More aggressive freshening to avoid shadowing issues

This commit is contained in:
Ulf Norell 2019-09-24 16:22:25 +02:00
parent 63d51baaa3
commit c8153f94a6

View File

@ -1681,8 +1681,18 @@ bottom_up(F, Env, Expr) ->
{lam, Xs, B} -> {lam, Xs, bottom_up(F, Env, B)};
{'let', X, E, Body} ->
E1 = bottom_up(F, Env, E),
%% Always freshen user variables to avoid shadowing issues.
ShouldFreshen = fun(Y = "%" ++ _) -> maps:is_key(Y, Env);
(_) -> true end,
case ShouldFreshen(X) of
true ->
Z = fresh_name(),
Env1 = Env#{ Z => E1 },
{'let', Z, E1, bottom_up(F, Env1, rename([{X, Z}], Body))};
false ->
Env1 = Env#{ X => E1 },
{'let', X, E1, bottom_up(F, Env1, Body)};
{'let', X, E1, bottom_up(F, Env1, Body)}
end;
{split, Type, X, Cases} -> {split, Type, X, [bottom_up(F, Env, Case) || Case <- Cases]};
{nosplit, E} -> {nosplit, bottom_up(F, Env, E)};
{'case', Pat, Split} -> {'case', Pat, bottom_up(F, Env, Split)}