diff --git a/pkg/front_end/testcases/extension_methods.dart b/pkg/front_end/testcases/extension_methods.dart
new file mode 100644
index 0000000..51013db
--- /dev/null
+++ b/pkg/front_end/testcases/extension_methods.dart
@@ -0,0 +1,21 @@
+// 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.
+
+// SharedOptions=--enable-experiment=extension-methods
+
+import 'package:expect/expect.dart';
+
+class C {
+  int get one => 1;
+}
+
+extension E on C {
+  int get two => 2;
+}
+
+main() {
+  C c = C();
+  var result = c.one + c.two;
+  Expect.equals(result, 3);
+}
diff --git a/pkg/front_end/testcases/extension_methods.dart.hierarchy.expect b/pkg/front_end/testcases/extension_methods.dart.hierarchy.expect
new file mode 100644
index 0000000..af7781c
--- /dev/null
+++ b/pkg/front_end/testcases/extension_methods.dart.hierarchy.expect
@@ -0,0 +1,418 @@
+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:
+
+C:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+    C.one
+  classSetters:
+
+Expect:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Expect.identical
+    Expect.throwsCastError
+    Expect._fail
+    Expect.notIdentical
+    Expect.isNotNull
+    Expect._getMessage
+    Expect.allIdentical
+    Expect._escapeSubstring
+    Expect.fail
+    Expect._truncateString
+    Expect.isFalse
+    Expect.isTrue
+    Object.toString
+    Expect.subtype
+    Expect.throwsRangeError
+    Expect._stringDifference
+    Expect.throwsArgumentError
+    Expect.stringEquals
+    Object.runtimeType
+    Expect.testError
+    Expect.throwsStateError
+    Object._simpleInstanceOf
+    Expect.isNull
+    Expect.approxEquals
+    Expect.equals
+    Object._instanceOf
+    Expect.allDistinct
+    Expect.throwsTypeError
+    Expect._subtypeAtRuntime
+    Expect.setEquals
+    Object.noSuchMethod
+    Expect.notEquals
+    Expect.listEquals
+    Expect._findEquivalences
+    Expect.mapEquals
+    Object._identityHashCode
+    Expect.throwsUnsupportedError
+    Expect.notType
+    Expect.deepEquals
+    Expect._escapeString
+    Expect.type
+    Object.hashCode
+    Expect.throwsNoSuchMethodError
+    Expect.notSubtype
+    Expect.throws
+    Object._simpleInstanceOfFalse
+    Expect._writeEquivalences
+    Expect.throwsAssertionError
+    Object._simpleInstanceOfTrue
+    Object.==
+    Expect.throwsFormatException
+  classSetters:
+
+Exception:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+ExpectException:
+  Longest path to Object: 2
+  superclasses:
+    Object
+  interfaces: Exception
+  classMembers:
+    ExpectException.message
+    ExpectException.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+  interfaceMembers:
+    ExpectException.message
+    ExpectException.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  interfaceSetters:
+
+Immutable:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Immutable.reason
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+Required:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Required.reason
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_AlwaysThrows:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_Checked:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_Experimental:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_Factory:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_IsTest:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_IsTestGroup:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_Literal:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_MustCallSuper:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_OptionalTypeArgs:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_Protected:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_Sealed:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_Virtual:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_VisibleForOverriding:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
+
+_VisibleForTesting:
+  superclasses:
+    Object
+  interfaces:
+  classMembers:
+    Object.toString
+    Object.runtimeType
+    Object._simpleInstanceOf
+    Object._instanceOf
+    Object.noSuchMethod
+    Object._identityHashCode
+    Object.hashCode
+    Object._simpleInstanceOfFalse
+    Object._simpleInstanceOfTrue
+    Object.==
+  classSetters:
diff --git a/pkg/front_end/testcases/extension_methods.dart.legacy.expect b/pkg/front_end/testcases/extension_methods.dart.legacy.expect
new file mode 100644
index 0000000..7fd1230
--- /dev/null
+++ b/pkg/front_end/testcases/extension_methods.dart.legacy.expect
@@ -0,0 +1,71 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Error: This requires the 'extension-methods' experiment to be enabled.
+// Try enabling this experiment by adding it to the command line when compiling and running.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:16: Error: A function declaration needs an explicit list of parameters.
+// Try adding a parameter list to the function declaration.
+// extension E on C {
+//                ^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:16: Error: 'C' is already declared in this scope.
+// extension E on C {
+//                ^
+// pkg/front_end/testcases/extension_methods.dart:9:7: Context: Previous declaration of 'C'.
+// class C {
+//       ^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Warning: Type 'extension' not found.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:13: Warning: Type 'on' not found.
+// extension E on C {
+//             ^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Warning: 'extension' isn't a type.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:14:7: Error: Expected ';' after this.
+//   int get two => 2;
+//       ^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:14:15: Error: A function declaration needs an explicit list of parameters.
+// Try adding a parameter list to the function declaration.
+//   int get two => 2;
+//               ^^
+//
+// pkg/front_end/testcases/extension_methods.dart:18:3: Error: Can't use 'C' because it is declared more than once.
+//   C c = C();
+//   ^
+//
+// pkg/front_end/testcases/extension_methods.dart:18:9: Error: Can't use 'C' because it is declared more than once.
+//   C c = C();
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+import "package:expect/expect.dart" as exp;
+
+import "package:expect/expect.dart";
+
+class C extends core::Object {
+  synthetic constructor •() → self::C
+    : super core::Object::•()
+    ;
+  get one() → core::int
+    return 1;
+}
+static field invalid-type E;
+static method main() → dynamic {
+  invalid-type c = invalid-expression "pkg/front_end/testcases/extension_methods.dart:18:9: Error: Can't use 'C' because it is declared more than once.
+  C c = C();
+        ^".call();
+  dynamic result = c.one.+(c.two);
+  exp::Expect::equals(result, 3);
+}
diff --git a/pkg/front_end/testcases/extension_methods.dart.legacy.transformed.expect b/pkg/front_end/testcases/extension_methods.dart.legacy.transformed.expect
new file mode 100644
index 0000000..7fd1230
--- /dev/null
+++ b/pkg/front_end/testcases/extension_methods.dart.legacy.transformed.expect
@@ -0,0 +1,71 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Error: This requires the 'extension-methods' experiment to be enabled.
+// Try enabling this experiment by adding it to the command line when compiling and running.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:16: Error: A function declaration needs an explicit list of parameters.
+// Try adding a parameter list to the function declaration.
+// extension E on C {
+//                ^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:16: Error: 'C' is already declared in this scope.
+// extension E on C {
+//                ^
+// pkg/front_end/testcases/extension_methods.dart:9:7: Context: Previous declaration of 'C'.
+// class C {
+//       ^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Warning: Type 'extension' not found.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:13: Warning: Type 'on' not found.
+// extension E on C {
+//             ^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Warning: 'extension' isn't a type.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:14:7: Error: Expected ';' after this.
+//   int get two => 2;
+//       ^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:14:15: Error: A function declaration needs an explicit list of parameters.
+// Try adding a parameter list to the function declaration.
+//   int get two => 2;
+//               ^^
+//
+// pkg/front_end/testcases/extension_methods.dart:18:3: Error: Can't use 'C' because it is declared more than once.
+//   C c = C();
+//   ^
+//
+// pkg/front_end/testcases/extension_methods.dart:18:9: Error: Can't use 'C' because it is declared more than once.
+//   C c = C();
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+import "package:expect/expect.dart" as exp;
+
+import "package:expect/expect.dart";
+
+class C extends core::Object {
+  synthetic constructor •() → self::C
+    : super core::Object::•()
+    ;
+  get one() → core::int
+    return 1;
+}
+static field invalid-type E;
+static method main() → dynamic {
+  invalid-type c = invalid-expression "pkg/front_end/testcases/extension_methods.dart:18:9: Error: Can't use 'C' because it is declared more than once.
+  C c = C();
+        ^".call();
+  dynamic result = c.one.+(c.two);
+  exp::Expect::equals(result, 3);
+}
diff --git a/pkg/front_end/testcases/extension_methods.dart.outline.expect b/pkg/front_end/testcases/extension_methods.dart.outline.expect
new file mode 100644
index 0000000..ccb8e3f
--- /dev/null
+++ b/pkg/front_end/testcases/extension_methods.dart.outline.expect
@@ -0,0 +1,43 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Error: This requires the 'extension-methods' experiment to be enabled.
+// Try enabling this experiment by adding it to the command line when compiling and running.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:16: Error: A function declaration needs an explicit list of parameters.
+// Try adding a parameter list to the function declaration.
+// extension E on C {
+//                ^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:16: Error: 'C' is already declared in this scope.
+// extension E on C {
+//                ^
+// pkg/front_end/testcases/extension_methods.dart:9:7: Context: Previous declaration of 'C'.
+// class C {
+//       ^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Warning: Type 'extension' not found.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:13: Warning: Type 'on' not found.
+// extension E on C {
+//             ^^
+//
+import self as self;
+import "dart:core" as core;
+
+import "package:expect/expect.dart";
+
+class C extends core::Object {
+  synthetic constructor •() → self::C
+    ;
+  get one() → core::int
+    ;
+}
+static field invalid-type E;
+static method main() → dynamic
+  ;
diff --git a/pkg/front_end/testcases/extension_methods.dart.strong.expect b/pkg/front_end/testcases/extension_methods.dart.strong.expect
new file mode 100644
index 0000000..b3845b4
--- /dev/null
+++ b/pkg/front_end/testcases/extension_methods.dart.strong.expect
@@ -0,0 +1,71 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Error: This requires the 'extension-methods' experiment to be enabled.
+// Try enabling this experiment by adding it to the command line when compiling and running.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:16: Error: A function declaration needs an explicit list of parameters.
+// Try adding a parameter list to the function declaration.
+// extension E on C {
+//                ^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:16: Error: 'C' is already declared in this scope.
+// extension E on C {
+//                ^
+// pkg/front_end/testcases/extension_methods.dart:9:7: Context: Previous declaration of 'C'.
+// class C {
+//       ^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Error: Type 'extension' not found.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:13: Error: Type 'on' not found.
+// extension E on C {
+//             ^^
+//
+// pkg/front_end/testcases/extension_methods.dart:13:1: Error: 'extension' isn't a type.
+// extension E on C {
+// ^^^^^^^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:14:7: Error: Expected ';' after this.
+//   int get two => 2;
+//       ^^^
+//
+// pkg/front_end/testcases/extension_methods.dart:14:15: Error: A function declaration needs an explicit list of parameters.
+// Try adding a parameter list to the function declaration.
+//   int get two => 2;
+//               ^^
+//
+// pkg/front_end/testcases/extension_methods.dart:18:3: Error: Can't use 'C' because it is declared more than once.
+//   C c = C();
+//   ^
+//
+// pkg/front_end/testcases/extension_methods.dart:18:9: Error: Can't use 'C' because it is declared more than once.
+//   C c = C();
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+import "package:expect/expect.dart" as exp;
+
+import "package:expect/expect.dart";
+
+class C extends core::Object {
+  synthetic constructor •() → self::C
+    : super core::Object::•()
+    ;
+  get one() → core::int
+    return 1;
+}
+static field invalid-type E;
+static method main() → dynamic {
+  invalid-type c = invalid-expression "pkg/front_end/testcases/extension_methods.dart:18:9: Error: Can't use 'C' because it is declared more than once.
+  C c = C();
+        ^".call() as{TypeError} invalid-type;
+  dynamic result = c.one.+(c.two);
+  exp::Expect::equals(result, 3);
+}
diff --git a/pkg/front_end/testcases/legacy.status b/pkg/front_end/testcases/legacy.status
index b1b1917..e98216b 100644
--- a/pkg/front_end/testcases/legacy.status
+++ b/pkg/front_end/testcases/legacy.status
@@ -13,6 +13,7 @@
 constructor_initializer_invalid: RuntimeError # Fails execution after recovery
 control_flow_collection: RuntimeError
 duplicated_field_initializer: RuntimeError
+extension_methods: RuntimeError
 external_import: RuntimeError # Expected -- test uses import which doesn't exist.
 fallthrough: Fail # Missing FallThroughError.
 function_type_recovery: Fail
diff --git a/pkg/front_end/testcases/strong.status b/pkg/front_end/testcases/strong.status
index 79ac736..58b6314 100644
--- a/pkg/front_end/testcases/strong.status
+++ b/pkg/front_end/testcases/strong.status
@@ -22,6 +22,7 @@
 duplicated_field_initializer: RuntimeError
 dynamic_and_void: InstrumentationMismatch # Test assumes Dart 1.0 semantics
 expressions: RuntimeError
+extension_methods: TypeCheckError
 external_import: RuntimeError # The native extension to import doesn't exist. This is ok.
 fallthrough: ExpectationFileMismatch
 incomplete_field_formal_parameter: RuntimeError
diff --git a/pkg/front_end/testcases/text_serialization.status b/pkg/front_end/testcases/text_serialization.status
index 8508fee..da910da 100644
--- a/pkg/front_end/testcases/text_serialization.status
+++ b/pkg/front_end/testcases/text_serialization.status
@@ -90,6 +90,7 @@
 expression/eval: TextSerializationFailure # Was: Pass
 expression/main: TextSerializationFailure # Was: Pass
 expressions: TextSerializationFailure # Was: RuntimeError
+extension_methods: TypeCheckError
 external: TextSerializationFailure # Was: Pass
 external_import: TextSerializationFailure # Was: RuntimeError # The native extension to import doesn't exist. This is ok.
 fallthrough: ExpectationFileMismatch