Avoid crashing on this property access

Fixes #35875

Change-Id: I5ae2f73cd792aae165e787d7856b0af9a7c2e19e
Reviewed-on: https://dart-review.googlesource.com/c/92282
Commit-Queue: Peter von der Ahé <[email protected]>
Commit-Queue: Kevin Millikin <[email protected]>
Auto-Submit: Peter von der Ahé <[email protected]>
Reviewed-by: Kevin Millikin <[email protected]>

Author: peter-ahe-google

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

@@ -296,7 +296,10 @@ abstract class PropertyAccessGenerator implements Generator {
       Member setter,
       bool isNullAware) {
     if (helper.forest.isThisExpression(receiver)) {
-      return unsupported("ThisExpression", offsetForToken(token), helper.uri);
+      getter ??= helper.lookupInstanceMember(name);
+      setter ??= helper.lookupInstanceMember(name, isSetter: true);
+      return new ThisPropertyAccessGenerator(
+          helper, token, name, getter, setter);
     } else {
       return isNullAware
           ? new NullAwarePropertyAccessGenerator(

pkg/front_end/testcases/issue35875.dart

@@ -0,0 +1,12 @@
+// 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 A {
+  int a;
+  A(int a) {
+    (this).a = a;
+  }
+}
+
+main() {}

pkg/front_end/testcases/issue35875.dart.hierarchy.expect

@@ -0,0 +1,38 @@
+Object:
+  superclasses:
+  interfaces:
+  classMembers:
+    Object._haveSameRuntimeType
+    Object.toString
+    Object.runtimeType
+    Object._toString
+    Object._simpleInstanceOf
+    Object._hashCodeRnd
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._objectHashCode
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+A:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    A.a
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+    A.a

pkg/front_end/testcases/issue35875.dart.legacy.expect

@@ -0,0 +1,12 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int a = null;
+  constructor •(core::int a) → self::A
+    : super core::Object::•() {
+    this.{self::A::a} = a;
+  }
+}
+static method main() → dynamic {}

pkg/front_end/testcases/issue35875.dart.legacy.transformed.expect

@@ -0,0 +1,12 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int a = null;
+  constructor •(core::int a) → self::A
+    : super core::Object::•() {
+    this.{self::A::a} = a;
+  }
+}
+static method main() → dynamic {}

pkg/front_end/testcases/issue35875.dart.outline.expect

@@ -0,0 +1,11 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int a;
+  constructor •(core::int a) → self::A
+    ;
+}
+static method main() → dynamic
+  ;

pkg/front_end/testcases/issue35875.dart.strong.expect

@@ -0,0 +1,12 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int a = null;
+  constructor •(core::int a) → self::A
+    : super core::Object::•() {
+    this.{self::A::a} = a;
+  }
+}
+static method main() → dynamic {}

pkg/front_end/testcases/issue35875.dart.strong.transformed.expect

@@ -0,0 +1,12 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  field core::int a = null;
+  constructor •(core::int a) → self::A
+    : super core::Object::•() {
+    this.{self::A::a} = a;
+  }
+}
+static method main() → dynamic {}

pkg/front_end/testcases/text_serialization.status

@@ -667,6 +667,7 @@ invalid_type: TypeCheckError
 invocations: TextSerializationFailure # Was: RuntimeError
 issue34515: TextSerializationFailure
 issue34899: TypeCheckError
+issue35875: TextSerializationFailure
 literals: TextSerializationFailure # Was: Pass
 local_generic_function: TextSerializationFailure # Was: Pass
 magic_const: TextSerializationFailure # Was: Pass