Generate unique vars in defguard

Author: josevalim

lib/elixir/lib/kernel/utils.ex

@@ -375,7 +375,7 @@ defmodule Kernel.Utils do
 
                 %{} ->
                   generated = String.to_atom("arg" <> Integer.to_string(map_size(acc) + 1))
-                  new_var = Macro.var(generated, Elixir)
+                  new_var = Macro.unique_var(generated, Elixir)
                   {new_var, Map.put(acc, pair, {new_var, var})}
               end
 

lib/elixir/src/elixir_erl_var.erl

@@ -109,13 +109,11 @@ dump_binding(Binding, ErlS, ExS, PruneBefore) ->
   #elixir_ex{vars={ExVars, _}, unused={Unused, _}} = ExS,
 
   maps:fold(fun
-    %% If the variable is part of the pruning (usually the input binding)
-    %% and is unused, we removed it from vars.
-    (Pair, Version, {B, V})
-    when Version =< PruneBefore, not is_map_key({Pair, Version}, Unused) ->
-      {B, maps:remove(Pair, V)};
-
-    ({Var, Kind} = Pair, Version, {B, V}) when is_atom(Kind) ->
+    ({Var, Kind} = Pair, Version, {B, V})
+    when is_atom(Kind),
+         %% If the variable is part of the pruning (usually the input binding)
+         %% and is unused, we removed it from vars.
+         Version > PruneBefore orelse is_map_key({Pair, Version}, Unused) ->
       Key = case Kind of
         nil -> Var;
         _ -> Pair
@@ -125,6 +123,9 @@ dump_binding(Binding, ErlS, ExS, PruneBefore) ->
       Value = find_binding(ErlName, Binding),
       {[{Key, Value} | B], V};
 
+    (Pair, _, {B, V}) when PruneBefore >= 0 ->
+      {B, maps:remove(Pair, V)};
+
     (_, _, Acc) ->
       Acc
   end, {[], ExVars}, ExVars).

lib/elixir/test/elixir/code_test.exs

@@ -234,6 +234,15 @@ defmodule CodeTest do
     assert trace_env.versioned_vars == %{{:result, Kernel} => 5, {:x, nil} => 1, {:y, nil} => 4}
   end
 
+  test "eval_quoted_with_env/3 with defguard" do
+    require Integer
+    env = Code.env_for_eval(__ENV__)
+    quoted = quote do: Integer.is_even(1)
+    {false, binding, env} = Code.eval_quoted_with_env(quoted, [], env, prune_binding: true)
+    assert binding == []
+    assert Macro.Env.vars(env) == []
+  end
+
   test "compile_file/1" do
     assert Code.compile_file(fixture_path("code_sample.exs")) == []
     refute fixture_path("code_sample.exs") in Code.required_files()