16:29:35karloszi think separating references from variables at the ast-level is pretty orthogonal to the issue of map-ast having to keep a hash table
16:29:51karloszbut we should probably do it anyway for better policy and source like your old commit said
16:30:27karloszall we really need to do to make map-ast not use the hash table is to make sure we don't visit any child more than once, which we can do by controlling the children method
16:30:53karloszi.e. only function-ast and lexical-bind-ast have lexical-ast/lexical-variable as children