx_T *cctx)
  {
      int		ret;
  
      ++*arg;
      if (**arg == NUL)
      {
  	semsg(_(e_syntax_error_at_str), *arg - 1);
  	return FAIL;
      }
      if (!valid_yank_reg(**arg, FALSE))
      {
  	emsg_invreg(**arg);
  	return FAIL;
      }
      ret = generate_LOAD(cctx, ISN_LOADREG, **arg, NULL, &t_string);
      ++*arg;
      return ret;
  }
  
  /*
   * Apply leading '!', '-' and '+' to constant "rettv".
   * When "numeric_only" is TRUE do not apply '!'.
   */
      static int
  apply_leader(typval_T *rettv, int numeric_only, char_u *start, char_u **end)
  {
      char_u *p = *end;
  
      // this works from end to start
      while (p > start)
      {
  	--p;
  	if (*p == '-' || *p == '+')
  	{
  	    // only '-' has an effect, for '+' we only check the type
  #ifdef FEAT_FLOAT
  	    if (rettv->v_type == VAR_FLOAT)
  	    {
  		if (*p == '-')
  		    rettv->vval.v_float = -rettv->vval.v_float;
  	    }
  	    else
  #endif
  	    {
  		varnumber_T	val;
  		int		error = FALSE;
  
  		// tv_get_number_chk() accepts a string, but we don't want that
  		// here
  		if (check_not_string(rettv) == FAIL)
  		    return FAIL;
  		val = tv_get_number_chk(rettv, &error);
  		clear_tv(rettv);
  		if (error)
  		    return FAIL;
  		if (*p == '-')
  		    val = -val;
  		rettv->v_type = VAR_NUMBER;
  		rettv->vval.v_number = val;
  	    }
  	}
  	else if (numeric_only)
  	{
  	    ++p;
  	    break;
  	}
  	else if (*p == '!')
  	{
  	    int v = tv2bool(rettv);
  
  	    // '!' is permissive in the type.
  	    clear_tv(rettv);
  	    rettv->v_type = VAR_BOOL;
  	    rettv->vval.v_number = v ? VVAL_FALSE : VVAL_TRUE;
  	}
      }
      *end = p;
      return OK;
  }
  
  /*
   * Recognize v: variables that are constants and set "rettv".
   */
      static void
  get_vim_constant(char_u **arg, typval_T *rettv)
  {
      if (STRNCMP(*arg, "v:true", 6) == 0)
      {
  	rettv->v_type = VAR_BOOL;
  	rettv->vval.v_number = VVAL_TRUE;
  	*arg += 6;
      }
      else if (STRNCMP(*arg, "v:false", 7) == 0)
      {
  	rettv->v_type = VAR_BOOL;
  	rettv->vval.v_number = VVAL_FALSE;
  	*arg += 7;
      }
      else if (STRNCMP(*arg, "v:null", 6) == 0)
      {
  	rettv->v_type = VAR_SPECIAL;
  	rettv->vval.v_number = VVAL_NULL;
  	*arg += 6;
      }
      else if (STRNCMP(*arg, "v:none", 6) == 0)
      {
  	rettv->v_type = VAR_SPECIAL;
  	rettv->vval.v_number = VVAL_NONE;
  	*arg += 6;
      }
  }
  
      exprtype_T
  get_compare_type(char_u *p, int *len, int *type_is)
  {
      exprtype_T	type = EXPR_UNKNOWN;
      int		i;
  
      switch (p[0])
      {
  	case '=':   if (p[1] == '=')
  			type = EXPR_EQUAL;
  		    else if (p[1] == '~')
  			type = EXPR_MATCH;
  		    break;
  	case '!':   if (p[1] == '=')
  			type = EXPR_NEQUAL;
  		    else if (p[1] == '~')
  			type = EXPR_NOMATCH;
  		    break;
  	case '>':   if (p[1] != '=')
  		    {
  			type = EXPR_GREATER;
  			*len = 1;
  		    }
  		    else
  			type = EXPR_GEQUAL;
  		    break;
  	case '<':   if (p[1] != '=')
  		    {
  			type = EXPR_SMALLER;
  			*len = 1;
  		    }
  		    else
  			type = EXPR_SEQUAL;
  		    break;
  	case 'i':   if (p[1] == 's')
  		    {
  			// "is" and "isnot"; but not a prefix of a name
  			if (p[2] == 'n' && p[3] == 'o' && p[4] == 't')
  			    *len = 5;
  			i = p[*len];
  			if (!isalnum(i) && i != '_')
  			{
  			    type = *len == 2 ? EXPR_IS : EXPR_ISNOT;
  			    *type_is = TRUE;
  			}
  		    }
  		    break;
      }
      return type;
  }
  
  /*
   * Skip over an expression, ignoring most errors.
   */
      static void
  skip_expr_cctx(char_u **arg, cctx_T *cctx)
  {
      evalarg_T	evalarg;
  
      CLEAR_FIELD(evalarg);
      evalarg.eval_cctx = cctx;
      skip_expr(arg, &evalarg);
  }
  
  /*
   * Compile code to apply '-', '+' and '!'.
   * When "numeric_only" is TRUE do not apply '!'.
   */
      static int
  compile_leader(cctx_T *cctx, int numeric_only, char_u *start, char_u **end)
  {
      char_u	*p = *end;
  
      // this works from end to start
      while (p > start)
      {
  	--p;
  	while (VIM_ISWHITE(*p))
  	    --p;
  	if (*p == '-' || *p == '+')
  	{
  	    int	    negate = *p == '-';
  	    isn_T   *isn;
  
  	    // TODO: check type
  	    while (p > start && (p[-1] == '-' || p[-1] == '+'))
  	    {
  		--p;
  		if (*p == '-')
  		    negate = !negate;
  	    }
  	    // only '-' has an effect, for '+' we only check the type
  	    if (negate)
  		isn = generate_instr(cctx, ISN_NEGATENR);
  	    else
  		isn = generate_instr(cctx, ISN_CHECKNR);
  	    if (isn == NULL)
  		return FAIL;
  	}
  	else if (numeric_only)
  	{
  	    ++p;
  	    break;
  	}
  	else
  	{
  	    int  invert = *p == '!';
  
  	    while (p > start && (p[-1] == '!' || VIM_ISWHITE(p[-1])))
  	    {
  		if (p[-1] == '!')
  		    invert = !invert;
  		--p;
  	    }
  	    if (generate_2BOOL(cctx, invert) == FAIL)
  		return FAIL;
  	}
      }
      *end = p;
      return OK;
  }
  
  /*
   * Compile "(expression)": recursive!
   * Return FAIL/OK.
   */
      static int
  compile_parenthesis(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
  {
      int	    ret;
      char_u  *p = *arg + 1;
  
      if (may_get_next_line_error(p, arg, cctx) == FAIL)
  	return FAIL;
      if (ppconst->pp_used <= PPSIZE - 10)
      {
  	ret = compile_expr1(arg, cctx, ppconst);
      }
      else
      {
  	// Not enough space in ppconst, flush constants.
  	if (generate_ppconst(cctx, ppconst) == FAIL)
  	    return FAIL;
  	ret = compile_expr0(arg, cctx);
      }
      if (may_get_next_line_error(*arg, arg, cctx) == FAIL)
  	return FAIL;
      if (**arg == ')')
  	++*arg;
      else if (ret == OK)
      {
  	emsg(_(e_missing_close));
  	ret = FAIL;
      }
      return ret;
  }
  
  /*
   * Compile whatever comes after "name" or "name()".
   * Advances "*arg" only when something was recognized.
   */
      static int
  compile_subscript(
  	char_u **arg,
  	cctx_T *cctx,
  	char_u *start_leader,
  	char_u **end_leader,
  	ppconst_T *ppconst)
  {
      char_u	*name_start = *end_leader;
  
      for (;;)
      {
  	char_u *p = skipwhite(*arg);
  
  	if (*p == NUL || (VIM_ISWHITE(**arg) && vim9_comment_start(p)))
  	{
  	    char_u *next = peek_next_line_from_context(cctx);
  
  	    // If a following line starts with "->{" or "->X" advance to that
  	    // line, so that a line break before "->" is allowed.
  	    // Also if a following line starts with ".x".
  	    if (next != NULL &&
  		    ((next[0] == '-' && next[1] == '>'
  				 && (next[2] == '{' || ASCII_ISALPHA(next[2])))
  		    || (next[0] == '.' && eval_isdictc(next[1]))))
  	    {
  		next = next_line_from_context(cctx, TRUE);
  		if (next == NULL)
  		    return FAIL;
  		*arg = next;
  		p = skipwhite(*arg);
  	    }
  	}
  
  	// Do not skip over white space to find the "(", "execute 'x' ()" is
  	// not a function call.
  	if (**arg == '(')
  	{
  	    garray_T    *stack = &cctx->ctx_type_stack;
  	    type_T	*type;
  	    int		argcount = 0;
  
  	    if (generate_ppconst(cctx, ppconst) == FAIL)
  		return FAIL;
  	    ppconst->pp_is_const = FALSE;
  
  	    // funcref(arg)
  	    type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
  
  	    *arg = skipwhite(p + 1);
  	    if (compile_arguments(arg, cctx, &argcount) == FAIL)
  		return FAIL;
  	    if (generate_PCALL(cctx, argcount, name_start, type, TRUE) == FAIL)
  		return FAIL;
  	}
  	else if (*p == '-' && p[1] == '>')
  	{
  	    char_u *pstart = p;
  
  	    if (generate_ppconst(cctx, ppconst) == FAIL)
  		return FAIL;
  	    ppconst->pp_is_const = FALSE;
  
  	    // something->method()
  	    // Apply the '!', '-' and '+' first:
  	    //   -1.0->func() works like (-1.0)->func()
  	    if (compile_leader(cctx, TRUE, start_leader, end_leader) == FAIL)
  		return FAIL;
  
  	    p += 2;
  	    *arg = skipwhite(p);
  	    // No line break supported right after "->".
  	    if (**arg == '(')
  	    {
  		int	    argcount = 1;
  		char_u	    *expr;
  		garray_T    *stack;
  		type_T	    *type;
  
  		// Funcref call:  list->(Refs[2])(arg)
  		// or lambda:	  list->((arg) => expr)(arg)
  		// Fist compile the arguments.
  		expr = *arg;
  		*arg = skipwhite(*arg + 1);
  		skip_expr_cctx(arg, cctx);
  		*arg = skipwhite(*arg);
  		if (**arg != ')')
  		{
  		    semsg(_(e_missing_paren), *arg);
  		    return FAIL;
  		}
  		++*arg;
  		if (**arg != '(')
  		{
  		    if (*skipwhite(*arg) == '(')
  			emsg(_(e_nowhitespace));
  		    else
  			semsg(_(e_missing_paren), *arg);
  		    return FAIL;
  		}
  
  		*arg = skipwhite(*arg + 1);
  		if (compile_arguments(arg, cctx, &argcount) == FAIL)
  		    return FAIL;
  
  		// Compile the function expression.
  		if (compile_parenthesis(&expr, cctx, ppconst) == FAIL)
  		    return FAIL;
  
  		stack = &cctx->ctx_type_stack;
  		type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
  		if (generate_PCALL(cctx, argcount,
  				(char_u *)"[expression]", type, FALSE) == FAIL)
  		    return FAIL;
  	    }
  	    else
  	    {
  		// method call:  list->method()
  		p = *arg;
  		if (!eval_isnamec1(*p))
  		{
  		    semsg(_(e_trailing_arg), pstart);
  		    return FAIL;
  		}
  		if (ASCII_ISALPHA(*p) && p[1] == ':')
  		    p += 2;
  		for ( ; eval_isnamec(*p); ++p)
  		    ;
  		if (*p != '(')
  		{
  		    semsg(_(e_missing_paren), *arg);
  		    return FAIL;
  		}
  		// TODO: base value may not be the first argument
  		if (compile_call(arg, p - *arg, cctx, ppconst, 1) == FAIL)
  		    return FAIL;
  	    }
  	}
  	else if (**arg == '[')
  	{
  	    garray_T	*stack = &cctx->ctx_type_stack;
  	    type_T	**typep;
  	    type_T	*valtype;
  	    vartype_T	vtype;
  	    int		is_slice = FALSE;
  
  	    // list index: list[123]
  	    // dict member: dict[key]
  	    // string index: text[123]
  	    // TODO: blob index
  	    // TODO: more arguments
  	    // TODO: recognize list or dict at runtime
  	    if (generate_ppconst(cctx, ppconst) == FAIL)
  		return FAIL;
  	    ppconst->pp_is_const = FALSE;
  
  	    ++p;
  	    if (may_get_next_line_error(p, arg, cctx) == FAIL)
  		return FAIL;
  	    if (**arg == ':')
  	    {
  		// missing first index is equal to zero
  		generate_PUSHNR(cctx, 0);
  	    }
  	    else
  	    {
  		if (compile_expr0(arg, cctx) == FAIL)
  		    return FAIL;
  		if (**arg == ':')
  		{
  		    semsg(_(e_white_space_required_before_and_after_str_at_str),
  								    ":", *arg);
  		    return FAIL;
  		}
  		if (may_get_next_line_error(*arg, arg, cctx) == FAIL)
  		    return FAIL;
  		*arg = skipwhite(*arg);
  	    }
  	    if (**arg == ':')
  	    {
  		is_slice = TRUE;
  		++*arg;
  		if (!IS_WHITE_OR_NUL(**arg) && **arg != ']')
  		{
  		    semsg(_(e_white_space_required_before_and_after_str_at_str),
  								    ":", *arg);
  		    return FAIL;
  		}
  		if (may_get_next_line_error(*arg, arg, cctx) == FAIL)
  		    return FAIL;
  		if (**arg == ']')
  		    // missing second index is equal to end of string
  		    generate_PUSHNR(cctx, -1);
  		else
  		{
  		    if (compile_expr0(arg, cctx) == FAIL)
  			return FAIL;
  		    if (may_get_next_line_error(*arg, arg, cctx) == FAIL)
  			return FAIL;
  		    *arg = skipwhite(*arg);
  		}
  	    }
  
  	    if (**arg != ']')
  	    {
  		emsg(_(e_missbrac));
  		return FAIL;
  	    }
  	    *arg = *arg + 1;
  
  	    // We can index a list and a dict.  If we don't know the type
  	    // we can use the index value type.
  	    // TODO: If we don't know use an instruction to figure it out at
  	    // runtime.
  	    typep = ((type_T **)stack->ga_data) + stack->ga_len
  							  - (is_slice ? 3 : 2);
  	    vtype = (*typep)->tt_type;
  	    valtype = ((type_T **)stack->ga_data)[stack->ga_len - 1];
  	    // If the index is a string, the variable must be a Dict.
  	    if (*typep == &t_any && valtype == &t_string)
  		vtype = VAR_DICT;
  	    if (vtype == VAR_STRING || vtype == VAR_LIST || vtype == VAR_BLOB)
  	    {
  		if (need_type(valtype, &t_number, -1, 0, cctx,
  							 FALSE, FALSE) == FAIL)
  		    return FAIL;
  		if (is_slice)
  		{
  		    valtype = ((type_T **)stack->ga_data)[stack->ga_len - 2];
  		    if (need_type(valtype, &t_number, -2, 0, cctx,
  							 FALSE, FALSE) == FAIL)
  			return FAIL;
  		}
  	    }
  
  	    if (vtype == VAR_DICT)
  	    {
  		if (is_slice)
  		{
  		    emsg(_(e_cannot_slice_dictionary));
  		    return FAIL;
  		}
  		if ((*typep)->tt_type == VAR_DICT)
  		{
  		    *typep = (*typep)->tt_member;
  		    if (*typep == &t_unknown)
  			// empty dict was used
  			*typep = &t_any;
  		}
  		else
  		{
  		    if (need_type(*typep, &t_dict_any, -2, 0, cctx,
  							 FALSE, FALSE) == FAIL)
  			return FAIL;
  		    *typep = &t_any;
  		}
  		if (may_generate_2STRING(-1, cctx) == FAIL)
  		    return FAIL;
  		if (generate_instr_drop(cctx, ISN_MEMBER, 1) == FAIL)
  		    return FAIL;
  	    }
  	    else if (vtype == VAR_STRING)
  	    {
  		*typep = &t_string;
  		if ((is_slice
  			? generate_instr_drop(cctx, ISN_STRSLICE, 2)
  			: generate_instr_drop(cctx, ISN_STRINDEX, 1)) == FAIL)
  		    return FAIL;
  	    }
  	    else if (vtype == VAR_BLOB)
  	    {
  		emsg("Sorry, blob index and slice not implemented yet");
  		return FAIL;
  	    }
  	    else if (vtype == VAR_LIST || *typep == &t_any)
  	    {
  		if (is_slice)
  		{
  		    if (generate_instr_drop(cctx,
  			     vtype == VAR_LIST ?  ISN_LISTSLICE : ISN_ANYSLICE,
  								    2) == FAIL)
  			return FAIL;
  		}
  		else
  		{
  		    if ((*typep)->tt_type == VAR_LIST)
  		    {
  			*typep = (*typep)->tt_member;
  			if (*typep == &t_unknown)
  			    // empty list was used
  			    *typep = &t_any;
  		    }
  		    if (generate_instr_drop(cctx,
  			     vtype == VAR_LIST ?  ISN_LISTINDEX : ISN_ANYINDEX,
  								    1) == FAIL)
  			return FAIL;
  		}
  	    }
  	    else
  	    {
  		emsg(_(e_string_list_dict_or_blob_required));
  		return FAIL;
  	    }
  	}
  	else if (*p == '.' && p[1] != '.')
  	{
  	    // dictionary member: dict.name
  	    if (generate_ppconst(cctx, ppconst) == FAIL)
  		return FAIL;
  	    ppconst->pp_is_const = FALSE;
  
  	    *arg = p + 1;
  	    if (may_get_next_line(*arg, arg, cctx) == FAIL)
  	    {
  		emsg(_(e_missing_name_after_dot));
  		return FAIL;
  	    }
  	    p = *arg;
  	    if (eval_isdictc(*p))
  		while (eval_isnamec(*p))
  		    MB_PTR_ADV(p);
  	    if (p == *arg)
  	    {
  		semsg(_(e_syntax_error_at_str), *arg);
  		return FAIL;
  	    }
  	    if (generate_STRINGMEMBER(cctx, *arg, p - *arg) == FAIL)
  		return FAIL;
  	    *arg = p;
  	}
  	else
  	    break;
      }
  
      // TODO - see handle_subscript():
      // Turn "dict.Func" into a partial for "Func" bound to "dict".
      // Don't do this when "Func" is already a partial that was bound
      // explicitly (pt_auto is FALSE).
  
      return OK;
  }
  
  /*
   * Compile an expression at "*arg" and add instructions to "cctx->ctx_instr".
   * "arg" is advanced until after the expression, skipping white space.
   *
   * If the value is a constant "ppconst->pp_used" will be non-zero.
   * Before instructions are generated, any values in "ppconst" will generated.
   *
   * This is the compiling equivalent of eval1(), eval2(), etc.
   */
  
  /*
   *  number		number constant
   *  0zFFFFFFFF		Blob constant
   *  "string"		string constant
   *  'string'		literal string constant
   *  &option-name	option value
   *  @r			register contents
   *  identifier		variable value
   *  function()		function call
   *  $VAR		environment variable
   *  (expression)	nested expression
   *  [expr, expr]	List
   *  {key: val, [key]: val}   Dictionary
   *
   *  Also handle:
   *  ! in front		logical NOT
   *  - in front		unary minus
   *  + in front		unary plus (ignored)
   *  trailing (arg)	funcref/partial call
   *  trailing []		subscript in String or List
   *  trailing .name	entry in Dictionary
   *  trailing ->name()	method call
   */
      static int
  compile_expr7(
  	char_u **arg,
  	cctx_T *cctx,
  	ppconst_T *ppconst)
  {
      char_u	*start_leader, *end_leader;
      int		ret = OK;
      typval_T	*rettv = &ppconst->pp_tv[ppconst->pp_used];
      int		used_before = ppconst->pp_used;
  
      ppconst->pp_is_const = FALSE;
  
      /*
       * Skip '!', '-' and '+' characters.  They are handled later.
       */
      start_leader = *arg;
      if (eval_leader(arg, TRUE) == FAIL)
  	return FAIL;
      end_leader = *arg;
  
      rettv->v_type = VAR_UNKNOWN;
      switch (**arg)
      {
  	/*
  	 * Number constant.
  	 */
  	case '0':	// also for blob starting with 0z
  	case '1':
  	case '2':
  	case '3':
  	case '4':
  	case '5':
  	case '6':
  	case '7':
  	case '8':
  	case '9':
  	case '.':   if (eval_number(arg, rettv, TRUE, FALSE) == FAIL)
  			return FAIL;
  		    // Apply "-" and "+" just before the number now, right to
  		    // left.  Matters especially when "->" follows.  Stops at
  		    // '!'.
  		    if (apply_leader(rettv, TRUE,
  					    start_leader, &end_leader) == FAIL)
  		    {
  			clear_tv(rettv);
  			return FAIL;
  		    }
  		    break;
  
  	/*
  	 * String constant: "string".
  	 */
  	case '"':   if (eval_string(arg, rettv, TRUE) == FAIL)
  			return FAIL;
  		    break;
  
  	/*
  	 * Literal string constant: 'str''ing'.
  	 */
  	case '\'':  if (eval_lit_string(arg, rettv, TRUE) == FAIL)
  			return FAIL;
  		    break;
  
  	/*
  	 * Constant Vim variable.
  	 */
  	case 'v':   get_vim_constant(arg, rettv);
  		    ret = NOTDONE;
  		    break;
  
  	/*
  	 * "true" constant
  	 */
  	case 't':   if (STRNCMP(*arg, "true", 4) == 0
  						   && !eval_isnamec((*arg)[4]))
  		    {
  			*arg += 4;
  			rettv->v_type = VAR_BOOL;
  			rettv->vval.v_number = VVAL_TRUE;
  		    }
  		    else
  			ret = NOTDONE;
  		    break;
  
  	/*
  	 * "false" constant
  	 */
  	case 'f':   if (STRNCMP(*arg, "false", 5) == 0
  						   && !eval_isnamec((*arg)[5]))
  		    {
  			*arg += 5;
  			rettv->v_type = VAR_BOOL;
  			rettv->vval.v_number = VVAL_FALSE;
  		    }
  		    else
  			ret = NOTDONE;
  		    break;
  
  	/*
  	 * "null" constant
  	 */
  	case 'n':   if (STRNCMP(*arg, "null", 4) == 0
  						   && !eval_isnamec((*arg)[5]))
  		    {
  			*arg += 4;
  			rettv->v_type = VAR_SPECIAL;
  			rettv->vval.v_number = VVAL_NULL;
  		    }
  		    else
  			ret = NOTDONE;
  		    break;
  
  	/*
  	 * List: [expr, expr]
  	 */
  	case '[':   ret = compile_list(arg, cctx, ppconst);
  		    break;
  
  	/*
  	 * Dictionary: {'key': val, 'key': val}
  	 */
  	case '{':   ret = compile_dict(arg, cctx, ppconst);
  		    break;
  
  	/*
  	 * Option value: &name
  	 */
  	case '&':	if (generate_ppconst(cctx, ppconst) == FAIL)
  			    return FAIL;
  			ret = compile_get_option(arg, cctx);
  			break;
  
  	/*
  	 * Environment variable: $VAR.
  	 */
  	case '$':	if (generate_ppconst(cctx, ppconst) == FAIL)
  			    return FAIL;
  			ret = compile_get_env(arg, cctx);
  			break;
  
  	/*
  	 * Register contents: @r.
  	 */
  	case '@':	if (generate_ppconst(cctx, ppconst) == FAIL)
  			    return FAIL;
  			ret = compile_get_register(arg, cctx);
  			break;
  	/*
  	 * nested expression: (expression).
  	 * lambda: (arg, arg) => expr
  	 * funcref: (arg, arg) => { statement }
  	 */
  	case '(':   // if compile_lambda returns NOTDONE then it must be (expr)
  		    ret = compile_lambda(arg, cctx);
  		    if (ret == NOTDONE)
  			ret = compile_parenthesis(arg, cctx, ppconst);
  		    break;
  
  	default:    ret = NOTDONE;
  		    break;
      }
      if (ret == FAIL)
  	return FAIL;
  
      if (rettv->v_type != VAR_UNKNOWN && used_before == ppconst->pp_used)
      {
  	if (cctx->ctx_skip == SKIP_YES)
  	    clear_tv(rettv);
  	else
  	    // A constant expression can possibly be handled compile time,
  	    // return the value instead of generating code.
  	    ++ppconst->pp_used;
      }
      else if (ret == NOTDONE)
      {
  	char_u	    *p;
  	int	    r;
  
  	if (!eval_isnamec1(**arg))
  	{
  	    if (ends_excmd(*skipwhite(*arg)))
  		semsg(_(e_empty_expression_str), *arg);
  	    else
  		semsg(_(e_name_expected_str), *arg);
  	    return FAIL;
  	}
  
  	// "name" or "name()"
  	p = to_name_end(*arg, TRUE);
  	if (*p == '(')
  	{
  	    r = compile_call(arg, p - *arg, cctx, ppconst, 0);
  	}
  	else
  	{
  	    if (generate_ppconst(cctx, ppconst) == FAIL)
  		return FAIL;
  	    r = compile_load(arg, p, cctx, TRUE, TRUE);
  	}
  	if (r == FAIL)
  	    return FAIL;
      }
  
      // Handle following "[]", ".member", etc.
      // Then deal with prefixed '-', '+' and '!', if not done already.
      if (compile_subscript(arg, cctx, start_leader, &end_leader,
  							     ppconst) == FAIL)
  	return FAIL;
      if (ppconst->pp_used > 0)
      {
  	// apply the '!', '-' and '+' before the constant
  	rettv = &ppconst->pp_tv[ppconst->pp_used - 1];
  	if (apply_leader(rettv, FALSE, start_leader, &end_leader) == FAIL)
  	    return FAIL;
  	return OK;
      }
      if (compile_leader(cctx, FALSE, start_leader, &end_leader) == FAIL)
  	return FAIL;
      return OK;
  }
  
  /*
   * Give the "white on both sides" error, taking the operator from "p[len]".
   */
      void
  error_white_both(char_u *op, int len)
  {
      char_u	buf[10];
  
      vim_strncpy(buf, op, len);
      semsg(_(e_white_space_required_before_and_after_str_at_str), buf, op);
  }
  
  /*
   * <type>expr7: runtime type check / conversion
   */
      static int
  compile_expr7t(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
  {
      type_T *want_type = NULL;
  
      // Recognize <type>
      if (**arg == '<' && eval_isnamec1((*arg)[1]))
      {
  	++*arg;
  	want_type = parse_type(arg, cctx->ctx_type_list, TRUE);
  	if (want_type == NULL)
  	    return FAIL;
  
  	if (**arg != '>')
  	{
  	    if (*skipwhite(*arg) == '>')
  		semsg(_(e_no_white_space_allowed_before_str), ">");
  	    else
  		emsg(_(e_missing_gt));
  	    return FAIL;
  	}
  	++*arg;
  	if (may_get_next_line_error(*arg, arg, cctx) == FAIL)
  	    return FAIL;
      }
  
      if (compile_expr7(arg, cctx, ppconst) == FAIL)
  	return FAIL;
  
      if (want_type != NULL)
      {
  	garray_T    *stack = &cctx->ctx_type_stack;
  	type_T	    *actual;
  
  	generate_ppconst(cctx, ppconst);
  	actual = ((type_T **)stack->ga_data)[stack->ga_len - 1];
  	if (check_type(want_type, actual, FALSE, 0) == FAIL)
  	{
  	    if (need_type(actual, want_type, -1, 0, cctx, FALSE, FALSE) == FAIL)
  		return FAIL;
  	}
      }
  
      return OK;
  }
  
  /*
   *	*	number multiplication
   *	/	number division
   *	%	number modulo
   */
      static int
  compile_expr6(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
  {
      char_u	*op;
      char_u	*next;
      int		ppconst_used = ppconst->pp_used;
  
      // get the first expression
      if (compile_expr7t(arg, cctx, ppconst) == FAIL)
  	return FAIL;
  
      /*
       * Repeat computing, until no "*", "/" or "%" is following.
       */
      for (;;)
      {
  	op = may_peek_next_line(cctx, *arg, &next);
  	if (*op != '*' && *op != '/' && *op != '%')
  	    break;
  	if (next != NULL)
  	{
  	    *arg = next_line_from_context(cctx, TRUE);
  	    op = skipwhite(*arg);
  	}
  
  	if (!IS_WHITE_OR_NUL(**arg) || !IS_WHITE_OR_NUL(op[1]))
  	{
  	    error_white_both(op, 1);
  	    return FAIL;
  	}
  	if (may_get_next_line_error(op + 1, arg, cctx) == FAIL)
  	    return FAIL;
  
  	// get the second expression
  	if (compile_expr7t(arg, cctx, ppconst) == FAIL)
  	    return FAIL;
  
  	if (ppconst->pp_used == ppconst_used + 2
  		&& ppconst->pp_tv[ppconst_used].v_type == VAR_NUMBER
  		&& ppconst->pp_tv[ppconst_used + 1].v_type == VAR_NUMBER)
  	{
  	    typval_T *tv1 = &ppconst->pp_tv[ppconst_used];
  	    typval_T *tv2 = &ppconst->pp_tv[ppconst_used + 1];
  	    varnumber_T res = 0;
  
  	    // both are numbers: compute the result
  	    switch (*op)
  	    {
  		case '*': res = tv1->vval.v_number * tv2->vval.v_number;
  			  break;
  		case '/': res = tv1->vval.v_number / tv2->vval.v_number;
  			  break;
  		case '%': res = tv1->vval.v_number % tv2->vval.v_number;
  			  break;
  	    }
  	    tv1->vval.v_number = res;
  	    --ppconst->pp_used;
  	}
  	else
  	{
  	    generate_ppconst(cctx, ppconst);
  	    generate_two_op(cctx, op);
  	}
      }
  
      return OK;
  }
  
  /*
   *      +	number addition
   *      -	number subtraction
   *      ..	string concatenation
   */
      static int
  compile_expr5(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
  {
      char_u	*op;
      char_u	*next;
      int		oplen;
      int		ppconst_used = ppconst->pp_used;
  
      // get the first variable
      if (compile_expr6(arg, cctx, ppconst) == FAIL)
  	return FAIL;
  
      /*
       * Repeat computing, until no "+", "-" or ".." is following.
       */
      for (;;)
      {
  	op = may_peek_next_line(cctx, *arg, &next);
  	if (*op != '+' && *op != '-' && !(*op == '.' && *(op + 1) == '.'))
  	    break;
  	oplen = (*op == '.' ? 2 : 1);
  	if (next != NULL)
  	{
  	    *arg = next_line_from_context(cctx, TRUE);
  	    op = skipwhite(*arg);
  	}
  
  	if (!IS_WHITE_OR_NUL(**arg) || !IS_WHITE_OR_NUL(op[oplen]))
  	{
  	    error_white_both(op, oplen);
  	    return FAIL;
  	}
  
  	if (may_get_next_line_error(op + oplen, arg, cctx) == FAIL)
  	    return FAIL;
  
  	// get the second expression
  	if (compile_expr6(arg, cctx, ppconst) == FAIL)
  	    return FAIL;
  
  	if (ppconst->pp_used == ppconst_used + 2
  		&& (*op == '.'
  		    ? (ppconst->pp_tv[ppconst_used].v_type == VAR_STRING
  		    && ppconst->pp_tv[ppconst_used + 1].v_type == VAR_STRING)
  		    : (ppconst->pp_tv[ppconst_used].v_type == VAR_NUMBER
  		    && ppconst->pp_tv[ppconst_used + 1].v_type == VAR_NUMBER)))
  	{
  	    typval_T *tv1 = &ppconst->pp_tv[ppconst_used];
  	    typval_T *tv2 = &ppconst->pp_tv[ppconst_used + 1];
  
  	    // concat/subtract/add constant numbers
  	    if (*op == '+')
  		tv1->vval.v_number = tv1->vval.v_number + tv2->vval.v_number;
  	    else if (*op == '-')
  		tv1->vval.v_number = tv1->vval.v_number - tv2->vval.v_number;
  	    else
  	    {
  		// concatenate constant strings
  		char_u *s1 = tv1->vval.v_string;
  		char_u *s2 = tv2->vval.v_string;
  		size_t len1 = STRLEN(s1);
  
  		tv1->vval.v_string = alloc((int)(len1 + STRLEN(s2) + 1));
  		if (tv1->vval.v_string == NULL)
  		{
  		    clear_ppconst(ppconst);
  		    return FAIL;
  		}
  		mch_memmove(tv1->vval.v_string, s1, len1);
  		STRCPY(tv1->vval.v_string + len1, s2);
  		vim_free(s1);
  		vim_free(s2);
  	    }
  	    --ppconst->pp_used;
  	}
  	else
  	{
  	    generate_ppconst(cctx, ppconst);
  	    if (*op == '.')
  	    {
  		if (may_generate_2STRING(-2, cctx) == FAIL
  			|| may_generate_2STRING(-1, cctx) == FAIL)
  		    return FAIL;
  		generate_instr_drop(cctx, ISN_CONCAT, 1);
  	    }
  	    else
  		generate_two_op(cctx, op);
  	}
      }
  
      return OK;
  }
  
  /*
   * expr5a == expr5b
   * expr5a =~ expr5b
   * expr5a != expr5b
   * expr5a !~ expr5b
   * expr5a > expr5b
   * expr5a >= expr5b
   * expr5a < expr5b
   * expr5a <= expr5b
   * expr5a is expr5b
   * expr5a isnot expr5b
   *
   * Produces instructions:
   *	EVAL expr5a		Push result of "expr5a"
   *	EVAL expr5b		Push result of "expr5b"
   *	COMPARE			one of the compare instructions
   */
      static int
  compile_expr4(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
  {
      exprtype_T	type = EXPR_UNKNOWN;
      char_u	*p;
      char_u	*next;
      int		len = 2;
      int		type_is = FALSE;
      int		ppconst_used = ppconst->pp_used;
  
      // get the first variable
      if (compile_expr5(arg, cctx, ppconst) == FAIL)
  	return FAIL;
  
      p = may_peek_next_line(cctx, *arg, &next);
      type = get_compare_type(p, &len, &type_is);
  
      /*
       * If there is a comparative operator, use it.
       */
      if (type != EXPR_UNKNOWN)
      {
  	int ic = FALSE;  // Default: do not ignore case
  
  	if (next != NULL)
  	{
  	    *arg = next_line_from_context(cctx, TRUE);
  	    p = skipwhite(*arg);
  	}
  	if (type_is && (p[len] == '?' || p[len] == '#'))
  	{
  	    semsg(_(e_invexpr2), *arg);
  	    return FAIL;
  	}
  	// extra question mark appended: ignore case
  	if (p[len] == '?')
  	{
  	    ic = TRUE;
  	    ++len;
  	}
  	// extra '#' appended: match case (ignored)
  	else if (p[len] == '#')
  	    ++len;
  	// nothing appended: match case
  
  	if (!IS_WHITE_OR_NUL(**arg) || !IS_WHITE_OR_NUL(p[len]))
  	{
  	    error_white_both(p, len);
  	    return FAIL;
  	}
  
  	// get the second variable
  	if (may_get_next_line_error(p + len, arg, cctx) == FAIL)
  	    return FAIL;
  
  	if (compile_expr5(arg, cctx, ppconst) == FAIL)
  	    return FAIL;
  
  	if (ppconst->pp_used == ppconst_used + 2)
  	{
  	    typval_T *	tv1 = &ppconst->pp_tv[ppconst->pp_used - 2];
  	    typval_T	*tv2 = &ppconst->pp_tv[ppconst->pp_used - 1];
  	    int		ret;
  
  	    // Both sides are a constant, compute the result now.
  	    // First check for a valid combination of types, this is more
  	    // strict than typval_compare().
  	    if (check_compare_types(type, tv1, tv2) == FAIL)
  		ret = FAIL;
  	    else
  	    {
  		ret = typval_compare(tv1, tv2, type, ic);
  		tv1->v_type = VAR_BOOL;
  		tv1->vval.v_number = tv1->vval.v_number
  						      ? VVAL_TRUE : VVAL_FALSE;
  		clear_tv(tv2);
  		--ppconst->pp_used;
  	    }
  	    return ret;
  	}
  
  	generate_ppconst(cctx, ppconst);
  	return generate_COMPARE(cctx, type, ic);
      }
  
      return OK;
  }
  
  static int compile_expr3(char_u **arg,  cctx_T *cctx, ppconst_T *ppconst);
  
  /*
   * Compile || or &&.
   */
      static int
  compile_and_or(
  	char_u **arg,
  	cctx_T	*cctx,
  	char	*op,
  	ppconst_T *ppconst,
  	int	ppconst_used UNUSED)
  {
      char_u	*next;
      char_u	*p = may_peek_next_line(cctx, *arg, &next);
      int		opchar = *op;
  
      if (p[0] == opchar && p[1] == opchar)
      {
  	garray_T	*instr = &cctx->ctx_instr;
  	garray_T	end_ga;
  
  	/*
  	 * Repeat until there is no following "||" or "&&"
  	 */
  	ga_init2(&end_ga, sizeof(int), 10);
  	while (p[0] == opchar && p[1] == opchar)
  	{
  	    if (next != NULL)
  	    {
  		*arg = next_line_from_context(cctx, TRUE);
  		p = skipwhite(*arg);
  	    }
  
  	    if (!IS_WHITE_OR_NUL(**arg) || !IS_WHITE_OR_NUL(p[2]))
  	    {
  		semsg(_(e_white_space_required_before_and_after_str_at_str),
  								     op, *arg);
  		return FAIL;
  	    }
  
  	    // TODO: use ppconst if the value is a constant and check
  	    // evaluating to bool
  	    generate_ppconst(cctx, ppconst);
  
  	    // Every part must evaluate to a bool.
  	    if (bool_on_stack(cctx) == FAIL)
  	    {
  		ga_clear(&end_ga);
  		return FAIL;
  	    }
  
  	    if (ga_grow(&end_ga, 1) == FAIL)
  	    {
  		ga_clear(&end_ga);
  		return FAIL;
  	    }
  	    *(((int *)end_ga.ga_data) + end_ga.ga_len) = instr->ga_len;
  	    ++end_ga.ga_len;
  	    generate_JUMP(cctx, opchar == '|'
  				 ?  JUMP_IF_COND_TRUE : JUMP_IF_COND_FALSE, 0);
  
  	    // eval the next expression
  	    if (may_get_next_line_error(p + 2, arg, cctx) == FAIL)
  	    {
  		ga_clear(&end_ga);
  		return FAIL;
  	    }
  
  	    if ((opchar == '|' ? compile_expr3(arg, cctx, ppconst)
  				  : compile_expr4(arg, cctx, ppconst)) == FAIL)
  	    {
  		ga_clear(&end_ga);
  		return FAIL;
  	    }
  
  	    p = may_peek_next_line(cctx, *arg, &next);
  	}
  	generate_ppconst(cctx, ppconst);
  
  	// Every part must evaluate to a bool.
  	if (bool_on_stack(cctx) == FAIL)
  	{
  	    ga_clear(&end_ga);
  	    return FAIL;
  	}
  
  	// Fill in the end label in all jumps.
  	while (end_ga.ga_len > 0)
  	{
  	    isn_T	*isn;
  
  	    --end_ga.ga_len;
  	    isn = ((isn_T *)instr->ga_data)
  				  + *(((int *)end_ga.ga_data) + end_ga.ga_len);
  	    isn->isn_arg.jump.jump_where = instr->ga_len;
  	}
  	ga_clear(&end_ga);
      }
  
      return OK;
  }
  
  /*
   * expr4a && expr4a && expr4a	    logical AND
   *
   * Produces instructions:
   *	EVAL expr4a		Push result of "expr4a"
   *	COND2BOOL		convert to bool if needed
   *	JUMP_IF_COND_FALSE end
   *	EVAL expr4b		Push result of "expr4b"
   *	JUMP_IF_COND_FALSE end
   *	EVAL expr4c		Push result of "expr4c"
   * end:
   */
      static int
  compile_expr3(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
  {
      int		ppconst_used = ppconst->pp_used;
  
      // get the first variable
      if (compile_expr4(arg, cctx, ppconst) == FAIL)
  	return FAIL;
  
      // || and && work almost the same
      return compile_and_or(arg, cctx, "&&", ppconst, ppconst_used);
  }
  
  /*
   * expr3a || expr3b || expr3c	    logical OR
   *
   * Produces instructions:
   *	EVAL expr3a		Push result of "expr3a"
   *	COND2BOOL		convert to bool if needed
   *	JUMP_IF_COND_TRUE end
   *	EVAL expr3b		Push result of "expr3b"
   *	JUMP_IF_COND_TRUE end
   *	EVAL expr3c		Push result of "expr3c"
   * end:
   */
      static int
  compile_expr2(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
  {
      int		ppconst_used = ppconst->pp_used;
  
      // eval the first expression
      if (compile_expr3(arg, cctx, ppconst) == FAIL)
  	return FAIL;
  
      // || and && work almost the same
      return compile_and_or(arg, cctx, "||", ppconst, ppconst_used);
  }
  
  /*
   * Toplevel expression: expr2 ? expr1a : expr1b
   * Produces instructions:
   *	EVAL expr2		Push result of "expr2"
   *      JUMP_IF_FALSE alt	jump if false
   *      EVAL expr1a
   *      JUMP_ALWAYS end
   * alt:	EVAL expr1b
   * end:
   *
   * Toplevel expression: expr2 ?? expr1
   * Produces instructions:
   *	EVAL expr2		    Push result of "expr2"
   *      JUMP_AND_KEEP_IF_TRUE end   jump if true
   *      EVAL expr1
   * end:
   */
      static int
  compile_expr1(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
  {
      char_u	*p;
      int		ppconst_used = ppconst->pp_used;
      char_u	*next;
  
      // Ignore all kinds of errors when not producing code.
      if (cctx->ctx_skip == SKIP_YES)
      {
  	skip_expr_cctx(arg, cctx);
  	return OK;
      }
  
      // Evaluate the first expression.
      if (compile_expr2(arg, cctx, ppconst) == FAIL)
  	return FAIL;
  
      p = may_peek_next_line(cctx, *arg, &next);
      if (*p == '?')
      {
  	int		op_falsy = p[1] == '?';
  	garray_T	*instr = &cctx->ctx_instr;
  	garray_T	*stack = &cctx->ctx_type_stack;
  	int		alt_idx = instr->ga_len;
  	int		end_idx = 0;
  	isn_T		*isn;
  	type_T		*type1 = NULL;
  	int		has_const_expr = FALSE;
  	int		const_value = FALSE;
  	int		save_skip = cctx->ctx_skip;
  
  	if (next != NULL)
  	{
  	    *arg = next_line_from_context(cctx, TRUE);
  	    p = skipwhite(*arg);
  	}
  
  	if (!IS_WHITE_OR_NUL(**arg) || !IS_WHITE_OR_NUL(p[1 + op_falsy]))
  	{
  	    semsg(_(e_white_space_required_before_and_after_str_at_str),
  						  op_falsy ? "??" : "?", *arg);
  	    return FAIL;
  	}
  
  	if (ppconst->pp_used == ppconst_used + 1)
  	{
  	    // the condition is a constant, we know whether the ? or the :
  	    // expression is to be evaluated.
  	    has_const_expr = TRUE;
  	    if (op_falsy)
  		const_value = tv2bool(&ppconst->pp_tv[ppconst_used]);
  	    else
  	    {
  		int error = FALSE;
  
  		const_value = tv_get_bool_chk(&ppconst->pp_tv[ppconst_used],
  								       &error);
  		if (error)
  		    return FAIL;
  	    }
  	    cctx->ctx_skip = save_skip == SKIP_YES ||
  		 (op_falsy ? const_value : !const_value) ? SKIP_YES : SKIP_NOT;
  
  	    if (op_falsy && cctx->ctx_skip == SKIP_YES)
  		// "left ?? right" and "left" is truthy: produce "left"
  		generate_ppconst(cctx, ppconst);
  	    else
  	    {
  		clear_tv(&ppconst->pp_tv[ppconst_used]);
  		--ppconst->pp_used;
  	    }
  	}
  	else
  	{
  	    generate_ppconst(cctx, ppconst);
  	    if (op_falsy)
  		end_idx = instr->ga_len;
  	    generate_JUMP(cctx, op_falsy
  				   ? JUMP_AND_KEEP_IF_TRUE : JUMP_IF_FALSE, 0);
  	    if (op_falsy)
  		type1 = ((type_T **)stack->ga_data)[stack->ga_len];
  	}
  
  	// evaluate the second expression; any type is accepted
  	if (may_get_next_line_error(p + 1 + op_falsy, arg, cctx) == FAIL)
  	    return FAIL;
  	if (compile_expr1(arg, cctx, ppconst) == FAIL)
  	    return FAIL;
  
  	if (!has_const_expr)
  	{
  	    generate_ppconst(cctx, ppconst);
  
  	    if (!op_falsy)
  	    {
  		// remember the type and drop it
  		--stack->ga_len;
  		type1 = ((type_T **)stack->ga_data)[stack->ga_len];
  
  		end_idx = instr->ga_len;
  		generate_JUMP(cctx, JUMP_ALWAYS, 0);
  
  		// jump here from JUMP_IF_FALSE
  		isn = ((isn_T *)instr->ga_data) + alt_idx;
  		isn->isn_arg.jump.jump_where = instr->ga_len;
  	    }
  	}
  
  	if (!op_falsy)
  	{
  	    // Check for the ":".
  	    p = may_peek_next_line(cctx, *arg, &next);
  	    if (*p != ':')
  	    {
  		emsg(_(e_missing_colon));
  		return FAIL;
  	    }
  	    if (next != NULL)
  	    {
  		*arg = next_line_from_context(cctx, TRUE);
  		p = skipwhite(*arg);
  	    }
  
  	    if (!IS_WHITE_OR_NUL(**arg) || !IS_WHITE_OR_NUL(p[1]))
  	    {
  		semsg(_(e_white_space_required_before_and_after_str_at_str),
  								       ":", p);
  		return FAIL;
  	    }
  
  	    // evaluate the third expression
  	    if (has_const_expr)
  		cctx->ctx_skip = save_skip == SKIP_YES || const_value
  							 ? SKIP_YES : SKIP_NOT;
  	    if (may_get_next_line_error(p + 1, arg, cctx) == FAIL)
  		return FAIL;
  	    if (compile_expr1(arg, cctx, ppconst) == FAIL)
  		return FAIL;
  	}
  
  	if (!has_const_expr)
  	{
  	    type_T	**typep;
  
  	    generate_ppconst(cctx, ppconst);
  
  	    // If the types differ, the result has a more generic type.
  	    typep = ((type_T **)stack->ga_data) + stack->ga_len - 1;
  	    common_type(type1, *typep, typep, cctx->ctx_type_list);
  
  	    // jump here from JUMP_ALWAYS or JUMP_AND_KEEP_IF_TRUE
  	    isn = ((isn_T *)instr->ga_data) + end_idx;
  	    isn->isn_arg.jump.jump_where = instr->ga_len;
  	}
  
  	cctx->ctx_skip = save_skip;
      }
      return OK;
  }
  
  /*
   * Toplevel expression.
   * Sets "is_const" (if not NULL) to indicate the value is a constant.
   * Returns OK or FAIL.
   */
      static int
  compile_expr0_ext(char_u **arg,  cctx_T *cctx, int *is_const)
  {
      ppconst_T	ppconst;
  
      CLEAR_FIELD(ppconst);
      if (compile_expr1(arg, cctx, &ppconst) == FAIL)
      {
  	clear_ppconst(&ppconst);
  	return FAIL;
      }
      if (is_const != NULL)
  	*is_const = ppconst.pp_used > 0 || ppconst.pp_is_const;
      if (generate_ppconst(cctx, &ppconst) == FAIL)
  	return FAIL;
      return OK;
  }
  
  /*
   * Toplevel expression.
   */
      static int
  compile_expr0(char_u **arg,  cctx_T *cctx)
  {
      return compile_expr0_ext(arg, cctx, NULL);
  }
  
  /*
   * compile "return [expr]"
   */
      static char_u *
  compile_return(char_u *arg, int check_return_type, cctx_T *cctx)
  {
      char_u	*p = arg;
      garray_T	*stack = &cctx->ctx_type_stack;
      type_T	*stack_type;
  
      if (*p != NUL && *p != '|' && *p != '\n')
      {
  	// compile return argument into instructions
  	if (compile_expr0(&p, cctx) == FAIL)
  	    return NULL;
  
  	if (cctx->ctx_skip != SKIP_YES)
  	{
  	    stack_type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
  	    if (check_return_type && (cctx->ctx_ufunc->uf_ret_type == NULL
  				|| cctx->ctx_ufunc->uf_ret_type == &t_unknown
  				|| cctx->ctx_ufunc->uf_ret_type == &t_any))
  	    {
  		cctx->ctx_ufunc->uf_ret_type = stack_type;
  	    }
  	    else
  	    {
  		if (cctx->ctx_ufunc->uf_ret_type->tt_type == VAR_VOID
  			&& stack_type->tt_type != VAR_VOID
  			&& stack_type->tt_type != VAR_UNKNOWN)
  		{
  		    emsg(_(e_returning_value_in_function_without_return_type));
  		    return NULL;
  		}
  		if (need_type(stack_type, cctx->ctx_ufunc->uf_ret_type, -1,
  						0, cctx, FALSE, FALSE) == FAIL)
  		    return NULL;
  	    }
  	}
      }
      else
      {
  	// "check_return_type" cannot be TRUE, only used for a lambda which
  	// always has an argument.
  	if (cctx->ctx_ufunc->uf_ret_type->tt_type != VAR_VOID
  		&& cctx->ctx_ufunc->uf_ret_type->tt_type != VAR_UNKNOWN)
  	{
  	    emsg(_(e_missing_return_value));
  	    return NULL;
  	}
  
  	// No argument, return zero.
  	generate_PUSHNR(cctx, 0);
      }
  
      // Undo any command modifiers.
      generate_undo_cmdmods(cctx);
  
      if (cctx->ctx_skip != SKIP_YES && generate_instr(cctx, ISN_RETURN) == NULL)
  	return NULL;
  
      // "return val | endif" is possible
      return skipwhite(p);
  }
  
  /*
   * Get a line from the compilation context, compatible with exarg_T getline().
   * Return a pointer to the line in allocated memory.
   * Return NULL for end-of-file or some error.
   */
      static char_u *
  exarg_getline(
  	int c UNUSED,
  	void *cookie,
  	int indent UNUSED,
  	getline_opt_T options UNUSED)
  {
      cctx_T  *cctx = (cctx_T *)cookie;
      char_u  *p;
  
      for (;;)
      {
  	if (cctx->ctx_lnum >= cctx->ctx_ufunc->uf_lines.ga_len - 1)
  	    return NULL;
  	++cctx->ctx_lnum;
  	p = ((char_u **)cctx->ctx_ufunc->uf_lines.ga_data)[cctx->ctx_lnum];
  	// Comment lines result in NULL pointers, skip them.
  	if (p != NULL)
  	    return vim_strsave(p);
      }
  }
  
  /*
   * Compile a nested :def command.
   */
      static char_u *
  compile_nested_function(exarg_T *eap, cctx_T *cctx)
  {
      int		is_global = *eap->arg == 'g' && eap->arg[1] == ':';
      char_u	*name_start = eap->arg;
      char_u	*name_end = to_name_end(eap->arg, TRUE);
      char_u	*lambda_name;
      ufunc_T	*ufunc;
      int		r = FAIL;
  
      if (eap->forceit)
      {
  	emsg(_(e_cannot_use_bang_with_nested_def));
  	return NULL;
      }
  
      if (*name_start == '/')
      {
  	name_end = skip_regexp(name_start + 1, '/', TRUE);
  	if (*name_end == '/')
  	    ++name_end;
  	eap->nextcmd = check_nextcmd(name_end);
      }
      if (name_end == name_start || *skipwhite(name_end) != '(')
      {
  	if (!ends_excmd2(name_start, name_end))
  	{
  	    semsg(_(e_invalid_command_str), eap->cmd);
  	    return NULL;
  	}
  
  	// "def" or "def Name": list functions
  	if (generate_DEF(cctx, name_start, name_end - name_start) == FAIL)
  	    return NULL;
  	return eap->nextcmd == NULL ? (char_u *)"" : eap->nextcmd;
      }
  
      // Only g:Func() can use a namespace.
      if (name_start[1] == ':' && !is_global)
      {
  	semsg(_(e_namespace_not_supported_str), name_start);
  	return NULL;
      }
      if (check_defined(name_start, name_end - name_start, cctx) == FAIL)
  	return NULL;
  
      eap->arg = name_end;
      eap->getline = exarg_getline;
      eap->cookie = cctx;
      eap->skip = cctx->ctx_skip == SKIP_YES;
      eap->forceit = FALSE;
      lambda_name = vim_strsave(get_lambda_name());
      if (lambda_name == NULL)
  	return NULL;
      ufunc = define_function(eap, lambda_name);
  
      if (ufunc == NULL)
      {
  	r = eap->skip ? OK : FAIL;
  	goto theend;
      }
      if (ufunc->uf_def_status == UF_TO_BE_COMPILED
  	    && compile_def_function(ufunc, TRUE, cctx) == FAIL)
      {
  	func_ptr_unref(ufunc);
  	goto theend;
      }
  
      if (is_global)
      {
  	char_u *func_name = vim_strnsave(name_start + 2,
  						    name_end - name_start - 2);
  
  	if (func_name == NULL)
  	    r = FAIL;
  	else
  	{
  	    r = generate_NEWFUNC(cctx, lambda_name, func_name);
  	    lambda_name = NULL;
  	}
      }
      else
      {
  	// Define a local variable for the function reference.
  	lvar_T	*lvar = reserve_local(cctx, name_start, name_end - name_start,
  						    TRUE, ufunc->uf_func_type);
  	int block_depth = cctx->ctx_ufunc->uf_block_depth;
  
  	if (lvar == NULL)
  	    goto theend;
  	if (generate_FUNCREF(cctx, ufunc) == FAIL)
  	    goto theend;
  	r = generate_STORE(cctx, ISN_STORE, lvar->lv_idx, NULL);
  
  	// copy over the block scope IDs
  	if (block_depth > 0)
  	{
  	    ufunc->uf_block_ids = ALLOC_MULT(int, block_depth);
  	    if (ufunc->uf_block_ids != NULL)
  	    {
  		mch_memmove(ufunc->uf_block_ids, cctx->ctx_ufunc->uf_block_ids,
  						    sizeof(int) * block_depth);
  		ufunc->uf_block_depth = block_depth;
  	    }
  	}
      }
      // TODO: warning for trailing text?
      r = OK;
  
  theend:
      vim_free(lambda_name);
      return r == FAIL ? NULL : (char_u *)"";
  }
  
  /*
   * Return the length of an assignment operator, or zero if there isn't one.
   */
      int
  assignment_len(char_u *p, int *heredoc)
  {
      if (*p == '=')
      {
  	if (p[1] == '<' && p[2] == '<')
  	{
  	    *heredoc = TRUE;
  	    return 3;
  	}
  	return 1;
      }
      if (vim_strchr((char_u *)"+-*/%", *p) != NULL && p[1] == '=')
  	return 2;
      if (STRNCMP(p, "..=", 3) == 0)
  	return 3;
      return 0;
  }
  
  // words that cannot be used as a variable
  static char *reserved[] = {
      "true",
      "false",
      "null",
      NULL
  };
  
  // Destination for an assignment or ":unlet" with an index.
  typedef enum {
      dest_local,
      dest_option,
      dest_env,
      dest_global,
      dest_buffer,
      dest_window,
      dest_tab,
      dest_vimvar,
      dest_script,
      dest_reg,
      dest_expr,
  } assign_dest_T;
  
  // Used by compile_lhs() to store information about the LHS of an assignment
  // and one argument of ":unlet" with an index.
  typedef struct {
      assign_dest_T   lhs_dest;	    // type of destination
  
      char_u	    *lhs_name;	    // allocated name including
  				    // "[expr]" or ".name".
      size_t	    lhs_varlen;	    // length of the variable without
  				    // "[expr]" or ".name"
      char_u	    *lhs_dest_end;  // end of the destination, including
  				    // "[expr]" or ".name".
  
      int		    lhs_has_index;  // has "[expr]" or ".name"
  
      int		    lhs_new_local;  // create new local variable
      int		    lhs_opt_flags;  // for when destination is an option
      int		    lhs_vimvaridx;  // for when destination is a v:var
  
      lvar_T	    lhs_local_lvar; // used for existing local destination
      lvar_T	    lhs_arg_lvar;   // used for argument destination
      lvar_T	    *lhs_lvar;	    // points to destination lvar
      int		    lhs_scriptvar_sid;
      int		    lhs_scriptvar_idx;
  
      int		    lhs_has_type;   // type was specified
      type_T	    *lhs_type;
      type_T	    *lhs_member_type;
  } lhs_T;
  
  /*
   * Generate the load instruction for "name".
   */
      static void
  generate_loadvar(
  	cctx_T		*cctx,
  	assign_dest_T	dest,
  	char_u		*name,
  	lvar_T		*lvar,
  	type_T		*type)
  {
      switch (dest)
      {
  	case dest_option:
  	    // TODO: check the option exists
  	    generate_LOAD(cctx, ISN_LOADOPT, 0, name, type);
  	    break;
  	case dest_global:
  	    if (vim_strchr(name, AUTOLOAD_CHAR) == NULL)
  		generate_LOAD(cctx, ISN_LOADG, 0, name + 2, type);
  	    else
  		generate_LOAD(cctx, ISN_LOADAUTO, 0, name, type);
  	    break;
  	case dest_buffer:
  	    generate_LOAD(cctx, ISN_LOADB, 0, name + 2, type);
  	    break;
  	case dest_window:
  	    generate_LOAD(cctx, ISN_LOADW, 0, name + 2, type);
  	    break;
  	case dest_tab:
  	    generate_LOAD(cctx, ISN_LOADT, 0, name + 2, type);
  	    break;
  	case dest_script:
  	    compile_load_scriptvar(cctx,
  		    name + (name[1] == ':' ? 2 : 0), NULL, NULL, TRUE);
  	    break;
  	case dest_env:
  	    // Include $ in the name here
  	    generate_LOAD(cctx, ISN_LOADENV, 0, name, type);
  	    break;
  	case dest_reg:
  	    generate_LOAD(cctx, ISN_LOADREG, name[1], NULL, &t_string);
  	    break;
  	case dest_vimvar:
  	    generate_LOADV(cctx, name + 2, TRUE);
  	    break;
  	case dest_local:
  	    if (lvar->lv_from_outer > 0)
  		generate_LOADOUTER(cctx, lvar->lv_idx, lvar->lv_from_outer,
  									 type);
  	    else
  		generate_LOAD(cctx, ISN_LOAD, lvar->lv_idx, NULL, type);
  	    break;
  	case dest_expr:
  	    // list or dict value should already be on the stack.
  	    break;
      }
  }
  
  /*
   * Skip over "[expr]" or ".member".
   * Does not check for any errors.
   */
      static char_u *
  skip_index(char_u *start)
  {
      char_u *p = start;
  
      if (*p == '[')
      {
  	p = skipwhite(p + 1);
  	(void)skip_expr(&p, NULL);
  	p = skipwhite(p);
  	if (*p == ']')
  	    return p + 1;
  	return p;
      }
      // if (*p == '.')
      return to_name_end(p + 1, TRUE);
  }
  
      void
  vim9_declare_error(char_u *name)
  {
      char *scope = "";
  
      switch (*name)
      {
  	case 'g': scope = _("global"); break;
  	case 'b': scope = _("buffer"); break;
  	case 'w': scope = _("window"); break;
  	case 't': scope = _("tab"); break;
  	case 'v': scope = "v:"; break;
  	case '$': semsg(_(e_cannot_declare_an_environment_variable), name);
  		  return;
  	case '&': semsg(_(e_cannot_declare_an_option), name);
  		  return;
  	case '@': semsg(_(e_cannot_declare_a_register_str), name);
  		  return;
  	default: return;
      }
      semsg(_(e_cannot_declare_a_scope_variable), scope, name);
  }
  
  /*
   * For one assignment figure out the type of destination.  Return it in "dest".
   * When not recognized "dest" is not set.
   * For an option "opt_flags" is set.
   * For a v:var "vimvaridx" is set.
   * "type" is set to the destination type if known, unchanted otherwise.
   * Return FAIL if an error message was given.
   */
      static int
  get_var_dest(
  	char_u		*name,
  	assign_dest_T	*dest,
  	int		cmdidx,
  	int		*opt_flags,
  	int		*vimvaridx,
  	type_T		**type,
  	cctx_T		*cctx)
  {
      char_u *p;
  
      if (*name == '&')
      {
  	int		cc;
  	long		numval;
  	getoption_T	opt_type;
  
  	*dest = dest_option;
  	if (cmdidx == CMD_final || cmdidx == CMD_const)
  	{
  	    emsg(_(e_const_option));
  	    return FAIL;
  	}
  	p = name;
  	p = find_option_end(&p, opt_flags);
  	if (p == NULL)
  	{
  	    // cannot happen?
  	    emsg(_(e_letunexp));
  	    return FAIL;
  	}
  	cc = *p;
  	*p = NUL;
  	opt_type = get_option_value(skip_option_env_lead(name),
  						    &numval, NULL, *opt_flags);
  	*p = cc;
  	switch (opt_type)
  	{
  	    case gov_unknown:
  		    semsg(_(e_unknown_option), name);
  		    return FAIL;
  	    case gov_string:
  	    case gov_hidden_string:
  		    *type = &t_string;
  		    break;
  	    case gov_bool:
  	    case gov_hidden_bool:
  		    *type = &t_bool;
  		    break;
  	    case gov_number:
  	    case gov_hidden_number:
  		    *type = &t_number;
  		    break;
  	}
      }
      else if (*name == '$')
      {
  	*dest = dest_env;
  	*type = &t_string;
      }
      else if (*name == '@')
      {
  	if (!valid_yank_reg(name[1], FALSE) || name[1] == '.')
  	{
  	    emsg_invreg(name[1]);
  	    return FAIL;
  	}
  	*dest = dest_reg;
  	*type = &t_string;
      }
      else if (STRNCMP(name, "g:", 2) == 0)
      {
  	*dest = dest_global;
      }
      else if (STRNCMP(name, "b:", 2) == 0)
      {
  	*dest = dest_buffer;
      }
      else if (STRNCMP(name, "w:", 2) == 0)
      {
  	*dest = dest_window;
      }
      else if (STRNCMP(name, "t:", 2) == 0)
      {
  	*dest = dest_tab;
      }
      else if (STRNCMP(name, "v:", 2) == 0)
      {
  	typval_T	*vtv;
  	int		di_flags;
  
  	*vimvaridx = find_vim_var(name + 2, &di_flags);
  	if (*vimvaridx < 0)
  	{
  	    semsg(_(e_variable_not_found_str), name);
  	    return FAIL;
  	}
  	// We use the current value of "sandbox" here, is that OK?
  	if (var_check_ro(di_flags, name, FALSE))
  	    return FAIL;
  	*dest = dest_vimvar;
  	vtv = get_vim_var_tv(*vimvaridx);
  	*type = typval2type_vimvar(vtv, cctx->ctx_type_list);
      }
      return OK;
  }
  
  /*
   * Generate a STORE instruction for "dest", not being "dest_local".
   * Return FAIL when out of memory.
   */
      static int
  generate_store_var(
  	cctx_T		*cctx,
  	assign_dest_T	dest,
  	int		opt_flags,
  	int		vimvaridx,
  	int		scriptvar_idx,
  	int		scriptvar_sid,
  	type_T		*type,
  	char_u		*name)
  {
      switch (dest)
      {
  	case dest_option:
  	    return generate_STOREOPT(cctx, skip_option_env_lead(name),
  								    opt_flags);
  	case dest_global:
  	    // include g: with the name, easier to execute that way
  	    return generate_STORE(cctx, vim_strchr(name, AUTOLOAD_CHAR) == NULL
  					? ISN_STOREG : ISN_STOREAUTO, 0, name);
  	case dest_buffer:
  	    // include b: with the name, easier to execute that way
  	    return generate_STORE(cctx, ISN_STOREB, 0, name);
  	case dest_window:
  	    // include w: with the name, easier to execute that way
  	    return generate_STORE(cctx, ISN_STOREW, 0, name);
  	case dest_tab:
  	    // include t: with the name, easier to execute that way
  	    return generate_STORE(cctx, ISN_STORET, 0, name);
  	case dest_env:
  	    return generate_STORE(cctx, ISN_STOREENV, 0, name + 1);
  	case dest_reg:
  	    return generate_STORE(cctx, ISN_STOREREG, name[1], NULL);
  	case dest_vimvar:
  	    return generate_STORE(cctx, ISN_STOREV, vimvaridx, NULL);
  	case dest_script:
  	    if (scriptvar_idx < 0)
  	    {
  		char_u  *name_s = name;
  		int	r;
  
  		// "s:" is included in the name.
  		r = generate_OLDSCRIPT(cctx, ISN_STORES, name_s,
  							  scriptvar_sid, type);
  		if (name_s != name)
  		    vim_free(name_s);
  		return r;
  	    }
  	    return generate_VIM9SCRIPT(cctx, ISN_STORESCRIPT,
  					   scriptvar_sid, scriptvar_idx, type);
  	case dest_local:
  	case dest_expr:
  	    // cannot happen
  	    break;
      }
      return FAIL;
  }
  
      static int
  is_decl_command(int cmdidx)
  {
      return cmdidx == CMD_let || cmdidx == CMD_var
  				 || cmdidx == CMD_final || cmdidx == CMD_const;
  }
  
  /*
   * Figure out the LHS type and other properties for an assignment or one item
   * of ":unlet" with an index.
   * Returns OK or FAIL.
   */
      static int
  compile_lhs(
  	char_u	*var_start,
  	lhs_T	*lhs,
  	int	cmdidx,
  	int	heredoc,
  	int	oplen,
  	cctx_T	*cctx)
  {
      char_u	*var_end;
      int		is_decl = is_decl_command(cmdidx);
  
      CLEAR_POINTER(lhs);
      lhs->lhs_dest = dest_local;
      lhs->lhs_vimvaridx = -1;
      lhs->lhs_scriptvar_idx = -1;
  
      // "dest_end" is the end of the destination, including "[expr]" or
      // ".name".
      // "var_end" is the end of the variable/option/etc. name.
      lhs->lhs_dest_end = skip_var_one(var_start, FALSE);
      if (*var_start == '@')
  	var_end = var_start + 2;
      else
      {
  	// skip over the leading "&", "&l:", "&g:" and "$"
  	var_end = skip_option_env_lead(var_start);
  	var_end = to_name_end(var_end, TRUE);
      }
  
      // "a: type" is declaring variable "a" with a type, not dict "a:".
      if (is_decl && lhs->lhs_dest_end == var_start + 2
  					       && lhs->lhs_dest_end[-1] == ':')
  	--lhs->lhs_dest_end;
      if (is_decl && var_end == var_start + 2 && var_end[-1] == ':')
  	--var_end;
  
      // compute the length of the destination without "[expr]" or ".name"
      lhs->lhs_varlen = var_end - var_start;
      lhs->lhs_name = vim_strnsave(var_start, lhs->lhs_varlen);
      if (lhs->lhs_name == NULL)
  	return FAIL;
  
      if (lhs->lhs_dest_end > var_start + lhs->lhs_varlen)
  	// Something follows after the variable: "var[idx]" or "var.key".
  	lhs->lhs_has_index = TRUE;
  
      if (heredoc)
  	lhs->lhs_type = &t_list_string;
      else
  	lhs->lhs_type = &t_any;
  
      if (cctx->ctx_skip != SKIP_YES)
      {
  	int	    declare_error = FALSE;
  
  	if (get_var_dest(lhs->lhs_name, &lhs->lhs_dest, cmdidx,
  				      &lhs->lhs_opt_flags, &lhs->lhs_vimvaridx,
  						 &lhs->lhs_type, cctx) == FAIL)
  	    return FAIL;
  	if (lhs->lhs_dest != dest_local)
  	{
  	    // Specific kind of variable recognized.
  	    declare_error = is_decl;
  	}
  	else
  	{
  	    int	    idx;
  
  	    // No specific kind of variable recognized, just a name.
  	    for (idx = 0; reserved[idx] != NULL; ++idx)
  		if (STRCMP(reserved[idx], lhs->lhs_name) == 0)
  		{
  		    semsg(_(e_cannot_use_reserved_name), lhs->lhs_name);
  		    return FAIL;
  		}
  
  
  	    if (lookup_local(var_start, lhs->lhs_varlen,
  					     &lhs->lhs_local_lvar, cctx) == OK)
  		lhs->lhs_lvar = &lhs->lhs_local_lvar;
  	    else
  	    {
  		CLEAR_FIELD(lhs->lhs_arg_lvar);
  		if (arg_exists(var_start, lhs->lhs_varlen,
  			 &lhs->lhs_arg_lvar.lv_idx, &lhs->lhs_arg_lvar.lv_type,
  			    &lhs->lhs_arg_lvar.lv_from_outer, cctx) == OK)
  		{
  		    if (is_decl)
  		    {
  			semsg(_(e_str_is_used_as_argument), lhs->lhs_name);
  			return FAIL;
  		    }
  		    lhs->lhs_lvar = &lhs->lhs_arg_lvar;
  		}
  	    }
  	    if (lhs->lhs_lvar != NULL)
  	    {
  		if (is_decl)
  		{
  		    semsg(_(e_variable_already_declared), lhs->lhs_name);
  		    return FAIL;
  		}
  	    }
  	    else
  	    {
  		int script_namespace = lhs->lhs_varlen > 1
  				       && STRNCMP(var_start, "s:", 2) == 0;
  		int script_var = (script_namespace
  			? script_var_exists(var_start + 2, lhs->lhs_varlen - 2,
  							       FALSE, cctx)
  			  : script_var_exists(var_start, lhs->lhs_varlen,
  							    TRUE, cctx)) == OK;
  		imported_T  *import =
  			       find_imported(var_start, lhs->lhs_varlen, cctx);
  
  		if (script_namespace || script_var || import != NULL)
  		{
  		    char_u	*rawname = lhs->lhs_name
  					   + (lhs->lhs_name[1] == ':' ? 2 : 0);
  
  		    if (is_decl)
  		    {
  			if (script_namespace)
  			    semsg(_(e_cannot_declare_script_variable_in_function),
  								lhs->lhs_name);
  			else
  			    semsg(_(e_variable_already_declared_in_script),
  								lhs->lhs_name);
  			return FAIL;
  		    }
  		    else if (cctx->ctx_ufunc->uf_script_ctx_version
  							 == SCRIPT_VERSION_VIM9
  				    && script_namespace
  				    && !script_var && import == NULL)
  		    {
  			semsg(_(e_unknown_variable_str), lhs->lhs_name);
  			return FAIL;
  		    }
  
  		    lhs->lhs_dest = dest_script;
  
  		    // existing script-local variables should have a type
  		    lhs->lhs_scriptvar_sid = current_sctx.sc_sid;
  		    if (import != NULL)
  			lhs->lhs_scriptvar_sid = import->imp_sid;
  		    if (SCRIPT_ID_VALID(lhs->lhs_scriptvar_sid))
  		    {
  			// Check writable only when no index follows.
  			lhs->lhs_scriptvar_idx = get_script_item_idx(
  					       lhs->lhs_scriptvar_sid, rawname,
  			      lhs->lhs_has_index ? ASSIGN_FINAL : ASSIGN_CONST,
  									 cctx);
  			if (lhs->lhs_scriptvar_idx >= 0)
  			{
  			    scriptitem_T *si = SCRIPT_ITEM(
  						       lhs->lhs_scriptvar_sid);
  			    svar_T	 *sv =
  					    ((svar_T *)si->sn_var_vals.ga_data)
  						      + lhs->lhs_scriptvar_idx;
  			    lhs->lhs_type = sv->sv_type;
  			}
  		    }
  		}
  		else if (check_defined(var_start, lhs->lhs_varlen, cctx)
  								       == FAIL)
  		    return FAIL;
  	    }
  	}
  
  	if (declare_error)
  	{
  	    vim9_declare_error(lhs->lhs_name);
  	    return FAIL;
  	}
      }
  
      // handle "a:name" as a name, not index "name" on "a"
      if (lhs->lhs_varlen > 1 || var_start[lhs->lhs_varlen] != ':')
  	var_end = lhs->lhs_dest_end;
  
      if (lhs->lhs_dest != dest_option)
      {
  	if (is_decl && *var_end == ':')
  	{
  	    char_u *p;
  
  	    // parse optional type: "let var: type = expr"
  	    if (!VIM_ISWHITE(var_end[1]))
  	    {
  		semsg(_(e_white_space_required_after_str), ":");
  		return FAIL;
  	    }
  	    p = skipwhite(var_end + 1);
  	    lhs->lhs_type = parse_type(&p, cctx->ctx_type_list, TRUE);
  	    if (lhs->lhs_type == NULL)
  		return FAIL;
  	    lhs->lhs_has_type = TRUE;
  	}
  	else if (lhs->lhs_lvar != NULL)
  	    lhs->lhs_type = lhs->lhs_lvar->lv_type;
      }
  
      if (oplen == 3 && !heredoc && lhs->lhs_dest != dest_global
  		    && lhs->lhs_type->tt_type != VAR_STRING
  		    && lhs->lhs_type->tt_type != VAR_ANY)
      {
  	emsg(_(e_can_only_concatenate_to_string));
  	return FAIL;
      }
  
      if (lhs->lhs_lvar == NULL && lhs->lhs_dest == dest_local
  						 && cctx->ctx_skip != SKIP_YES)
      {
  	if (oplen > 1 && !heredoc)
  	{
  	    // +=, /=, etc. require an existing variable
  	    semsg(_(e_cannot_use_operator_on_new_variable), lhs->lhs_name);
  	    return FAIL;
  	}
  	if (!is_decl)
  	{
  	    semsg(_(e_unknown_variable_str), lhs->lhs_name);
  	    return FAIL;
  	}
  
  	// new local variable
  	if ((lhs->lhs_type->tt_type == VAR_FUNC
  				      || lhs->lhs_type->tt_type == VAR_PARTIAL)
  				   && var_wrong_func_name(lhs->lhs_name, TRUE))
  	    return FAIL;
  	lhs->lhs_lvar = reserve_local(cctx, var_start, lhs->lhs_varlen,
  		    cmdidx == CMD_final || cmdidx == CMD_const, lhs->lhs_type);
  	if (lhs->lhs_lvar == NULL)
  	    return FAIL;
  	lhs->lhs_new_local = TRUE;
      }
  
      lhs->lhs_member_type = lhs->lhs_type;
      if (lhs->lhs_has_index)
      {
  	// Something follows after the variable: "var[idx]" or "var.key".
  	// TODO: should we also handle "->func()" here?
  	if (is_decl)
  	{
  	    emsg(_(e_cannot_use_index_when_declaring_variable));
  	    return FAIL;
  	}
  
  	if (var_start[lhs->lhs_varlen] == '['
  					  || var_start[lhs->lhs_varlen] == '.')
  	{
  	    char_u	*after = var_start + lhs->lhs_varlen;
  	    char_u	*p;
  
  	    // Only the last index is used below, if there are others
  	    // before it generate code for the expression.  Thus for
  	    // "ll[1][2]" the expression is "ll[1]" and "[2]" is the index.
  	    for (;;)
  	    {
  		p = skip_index(after);
  		if (*p != '[' && *p != '.')
  		    break;
  		after = p;
  	    }
  	    if (after > var_start + lhs->lhs_varlen)
  	    {
  		lhs->lhs_varlen = after - var_start;
  		lhs->lhs_dest = dest_expr;
  		// We don't know the type before evaluating the expression,
  		// use "any" until then.
  		lhs->lhs_type = &t_any;
  	    }
  
  	    if (lhs->lhs_type->tt_member == NULL)
  		lhs->lhs_member_type = &t_any;
  	    else
  		lhs->lhs_member_type = lhs->lhs_type->tt_member;
  	}
  	else
  	{
  	    semsg("Not supported yet: %s", var_start);
  	    return FAIL;
  	}
      }
      return OK;
  }
  
  /*
   * Assignment to a list or dict member, or ":unlet" for the item, using the
   * information in "lhs".
   * Returns OK or FAIL.
   */
      static int
  compile_assign_unlet(
  	char_u	*var_start,
  	lhs_T	*lhs,
  	int	is_assign,
  	type_T	*rhs_type,
  	cctx_T	*cctx)
  {
      char_u	*p;
      int		r;
      vartype_T	dest_type;
      size_t	varlen = lhs->lhs_varlen;
      garray_T    *stack = &cctx->ctx_type_stack;
  
      // Compile the "idx" in "var[idx]" or "key" in "var.key".
      p = var_start + varlen;
      if (*p == '[')
      {
  	p = skipwhite(p + 1);
  	r = compile_expr0(&p, cctx);
  	if (r == OK && *skipwhite(p) != ']')
  	{
  	    // this should not happen
  	    emsg(_(e_missbrac));
  	    r = FAIL;
  	}
      }
      else // if (*p == '.')
      {
  	char_u *key_end = to_name_end(p + 1, TRUE);
  	char_u *key = vim_strnsave(p + 1, key_end - p - 1);
  
  	r = generate_PUSHS(cctx, key);
      }
      if (r == FAIL)
  	return FAIL;
  
      if (lhs->lhs_type == &t_any)
      {
  	// Index on variable of unknown type: check at runtime.
  	dest_type = VAR_ANY;
      }
      else
      {
  	dest_type = lhs->lhs_type->tt_type;
  	if (dest_type == VAR_DICT && may_generate_2STRING(-1, cctx) == FAIL)
  	    return FAIL;
  	if (dest_type == VAR_LIST
  		&& need_type(((type_T **)stack->ga_data)[stack->ga_len - 1],
  				 &t_number, -1, 0, cctx, FALSE, FALSE) == FAIL)
  	    return FAIL;
      }
  
      // Load the dict or list.  On the stack we then have:
      // - value (for assignment, not for :unlet)
      // - index
      // - variable
      if (lhs->lhs_dest == dest_expr)
      {
  	int	    c = var_start[varlen];
  
  	// Evaluate "ll[expr]" of "ll[expr][idx]"
  	p = var_start;
  	var_start[varlen] = NUL;
  	if (compile_expr0(&p, cctx) == OK && p != var_start + varlen)
  	{
  	    // this should not happen
  	    emsg(_(e_missbrac));
  	    return FAIL;
  	}
  	var_start[varlen] = c;
  
  	lhs->lhs_type = stack->ga_len == 0 ? &t_void
  		  : ((type_T **)stack->ga_data)[stack->ga_len - 1];
  	// now we can properly check the type
  	if (lhs->lhs_type->tt_member != NULL && rhs_type != &t_void
  		&& need_type(rhs_type, lhs->lhs_type->tt_member, -2, 0, cctx,
  							 FALSE, FALSE) == FAIL)
  	    return FAIL;
      }
      else
  	generate_loadvar(cctx, lhs->lhs_dest, lhs->lhs_name,
  						 lhs->lhs_lvar, lhs->lhs_type);
  
      if (dest_type == VAR_LIST || dest_type == VAR_DICT || dest_type == VAR_ANY)
      {
  	if (is_assign)
  	{
  	    isn_T	*isn = generate_instr_drop(cctx, ISN_STOREINDEX, 3);
  
  	    if (isn == NULL)
  		return FAIL;
  	    isn->isn_arg.vartype = dest_type;
  	}
  	else
  	{
  	    if (generate_instr_drop(cctx, ISN_UNLETINDEX, 2) == NULL)
  		return FAIL;
  	}
      }
      else
      {
  	emsg(_(e_indexable_type_required));
  	return FAIL;
      }
  
      return OK;
  }
  
  /*
   * Compile declaration and assignment:
   * "let name"
   * "var name = expr"
   * "final name = expr"
   * "const name = expr"
   * "name = expr"
   * "arg" points to "name".
   * Return NULL for an error.
   * Return "arg" if it does not look like a variable list.
   */
      static char_u *
  compile_assignment(char_u *arg, exarg_T *eap, cmdidx_T cmdidx, cctx_T *cctx)
  {
      char_u	*var_start;
      char_u	*p;
      char_u	*end = arg;
      char_u	*ret = NULL;
      int		var_count = 0;
      int		var_idx;
      int		semicolon = 0;
      garray_T	*instr = &cctx->ctx_instr;
      garray_T    *stack = &cctx->ctx_type_stack;
      char_u	*op;
      int		oplen = 0;
      int		heredoc = FALSE;
      type_T	*rhs_type = &t_any;
      char_u	*sp;
      int		is_decl = is_decl_command(cmdidx);
      lhs_T	lhs;
  
      // Skip over the "var" or "[var, var]" to get to any "=".
      p = skip_var_list(arg, TRUE, &var_count, &semicolon, TRUE);
      if (p == NULL)
  	return *arg == '[' ? arg : NULL;
  
      if (var_count > 0 && is_decl)
      {
  	// TODO: should we allow this, and figure out type inference from list
  	// members?
  	emsg(_(e_cannot_use_list_for_declaration));
  	return NULL;
      }
      lhs.lhs_name = NULL;
  
      sp = p;
      p = skipwhite(p);
      op = p;
      oplen = assignment_len(p, &heredoc);
  
      if (var_count > 0 && oplen == 0)
  	// can be something like "[1, 2]->func()"
  	return arg;
  
      if (oplen > 0 && (!VIM_ISWHITE(*sp) || !IS_WHITE_OR_NUL(op[oplen])))
      {
  	error_white_both(op, oplen);
  	return NULL;
      }
  
      if (heredoc)
      {
  	list_T	   *l;
  	listitem_T *li;
  
  	// [let] varname =<< [trim] {end}
  	eap->getline = exarg_getline;
  	eap->cookie = cctx;
  	l = heredoc_get(eap, op + 3, FALSE);
  	if (l == NULL)
  	    return NULL;
  
  	if (cctx->ctx_skip != SKIP_YES)
  	{
  	    // Push each line and the create the list.
  	    FOR_ALL_LIST_ITEMS(l, li)
  	    {
  		generate_PUSHS(cctx, li->li_tv.vval.v_string);
  		li->li_tv.vval.v_string = NULL;
  	    }
  	    generate_NEWLIST(cctx, l->lv_len);
  	}
  	list_free(l);
  	p += STRLEN(p);
  	end = p;
      }
      else if (var_count > 0)
      {
  	char_u *wp;
  
  	// for "[var, var] = expr" evaluate the expression here, loop over the
  	// list of variables below.
  	// A line break may follow the "=".
  
  	wp = op + oplen;
  	if (may_get_next_line_error(wp, &p, cctx) == FAIL)
  	    return FAIL;
  	if (compile_expr0(&p, cctx) == FAIL)
  	    return NULL;
  	end = p;
  
  	if (cctx->ctx_skip != SKIP_YES)
  	{
  	    type_T	*stacktype;
  
  	    stacktype = stack->ga_len == 0 ? &t_void
  			      : ((type_T **)stack->ga_data)[stack->ga_len - 1];
  	    if (stacktype->tt_type == VAR_VOID)
  	    {
  		emsg(_(e_cannot_use_void_value));
  		goto theend;
  	    }
  	    if (need_type(stacktype, &t_list_any, -1, 0, cctx,
  							 FALSE, FALSE) == FAIL)
  		goto theend;
  	    // TODO: check the length of a constant list here
  	    generate_CHECKLEN(cctx, semicolon ? var_count - 1 : var_count,
  								    semicolon);
  	    if (stacktype->tt_member != NULL)
  		rhs_type = stacktype->tt_member;
  	}
      }
  
      /*
       * Loop over variables in "[var, var] = expr".
       * For "var = expr" and "let var: type" this is done only once.
       */
      if (var_count > 0)
  	var_start = skipwhite(arg + 1);  // skip over the "["
      else
  	var_start = arg;
      for (var_idx = 0; var_idx == 0 || var_idx < var_count; var_idx++)
      {
  	int		instr_count = -1;
  
  	vim_free(lhs.lhs_name);
  
  	/*
  	 * Figure out the LHS type and other properties.
  	 */
  	if (compile_lhs(var_start, &lhs, cmdidx, heredoc, oplen, cctx) == FAIL)
  	    goto theend;
  
  	if (!lhs.lhs_has_index && lhs.lhs_lvar == &lhs.lhs_arg_lvar)
  	{
  	    semsg(_(e_cannot_assign_to_argument), lhs.lhs_name);
  	    goto theend;
  	}
  	if (!is_decl && lhs.lhs_lvar != NULL
  			       && lhs.lhs_lvar->lv_const && !lhs.lhs_has_index)
  	{
  	    semsg(_(e_cannot_assign_to_constant), lhs.lhs_name);
  	    goto theend;
  	}
  
  	if (!heredoc)
  	{
  	    if (cctx->ctx_skip == SKIP_YES)
  	    {
  		if (oplen > 0 && var_count == 0)
  		{
  		    // skip over the "=" and the expression
  		    p = skipwhite(op + oplen);
  		    compile_expr0(&p, cctx);
  		}
  	    }
  	    else if (oplen > 0)
  	    {
  		int	is_const = FALSE;
  		char_u	*wp;
  
  		// For "var = expr" evaluate the expression.
  		if (var_count == 0)
  		{
  		    int	r;
  
  		    // for "+=", "*=", "..=" etc. first load the current value
  		    if (*op != '=')
  		    {
  			generate_loadvar(cctx, lhs.lhs_dest, lhs.lhs_name,
  						   lhs.lhs_lvar, lhs.lhs_type);
  
  			if (lhs.lhs_has_index)
  			{
  			    // TODO: get member from list or dict
  			    emsg("Index with operation not supported yet");
  			    goto theend;
  			}
  		    }
  
  		    // Compile the expression.  Temporarily hide the new local
  		    // variable here, it is not available to this expression.
  		    if (lhs.lhs_new_local)
  			--cctx->ctx_locals.ga_len;
  		    instr_count = instr->ga_len;
  		    wp = op + oplen;
  		    if (may_get_next_line_error(wp, &p, cctx) == FAIL)
  		    {
  			if (lhs.lhs_new_local)
  			    ++cctx->ctx_locals.ga_len;
  			goto theend;
  		    }
  		    r = compile_expr0_ext(&p, cctx, &is_const);
  		    if (lhs.lhs_new_local)
  			++cctx->ctx_locals.ga_len;
  		    if (r == FAIL)
  			goto theend;
  		}
  		else if (semicolon && var_idx == var_count - 1)
  		{
  		    // For "[var; var] = expr" get the rest of the list
  		    if (generate_SLICE(cctx, var_count - 1) == FAIL)
  			goto theend;
  		}
  		else
  		{
  		    // For "[var, var] = expr" get the "var_idx" item from the
  		    // list.
  		    if (generate_GETITEM(cctx, var_idx) == FAIL)
  			goto theend;
  		}
  
  		rhs_type = stack->ga_len == 0 ? &t_void
  			      : ((type_T **)stack->ga_data)[stack->ga_len - 1];
  		if (lhs.lhs_lvar != NULL && (is_decl || !lhs.lhs_has_type))
  		{
  		    if ((rhs_type->tt_type == VAR_FUNC
  				|| rhs_type->tt_type == VAR_PARTIAL)
  			    && var_wrong_func_name(lhs.lhs_name, TRUE))
  			goto theend;
  
  		    if (lhs.lhs_new_local && !lhs.lhs_has_type)
  		    {
  			if (rhs_type->tt_type == VAR_VOID)
  			{
  			    emsg(_(e_cannot_use_void_value));
  			    goto theend;
  			}
  			else
  			{
  			    // An empty list or dict has a &t_unknown member,
  			    // for a variable that implies &t_any.
  			    if (rhs_type == &t_list_empty)
  				lhs.lhs_lvar->lv_type = &t_list_any;
  			    else if (rhs_type == &t_dict_empty)
  				lhs.lhs_lvar->lv_type = &t_dict_any;
  			    else if (rhs_type == &t_unknown)
  				lhs.lhs_lvar->lv_type = &t_any;
  			    else
  				lhs.lhs_lvar->lv_type = rhs_type;
  			}
  		    }
  		    else if (*op == '=')
  		    {
  			type_T *use_type = lhs.lhs_lvar->lv_type;
  
  			// without operator check type here, otherwise below
  			if (lhs.lhs_has_index)
  			    use_type = lhs.lhs_member_type;
  			if (need_type(rhs_type, use_type, -1, 0, cctx,
  						      FALSE, is_const) == FAIL)
  			    goto theend;
  		    }
  		}
  		else if (*p != '=' && need_type(rhs_type, lhs.lhs_member_type,
  					    -1, 0, cctx, FALSE, FALSE) == FAIL)
  		    goto theend;
  	    }
  	    else if (cmdidx == CMD_final)
  	    {
  		emsg(_(e_final_requires_a_value));
  		goto theend;
  	    }
  	    else if (cmdidx == CMD_const)
  	    {
  		emsg(_(e_const_requires_a_value));
  		goto theend;
  	    }
  	    else if (!lhs.lhs_has_type || lhs.lhs_dest == dest_option)
  	    {
  		emsg(_(e_type_or_initialization_required));
  		goto theend;
  	    }
  	    else
  	    {
  		// variables are always initialized
  		if (ga_grow(instr, 1) == FAIL)
  		    goto theend;
  		switch (lhs.lhs_member_type->tt_type)
  		{
  		    case VAR_BOOL:
  			generate_PUSHBOOL(cctx, VVAL_FALSE);
  			break;
  		    case VAR_FLOAT:
  #ifdef FEAT_FLOAT
  			generate_PUSHF(cctx, 0.0);
  #endif
  			break;
  		    case VAR_STRING:
  			generate_PUSHS(cctx, NULL);
  			break;
  		    case VAR_BLOB:
  			generate_PUSHBLOB(cctx, blob_alloc());
  			break;
  		    case VAR_FUNC:
  			generate_PUSHFUNC(cctx, NULL, &t_func_void);
  			break;
  		    case VAR_LIST:
  			generate_NEWLIST(cctx, 0);
  			break;
  		    case VAR_DICT:
  			generate_NEWDICT(cctx, 0);
  			break;
  		    case VAR_JOB:
  			generate_PUSHJOB(cctx, NULL);
  			break;
  		    case VAR_CHANNEL:
  			generate_PUSHCHANNEL(cctx, NULL);
  			break;
  		    case VAR_NUMBER:
  		    case VAR_UNKNOWN:
  		    case VAR_ANY:
  		    case VAR_PARTIAL:
  		    case VAR_VOID:
  		    case VAR_SPECIAL:  // cannot happen
  			generate_PUSHNR(cctx, 0);
  			break;
  		}
  	    }
  	    if (var_count == 0)
  		end = p;
  	}
  
  	// no need to parse more when skipping
  	if (cctx->ctx_skip == SKIP_YES)
  	    break;
  
  	if (oplen > 0 && *op != '=')
  	{
  	    type_T	    *expected;
  	    type_T	    *stacktype;
  
  	    if (*op == '.')
  		expected = &t_string;
  	    else
  		expected = lhs.lhs_member_type;
  	    stacktype = ((type_T **)stack->ga_data)[stack->ga_len - 1];
  	    if (
  #ifdef FEAT_FLOAT
  		// If variable is float operation with number is OK.
  		!(expected == &t_float && stacktype == &t_number) &&
  #endif
  		    need_type(stacktype, expected, -1, 0, cctx,
  							 FALSE, FALSE) == FAIL)
  		goto theend;
  
  	    if (*op == '.')
  	    {
  		if (generate_instr_drop(cctx, ISN_CONCAT, 1) == NULL)
  		    goto theend;
  	    }
  	    else if (*op == '+')
  	    {
  		if (generate_add_instr(cctx,
  			    operator_type(lhs.lhs_member_type, stacktype),
  				       lhs.lhs_member_type, stacktype) == FAIL)
  		    goto theend;
  	    }
  	    else if (generate_two_op(cctx, op) == FAIL)
  		goto theend;
  	}
  
  	if (lhs.lhs_has_index)
  	{
  	    // Use the info in "lhs" to store the value at the index in the
  	    // list or dict.
  	    if (compile_assign_unlet(var_start, &lhs, TRUE, rhs_type, cctx)
  								       == FAIL)
  		goto theend;
  	}
  	else
  	{
  	    if (is_decl && cmdidx == CMD_const && (lhs.lhs_dest == dest_script
  						|| lhs.lhs_dest == dest_local))
  		// ":const var": lock the value, but not referenced variables
  		generate_LOCKCONST(cctx);
  
  	    if (is_decl
  		    && (lhs.lhs_type->tt_type == VAR_DICT
  					  || lhs.lhs_type->tt_type == VAR_LIST)
  		    && lhs.lhs_type->tt_member != NULL
  		    && lhs.lhs_type->tt_member != &t_any
  		    && lhs.lhs_type->tt_member != &t_unknown)
  		// Set the type in the list or dict, so that it can be checked,
  		// also in legacy script.
  		generate_SETTYPE(cctx, lhs.lhs_type);
  
  	    if (lhs.lhs_dest != dest_local)
  	    {
  		if (generate_store_var(cctx, lhs.lhs_dest,
  			    lhs.lhs_opt_flags, lhs.lhs_vimvaridx,
  			    lhs.lhs_scriptvar_idx, lhs.lhs_scriptvar_sid,
  					   lhs.lhs_type, lhs.lhs_name) == FAIL)
  		    goto theend;
  	    }
  	    else if (lhs.lhs_lvar != NULL)
  	    {
  		isn_T *isn = ((isn_T *)instr->ga_data)
  						   + instr->ga_len - 1;
  
  		// optimization: turn "var = 123" from ISN_PUSHNR +
  		// ISN_STORE into ISN_STORENR
  		if (lhs.lhs_lvar->lv_from_outer == 0
  				&& instr->ga_len == instr_count + 1
  				&& isn->isn_type == ISN_PUSHNR)
  		{
  		    varnumber_T val = isn->isn_arg.number;
  
  		    isn->isn_type = ISN_STORENR;
  		    isn->isn_arg.storenr.stnr_idx = lhs.lhs_lvar->lv_idx;
  		    isn->isn_arg.storenr.stnr_val = val;
  		    if (stack->ga_len > 0)
  			--stack->ga_len;
  		}
  		else if (lhs.lhs_lvar->lv_from_outer > 0)
  		    generate_STOREOUTER(cctx, lhs.lhs_lvar->lv_idx,
  						  lhs.lhs_lvar->lv_from_outer);
  		else
  		    generate_STORE(cctx, ISN_STORE, lhs.lhs_lvar->lv_idx, NULL);
  	    }
  	}
  
  	if (var_idx + 1 < var_count)
  	    var_start = skipwhite(lhs.lhs_dest_end + 1);
      }
  
      // for "[var, var] = expr" drop the "expr" value
      if (var_count > 0 && !semicolon)
      {
  	if (generate_instr_drop(cctx, ISN_DROP, 1) == NULL)
  	    goto theend;
      }
  
      ret = skipwhite(end);
  
  theend:
      vim_free(lhs.lhs_name);
      return ret;
  }
  
  /*
   * Check for an assignment at "eap->cmd", compile it if found.
   * Return NOTDONE if there is none, FAIL for failure, OK if done.
   */
      static int
  may_compile_assignment(exarg_T *eap, char_u **line, cctx_T *cctx)
  {
      char_u  *pskip;
      char_u  *p;
  
      // Assuming the command starts with a variable or function name,
      // find what follows.
      // Skip over "var.member", "var[idx]" and the like.
      // Also "&opt = val", "$ENV = val" and "@r = val".
      pskip = (*eap->cmd == '&' || *eap->cmd == '$' || *eap->cmd == '@')
  						 ? eap->cmd + 1 : eap->cmd;
      p = to_name_end(pskip, TRUE);
      if (p > eap->cmd && *p != NUL)
      {
  	char_u *var_end;
  	int	oplen;
  	int	heredoc;
  
  	if (eap->cmd[0] == '@')
  	    var_end = eap->cmd + 2;
  	else
  	    var_end = find_name_end(pskip, NULL, NULL,
  					FNE_CHECK_START | FNE_INCL_BR);
  	oplen = assignment_len(skipwhite(var_end), &heredoc);
  	if (oplen > 0)
  	{
  	    size_t len = p - eap->cmd;
  
  	    // Recognize an assignment if we recognize the variable
  	    // name:
  	    // "g:var = expr"
  	    // "local = expr"  where "local" is a local var.
  	    // "script = expr"  where "script" is a script-local var.
  	    // "import = expr"  where "import" is an imported var
  	    // "&opt = expr"
  	    // "$ENV = expr"
  	    // "@r = expr"
  	    if (*eap->cmd == '&'
  		    || *eap->cmd == '$'
  		    || *eap->cmd == '@'
  		    || ((len) > 2 && eap->cmd[1] == ':')
  		    || lookup_local(eap->cmd, len, NULL, cctx) == OK
  		    || arg_exists(eap->cmd, len, NULL, NULL, NULL, cctx) == OK
  		    || script_var_exists(eap->cmd, len, FALSE, cctx) == OK
  		    || find_imported(eap->cmd, len, cctx) != NULL)
  	    {
  		*line = compile_assignment(eap->cmd, eap, CMD_SIZE, cctx);
  		if (*line == NULL || *line == eap->cmd)
  		    return FAIL;
  		return OK;
  	    }
  	}
      }
  
      if (*eap->cmd == '[')
      {
  	// [var, var] = expr
  	*line = compile_assignment(eap->cmd, eap, CMD_SIZE, cctx);
  	if (*line == NULL)
  	    return FAIL;
  	if (*line != eap->cmd)
  	    return OK;
      }
      return NOTDONE;
  }
  
  /*
   * Check if "name" can be "unlet".
   */
      int
  check_vim9_unlet(char_u *name)
  {
      if (name[1] != ':' || vim_strchr((char_u *)"gwtb", *name) == NULL)
      {
  	// "unlet s:var" is allowed in legacy script.
  	if (*name == 's' && !script_is_vim9())
  	    return OK;
  	semsg(_(e_cannot_unlet_str), name);
  	return FAIL;
      }
      return OK;
  }
  
  /*
   * Callback passed to ex_unletlock().
   */
      static int
  compile_unlet(
      lval_T  *lvp,
      char_u  *name_end,
      exarg_T *eap,
      int	    deep UNUSED,
      void    *coookie)
  {
      cctx_T	*cctx = coookie;
      char_u	*p = lvp->ll_name;
      int		cc = *name_end;
      int		ret = OK;
  
      if (cctx->ctx_skip == SKIP_YES)
  	return OK;
  
      *name_end = NUL;
      if (*p == '$')
      {
  	// :unlet $ENV_VAR
  	ret = generate_UNLET(cctx, ISN_UNLETENV, p + 1, eap->forceit);
      }
      else if (vim_strchr(p, '.') != NULL || vim_strchr(p, '[') != NULL)
      {
  	lhs_T	    lhs;
  
  	// This is similar to assigning: lookup the list/dict, compile the
  	// idx/key.  Then instead of storing the value unlet the item.
  	// unlet {list}[idx]
  	// unlet {dict}[key]  dict.key
  	//
  	// Figure out the LHS type and other properties.
  	//
  	ret = compile_lhs(p, &lhs, CMD_unlet, FALSE, 0, cctx);
  
  	// : unlet an indexed item
  	if (!lhs.lhs_has_index)
  	{
  	    iemsg("called compile_lhs() without an index");
  	    ret = FAIL;
  	}
  	else
  	{
  	    // Use the info in "lhs" to unlet the item at the index in the
  	    // list or dict.
  	    ret = compile_assign_unlet(p, &lhs, FALSE, &t_void, cctx);
  	}
  
  	vim_free(lhs.lhs_name);
      }
      else if (check_vim9_unlet(p) == FAIL)
      {
  	ret = FAIL;
      }
      else
      {
  	// Normal name.  Only supports g:, w:, t: and b: namespaces.
  	ret = generate_UNLET(cctx, ISN_UNLET, p, eap->forceit);
      }
  
      *name_end = cc;
      return ret;
  }
  
  /*
   * compile "unlet var", "lock var" and "unlock var"
   * "arg" points to "var".
   */
      static char_u *
  compile_unletlock(char_u *arg, exarg_T *eap, cctx_T *cctx)
  {
      char_u *p = arg;
  
      if (eap->cmdidx != CMD_unlet)
      {
  	emsg("Sorry, :lock and unlock not implemented yet");
  	return NULL;
      }
  
      ex_unletlock(eap, p, 0, GLV_NO_AUTOLOAD | GLV_COMPILING,
  							  compile_unlet, cctx);
      return eap->nextcmd == NULL ? (char_u *)"" : eap->nextcmd;
  }
  
  /*
   * Compile an :import command.
   */
      static char_u *
  compile_import(char_u *arg, cctx_T *cctx)
  {
      return handle_import(arg, &cctx->ctx_imports, 0, NULL, cctx);
  }
  
  /*
   * generate a jump to the ":endif"/":endfor"/":endwhile"/":finally"/":endtry".
   */
      static int
  compile_jump_to_end(endlabel_T **el, jumpwhen_T when, cctx_T *cctx)
  {
      garray_T	*instr = &cctx->ctx_instr;
      endlabel_T  *endlabel = ALLOC_CLEAR_ONE(endlabel_T);
  
      if (endlabel == NULL)
  	return FAIL;
      endlabel->el_next = *el;
      *el = endlabel;
      endlabel->el_end_label = instr->ga_len;
  
      generate_JUMP(cctx, when, 0);
      return OK;
  }
  
      static void
  compile_fill_jump_to_end(endlabel_T **el, cctx_T *cctx)
  {
      garray_T	*instr = &cctx->ctx_instr;
  
      while (*el != NULL)
      {
  	endlabel_T  *cur = (*el);
  	isn_T	    *isn;
  
  	isn = ((isn_T *)instr->ga_data) + cur->el_end_label;
  	isn->isn_arg.jump.jump_where = instr->ga_len;
  	*el = cur->el_next;
  	vim_free(cur);
      }
  }
  
      static void
  compile_free_jump_to_end(endlabel_T **el)
  {
      while (*el != NULL)
      {
  	endlabel_T  *cur = (*el);
  
  	*el = cur->el_next;
  	vim_free(cur);
      }
  }
  
  /*
   * Create a new scope and set up the generic items.
   */
      static scope_T *
  new_scope(cctx_T *cctx, scopetype_T type)
  {
      scope_T *scope = ALLOC_CLEAR_ONE(scope_T);
  
      if (scope == NULL)
  	return NULL;
      scope->se_outer = cctx->ctx_scope;
      cctx->ctx_scope = scope;
      scope->se_type = type;
      scope->se_local_count = cctx->ctx_locals.ga_len;
      return scope;
  }
  
  /*
   * Free the current scope and go back to the outer scope.
   */
      static void
  drop_scope(cctx_T *cctx)
  {
      scope_T *scope = cctx->ctx_scope;
  
      if (scope == NULL)
      {
  	iemsg("calling drop_scope() without a scope");
  	return;
      }
      cctx->ctx_scope = scope->se_outer;
      switch (scope->se_type)
      {
  	case IF_SCOPE:
  	    compile_free_jump_to_end(&scope->se_u.se_if.is_end_label); break;
  	case FOR_SCOPE:
  	    compile_free_jump_to_end(&scope->se_u.se_for.fs_end_label); break;
  	case WHILE_SCOPE:
  	    compile_free_jump_to_end(&scope->se_u.se_while.ws_end_label); break;
  	case TRY_SCOPE:
  	    compile_free_jump_to_end(&scope->se_u.se_try.ts_end_label); break;
  	case NO_SCOPE:
  	case BLOCK_SCOPE:
  	    break;
      }
      vim_free(scope);
  }
  
  /*
   * compile "if expr"
   *
   * "if expr" Produces instructions:
   *	EVAL expr		Push result of "expr"
   *	JUMP_IF_FALSE end
   *	... body ...
   * end:
   *
   * "if expr | else" Produces instructions:
   *	EVAL expr		Push result of "expr"
   *	JUMP_IF_FALSE else
   *	... body ...
   *	JUMP_ALWAYS end
   * else:
   *	... body ...
   * end:
   *
   * "if expr1 | elseif expr2 | else" Produces instructions:
   *	EVAL expr		Push result of "expr"
   *	JUMP_IF_FALSE elseif
   *	... body ...
   *	JUMP_ALWAYS end
   * elseif:
   *	EVAL expr		Push result of "expr"
   *	JUMP_IF_FALSE else
   *	... body ...
   *	JUMP_ALWAYS end
   * else:
   *	... body ...
   * end:
   */
      static char_u *
  compile_if(char_u *arg, cctx_T *cctx)
  {
      char_u	*p = arg;
      garray_T	*instr = &cctx->ctx_instr;
      int		instr_count = instr->ga_len;
      scope_T	*scope;
      skip_T	skip_save = cctx->ctx_skip;
      ppconst_T	ppconst;
  
      CLEAR_FIELD(ppconst);
      if (compile_expr1(&p, cctx, &ppconst) == FAIL)
      {
  	clear_ppconst(&ppconst);
  	return NULL;
      }
      if (cctx->ctx_skip == SKIP_YES)
  	clear_ppconst(&ppconst);
      else if (instr->ga_len == instr_count && ppconst.pp_used == 1)
      {
  	int error = FALSE;
  	int v;
  
  	// The expression results in a constant.
  	v = tv_get_bool_chk(&ppconst.pp_tv[0], &error);
  	clear_ppconst(&ppconst);
  	if (error)
  	    return NULL;
  	cctx->ctx_skip = v ? SKIP_NOT : SKIP_YES;
      }
      else
      {
  	// Not a constant, generate instructions for the expression.
  	cctx->ctx_skip = SKIP_UNKNOWN;
  	if (generate_ppconst(cctx, &ppconst) == FAIL)
  	    return NULL;
  	if (bool_on_stack(cctx) == FAIL)
  	    return NULL;
      }
  
      scope = new_scope(cctx, IF_SCOPE);
      if (scope == NULL)
  	return NULL;
      scope->se_skip_save = skip_save;
      // "is_had_return" will be reset if any block does not end in :return
      scope->se_u.se_if.is_had_return = TRUE;
  
      if (cctx->ctx_skip == SKIP_UNKNOWN)
      {
  	// "where" is set when ":elseif", "else" or ":endif" is found
  	scope->se_u.se_if.is_if_label = instr->ga_len;
  	generate_JUMP(cctx, JUMP_IF_FALSE, 0);
      }
      else
  	scope->se_u.se_if.is_if_label = -1;
  
      return p;
  }
  
      static char_u *
  compile_elseif(char_u *arg, cctx_T *cctx)
  {
      char_u	*p = arg;
      garray_T	*instr = &cctx->ctx_instr;
      int		instr_count = instr->ga_len;
      isn_T	*isn;
      scope_T	*scope = cctx->ctx_scope;
      ppconst_T	ppconst;
      skip_T	save_skip = cctx->ctx_skip;
  
      if (scope == NULL || scope->se_type != IF_SCOPE)
      {
  	emsg(_(e_elseif_without_if));
  	return NULL;
      }
      unwind_locals(cctx, scope->se_local_count);
      if (!cctx->ctx_had_return)
  	scope->se_u.se_if.is_had_return = FALSE;
  
      if (cctx->ctx_skip == SKIP_UNKNOWN)
      {
  	if (compile_jump_to_end(&scope->se_u.se_if.is_end_label,
  						    JUMP_ALWAYS, cctx) == FAIL)
  	    return NULL;
  	// previous "if" or "elseif" jumps here
  	isn = ((isn_T *)instr->ga_data) + scope->se_u.se_if.is_if_label;
  	isn->isn_arg.jump.jump_where = instr->ga_len;
      }
  
      // compile "expr"; if we know it evaluates to FALSE skip the block
      CLEAR_FIELD(ppconst);
      if (cctx->ctx_skip == SKIP_YES)
  	cctx->ctx_skip = SKIP_UNKNOWN;
      if (compile_expr1(&p, cctx, &ppconst) == FAIL)
      {
  	clear_ppconst(&ppconst);
  	return NULL;
      }
      cctx->ctx_skip = save_skip;
      if (scope->se_skip_save == SKIP_YES)
  	clear_ppconst(&ppconst);
      else if (instr->ga_len == instr_count && ppconst.pp_used == 1)
      {
  	int error = FALSE;
  	int v;
  
  	// The expression results in a constant.
  	// TODO: how about nesting?
  	v = tv_get_bool_chk(&ppconst.pp_tv[0], &error);
  	if (error)
  	    return NULL;
  	cctx->ctx_skip = v ? SKIP_NOT : SKIP_YES;
  	clear_ppconst(&ppconst);
  	scope->se_u.se_if.is_if_label = -1;
      }
      else
      {
  	// Not a constant, generate instructions for the expression.
  	cctx->ctx_skip = SKIP_UNKNOWN;
  	if (generate_ppconst(cctx, &ppconst) == FAIL)
  	    return NULL;
  	if (bool_on_stack(cctx) == FAIL)
  	    return NULL;
  
  	// "where" is set when ":elseif", "else" or ":endif" is found
  	scope->se_u.se_if.is_if_label = instr->ga_len;
  	generate_JUMP(cctx, JUMP_IF_FALSE, 0);
      }
  
      return p;
  }
  
      static char_u *
  compile_else(char_u *arg, cctx_T *cctx)
  {
      char_u	*p = arg;
      garray_T	*instr = &cctx->ctx_instr;
      isn_T	*isn;
      scope_T	*scope = cctx->ctx_scope;
  
      if (scope == NULL || scope->se_type != IF_SCOPE)
      {
  	emsg(_(e_else_without_if));
  	return NULL;
      }
      unwind_locals(cctx, scope->se_local_count);
      if (!cctx->ctx_had_return)
  	scope->se_u.se_if.is_had_return = FALSE;
      scope->se_u.se_if.is_seen_else = TRUE;
  
      if (scope->se_skip_save != SKIP_YES)
      {
  	// jump from previous block to the end, unless the else block is empty
  	if (cctx->ctx_skip == SKIP_UNKNOWN)
  	{
  	    if (!cctx->ctx_had_return
  		    && compile_jump_to_end(&scope->se_u.se_if.is_end_label,
  						    JUMP_ALWAYS, cctx) == FAIL)
  		return NULL;
  	}
  
  	if (cctx->ctx_skip == SKIP_UNKNOWN)
  	{
  	    if (scope->se_u.se_if.is_if_label >= 0)
  	    {
  		// previous "if" or "elseif" jumps here
  		isn = ((isn_T *)instr->ga_data) + scope->se_u.se_if.is_if_label;
  		isn->isn_arg.jump.jump_where = instr->ga_len;
  		scope->se_u.se_if.is_if_label = -1;
  	    }
  	}
  
  	if (cctx->ctx_skip != SKIP_UNKNOWN)
  	    cctx->ctx_skip = cctx->ctx_skip == SKIP_YES ? SKIP_NOT : SKIP_YES;
      }
  
      return p;
  }
  
      static char_u *
  compile_endif(char_u *arg, cctx_T *cctx)
  {
      scope_T	*scope = cctx->ctx_scope;
      ifscope_T	*ifscope;
      garray_T	*instr = &cctx->ctx_instr;
      isn_T	*isn;
  
      if (scope == NULL || scope->se_type != IF_SCOPE)
      {
  	emsg(_(e_endif_without_if));
  	return NULL;
      }
      ifscope = &scope->se_u.se_if;
      unwind_locals(cctx, scope->se_local_count);
      if (!cctx->ctx_had_return)
  	ifscope->is_had_return = FALSE;
  
      if (scope->se_u.se_if.is_if_label >= 0)
      {
  	// previous "if" or "elseif" jumps here
  	isn = ((isn_T *)instr->ga_data) + scope->se_u.se_if.is_if_label;
  	isn->isn_arg.jump.jump_where = instr->ga_len;
      }
      // Fill in the "end" label in jumps at the end of the blocks.
      compile_fill_jump_to_end(&ifscope->is_end_label, cctx);
      cctx->ctx_skip = scope->se_skip_save;
  
      // If all the blocks end in :return and there is an :else then the
      // had_return flag is set.
      cctx->ctx_had_return = ifscope->is_had_return && ifscope->is_seen_else;
  
      drop_scope(cctx);
      return arg;
  }
  
  /*
   * Compile "for var in expr":
   *
   * Produces instructions:
   *       PUSHNR -1
   *       STORE loop-idx		Set index to -1
   *       EVAL expr		result of "expr" on top of stack
   * top:  FOR loop-idx, end	Increment index, use list on bottom of stack
   *				- if beyond end, jump to "end"
   *				- otherwise get item from list and push it
   *       STORE var		Store item in "var"
   *       ... body ...
   *       JUMP top		Jump back to repeat
   * end:	 DROP			Drop the result of "expr"
   *
   * Compile "for [var1, var2] in expr" - as above, but instead of "STORE var":
   *	 UNPACK 2		Split item in 2
   *       STORE var1		Store item in "var1"
   *       STORE var2		Store item in "var2"
   */
      static char_u *
  compile_for(char_u *arg_start, cctx_T *cctx)
  {
      char_u	*arg;
      char_u	*arg_end;
      char_u	*name = NULL;
      char_u	*p;
      char_u	*wp;
      int		var_count = 0;
      int		semicolon = FALSE;
      size_t	varlen;
      garray_T	*instr = &cctx->ctx_instr;
      garray_T	*stack = &cctx->ctx_type_stack;
      scope_T	*scope;
      lvar_T	*loop_lvar;	// loop iteration variable
      lvar_T	*var_lvar;	// variable for "var"
      type_T	*vartype;
      type_T	*item_type = &t_any;
      int		idx;
  
      p = skip_var_list(arg_start, TRUE, &var_count, &semicolon, FALSE);
      if (p == NULL)
  	return NULL;
      if (var_count == 0)
  	var_count = 1;
  
      // consume "in"
      wp = p;
      if (may_get_next_line_error(wp, &p, cctx) == FAIL)
  	return NULL;
      if (STRNCMP(p, "in", 2) != 0 || !IS_WHITE_OR_NUL(p[2]))
      {
  	emsg(_(e_missing_in));
  	return NULL;
      }
      wp = p + 2;
      if (may_get_next_line_error(wp, &p, cctx) == FAIL)
  	return NULL;
  
      scope = new_scope(cctx, FOR_SCOPE);
      if (scope == NULL)
  	return NULL;
  
      // Reserve a variable to store the loop iteration counter and initialize it
      // to -1.
      loop_lvar = reserve_local(cctx, (char_u *)"", 0, FALSE, &t_number);
      if (loop_lvar == NULL)
      {
  	// out of memory
  	drop_scope(cctx);
  	return NULL;
      }
      generate_STORENR(cctx, loop_lvar->lv_idx, -1);
  
      // compile "expr", it remains on the stack until "endfor"
      arg = p;
      if (compile_expr0(&arg, cctx) == FAIL)
      {
  	drop_scope(cctx);
  	return NULL;
      }
      arg_end = arg;
  
      // Now that we know the type of "var", check that it is a list, now or at
      // runtime.
      vartype = ((type_T **)stack->ga_data)[stack->ga_len - 1];
      if (need_type(vartype, &t_list_any, -1, 0, cctx, FALSE, FALSE) == FAIL)
      {
  	drop_scope(cctx);
  	return NULL;
      }
  
      if (vartype->tt_type == VAR_LIST && vartype->tt_member->tt_type != VAR_ANY)
      {
  	if (var_count == 1)
  	    item_type = vartype->tt_member;
  	else if (vartype->tt_member->tt_type == VAR_LIST
  		      && vartype->tt_member->tt_member->tt_type != VAR_ANY)
  	    item_type = vartype->tt_member->tt_member;
      }
  
      // "for_end" is set when ":endfor" is found
      scope->se_u.se_for.fs_top_label = instr->ga_len;
      generate_FOR(cctx, loop_lvar->lv_idx);
  
      arg = arg_start;
      if (var_count > 1)
      {
  	generate_UNPACK(cctx, var_count, semicolon);
  	arg = skipwhite(arg + 1);	// skip white after '['
  
  	// the list item is replaced by a number of items
  	if (ga_grow(stack, var_count - 1) == FAIL)
  	{
  	    drop_scope(cctx);
  	    return NULL;
  	}
  	--stack->ga_len;
  	for (idx = 0; idx < var_count; ++idx)
  	{
  	    ((type_T **)stack->ga_data)[stack->ga_len] =
  				(semicolon && idx == 0) ? vartype : item_type;
  	    ++stack->ga_len;
  	}
      }
  
      for (idx = 0; idx < var_count; ++idx)
      {
  	assign_dest_T	dest = dest_local;
  	int		opt_flags = 0;
  	int		vimvaridx = -1;
  	type_T		*type = &t_any;
  
  	p = skip_var_one(arg, FALSE);
  	varlen = p - arg;
  	name = vim_strnsave(arg, varlen);
  	if (name == NULL)
  	    goto failed;
  
  	// TODO: script var not supported?
  	if (get_var_dest(name, &dest, CMD_for, &opt_flags,
  					      &vimvaridx, &type, cctx) == FAIL)
  	    goto failed;
  	if (dest != dest_local)
  	{
  	    if (generate_store_var(cctx, dest, opt_flags, vimvaridx,
  						     0, 0, type, name) == FAIL)
  		goto failed;
  	}
  	else
  	{
  	    if (lookup_local(arg, varlen, NULL, cctx) == OK)
  	    {
  		semsg(_(e_variable_already_declared), arg);
  		goto failed;
  	    }
  
  	    if (STRNCMP(name, "s:", 2) == 0)
  	    {
  		semsg(_(e_cannot_declare_script_variable_in_function), name);
  		goto failed;
  	    }
  
  	    // Reserve a variable to store "var".
  	    // TODO: check for type
  	    var_lvar = reserve_local(cctx, arg, varlen, FALSE, &t_any);
  	    if (var_lvar == NULL)
  		// out of memory or used as an argument
  		goto failed;
  
  	    if (semicolon && idx == var_count - 1)
  		var_lvar->lv_type = vartype;
  	    else
  		var_lvar->lv_type = item_type;
  	    generate_STORE(cctx, ISN_STORE, var_lvar->lv_idx, NULL);
  	}
  
  	if (*p == ':')
  	    p = skip_type(skipwhite(p + 1), FALSE);
  	if (*p == ',' || *p == ';')
  	    ++p;
  	arg = skipwhite(p);
  	vim_free(name);
      }
  
      return arg_end;
  
  failed:
      vim_free(name);
      drop_scope(cctx);
      return NULL;
  }
  
  /*
   * compile "endfor"
   */
      static char_u *
  compile_endfor(char_u *arg, cctx_T *cctx)
  {
      garray_T	*instr = &cctx->ctx_instr;
      scope_T	*scope = cctx->ctx_scope;
      forscope_T	*forscope;
      isn_T	*isn;
  
      if (scope == NULL || scope->se_type != FOR_SCOPE)
      {
  	emsg(_(e_for));
  	return NULL;
      }
      forscope = &scope->se_u.se_for;
      cctx->ctx_scope = scope->se_outer;
      unwind_locals(cctx, scope->se_local_count);
  
      // At end of ":for" scope jump back to the FOR instruction.
      generate_JUMP(cctx, JUMP_ALWAYS, forscope->fs_top_label);
  
      // Fill in the "end" label in the FOR statement so it can jump here
      isn = ((isn_T *)instr->ga_data) + forscope->fs_top_label;
      isn->isn_arg.forloop.for_end = instr->ga_len;
  
      // Fill in the "end" label any BREAK statements
      compile_fill_jump_to_end(&forscope->fs_end_label, cctx);
  
      // Below the ":for" scope drop the "expr" list from the stack.
      if (generate_instr_drop(cctx, ISN_DROP, 1) == NULL)
  	return NULL;
  
      vim_free(scope);
  
      return arg;
  }
  
  /*
   * compile "while expr"
   *
   * Produces instructions:
   * top:  EVAL expr		Push result of "expr"
   *       JUMP_IF_FALSE end	jump if false
   *       ... body ...
   *       JUMP top		Jump back to repeat
   * end:
   *
   */
      static char_u *
  compile_while(char_u *arg, cctx_T *cctx)
  {
      char_u	*p = arg;
      garray_T	*instr = &cctx->ctx_instr;
      scope_T	*scope;
  
      scope = new_scope(cctx, WHILE_SCOPE);
      if (scope == NULL)
  	return NULL;
  
      scope->se_u.se_while.ws_top_label = instr->ga_len;
  
      // compile "expr"
      if (compile_expr0(&p, cctx) == FAIL)
  	return NULL;
  
      if (bool_on_stack(cctx) == FAIL)
  	return FAIL;
  
      // "while_end" is set when ":endwhile" is found
      if (compile_jump_to_end(&scope->se_u.se_while.ws_end_label,
  						  JUMP_IF_FALSE, cctx) == FAIL)
  	return FAIL;
  
      return p;
  }
  
  /*
   * compile "endwhile"
   */
      static char_u *
  compile_endwhile(char_u *arg, cctx_T *cctx)
  {
      scope_T	*scope = cctx->ctx_scope;
  
      if (scope == NULL || scope->se_type != WHILE_SCOPE)
      {
  	emsg(_(e_while));
  	return NULL;
      }
      cctx->ctx_scope = scope->se_outer;
      unwind_locals(cctx, scope->se_local_count);
  
      // At end of ":for" scope jump back to the FOR instruction.
      generate_JUMP(cctx, JUMP_ALWAYS, scope->se_u.se_while.ws_top_label);
  
      // Fill in the "end" label in the WHILE statement so it can jump here.
      // And in any jumps for ":break"
      compile_fill_jump_to_end(&scope->se_u.se_while.ws_end_label, cctx);
  
      vim_free(scope);
  
      return arg;
  }
  
  /*
   * compile "continue"
   */
      static char_u *
  compile_continue(char_u *arg, cctx_T *cctx)
  {
      scope_T	*scope = cctx->ctx_scope;
  
      for (;;)
      {
  	if (scope == NULL)
  	{
  	    emsg(_(e_continue));
  	    return NULL;
  	}
  	if (scope->se_type == FOR_SCOPE || scope->se_type == WHILE_SCOPE)
  	    break;
  	scope = scope->se_outer;
      }
  
      // Jump back to the FOR or WHILE instruction.
      generate_JUMP(cctx, JUMP_ALWAYS,
  	    scope->se_type == FOR_SCOPE ? scope->se_u.se_for.fs_top_label
  					  : scope->se_u.se_while.ws_top_label);
      return arg;
  }
  
  /*
   * compile "break"
   */
      static char_u *
  compile_break(char_u *arg, cctx_T *cctx)
  {
      scope_T	*scope = cctx->ctx_scope;
      endlabel_T	**el;
  
      for (;;)
      {
  	if (scope == NULL)
  	{
  	    emsg(_(e_break));
  	    return NULL;
  	}
  	if (scope->se_type == FOR_SCOPE || scope->se_type == WHILE_SCOPE)
  	    break;
  	scope = scope->se_outer;
      }
  
      // Jump to the end of the FOR or WHILE loop.
      if (scope->se_type == FOR_SCOPE)
  	el = &scope->se_u.se_for.fs_end_label;
      else
  	el = &scope->se_u.se_while.ws_end_label;
      if (compile_jump_to_end(el, JUMP_ALWAYS, cctx) == FAIL)
  	return FAIL;
  
      return arg;
  }
  
  /*
   * compile "{" start of block
   */
      static char_u *
  compile_block(char_u *arg, cctx_T *cctx)
  {
      if (new_scope(cctx, BLOCK_SCOPE) == NULL)
  	return NULL;
      return skipwhite(arg + 1);
  }
  
  /*
   * compile end of block: drop one scope
   */
      static void
  compile_endblock(cctx_T *cctx)
  {
      scope_T	*scope = cctx->ctx_scope;
  
      cctx->ctx_scope = scope->se_outer;
      unwind_locals(cctx, scope->se_local_count);
      vim_free(scope);
  }
  
  /*
   * compile "try"
   * Creates a new scope for the try-endtry, pointing to the first catch and
   * finally.
   * Creates another scope for the "try" block itself.
   * TRY instruction sets up exception handling at runtime.
   *
   *	"try"
   *	    TRY -> catch1, -> finally  push trystack entry
   *	    ... try block
   *	"throw {exception}"
   *	    EVAL {exception}
   *	    THROW		create exception
   *	    ... try block
   *	" catch {expr}"
   *	    JUMP -> finally
   * catch1:  PUSH exception
   *	    EVAL {expr}
   *	    MATCH
   *	    JUMP nomatch -> catch2
   *	    CATCH   remove exception
   *	    ... catch block
   *	" catch"
   *	    JUMP -> finally
   * catch2:  CATCH   remove exception
   *	    ... catch block
   *	" finally"
   * finally:
   *	    ... finally block
   *	" endtry"
   *	    ENDTRY  pop trystack entry, may rethrow
   */
      static char_u *
  compile_try(char_u *arg, cctx_T *cctx)
  {
      garray_T	*instr = &cctx->ctx_instr;
      scope_T	*try_scope;
      scope_T	*scope;
  
      // scope that holds the jumps that go to catch/finally/endtry
      try_scope = new_scope(cctx, TRY_SCOPE);
      if (try_scope == NULL)
  	return NULL;
  
      if (cctx->ctx_skip != SKIP_YES)
      {
  	// "catch" is set when the first ":catch" is found.
  	// "finally" is set when ":finally" or ":endtry" is found
  	try_scope->se_u.se_try.ts_try_label = instr->ga_len;
  	if (generate_instr(cctx, ISN_TRY) == NULL)
  	    return NULL;
      }
  
      // scope for the try block itself
      scope = new_scope(cctx, BLOCK_SCOPE);
      if (scope == NULL)
  	return NULL;
  
      return arg;
  }
  
  /*
   * compile "catch {expr}"
   */
      static char_u *
  compile_catch(char_u *arg, cctx_T *cctx UNUSED)
  {
      scope_T	*scope = cctx->ctx_scope;
      garray_T	*instr = &cctx->ctx_instr;
      char_u	*p;
      isn_T	*isn;
  
      // end block scope from :try or :catch
      if (scope != NULL && scope->se_type == BLOCK_SCOPE)
  	compile_endblock(cctx);
      scope = cctx->ctx_scope;
  
      // Error if not in a :try scope
      if (scope == NULL || scope->se_type != TRY_SCOPE)
      {
  	emsg(_(e_catch));
  	return NULL;
      }
  
      if (scope->se_u.se_try.ts_caught_all)
      {
  	emsg(_(e_catch_unreachable_after_catch_all));
  	return NULL;
      }
  
      if (cctx->ctx_skip != SKIP_YES)
      {
  	// Jump from end of previous block to :finally or :endtry
  	if (compile_jump_to_end(&scope->se_u.se_try.ts_end_label,
  						    JUMP_ALWAYS, cctx) == FAIL)
  	    return NULL;
  
  	// End :try or :catch scope: set value in ISN_TRY instruction
  	isn = ((isn_T *)instr->ga_data) + scope->se_u.se_try.ts_try_label;
  	if (isn->isn_arg.try.try_catch == 0)
  	    isn->isn_arg.try.try_catch = instr->ga_len;
  	if (scope->se_u.se_try.ts_catch_label != 0)
  	{
  	    // Previous catch without match jumps here
  	    isn = ((isn_T *)instr->ga_data) + scope->se_u.se_try.ts_catch_label;
  	    isn->isn_arg.jump.jump_where = instr->ga_len;
  	}
      }
  
      p = skipwhite(arg);
      if (ends_excmd2(arg, p))
      {
  	scope->se_u.se_try.ts_caught_all = TRUE;
  	scope->se_u.se_try.ts_catch_label = 0;
      }
      else
      {
  	char_u *end;
  	char_u *pat;
  	char_u *tofree = NULL;
  	int	dropped = 0;
  	int	len;
  
  	// Push v:exception, push {expr} and MATCH
  	generate_instr_type(cctx, ISN_PUSHEXC, &t_string);
  
  	end = skip_regexp_ex(p + 1, *p, TRUE, &tofree, &dropped, NULL);
  	if (*end != *p)
  	{
  	    semsg(_(e_separator_mismatch_str), p);
  	    vim_free(tofree);
  	    return FAIL;
  	}
  	if (tofree == NULL)
  	    len = (int)(end - (p + 1));
  	else
  	    len = (int)(end - tofree);
  	pat = vim_strnsave(tofree == NULL ? p + 1 : tofree, len);
  	vim_free(tofree);
  	p += len + 2 + dropped;
  	if (pat == NULL)
  	    return FAIL;
  	if (generate_PUSHS(cctx, pat) == FAIL)
  	    return FAIL;
  
  	if (generate_COMPARE(cctx, EXPR_MATCH, FALSE) == FAIL)
  	    return NULL;
  
  	scope->se_u.se_try.ts_catch_label = instr->ga_len;
  	if (generate_JUMP(cctx, JUMP_IF_FALSE, 0) == FAIL)
  	    return NULL;
      }
  
      if (cctx->ctx_skip != SKIP_YES && generate_instr(cctx, ISN_CATCH) == NULL)
  	return NULL;
  
      if (new_scope(cctx, BLOCK_SCOPE) == NULL)
  	return NULL;
      return p;
  }
  
      static char_u *
  compile_finally(char_u *arg, cctx_T *cctx)
  {
      scope_T	*scope = cctx->ctx_scope;
      garray_T	*instr = &cctx->ctx_instr;
      isn_T	*isn;
  
      // end block scope from :try or :catch
      if (scope != NULL && scope->se_type == BLOCK_SCOPE)
  	compile_endblock(cctx);
      scope = cctx->ctx_scope;
  
      // Error if not in a :try scope
      if (scope == NULL || scope->se_type != TRY_SCOPE)
      {
  	emsg(_(e_finally));
  	return NULL;
      }
  
      // End :catch or :finally scope: set value in ISN_TRY instruction
      isn = ((isn_T *)instr->ga_data) + scope->se_u.se_try.ts_try_label;
      if (isn->isn_arg.try.try_finally != 0)
      {
  	emsg(_(e_finally_dup));
  	return NULL;
      }
  
      // Fill in the "end" label in jumps at the end of the blocks.
      compile_fill_jump_to_end(&scope->se_u.se_try.ts_end_label, cctx);
  
      isn->isn_arg.try.try_finally = instr->ga_len;
      if (scope->se_u.se_try.ts_catch_label != 0)
      {
  	// Previous catch without match jumps here
  	isn = ((isn_T *)instr->ga_data) + scope->se_u.se_try.ts_catch_label;
  	isn->isn_arg.jump.jump_where = instr->ga_len;
  	scope->se_u.se_try.ts_catch_label = 0;
      }
  
      // TODO: set index in ts_finally_label jumps
  
      return arg;
  }
  
      static char_u *
  compile_endtry(char_u *arg, cctx_T *cctx)
  {
      scope_T	*scope = cctx->ctx_scope;
      garray_T	*instr = &cctx->ctx_instr;
      isn_T	*isn;
  
      // end block scope from :catch or :finally
      if (scope != NULL && scope->se_type == BLOCK_SCOPE)
  	compile_endblock(cctx);
      scope = cctx->ctx_scope;
  
      // Error if not in a :try scope
      if (scope == NULL || scope->se_type != TRY_SCOPE)
      {
  	if (scope == NULL)
  	    emsg(_(e_no_endtry));
  	else if (scope->se_type == WHILE_SCOPE)
  	    emsg(_(e_endwhile));
  	else if (scope->se_type == FOR_SCOPE)
  	    emsg(_(e_endfor));
  	else
  	    emsg(_(e_endif));
  	return NULL;
      }
  
      if (cctx->ctx_skip != SKIP_YES)
      {
  	isn = ((isn_T *)instr->ga_data) + scope->se_u.se_try.ts_try_label;
  	if (isn->isn_arg.try.try_catch == 0
  					  && isn->isn_arg.try.try_finally == 0)
  	{
  	    emsg(_(e_missing_catch_or_finally));
  	    return NULL;
  	}
  
  	// Fill in the "end" label in jumps at the end of the blocks, if not
  	// done by ":finally".
  	compile_fill_jump_to_end(&scope->se_u.se_try.ts_end_label, cctx);
  
  	// End :catch or :finally scope: set value in ISN_TRY instruction
  	if (isn->isn_arg.try.try_catch == 0)
  	    isn->isn_arg.try.try_catch = instr->ga_len;
  	if (isn->isn_arg.try.try_finally == 0)
  	    isn->isn_arg.try.try_finally = instr->ga_len;
  
  	if (scope->se_u.se_try.ts_catch_label != 0)
  	{
  	    // Last catch without match jumps here
  	    isn = ((isn_T *)instr->ga_data) + scope->se_u.se_try.ts_catch_label;
  	    isn->isn_arg.jump.jump_where = instr->ga_len;
  	}
      }
  
      compile_endblock(cctx);
  
      if (cctx->ctx_skip != SKIP_YES && generate_instr(cctx, ISN_ENDTRY) == NULL)
  	return NULL;
      return arg;
  }
  
  /*
   * compile "throw {expr}"
   */
      static char_u *
  compile_throw(char_u *arg, cctx_T *cctx UNUSED)
  {
      char_u *p = skipwhite(arg);
  
      if (compile_expr0(&p, cctx) == FAIL)
  	return NULL;
      if (cctx->ctx_skip == SKIP_YES)
  	return p;
      if (may_generate_2STRING(-1, cctx) == FAIL)
  	return NULL;
      if (generate_instr_drop(cctx, ISN_THROW, 1) == NULL)
  	return NULL;
  
      return p;
  }
  
  /*
   * compile "echo expr"
   * compile "echomsg expr"
   * compile "echoerr expr"
   * compile "execute expr"
   */
      static char_u *
  compile_mult_expr(char_u *arg, int cmdidx, cctx_T *cctx)
  {
      char_u	*p = arg;
      char_u	*prev = arg;
      int		count = 0;
  
      for (;;)
      {
  	if (ends_excmd2(prev, p))
  	    break;
  	if (compile_expr0(&p, cctx) == FAIL)
  	    return NULL;
  	++count;
  	prev = p;
  	p = skipwhite(p);
      }
  
      if (count > 0)
      {
  	if (cmdidx == CMD_echo || cmdidx == CMD_echon)
  	    generate_ECHO(cctx, cmdidx == CMD_echo, count);
  	else if (cmdidx == CMD_execute)
  	    generate_MULT_EXPR(cctx, ISN_EXECUTE, count);
  	else if (cmdidx == CMD_echomsg)
  	    generate_MULT_EXPR(cctx, ISN_ECHOMSG, count);
  	else
  	    generate_MULT_EXPR(cctx, ISN_ECHOERR, count);
      }
      return p;
  }
  
  /*
   * If "eap" has a range that is not a constant generate an ISN_RANGE
   * instruction to compute it and return OK.
   * Otherwise return FAIL, the caller must deal with any range.
   */
      static int
  compile_variable_range(exarg_T *eap, cctx_T *cctx)
  {
      char_u *range_end = skip_range(eap->cmd, TRUE, NULL);
      char_u *p = skipdigits(eap->cmd);
  
      if (p == range_end)
  	return FAIL;
      return generate_RANGE(cctx, vim_strnsave(eap->cmd, range_end - eap->cmd));
  }
  
  /*
   * :put r
   * :put ={expr}
   */
      static char_u *
  compile_put(char_u *arg, exarg_T *eap, cctx_T *cctx)
  {
      char_u	*line = arg;
      linenr_T	lnum;
      char	*errormsg;
      int		above = eap->forceit;
  
      eap->regname = *line;
  
      if (eap->regname == '=')
      {
  	char_u *p = line + 1;
  
  	if (compile_expr0(&p, cctx) == FAIL)
  	    return NULL;
  	line = p;
      }
      else if (eap->regname != NUL)
  	++line;
  
      if (compile_variable_range(eap, cctx) == OK)
      {
  	lnum = above ? LNUM_VARIABLE_RANGE_ABOVE : LNUM_VARIABLE_RANGE;
      }
      else
      {
  	// Either no range or a number.
  	// "errormsg" will not be set because the range is ADDR_LINES.
  	if (parse_cmd_address(eap, &errormsg, FALSE) == FAIL)
  	    // cannot happen
  	    return NULL;
  	if (eap->addr_count == 0)
  	    lnum = -1;
  	else
  	    lnum = eap->line2;
  	if (above)
  	    --lnum;
      }
  
      generate_PUT(cctx, eap->regname, lnum);
      return line;
  }
  
  /*
   * A command that is not compiled, execute with legacy code.
   */
      static char_u *
  compile_exec(char_u *line, exarg_T *eap, cctx_T *cctx)
  {
      char_u  *p;
      int	    has_expr = FALSE;
      char_u  *nextcmd = (char_u *)"";
  
      if (cctx->ctx_skip == SKIP_YES)
  	goto theend;
  
      if (eap->cmdidx >= 0 && eap->cmdidx < CMD_SIZE)
      {
  	long	argt = eap->argt;
  	int	usefilter = FALSE;
  
  	has_expr = argt & (EX_XFILE | EX_EXPAND);
  
  	// If the command can be followed by a bar, find the bar and truncate
  	// it, so that the following command can be compiled.
  	// The '|' is overwritten with a NUL, it is put back below.
  	if ((eap->cmdidx == CMD_write || eap->cmdidx == CMD_read)
  							   && *eap->arg == '!')
  	    // :w !filter or :r !filter or :r! filter
  	    usefilter = TRUE;
  	if ((argt & EX_TRLBAR) && !usefilter)
  	{
  	    eap->argt = argt;
  	    separate_nextcmd(eap);
  	    if (eap->nextcmd != NULL)
  		nextcmd = eap->nextcmd;
  	}
  	else if (eap->cmdidx == CMD_wincmd)
  	{
  	    p = eap->arg;
  	    if (*p != NUL)
  		++p;
  	    if (*p == 'g' || *p == Ctrl_G)
  		++p;
  	    p = skipwhite(p);
  	    if (*p == '|')
  	    {
  		*p = NUL;
  		nextcmd = p + 1;
  	    }
  	}
      }
  
      if (eap->cmdidx == CMD_syntax && STRNCMP(eap->arg, "include ", 8) == 0)
      {
  	// expand filename in "syntax include [@group] filename"
  	has_expr = TRUE;
  	eap->arg = skipwhite(eap->arg + 7);
  	if (*eap->arg == '@')
  	    eap->arg = skiptowhite(eap->arg);
      }
  
      if ((eap->cmdidx == CMD_global || eap->cmdidx == CMD_vglobal)
  						       && STRLEN(eap->arg) > 4)
      {
  	int delim = *eap->arg;
  
  	p = skip_regexp_ex(eap->arg + 1, delim, TRUE, NULL, NULL, NULL);
  	if (*p == delim)
  	{
  	    eap->arg = p + 1;
  	    has_expr = TRUE;
  	}
      }
  
      if (eap->cmdidx == CMD_folddoopen || eap->cmdidx == CMD_folddoclosed)
      {
  	// TODO: should only expand when appropriate for the command
  	eap->arg = skiptowhite(eap->arg);
  	has_expr = TRUE;
      }
  
      if (has_expr && (p = (char_u *)strstr((char *)eap->arg, "`=")) != NULL)
      {
  	int	count = 0;
  	char_u	*start = skipwhite(line);
  
  	// :cmd xxx`=expr1`yyy`=expr2`zzz
  	// PUSHS ":cmd xxx"
  	// eval expr1
  	// PUSHS "yyy"
  	// eval expr2
  	// PUSHS "zzz"
  	// EXECCONCAT 5
  	for (;;)
  	{
  	    if (p > start)
  	    {
  		generate_PUSHS(cctx, vim_strnsave(start, p - start));
  		++count;
  	    }
  	    p += 2;
  	    if (compile_expr0(&p, cctx) == FAIL)
  		return NULL;
  	    may_generate_2STRING(-1, cctx);
  	    ++count;
  	    p = skipwhite(p);
  	    if (*p != '`')
  	    {
  		emsg(_(e_missing_backtick));
  		return NULL;
  	    }
  	    start = p + 1;
  
  	    p = (char_u *)strstr((char *)start, "`=");
  	    if (p == NULL)
  	    {
  		if (*skipwhite(start) != NUL)
  		{
  		    generate_PUSHS(cctx, vim_strsave(start));
  		    ++count;
  		}
  		break;
  	    }
  	}
  	generate_EXECCONCAT(cctx, count);
      }
      else
  	generate_EXEC(cctx, line);
  
  theend:
      if (*nextcmd != NUL)
      {
  	// the parser expects a pointer to the bar, put it back
  	--nextcmd;
  	*nextcmd = '|';
      }
  
      return nextcmd;
  }
  
  /*
   * Add a function to the list of :def functions.
   * This sets "ufunc->uf_dfunc_idx" but the function isn't compiled yet.
   */
      static int
  add_def_function(ufunc_T *ufunc)
  {
      dfunc_T *dfunc;
  
      if (def_functions.ga_len == 0)
      {
  	// The first position is not used, so that a zero uf_dfunc_idx means it
  	// wasn't set.
  	if (ga_grow(&def_functions, 1) == FAIL)
  	    return FAIL;
  	++def_functions.ga_len;
      }
  
      // Add the function to "def_functions".
      if (ga_grow(&def_functions, 1) == FAIL)
  	return FAIL;
      dfunc = ((dfunc_T *)def_functions.ga_data) + def_functions.ga_len;
      CLEAR_POINTER(dfunc);
      dfunc->df_idx = def_functions.ga_len;
      ufunc->uf_dfunc_idx = dfunc->df_idx;
      dfunc->df_ufunc = ufunc;
      dfunc->df_name = vim_strsave(ufunc->uf_name);
      ++dfunc->df_refcount;
      ++def_functions.ga_len;
      return OK;
  }
  
  /*
   * After ex_function() has collected all the function lines: parse and compile
   * the lines into instructions.
   * Adds the function to "def_functions".
   * When "check_return_type" is set then set ufunc->uf_ret_type to the type of
   * the return statement (used for lambda).  When uf_ret_type is already set
   * then check that it matches.
   * "outer_cctx" is set for a nested function.
   * This can be used recursively through compile_lambda(), which may reallocate
   * "def_functions".
   * Returns OK or FAIL.
   */
      int
  compile_def_function(ufunc_T *ufunc, int check_return_type, cctx_T *outer_cctx)
  {
      char_u	*line = NULL;
      char_u	*p;
      char	*errormsg = NULL;	// error message
      cctx_T	cctx;
      garray_T	*instr;
      int		did_emsg_before = did_emsg;
      int		ret = FAIL;
      sctx_T	save_current_sctx = current_sctx;
      int		save_estack_compiling = estack_compiling;
      int		do_estack_push;
      int		new_def_function = FALSE;
  
      // When using a function that was compiled before: Free old instructions.
      // The index is reused.  Otherwise add a new entry in "def_functions".
      if (ufunc->uf_dfunc_idx > 0)
      {
  	dfunc_T *dfunc = ((dfunc_T *)def_functions.ga_data)
  							 + ufunc->uf_dfunc_idx;
  	delete_def_function_contents(dfunc, FALSE);
      }
      else
      {
  	if (add_def_function(ufunc) == FAIL)
  	    return FAIL;
  	new_def_function = TRUE;
      }
  
      ufunc->uf_def_status = UF_COMPILING;
  
      CLEAR_FIELD(cctx);
      cctx.ctx_ufunc = ufunc;
      cctx.ctx_lnum = -1;
      cctx.ctx_outer = outer_cctx;
      ga_init2(&cctx.ctx_locals, sizeof(lvar_T), 10);
      ga_init2(&cctx.ctx_type_stack, sizeof(type_T *), 50);
      ga_init2(&cctx.ctx_imports, sizeof(imported_T), 10);
      cctx.ctx_type_list = &ufunc->uf_type_list;
      ga_init2(&cctx.ctx_instr, sizeof(isn_T), 50);
      instr = &cctx.ctx_instr;
  
      // Set the context to the function, it may be compiled when called from
      // another script.  Set the script version to the most modern one.
      // The line number will be set in next_line_from_context().
      current_sctx = ufunc->uf_script_ctx;
      current_sctx.sc_version = SCRIPT_VERSION_VIM9;
  
      // Make sure error messages are OK.
      do_estack_push = !estack_top_is_ufunc(ufunc, 1);
      if (do_estack_push)
  	estack_push_ufunc(ufunc, 1);
      estack_compiling = TRUE;
  
      if (ufunc->uf_def_args.ga_len > 0)
      {
  	int	count = ufunc->uf_def_args.ga_len;
  	int	first_def_arg = ufunc->uf_args.ga_len - count;
  	int	i;
  	char_u	*arg;
  	int	off = STACK_FRAME_SIZE + (ufunc->uf_va_name != NULL ? 1 : 0);
  	int	did_set_arg_type = FALSE;
  
  	// Produce instructions for the default values of optional arguments.
  	// Store the instruction index in uf_def_arg_idx[] so that we know
  	// where to start when the function is called, depending on the number
  	// of arguments.
  	ufunc->uf_def_arg_idx = ALLOC_CLEAR_MULT(int, count + 1);
  	if (ufunc->uf_def_arg_idx == NULL)
  	    goto erret;
  	for (i = 0; i < count; ++i)
  	{
  	    garray_T	*stack = &cctx.ctx_type_stack;
  	    type_T	*val_type;
  	    int		arg_idx = first_def_arg + i;
  
  	    ufunc->uf_def_arg_idx[i] = instr->ga_len;
  	    arg = ((char_u **)(ufunc->uf_def_args.ga_data))[i];
  	    if (compile_expr0(&arg, &cctx) == FAIL)
  		goto erret;
  
  	    // If no type specified use the type of the default value.
  	    // Otherwise check that the default value type matches the
  	    // specified type.
  	    val_type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
  	    if (ufunc->uf_arg_types[arg_idx] == &t_unknown)
  	    {
  		did_set_arg_type = TRUE;
  		ufunc->uf_arg_types[arg_idx] = val_type;
  	    }
  	    else if (check_type(ufunc->uf_arg_types[arg_idx], val_type,
  						    TRUE, arg_idx + 1) == FAIL)
  		goto erret;
  
  	    if (generate_STORE(&cctx, ISN_STORE, i - count - off, NULL) == FAIL)
  		goto erret;
  	}
  	ufunc->uf_def_arg_idx[count] = instr->ga_len;
  
  	if (did_set_arg_type)
  	    set_function_type(ufunc);
      }
  
      /*
       * Loop over all the lines of the function and generate instructions.
       */
      for (;;)
      {
  	exarg_T	    ea;
  	int	    starts_with_colon = FALSE;
  	char_u	    *cmd;
  	cmdmod_T    local_cmdmod;
  
  	// Bail out on the first error to avoid a flood of errors and report
  	// the right line number when inside try/catch.
  	if (did_emsg_before != did_emsg)
  	    goto erret;
  
  	if (line != NULL && *line == '|')
  	    // the line continues after a '|'
  	    ++line;
  	else if (line != NULL && *skipwhite(line) != NUL
  		&& !(*line == '#' && (line == cctx.ctx_line_start
  						    || VIM_ISWHITE(line[-1]))))
  	{
  	    semsg(_(e_trailing_arg), line);
  	    goto erret;
  	}
  	else
  	{
  	    line = next_line_from_context(&cctx, FALSE);
  	    if (cctx.ctx_lnum >= ufunc->uf_lines.ga_len)
  		// beyond the last line
  		break;
  	}
  
  	CLEAR_FIELD(ea);
  	ea.cmdlinep = &line;
  	ea.cmd = skipwhite(line);
  
  	// Some things can be recognized by the first character.
  	switch (*ea.cmd)
  	{
  	    case '#':
  		// "#" starts a comment
  		line = (char_u *)"";
  		continue;
  
  	    case '}':
  		{
  		    // "}" ends a block scope
  		    scopetype_T stype = cctx.ctx_scope == NULL
  					  ? NO_SCOPE : cctx.ctx_scope->se_type;
  
  		    if (stype == BLOCK_SCOPE)
  		    {
  			compile_endblock(&cctx);
  			line = ea.cmd;
  		    }
  		    else
  		    {
  			emsg(_(e_using_rcurly_outside_if_block_scope));
  			goto erret;
  		    }
  		    if (line != NULL)
  			line = skipwhite(ea.cmd + 1);
  		    continue;
  		}
  
  	    case '{':
  		// "{" starts a block scope
  		// "{'a': 1}->func() is something else
  		if (ends_excmd(*skipwhite(ea.cmd + 1)))
  		{
  		    line = compile_block(ea.cmd, &cctx);
  		    continue;
  		}
  		break;
  	}
  
  	/*
  	 * COMMAND MODIFIERS
  	 */
  	cctx.ctx_has_cmdmod = FALSE;
  	if (parse_command_modifiers(&ea, &errormsg, &local_cmdmod, FALSE)
  								       == FAIL)
  	{
  	    if (errormsg != NULL)
  		goto erret;
  	    // empty line or comment
  	    line = (char_u *)"";
  	    continue;
  	}
  	generate_cmdmods(&cctx, &local_cmdmod);
  	undo_cmdmod(&local_cmdmod);
  
  	// Check if there was a colon after the last command modifier or before
  	// the current position.
  	for (p = ea.cmd; p >= line; --p)
  	{
  	    if (*p == ':')
  		starts_with_colon = TRUE;
  	    if (p < ea.cmd && !VIM_ISWHITE(*p))
  		break;
  	}
  
  	// Skip ":call" to get to the function name.
  	p = ea.cmd;
  	if (checkforcmd(&ea.cmd, "call", 3))
  	{
  	    if (*ea.cmd == '(')
  		// not for "call()"
  		ea.cmd = p;
  	    else
  		ea.cmd = skipwhite(ea.cmd);
  	}
  
  	if (!starts_with_colon)
  	{
  	    int	    assign;
  
  	    // Check for assignment after command modifiers.
  	    assign = may_compile_assignment(&ea, &line, &cctx);
  	    if (assign == OK)
  		goto nextline;
  	    if (assign == FAIL)
  		goto erret;
  	}
  
  	/*
  	 * COMMAND after range
  	 * 'text'->func() should not be confused with 'a mark
  	 */
  	cmd = ea.cmd;
  	if (*cmd != '\'' || starts_with_colon)
  	{
  	    ea.cmd = skip_range(ea.cmd, TRUE, NULL);
  	    if (ea.cmd > cmd)
  	    {
  		if (!starts_with_colon)
  		{
  		    semsg(_(e_colon_required_before_range_str), cmd);
  		    goto erret;
  		}
  		if (ends_excmd2(line, ea.cmd))
  		{
  		    // A range without a command: jump to the line.
  		    // TODO: compile to a more efficient command, possibly
  		    // calling parse_cmd_address().
  		    ea.cmdidx = CMD_SIZE;
  		    line = compile_exec(line, &ea, &cctx);
  		    goto nextline;
  		}
  	    }
  	}
  	p = find_ex_command(&ea, NULL, starts_with_colon ? NULL
  		   : (int (*)(char_u *, size_t, void *, cctx_T *))lookup_local,
  									&cctx);
  
  	if (p == NULL)
  	{
  	    if (cctx.ctx_skip != SKIP_YES)
  		emsg(_(e_ambiguous_use_of_user_defined_command));
  	    goto erret;
  	}
  
  	if (p == ea.cmd && ea.cmdidx != CMD_SIZE)
  	{
  	    if (cctx.ctx_skip == SKIP_YES)
  	    {
  		line += STRLEN(line);
  		goto nextline;
  	    }
  
  	    // Expression or function call.
  	    if (ea.cmdidx != CMD_eval)
  	    {
  		// CMD_var cannot happen, compile_assignment() above would be
  		// used.  Most likely an assignment to a non-existing variable.
  		semsg(_(e_command_not_recognized_str), ea.cmd);
  		goto erret;
  	    }
  	}
  
  	if (cctx.ctx_had_return
  		&& ea.cmdidx != CMD_elseif
  		&& ea.cmdidx != CMD_else
  		&& ea.cmdidx != CMD_endif
  		&& ea.cmdidx != CMD_endfor
  		&& ea.cmdidx != CMD_endwhile
  		&& ea.cmdidx != CMD_catch
  		&& ea.cmdidx != CMD_finally
  		&& ea.cmdidx != CMD_endtry)
  	{
  	    emsg(_(e_unreachable_code_after_return));
  	    goto erret;
  	}
  
  	p = skipwhite(p);
  	if (ea.cmdidx != CMD_SIZE
  			    && ea.cmdidx != CMD_write && ea.cmdidx != CMD_read)
  	{
  	    if (ea.cmdidx >= 0)
  		ea.argt = excmd_get_argt(ea.cmdidx);
  	    if ((ea.argt & EX_BANG) && *p == '!')
  	    {
  		ea.forceit = TRUE;
  		p = skipwhite(p + 1);
  	    }
  	}
  
  	switch (ea.cmdidx)
  	{
  	    case CMD_def:
  		    ea.arg = p;
  		    line = compile_nested_function(&ea, &cctx);
  		    break;
  
  	    case CMD_function:
  		    // TODO: should we allow this, e.g. to declare a global
  		    // function?
  		    emsg(_(e_cannot_use_function_inside_def));
  		    goto erret;
  
  	    case CMD_return:
  		    line = compile_return(p, check_return_type, &cctx);
  		    cctx.ctx_had_return = TRUE;
  		    break;
  
  	    case CMD_let:
  		    emsg(_(e_cannot_use_let_in_vim9_script));
  		    break;
  	    case CMD_var:
  	    case CMD_final:
  	    case CMD_const:
  		    line = compile_assignment(p, &ea, ea.cmdidx, &cctx);
  		    if (line == p)
  			line = NULL;
  		    break;
  
  	    case CMD_unlet:
  	    case CMD_unlockvar:
  	    case CMD_lockvar:
  		    line = compile_unletlock(p, &ea, &cctx);
  		    break;
  
  	    case CMD_import:
  		    line = compile_import(p, &cctx);
  		    break;
  
  	    case CMD_if:
  		    line = compile_if(p, &cctx);
  		    break;
  	    case CMD_elseif:
  		    line = compile_elseif(p, &cctx);
  		    cctx.ctx_had_return = FALSE;
  		    break;
  	    case CMD_else:
  		    line = compile_else(p, &cctx);
  		    cctx.ctx_had_return = FALSE;
  		    break;
  	    case CMD_endif:
  		    line = compile_endif(p, &cctx);
  		    break;
  
  	    case CMD_while:
  		    line = compile_while(p, &cctx);
  		    break;
  	    case CMD_endwhile:
  		    line = compile_endwhile(p, &cctx);
  		    cctx.ctx_had_return = FALSE;
  		    break;
  
  	    case CMD_for:
  		    line = compile_for(p, &cctx);
  		    break;
  	    case CMD_endfor:
  		    line = compile_endfor(p, &cctx);
  		    cctx.ctx_had_return = FALSE;
  		    break;
  	    case CMD_continue:
  		    line = compile_continue(p, &cctx);
  		    break;
  	    case CMD_break:
  		    line = compile_break(p, &cctx);
  		    break;
  
  	    case CMD_try:
  		    line = compile_try(p, &cctx);
  		    break;
  	    case CMD_catch:
  		    line = compile_catch(p, &cctx);
  		    cctx.ctx_had_return = FALSE;
  		    break;
  	    case CMD_finally:
  		    line = compile_finally(p, &cctx);
  		    cctx.ctx_had_return = FALSE;
  		    break;
  	    case CMD_endtry:
  		    line = compile_endtry(p, &cctx);
  		    cctx.ctx_had_return = FALSE;
  		    break;
  	    case CMD_throw:
  		    line = compile_throw(p, &cctx);
  		    break;
  
  	    case CMD_eval:
  		    if (compile_expr0(&p, &cctx) == FAIL)
  			goto erret;
  
  		    // drop the result
  		    generate_instr_drop(&cctx, ISN_DROP, 1);
  
  		    line = skipwhite(p);
  		    break;
  
  	    case CMD_echo:
  	    case CMD_echon:
  	    case CMD_execute:
  	    case CMD_echomsg:
  	    case CMD_echoerr:
  		    line = compile_mult_expr(p, ea.cmdidx, &cctx);
  		    break;
  
  	    case CMD_put:
  		    ea.cmd = cmd;
  		    line = compile_put(p, &ea, &cctx);
  		    break;
  
  	    // TODO: any other commands with an expression argument?
  
  	    case CMD_append:
  	    case CMD_change:
  	    case CMD_insert:
  	    case CMD_t:
  	    case CMD_xit:
  		    not_in_vim9(&ea);
  		    goto erret;
  
  	    case CMD_SIZE:
  		    if (cctx.ctx_skip != SKIP_YES)
  		    {
  			semsg(_(e_invalid_command_str), ea.cmd);
  			goto erret;
  		    }
  		    // We don't check for a next command here.
  		    line = (char_u *)"";
  		    break;
  
  	    default:
  		    if (cctx.ctx_skip == SKIP_YES)
  		    {
  			// We don't check for a next command here.
  			line = (char_u *)"";
  		    }
  		    else
  		    {
  			// Not recognized, execute with do_cmdline_cmd().
  			ea.arg = p;
  			line = compile_exec(line, &ea, &cctx);
  		    }
  		    break;
  	}
  nextline:
  	if (line == NULL)
  	    goto erret;
  	line = skipwhite(line);
  
  	// Undo any command modifiers.
  	generate_undo_cmdmods(&cctx);
  
  	if (cctx.ctx_type_stack.ga_len < 0)
  	{
  	    iemsg("Type stack underflow");
  	    goto erret;
  	}
      }
  
      if (cctx.ctx_scope != NULL)
      {
  	if (cctx.ctx_scope->se_type == IF_SCOPE)
  	    emsg(_(e_endif));
  	else if (cctx.ctx_scope->se_type == WHILE_SCOPE)
  	    emsg(_(e_endwhile));
  	else if (cctx.ctx_scope->se_type == FOR_SCOPE)
  	    emsg(_(e_endfor));
  	else
  	    emsg(_(e_missing_rcurly));
  	goto erret;
      }
  
      if (!cctx.ctx_had_return)
      {
  	if (ufunc->uf_ret_type->tt_type != VAR_VOID)
  	{
  	    emsg(_(e_missing_return_statement));
  	    goto erret;
  	}
  
  	// Return zero if there is no return at the end.
  	generate_instr(&cctx, ISN_RETURN_ZERO);
      }
  
      {
  	dfunc_T	*dfunc = ((dfunc_T *)def_functions.ga_data)
  							 + ufunc->uf_dfunc_idx;
  	dfunc->df_deleted = FALSE;
  	dfunc->df_script_seq = current_sctx.sc_seq;
  	dfunc->df_instr = instr->ga_data;
  	dfunc->df_instr_count = instr->ga_len;
  	dfunc->df_varcount = cctx.ctx_locals_count;
  	dfunc->df_has_closure = cctx.ctx_has_closure;
  	if (cctx.ctx_outer_used)
  	    ufunc->uf_flags |= FC_CLOSURE;
  	ufunc->uf_def_status = UF_COMPILED;
      }
  
      ret = OK;
  
  erret:
      if (ret == FAIL)
      {
  	int idx;
  	dfunc_T	*dfunc = ((dfunc_T *)def_functions.ga_data)
  							 + ufunc->uf_dfunc_idx;
  
  	for (idx = 0; idx < instr->ga_len; ++idx)
  	    delete_instr(((isn_T *)instr->ga_data) + idx);
  	ga_clear(instr);
  	VIM_CLEAR(dfunc->df_name);
  
  	// If using the last entry in the table and it was added above, we
  	// might as well remove it.
  	if (!dfunc->df_deleted && new_def_function
  			    && ufunc->uf_dfunc_idx == def_functions.ga_len - 1)
  	{
  	    --def_functions.ga_len;
  	    ufunc->uf_dfunc_idx = 0;
  	}
  	ufunc->uf_def_status = UF_NOT_COMPILED;
  
  	while (cctx.ctx_scope != NULL)
  	    drop_scope(&cctx);
  
  	// Don't execute this function body.
  	ga_clear_strings(&ufunc->uf_lines);
  
  	if (errormsg != NULL)
  	    emsg(errormsg);
  	else if (did_emsg == did_emsg_before)
  	    emsg(_(e_compiling_def_function_failed));
      }
  
      current_sctx = save_current_sctx;
      estack_compiling = save_estack_compiling;
      if (do_estack_push)
  	estack_pop();
  
      free_imported(&cctx);
      free_locals(&cctx);
      ga_clear(&cctx.ctx_type_stack);
      return ret;
  }
  
      void
  set_function_type(ufunc_T *ufunc)
  {
      int varargs = ufunc->uf_va_name != NULL;
      int argcount = ufunc->uf_args.ga_len;
  
      // Create a type for the function, with the return type and any
      // argument types.
      // A vararg is included in uf_args.ga_len but not in uf_arg_types.
      // The type is included in "tt_args".
      if (argcount > 0 || varargs)
      {
  	ufunc->uf_func_type = alloc_func_type(ufunc->uf_ret_type,
  					   argcount, &ufunc->uf_type_list);
  	// Add argument types to the function type.
  	if (func_type_add_arg_types(ufunc->uf_func_type,
  				    argcount + varargs,
  				    &ufunc->uf_type_list) == FAIL)
  	    return;
  	ufunc->uf_func_type->tt_argcount = argcount + varargs;
  	ufunc->uf_func_type->tt_min_argcount =
  				      argcount - ufunc->uf_def_args.ga_len;
  	if (ufunc->uf_arg_types == NULL)
  	{
  	    int i;
  
  	    // lambda does not have argument types.
  	    for (i = 0; i < argcount; ++i)
  		ufunc->uf_func_type->tt_args[i] = &t_any;
  	}
  	else
  	    mch_memmove(ufunc->uf_func_type->tt_args,
  			 ufunc->uf_arg_types, sizeof(type_T *) * argcount);
  	if (varargs)
  	{
  	    ufunc->uf_func_type->tt_args[argcount] =
  		    ufunc->uf_va_type == NULL ? &t_any : ufunc->uf_va_type;
  	    ufunc->uf_func_type->tt_flags = TTFLAG_VARARGS;
  	}
      }
      else
  	// No arguments, can use a predefined type.
  	ufunc->uf_func_type = get_func_type(ufunc->uf_ret_type,
  					   argcount, &ufunc->uf_type_list);
  }
  
  
  /*
   * Delete an instruction, free what it contains.
   */
      void
  delete_instr(isn_T *isn)
  {
      switch (isn->isn_type)
      {
  	case ISN_DEF:
  	case ISN_EXEC:
  	case ISN_LOADAUTO:
  	case ISN_LOADB:
  	case ISN_LOADENV:
  	case ISN_LOADG:
  	case ISN_LOADOPT:
  	case ISN_LOADT:
  	case ISN_LOADW:
  	case ISN_PUSHEXC:
  	case ISN_PUSHFUNC:
  	case ISN_PUSHS:
  	case ISN_RANGE:
  	case ISN_STOREAUTO:
  	case ISN_STOREB:
  	case ISN_STOREENV:
  	case ISN_STOREG:
  	case ISN_STORET:
  	case ISN_STOREW:
  	case ISN_STRINGMEMBER:
  	    vim_free(isn->isn_arg.string);
  	    break;
  
  	case ISN_LOADS:
  	case ISN_STORES:
  	    vim_free(isn->isn_arg.loadstore.ls_name);
  	    break;
  
  	case ISN_UNLET:
  	case ISN_UNLETENV:
  	    vim_free(isn->isn_arg.unlet.ul_name);
  	    break;
  
  	case ISN_STOREOPT:
  	    vim_free(isn->isn_arg.storeopt.so_name);
  	    break;
  
  	case ISN_PUSHBLOB:   // push blob isn_arg.blob
  	    blob_unref(isn->isn_arg.blob);
  	    break;
  
  	case ISN_PUSHJOB:
  #ifdef FEAT_JOB_CHANNEL
  	    job_unref(isn->isn_arg.job);
  #endif
  	    break;
  
  	case ISN_PUSHCHANNEL:
  #ifdef FEAT_JOB_CHANNEL
  	    channel_unref(isn->isn_arg.channel);
  #endif
  	    break;
  
  	case ISN_UCALL:
  	    vim_free(isn->isn_arg.ufunc.cuf_name);
  	    break;
  
  	case ISN_FUNCREF:
  	    {
  		dfunc_T *dfunc = ((dfunc_T *)def_functions.ga_data)
  					       + isn->isn_arg.funcref.fr_func;
  		ufunc_T *ufunc = dfunc->df_ufunc;
  
  		if (ufunc != NULL && func_name_refcount(ufunc->uf_name))
  		    func_ptr_unref(ufunc);
  	    }
  	    break;
  
  	case ISN_DCALL:
  	    {
  		dfunc_T *dfunc = ((dfunc_T *)def_functions.ga_data)
  					       + isn->isn_arg.dfunc.cdf_idx;
  
  		if (dfunc->df_ufunc != NULL
  			       && func_name_refcount(dfunc->df_ufunc->uf_name))
  		    func_ptr_unref(dfunc->df_ufunc);
  	    }
  	    break;
  
  	case ISN_NEWFUNC:
  	    {
  		char_u  *lambda = isn->isn_arg.newfunc.nf_lambda;
  		ufunc_T *ufunc = find_func_even_dead(lambda, TRUE, NULL);
  
  		if (ufunc != NULL)
  		{
  		    unlink_def_function(ufunc);
  		    func_ptr_unref(ufunc);
  		}
  
  		vim_free(lambda);
  		vim_free(isn->isn_arg.newfunc.nf_global);
  	    }
  	    break;
  
  	case ISN_CHECKTYPE:
  	case ISN_SETTYPE:
  	    free_type(isn->isn_arg.type.ct_type);
  	    break;
  
  	case ISN_CMDMOD:
  	    vim_regfree(isn->isn_arg.cmdmod.cf_cmdmod
  					       ->cmod_filter_regmatch.regprog);
  	    vim_free(isn->isn_arg.cmdmod.cf_cmdmod);
  	    break;
  
  	case ISN_LOADSCRIPT:
  	case ISN_STORESCRIPT:
  	    vim_free(isn->isn_arg.script.scriptref);
  	    break;
  
  	case ISN_2BOOL:
  	case ISN_2STRING:
  	case ISN_2STRING_ANY:
  	case ISN_ADDBLOB:
  	case ISN_ADDLIST:
  	case ISN_ANYINDEX:
  	case ISN_ANYSLICE:
  	case ISN_BCALL:
  	case ISN_BLOBAPPEND:
  	case ISN_CATCH:
  	case ISN_CHECKLEN:
  	case ISN_CHECKNR:
  	case ISN_CMDMOD_REV:
  	case ISN_COMPAREANY:
  	case ISN_COMPAREBLOB:
  	case ISN_COMPAREBOOL:
  	case ISN_COMPAREDICT:
  	case ISN_COMPAREFLOAT:
  	case ISN_COMPAREFUNC:
  	case ISN_COMPARELIST:
  	case ISN_COMPARENR:
  	case ISN_COMPARESPECIAL:
  	case ISN_COMPARESTRING:
  	case ISN_CONCAT:
  	case ISN_COND2BOOL:
  	case ISN_DROP:
  	case ISN_ECHO:
  	case ISN_ECHOERR:
  	case ISN_ECHOMSG:
  	case ISN_ENDTRY:
  	case ISN_EXECCONCAT:
  	case ISN_EXECUTE:
  	case ISN_FOR:
  	case ISN_GETITEM:
  	case ISN_JUMP:
  	case ISN_LISTAPPEND:
  	case ISN_LISTINDEX:
  	case ISN_LISTSLICE:
  	case ISN_LOAD:
  	case ISN_LOADBDICT:
  	case ISN_LOADGDICT:
  	case ISN_LOADOUTER:
  	case ISN_LOADREG:
  	case ISN_LOADTDICT:
  	case ISN_LOADV:
  	case ISN_LOADWDICT:
  	case ISN_LOCKCONST:
  	case ISN_MEMBER:
  	case ISN_NEGATENR:
  	case ISN_NEWDICT:
  	case ISN_NEWLIST:
  	case ISN_OPANY:
  	case ISN_OPFLOAT:
  	case ISN_OPNR:
  	case ISN_PCALL:
  	case ISN_PCALL_END:
  	case ISN_PUSHBOOL:
  	case ISN_PUSHF:
  	case ISN_PUSHNR:
  	case ISN_PUSHSPEC:
  	case ISN_PUT:
  	case ISN_RETURN:
  	case ISN_RETURN_ZERO:
  	case ISN_SHUFFLE:
  	case ISN_SLICE:
  	case ISN_STORE:
  	case ISN_STOREINDEX:
  	case ISN_STORENR:
  	case ISN_STOREOUTER:
  	case ISN_STOREREG:
  	case ISN_STOREV:
  	case ISN_STRINDEX:
  	case ISN_STRSLICE:
  	case ISN_THROW:
  	case ISN_TRY:
  	case ISN_UNLETINDEX:
  	case ISN_UNPACK:
  	    // nothing allocated
  	    break;
      }
  }
  
  /*
   * Free all instructions for "dfunc" except df_name.
   */
      static void
  delete_def_function_contents(dfunc_T *dfunc, int mark_deleted)
  {
      int idx;
  
      ga_clear(&dfunc->df_def_args_isn);
  
      if (dfunc->df_instr != NULL)
      {
  	for (idx = 0; idx < dfunc->df_instr_count; ++idx)
  	    delete_instr(dfunc->df_instr + idx);
  	VIM_CLEAR(dfunc->df_instr);
  	dfunc->df_instr = NULL;
      }
  
      if (mark_deleted)
  	dfunc->df_deleted = TRUE;
      if (dfunc->df_ufunc != NULL)
  	dfunc->df_ufunc->uf_def_status = UF_NOT_COMPILED;
  }
  
  /*
   * When a user function is deleted, clear the contents of any associated def
   * function, unless another user function still uses it.
   * The position in def_functions can be re-used.
   */
      void
  unlink_def_function(ufunc_T *ufunc)
  {
      if (ufunc->uf_dfunc_idx > 0)
      {
  	dfunc_T *dfunc = ((dfunc_T *)def_functions.ga_data)
  							 + ufunc->uf_dfunc_idx;
  
  	if (--dfunc->df_refcount <= 0)
  	    delete_def_function_contents(dfunc, TRUE);
  	ufunc->uf_def_status = UF_NOT_COMPILED;
  	ufunc->uf_dfunc_idx = 0;
  	if (dfunc->df_ufunc == ufunc)
  	    dfunc->df_ufunc = NULL;
      }
  }
  
  /*
   * Used when a user function refers to an existing dfunc.
   */
      void
  link_def_function(ufunc_T *ufunc)
  {
      if (ufunc->uf_dfunc_idx > 0)
      {
  	dfunc_T *dfunc = ((dfunc_T *)def_functions.ga_data)
  							 + ufunc->uf_dfunc_idx;
  
  	++dfunc->df_refcount;
      }
  }
  
  #if defined(EXITFREE) || defined(PROTO)
  /*
   * Free all functions defined with ":def".
   */
      void
  free_def_functions(void)
  {
      int idx;
  
      for (idx = 0; idx < def_functions.ga_len; ++idx)
      {
  	dfunc_T *dfunc = ((dfunc_T *)def_functions.ga_data) + idx;
  
  	delete_def_function_contents(dfunc, TRUE);
  	vim_free(dfunc->df_name);
      }
  
      ga_clear(&def_functions);
  }
  #endif
  
  
  #endif // FEAT_EVAL
  