Fixes #497. Null-aware operators are allowed for explicit extension invocation

Author: Sergey G. Grekhov

LanguageFeatures/Extension-methods/explicit_extension_member_invocation_A02_t02.dart

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2019, 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.
+ */
+/**
+ * @assertion It is a compile-time error if the corresponding class constructor
+ * invocation would be a compile-time error.
+ *
+ * @description Check that it is a compile-time error if the corresponding class
+ * constructor invocation would be a compile-time error.
+ * @author [email protected]
+ */
+// SharedOptions=--enable-experiment=extension-methods
+
+class C {
+  String name = "My name is C";
+}
+
+extension Ext on C {
+  String checkme() => this.name;
+}
+
+main() {
+  C c = new C();
+  Ext(Ext(c)).checkme();
+//    ^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}

LanguageFeatures/Extension-methods/explicit_extension_member_invocation_A20_t01.dart

@@ -9,16 +9,16 @@
  * invocation. That is, the only valid use of an extension application is to
  * invoke members on it. This is similar to how prefix names can also only be
  * used as member invocation targets. The main difference is that extensions can
- * also declare operators. This also includes null-aware member access like
- * E(o)?.id or E(o)?.[v] because those need to evaluate the target to a value
- * and extension applications cannot evaluate to a value.
+ * also declare operators.
  *
- * @description Check that it is a compile-time error if null-aware member
- * access like E(o)?.id is used for explicit extension invocation
+ * @description Check that it is no compile-time error if null-aware member
+ * access like E(o)?.id() is used for explicit extension invocation
  * @issue 39325
+ * https://github.com/dart-lang/language/issues/677
  * @author [email protected]
  */
 // SharedOptions=--enable-experiment=extension-methods
+import "../../Utils/expect.dart";
 
 class C {
 }
@@ -29,8 +29,5 @@ extension Ext on C {
 
 main() {
   C c = C();
-  Ext(c)?.id();
-//^^^^^^^^^^^^
-// [analyzer] unspecified
-// [cfe] unspecified}
+  Expect.equals(42, Ext(c)?.id());
 }

LanguageFeatures/Extension-methods/explicit_extension_member_invocation_A20_t02.dart

@@ -9,16 +9,16 @@
  * invocation. That is, the only valid use of an extension application is to
  * invoke members on it. This is similar to how prefix names can also only be
  * used as member invocation targets. The main difference is that extensions can
- * also declare operators. This also includes null-aware member access like
- * E(o)?.id or E(o)?.[v] because those need to evaluate the target to a value
- * and extension applications cannot evaluate to a value.
+ * also declare operators.
  *
- * @description Check that it is a compile-time error if null-aware member
+ * @description Check that it is no compile-time error if null-aware member
  * access like E(o)?.id is used for explicit extension invocation
  * @issue 39325
+ * https://github.com/dart-lang/language/issues/677
  * @author [email protected]
  */
 // SharedOptions=--enable-experiment=extension-methods
+import "../../Utils/expect.dart";
 
 class C {
 }
@@ -29,8 +29,5 @@ extension Ext on C {
 
 main() {
   C c = C();
-  Ext(c)?.id;
-//^^^^^^^^^^^^
-// [analyzer] unspecified
-// [cfe] unspecified}
+  Expect.equals(42, Ext(c)?.id);
 }

LanguageFeatures/Extension-methods/explicit_extension_member_invocation_A20_t03.dart

@@ -9,28 +9,29 @@
  * invocation. That is, the only valid use of an extension application is to
  * invoke members on it. This is similar to how prefix names can also only be
  * used as member invocation targets. The main difference is that extensions can
- * also declare operators. This also includes null-aware member access like
- * E(o)?.id or E(o)?.[v] because those need to evaluate the target to a value
- * and extension applications cannot evaluate to a value.
+ * also declare operators.
  *
- * @description Check that it is a compile-time error if null-aware member
+ * @description Check that it is no compile-time error if null-aware member
  * access like E(o)?.id is used for explicit extension invocation
  * @issue 39325
+ * https://github.com/dart-lang/language/issues/677
  * @author [email protected]
  */
 // SharedOptions=--enable-experiment=extension-methods
+import "../../Utils/expect.dart";
 
 class C {
+  int v = 0;
 }
 
 extension Ext on C {
-  void set id(int val) {}
+  void set id(int val) {
+    this.v = val;
+  }
 }
 
 main() {
   C c = C();
   Ext(c)?.id = 42;
-//^^^^^^^^^^
-// [analyzer] unspecified
-// [cfe] unspecified}
+  Expect.equals(42, c.v);
 }

LanguageFeatures/Extension-methods/explicit_extension_member_invocation_A20_t04.dart

@@ -9,16 +9,16 @@
  * invocation. That is, the only valid use of an extension application is to
  * invoke members on it. This is similar to how prefix names can also only be
  * used as member invocation targets. The main difference is that extensions can
- * also declare operators. This also includes null-aware member access like
- * E(o)?.id or E(o)?.[v] because those need to evaluate the target to a value
- * and extension applications cannot evaluate to a value.
+ * also declare operators.
  *
- * @description Check that it is a compile-time error if null-aware member
+ * @description Check that it is no compile-time error if null-aware member
  * access like E(o)?.[v] is used for explicit extension invocation
  * @issue 39326
+ * https://github.com/dart-lang/language/issues/677
  * @author [email protected]
  */
 // SharedOptions=--enable-experiment=extension-methods
+import "../../Utils/expect.dart";
 
 class C {
 }
@@ -29,8 +29,5 @@ extension Ext on C {
 
 main() {
   C c = C();
-  Ext(c)?.[42];
-//^^^^^^^^^^^^
-// [analyzer] unspecified
-// [cfe] unspecified}
+  Expect.equals(42, Ext(c)?.[42]);
 }