[ddc] Fix covariant bound checks with new types

Issue: #48585
Change-Id: I7a5d9c412696ea038af8320734790456d4e2880a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/306914
Commit-Queue: Nicholas Shahan <[email protected]>
Reviewed-by: Mark Zhou <[email protected]>

Author: nshahan

sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart

@@ -745,9 +745,6 @@ cast(obj, type) {
 ///
 /// Will produce a warning/error (if enabled) when the subtype passes but would
 /// fail in sound null safety.
-///
-/// Currently only called from _checkAndCall to test type arguments applied to
-/// dynamic method calls.
 // TODO(48585) Revise argument types after removing old type representation.
 @notNull
 bool _isSubtypeWithWarning(@notNull t1, @notNull t2) {

sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/types.dart

@@ -1190,7 +1190,18 @@ bool isType(obj) => JS('', '#[#] === #', obj, _runtimeType, Type);
 
 void checkTypeBound(
     @notNull Object type, @notNull Object bound, @notNull String name) {
-  if (!isSubtypeOf(type, bound)) {
+  bool validSubtype;
+  if (JS_GET_FLAG('NEW_RUNTIME_TYPES')) {
+    validSubtype = compileTimeFlag('soundNullSafety')
+        // Check subtype directly in sound mode.
+        ? rti.isSubtype(JS_EMBEDDED_GLOBAL('', RTI_UNIVERSE),
+            JS<rti.Rti>('!', '#', type), JS<rti.Rti>('!', '#', bound))
+        // Check subtype but issue warnings/errors in weak mode.
+        : _isSubtypeWithWarning(type, bound);
+  } else {
+    validSubtype = isSubtypeOf(type, bound);
+  }
+  if (!validSubtype) {
     throwTypeError('type `$type` does not extend `$bound` of `$name`.');
   }
 }