[dart2wasm] Fix incorrect setup of checked entrypoints

A method may be overriden multiple times, the overriden methods may add
optional parameters. Dart2wasm generates a signature for such selectors
that includes all optional parameters from all overriden methods.

That means
* callers may pass more arguments than the signature of the target
  => it passes dummy values
* implementations get more parameters passed than their Dart function
  => it ignores them

The checked/unchecked entry functions need to also support this
mechanism.

Issue https://github.com/dart-lang/sdk/issues/60148

Change-Id: Ifb60c44d3c5e5b6e374a15731723e16d22bfc094
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/414720
Reviewed-by: Ömer Ağacan <omersa@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>

pkg/dart2wasm/lib/code_generator.dart

@@ -379,10 +379,18 @@ abstract class AstCodeGenerator
         canSafelyOmitImplicitChecks: !translator.needToCheckTypesFor(member));
   }
 
+  void setupParametersForCheckedEntry(Member member) {
+    assert(member.isInstanceMember);
+    assert(translator.needToCheckTypesFor(member));
+    setupParameters(member.checkedEntryReference,
+        canSafelyOmitImplicitChecks: false);
+  }
+
   void setupParametersForUncheckedEntry(Member member) {
     assert(member.isInstanceMember);
     assert(translator.needToCheckTypesFor(member));
-    setupParameters(member.reference, canSafelyOmitImplicitChecks: true);
+    setupParameters(member.uncheckedEntryReference,
+        canSafelyOmitImplicitChecks: true);
   }
 
   void setupContexts(Member member) {
@@ -3299,7 +3307,7 @@ class SynchronousProcedureCodeGenerator extends AstCodeGenerator {
     final function = member.function;
     final signature = translator.signatureForDirectCall(member.bodyReference);
     if (checked) {
-      setupParametersForNormalEntry(member);
+      setupParametersForCheckedEntry(member);
     } else {
       setupParametersForUncheckedEntry(member);
     }

tests/language/regress/regress60148_test.dart

@@ -0,0 +1,27 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:expect/expect.dart';
+
+main() async {
+  final l = <A<int>>[B<int>(), C<int>()];
+  Expect.equals('B.foo(1, first=1)', l[0].foo(1));
+  Expect.equals('C.foo(2, second=true)', l[1].foo(2));
+  Expect.equals('B.foo(3, first=2)', B<int>().foo(3, first: 2));
+  Expect.equals('C.foo(4, second=false)', C<int>().foo(4, second: false));
+}
+
+abstract class A<T> {
+  String foo(T a);
+}
+
+class B<T> extends A<T> {
+  String foo(T a, {int first = 1}) => 'B.foo($a, first=$first)';
+}
+
+class C<T> extends A<T> {
+  String foo(T a, {bool second = true}) => 'C.foo($a, second=$second)';
+}