fix(kernel/converter): missing case for local constants

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

library/standard/logic.lean

@@ -86,8 +86,8 @@ definition cast {A B : Type} (H : A = B) (a : A) : B
 := eq_rec a H
 
 -- TODO(Leo): check why unifier needs 'help' in the following theorem
-theorem cast_refl.{l} {A : Type.{l}} (a : A) : @cast.{l} A A (refl A) a = a
-:= refl (@cast.{l} A A (refl A) a)
+theorem cast_refl.{l} {A : Type.{l}} (a : A) : cast (refl A) a = a
+:= refl (cast (refl A) a)
 
 definition iff (a b : Bool) := (a → b) ∧ (b → a)
 infix `↔` 50 := iff

src/kernel/converter.cpp

@@ -415,6 +415,10 @@ struct default_converter : public converter {
             is_def_eq(const_levels(t_n), const_levels(s_n), c, jst))
             return true;
 
+        if (is_local(t_n) && is_local(s_n) && mlocal_name(t_n) == mlocal_name(s_n) &&
+            is_def_eq(mlocal_type(t_n), mlocal_type(s_n), c, jst))
+            return true;
+
         // At this point, t_n and s_n are in weak head normal form (modulo meta-variables and proof irrelevance)
         if (is_app(t_n) && is_app(s_n)) {
             type_checker::scope scope(c);