fix #26141, add support for type arguments to constants

pkg/analyzer/test/src/task/strong/checker_test.dart

Index: pkg/analyzer/test/src/task/strong/checker_test.dart
diff --git a/pkg/analyzer/test/src/task/strong/checker_test.dart b/pkg/analyzer/test/src/task/strong/checker_test.dart
index 343a2aea64f2d536eccfd8990508c8cf5fb9ef5e..6235e9ff30dd829e4b889a5445f1d394bfb0edb2 100644
--- a/pkg/analyzer/test/src/task/strong/checker_test.dart
+++ b/pkg/analyzer/test/src/task/strong/checker_test.dart
@@ -2164,6 +2164,40 @@ dynamic y1 = (<dynamic>[])[0];
     check(implicitDynamic: false);
   }
 
+  void test_constantGenericTypeArg_infer() {
+    // Regression test for https://github.com/dart-lang/sdk/issues/26141
+    checkFile('''
+abstract class Equality<R> {}
+class DefaultEquality<S> implements Equality<S> {
+  const DefaultEquality();
+}
+class SetEquality<T> implements Equality<T> {
+  final Equality<T> field = const DefaultEquality();
+  const SetEquality([Equality<T> inner = const DefaultEquality()]);
+}
+main() {
+  const SetEquality<String>();
+}
+    ''');
+  }
+
+  void test_constantGenericTypeArg_explict() {
+    // Regression test for https://github.com/dart-lang/sdk/issues/26141
+    checkFile('''
+abstract class Equality<R> {}
+class DefaultEquality<S> implements Equality<S> {
+  const DefaultEquality();
+}
+class SetEquality<T> implements Equality<T> {
+  final Equality<T> field = const DefaultEquality<T>();
+  const SetEquality([Equality<T> inner = const DefaultEquality<T>()]);
+}
+main() {
+  const SetEquality<String>();
+}
+    ''');
+  }
+
   void test_invalidOverrides_baseClassOverrideToChildInterface() {
     checkFile('''
 class A {}