Merge cda6b88 into 0eeadff

Author: RAJAGOPALAN-GANGADHARAN

Diff for: include/swift/AST/DiagnosticsSema.def

@@ -4067,9 +4067,6 @@ WARNING(bitcasting_to_change_function_rep, none,
         "'unsafeBitCast' from function type %0 to %1 changes @convention and "
         "is undefined; use an implicit conversion to change conventions",
         (Type, Type))
-WARNING(bitcasting_to_downcast, none,
-        "'unsafeBitCast' from %0 to %1 can be replaced with 'unsafeDowncast'",
-        (Type, Type))
 WARNING(bitcasting_is_no_op, none,
         "'unsafeBitCast' from %0 to %1 is unnecessary and can be removed",
         (Type, Type))

Diff for: lib/Sema/MiscDiagnostics.cpp

@@ -898,15 +898,6 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
           return;
         }
       }
-      
-      // Unchecked casting to a subclass is better done by unsafeDowncast.
-      if (fromTy->isBindableToSuperclassOf(toTy)) {
-        Ctx.Diags.diagnose(DRE->getLoc(), diag::bitcasting_to_downcast,
-                           fromTy, toTy)
-          .fixItReplace(DRE->getNameLoc().getBaseNameLoc(),
-                        "unsafeDowncast");
-        return;
-      }
 
       // Casting among pointer types should use the Unsafe*Pointer APIs for
       // rebinding typed memory or accessing raw memory instead.