Make language tests for issue #45551

Previously, the "why not promoted" test cases sort of exercised this
bug, but in an unclear way that wasn't really related to the "why not
promoted" functionality.  Better to have a separate test for it.

Bug: #45551
Change-Id: Idd44596f021eb91679a019f9f56da1661363d0d8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/193829
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Paul Berry <[email protected]>

Author: stereotype441

tests/language/extension_methods/issue_45551_error_test.dart

@@ -0,0 +1,22 @@
+// Copyright (c) 2021, 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.
+
+// This test illustrates the error scenario described in
+// https://github.com/dart-lang/sdk/issues/45551
+
+class C {}
+
+extension on C {
+  void Function() get call => () {};
+}
+
+test(C c) {
+  c();
+//^
+// [analyzer] COMPILE_TIME_ERROR.INVOCATION_OF_NON_FUNCTION_EXPRESSION
+// ^
+// [cfe] Cannot invoke an instance of 'C' because it declares 'call' to be something other than a method.
+}
+
+main() {}

tests/language/why_not_promoted/nullable_expression_call_error_test.dart

@@ -79,32 +79,19 @@ instance_getter_invocation(C6 c) {
 }
 
 class C8 {
-  C9? ok;
   C10? bad;
   //   ^^^
   // [context 4] 'bad' refers to a property so it couldn't be promoted.  See http://dart.dev/go/non-promo-property
   // [context 10] 'bad' refers to a property so it couldn't be promoted.
 }
 
-class C9 {}
-
 class C10 {}
 
-extension on C9? {
-  void Function() get call => () {};
-}
-
 extension on C10 {
   void Function() get call => () {};
 }
 
 extension_invocation_getter(C8 c) {
-  if (c.ok == null) return;
-  // Note: the analyzer produces an extraneous error on the line below due to
-  // https://github.com/dart-lang/sdk/issues/45551
-  c.ok();
-//^^^^
-// [analyzer] COMPILE_TIME_ERROR.INVOCATION_OF_NON_FUNCTION_EXPRESSION
   if (c.bad == null) return;
   c.bad();
 //^^^^^

tests/language_2/extension_methods/issue_45551_error_test.dart

@@ -0,0 +1,22 @@
+// Copyright (c) 2021, 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.
+
+// This test illustrates the error scenario described in
+// https://github.com/dart-lang/sdk/issues/45551
+
+class C {}
+
+extension on C {
+  void Function() get call => () {};
+}
+
+test(C c) {
+  c();
+//^
+// [analyzer] COMPILE_TIME_ERROR.INVOCATION_OF_NON_FUNCTION_EXPRESSION
+// ^
+// [cfe] Cannot invoke an instance of 'C' because it declares 'call' to be something other than a method.
+}
+
+main() {}