[cfe] Support implicit this access to extension methods in extensions

Change-Id: Idad98ca0d0fb27010ef4a522593f283b97ecc873
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/117720
Reviewed-by: Jens Johansen <jensj@google.com>

pkg/front_end/lib/src/fasta/kernel/expression_generator.dart

@@ -661,9 +661,6 @@ class ThisPropertyAccessGenerator extends Generator {
   }
 
   Expression _createRead() {
-    if (getter == null) {
-      _helper.warnUnresolvedGet(name, fileOffset);
-    }
     return new PropertyGet(
         _forest.createThisExpression(fileOffset), name, getter)
       ..fileOffset = fileOffset;
@@ -675,9 +672,6 @@ class ThisPropertyAccessGenerator extends Generator {
   }
 
   Expression _createWrite(int offset, Expression value) {
-    if (setter == null) {
-      _helper.warnUnresolvedSet(name, fileOffset);
-    }
     return new PropertySet(
         _forest.createThisExpression(fileOffset), name, value, setter)
       ..fileOffset = fileOffset;
@@ -745,9 +739,6 @@ class ThisPropertyAccessGenerator extends Generator {
   @override
   Expression doInvocation(int offset, Arguments arguments) {
     Member interfaceTarget = getter;
-    if (interfaceTarget == null) {
-      _helper.warnUnresolvedMethod(name, offset);
-    }
     if (interfaceTarget is Field) {
       // TODO(ahe): In strong mode we should probably rewrite this to
       // `this.name.call(arguments)`.

pkg/front_end/testcases/extensions/internal_resolution.dart

@@ -0,0 +1,33 @@
+// 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.
+
+class Class {
+  int field;
+}
+
+extension on Class {
+  int get property1 => property2;
+  void set property1(int value) => field = value;
+}
+
+extension on Class {
+  int get property2 => field;
+  void set property2(int value) => property1 = value;
+}
+
+main() {
+  var c = new Class();
+  expect(null, c.property1);
+  expect(null, c.property2);
+  expect(42, c.property1 = 42);
+  expect(42, c.property2);
+  expect(87, c.property2 = 87);
+  expect(87, c.property1);
+}
+
+expect(expected, actual) {
+  if (expected != actual) {
+    throw 'Mismatch: expected=$expected, actual=$actual';
+  }
+}

pkg/front_end/testcases/extensions/internal_resolution.dart.outline.expect

@@ -0,0 +1,29 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class Class extends core::Object {
+  field core::int* field;
+  synthetic constructor •() → self::Class*
+    ;
+}
+extension _extension#0 on self::Class* {
+  get property1 = self::_extension#0|get#property1;
+  set property1 = self::_extension#0|set#property1;
+}
+extension _extension#1 on self::Class* {
+  get property2 = self::_extension#1|get#property2;
+  set property2 = self::_extension#1|set#property2;
+}
+static method _extension#0|get#property1(final self::Class* #this) → core::int*
+  ;
+static method _extension#0|set#property1(final self::Class* #this, core::int* value) → void
+  ;
+static method _extension#1|get#property2(final self::Class* #this) → core::int*
+  ;
+static method _extension#1|set#property2(final self::Class* #this, core::int* value) → void
+  ;
+static method main() → dynamic
+  ;
+static method expect(dynamic expected, dynamic actual) → dynamic
+  ;

pkg/front_end/testcases/extensions/internal_resolution.dart.strong.expect

@@ -0,0 +1,46 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class Class extends core::Object {
+  field core::int* field = null;
+  synthetic constructor •() → self::Class*
+    : super core::Object::•()
+    ;
+}
+extension _extension#0 on self::Class* {
+  get property1 = self::_extension#0|get#property1;
+  set property1 = self::_extension#0|set#property1;
+}
+extension _extension#1 on self::Class* {
+  get property2 = self::_extension#1|get#property2;
+  set property2 = self::_extension#1|set#property2;
+}
+static method _extension#0|get#property1(final self::Class* #this) → core::int*
+  return self::_extension#1|get#property2(#this);
+static method _extension#0|set#property1(final self::Class* #this, core::int* value) → core::int* {
+  final core::int* #t1 = value;
+  return #this.{self::Class::field} = value;
+  return #t1;
+}
+static method _extension#1|get#property2(final self::Class* #this) → core::int*
+  return #this.{self::Class::field};
+static method _extension#1|set#property2(final self::Class* #this, core::int* value) → core::int* {
+  final core::int* #t2 = value;
+  return self::_extension#0|set#property1(#this, value);
+  return #t2;
+}
+static method main() → dynamic {
+  self::Class* c = new self::Class::•();
+  self::expect(null, self::_extension#0|get#property1(c));
+  self::expect(null, self::_extension#1|get#property2(c));
+  self::expect(42, self::_extension#0|set#property1(c, 42));
+  self::expect(42, self::_extension#1|get#property2(c));
+  self::expect(87, self::_extension#1|set#property2(c, 87));
+  self::expect(87, self::_extension#0|get#property1(c));
+}
+static method expect(dynamic expected, dynamic actual) → dynamic {
+  if(!expected.{core::Object::==}(actual)) {
+    throw "Mismatch: expected=${expected}, actual=${actual}";
+  }
+}

pkg/front_end/testcases/extensions/internal_resolution.dart.strong.transformed.expect

@@ -0,0 +1,46 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class Class extends core::Object {
+  field core::int* field = null;
+  synthetic constructor •() → self::Class*
+    : super core::Object::•()
+    ;
+}
+extension _extension#0 on self::Class* {
+  get property1 = self::_extension#0|get#property1;
+  set property1 = self::_extension#0|set#property1;
+}
+extension _extension#1 on self::Class* {
+  get property2 = self::_extension#1|get#property2;
+  set property2 = self::_extension#1|set#property2;
+}
+static method _extension#0|get#property1(final self::Class* #this) → core::int*
+  return self::_extension#1|get#property2(#this);
+static method _extension#0|set#property1(final self::Class* #this, core::int* value) → core::int* {
+  final core::int* #t1 = value;
+  return #this.{self::Class::field} = value;
+  return #t1;
+}
+static method _extension#1|get#property2(final self::Class* #this) → core::int*
+  return #this.{self::Class::field};
+static method _extension#1|set#property2(final self::Class* #this, core::int* value) → core::int* {
+  final core::int* #t2 = value;
+  return self::_extension#0|set#property1(#this, value);
+  return #t2;
+}
+static method main() → dynamic {
+  self::Class* c = new self::Class::•();
+  self::expect(null, self::_extension#0|get#property1(c));
+  self::expect(null, self::_extension#1|get#property2(c));
+  self::expect(42, self::_extension#0|set#property1(c, 42));
+  self::expect(42, self::_extension#1|get#property2(c));
+  self::expect(87, self::_extension#1|set#property2(c, 87));
+  self::expect(87, self::_extension#0|get#property1(c));
+}
+static method expect(dynamic expected, dynamic actual) → dynamic {
+  if(!expected.{core::Object::==}(actual)) {
+    throw "Mismatch: expected=${expected}, actual=${actual}";
+  }
+}

pkg/front_end/testcases/general/accessors.dart.strong.expect

@@ -2,20 +2,12 @@ library;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/accessors.dart:16:13: Error: Getter not found: 'onlySetter'.
-//       print(onlySetter);
-//             ^^^^^^^^^^
-//
 // pkg/front_end/testcases/general/accessors.dart:16:13: Error: The getter 'onlySetter' isn't defined for the class 'C'.
 //  - 'C' is from 'pkg/front_end/testcases/general/accessors.dart'.
 // Try correcting the name to the name of an existing getter, or defining a getter or field named 'onlySetter'.
 //       print(onlySetter);
 //             ^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/accessors.dart:25:11: Error: Getter not found: 'onlySetter'.
-//     print(onlySetter);
-//           ^^^^^^^^^^
-//
 // pkg/front_end/testcases/general/accessors.dart:25:11: Error: The getter 'onlySetter' isn't defined for the class 'C'.
 //  - 'C' is from 'pkg/front_end/testcases/general/accessors.dart'.
 // Try correcting the name to the name of an existing getter, or defining a getter or field named 'onlySetter'.

pkg/front_end/testcases/general/accessors.dart.strong.transformed.expect

@@ -2,20 +2,12 @@ library;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/accessors.dart:16:13: Error: Getter not found: 'onlySetter'.
-//       print(onlySetter);
-//             ^^^^^^^^^^
-//
 // pkg/front_end/testcases/general/accessors.dart:16:13: Error: The getter 'onlySetter' isn't defined for the class 'C'.
 //  - 'C' is from 'pkg/front_end/testcases/general/accessors.dart'.
 // Try correcting the name to the name of an existing getter, or defining a getter or field named 'onlySetter'.
 //       print(onlySetter);
 //             ^^^^^^^^^^
 //
-// pkg/front_end/testcases/general/accessors.dart:25:11: Error: Getter not found: 'onlySetter'.
-//     print(onlySetter);
-//           ^^^^^^^^^^
-//
 // pkg/front_end/testcases/general/accessors.dart:25:11: Error: The getter 'onlySetter' isn't defined for the class 'C'.
 //  - 'C' is from 'pkg/front_end/testcases/general/accessors.dart'.
 // Try correcting the name to the name of an existing getter, or defining a getter or field named 'onlySetter'.

pkg/front_end/testcases/general/for_in_without_declaration.dart.strong.expect

@@ -18,14 +18,6 @@ library;
 //     for (c.untypedSuperInstanceField in []) {}
 //           ^
 //
-// pkg/front_end/testcases/general/for_in_without_declaration.dart:37:10: Error: Setter not found: 'unresolved'.
-//     for (unresolved in []) {}
-//          ^^^^^^^^^^
-//
-// pkg/front_end/testcases/general/for_in_without_declaration.dart:38:10: Error: Getter not found: 'unresolved'.
-//     for (unresolved.foo in []) {}
-//          ^^^^^^^^^^
-//
 // pkg/front_end/testcases/general/for_in_without_declaration.dart:38:20: Error: Unexpected token '.'.
 //     for (unresolved.foo in []) {}
 //                    ^

pkg/front_end/testcases/general/for_in_without_declaration.dart.strong.transformed.expect

@@ -18,14 +18,6 @@ library;
 //     for (c.untypedSuperInstanceField in []) {}
 //           ^
 //
-// pkg/front_end/testcases/general/for_in_without_declaration.dart:37:10: Error: Setter not found: 'unresolved'.
-//     for (unresolved in []) {}
-//          ^^^^^^^^^^
-//
-// pkg/front_end/testcases/general/for_in_without_declaration.dart:38:10: Error: Getter not found: 'unresolved'.
-//     for (unresolved.foo in []) {}
-//          ^^^^^^^^^^
-//
 // pkg/front_end/testcases/general/for_in_without_declaration.dart:38:20: Error: Unexpected token '.'.
 //     for (unresolved.foo in []) {}
 //                    ^

pkg/front_end/testcases/rasta/issue_000044.dart.strong.expect

@@ -48,10 +48,6 @@ library;
 //   C notEvenAConstructor(a) = h;
 //                            ^
 //
-// pkg/front_end/testcases/rasta/issue_000044.dart:21:30: Error: Getter not found: 'h'.
-//   C notEvenAConstructor(a) = h;
-//                              ^
-//
 // pkg/front_end/testcases/rasta/issue_000044.dart:21:30: Error: The getter 'h' isn't defined for the class 'C'.
 //  - 'C' is from 'pkg/front_end/testcases/rasta/issue_000044.dart'.
 // Try correcting the name to the name of an existing getter, or defining a getter or field named 'h'.

pkg/front_end/testcases/rasta/issue_000044.dart.strong.transformed.expect

@@ -48,10 +48,6 @@ library;
 //   C notEvenAConstructor(a) = h;
 //                            ^
 //
-// pkg/front_end/testcases/rasta/issue_000044.dart:21:30: Error: Getter not found: 'h'.
-//   C notEvenAConstructor(a) = h;
-//                              ^
-//
 // pkg/front_end/testcases/rasta/issue_000044.dart:21:30: Error: The getter 'h' isn't defined for the class 'C'.
 //  - 'C' is from 'pkg/front_end/testcases/rasta/issue_000044.dart'.
 // Try correcting the name to the name of an existing getter, or defining a getter or field named 'h'.

pkg/front_end/testcases/rasta/unresolved_for_in.dart.strong.expect

@@ -2,14 +2,6 @@ library;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/rasta/unresolved_for_in.dart:12:13: Error: Getter not found: 'key'.
-//       print(key);
-//             ^^^
-//
-// pkg/front_end/testcases/rasta/unresolved_for_in.dart:11:10: Error: Setter not found: 'key'.
-//     for (key in x) {
-//          ^^^
-//
 // pkg/front_end/testcases/rasta/unresolved_for_in.dart:14:10: Error: Setter not found: 'Fisk'.
 //     for (Fisk in x) {
 //          ^^^^
@@ -30,10 +22,6 @@ library;
 //     for (1 in x) {
 //          ^
 //
-// pkg/front_end/testcases/rasta/unresolved_for_in.dart:24:13: Error: Getter not found: 'key'.
-//       print(key);
-//             ^^^
-//
 // pkg/front_end/testcases/rasta/unresolved_for_in.dart:23:10: Error: Can't assign to this, so it can't be used in a for-in loop.
 //     for (1 in x) {
 //          ^

pkg/front_end/testcases/rasta/unresolved_for_in.dart.strong.transformed.expect

@@ -2,14 +2,6 @@ library;
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/rasta/unresolved_for_in.dart:12:13: Error: Getter not found: 'key'.
-//       print(key);
-//             ^^^
-//
-// pkg/front_end/testcases/rasta/unresolved_for_in.dart:11:10: Error: Setter not found: 'key'.
-//     for (key in x) {
-//          ^^^
-//
 // pkg/front_end/testcases/rasta/unresolved_for_in.dart:14:10: Error: Setter not found: 'Fisk'.
 //     for (Fisk in x) {
 //          ^^^^
@@ -30,10 +22,6 @@ library;
 //     for (1 in x) {
 //          ^
 //
-// pkg/front_end/testcases/rasta/unresolved_for_in.dart:24:13: Error: Getter not found: 'key'.
-//       print(key);
-//             ^^^
-//
 // pkg/front_end/testcases/rasta/unresolved_for_in.dart:23:10: Error: Can't assign to this, so it can't be used in a for-in loop.
 //     for (1 in x) {
 //          ^

pkg/front_end/testcases/text_serialization.status

@@ -20,6 +20,7 @@ extensions/extension_methods: TextSerializationFailure
 extensions/implicit_extension_inference: TextSerializationFailure
 extensions/implicit_this: TextSerializationFailure
 extensions/index: TextSerializationFailure
+extensions/internal_resolution: TextSerializationFailure
 extensions/instance_access: TextSerializationFailure
 extensions/instance_access_of_static: TextSerializationFailure
 extensions/instance_members: TextSerializationFailure