anchor.diff:    case_expr
     case_clauses
     case_clause
  -  else_clause
     if_expr
     inline_if_expr
  +  else_clause
     if_op
     for_expr
     try_expr
  
positive.code: 
  if_op -> 'if'   : '$1'.
  if_op -> unless : '$1'.
  
  %% For loops
  for_expr -> for match_expr in expr eol indent statements dedent : {for, line('$1'), '$2', '$4', '$7'}.
  
negative.code: 
  %% Case expressions
  case_expr -> 'case' expr eol indent case_clauses dedent : {'case', line('$1'), '$2', '$5'}.
  
  case_clauses -> case_clause case_clauses : ['$1'|'$2'].
  case_clauses -> case_clause : ['$1'].
  
  case_clause -> expr ':' eol indent statements dedent : {clause, line('$2'), '$1', '$5'}.
  
  %% If expressions
  if_expr -> if_op expr eol indent statements dedent : if_forms({'$1', '$2', '$5'}).
  