anchor.diff:  
   -spec parse_let(clj_env:env(), 'clojerl.List':type()) -> clj_env:env().
   parse_let(Env, Form) ->
  -  {LetExprExtra, Env} = analyze_let(Env, Form),
  +  {LetExprExtra, Env2} = analyze_let(Env, Form),
     LetExpr = maps:merge(#{ op   => 'let'
                           , form => Form
  -                        , env  => ?DEBUG(Env)
  +                        , env  => ?DEBUG(Env2)
                           },
                          LetExprExtra),
   
  
positive.code:                         <<" requires an even number of forms in binding "
                            "vector, had: ">>,
                          clj_core:count(Bindings)]),
  
    ok.
  
  %%------------------------------------------------------------------------------
  
negative.code:          get/2,
           type/1]).
  
  -define(DEBUG(X), X).
  
  -spec analyze(clj_env:env(), any()) -> clj_env:env().
  analyze(Env0, Form) ->
  