diff --git a/pkg/front_end/lib/src/fasta/builder/extension_builder.dart b/pkg/front_end/lib/src/fasta/builder/extension_builder.dart
index 8984604182d..7d63204fc12 100644
--- a/pkg/front_end/lib/src/fasta/builder/extension_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/extension_builder.dart
@@ -93,4 +93,17 @@ abstract class ExtensionBuilder extends DeclarationBuilder {
 
   @override
   String get debugName => "ExtensionBuilder";
+
+  void buildOutlineExpressions(LibraryBuilder library) {
+    void build(String ignore, Builder declaration) {
+      MemberBuilder member = declaration;
+      member.buildOutlineExpressions(library);
+    }
+
+    // TODO(johnniwinther): Handle annotations on the extension declaration.
+    //MetadataBuilder.buildAnnotations(
+    //    isPatch ? origin.extension : extension,
+    //    metadata, library, this, null);
+    scope.forEach(build);
+  }
 }
diff --git a/pkg/front_end/lib/src/fasta/source/source_loader.dart b/pkg/front_end/lib/src/fasta/source/source_loader.dart
index eeb0bac1bf0..cd2c0bf4599 100644
--- a/pkg/front_end/lib/src/fasta/source/source_loader.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_loader.dart
@@ -37,6 +37,8 @@ import '../../base/instrumentation.dart' show Instrumentation;
 
 import '../blacklisted_classes.dart' show blacklistedCoreClasses;
 
+import '../builder/extension_builder.dart';
+
 import '../export.dart' show Export;
 
 import '../import.dart' show Import;
@@ -968,6 +970,8 @@ class SourceLoader extends Loader {
           Builder declaration = iterator.current;
           if (declaration is ClassBuilder) {
             declaration.buildOutlineExpressions(library);
+          } else if (declaration is ExtensionBuilder) {
+            declaration.buildOutlineExpressions(library);
           } else if (declaration is MemberBuilder) {
             declaration.buildOutlineExpressions(library);
           }
diff --git a/pkg/front_end/testcases/extensions/annotations.dart b/pkg/front_end/testcases/extensions/annotations.dart
new file mode 100644
index 00000000000..0e0b623b4c8
--- /dev/null
+++ b/pkg/front_end/testcases/extensions/annotations.dart
@@ -0,0 +1,24 @@
+// 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 {
+  @pragma('dart2js:noInline')
+  instanceMethod() {}
+
+  @pragma('dart2js:noInline')
+  static staticMethod() {}
+}
+
+extension Extension on Class {
+  @pragma('dart2js:noInline')
+  extensionInstanceMethod() {}
+
+  @pragma('dart2js:noInline')
+  static extensionStaticMethod() {}
+}
+
+@pragma('dart2js:noInline')
+topLevelMethod() {}
+
+main() {}
diff --git a/pkg/front_end/testcases/extensions/annotations.dart.outline.expect b/pkg/front_end/testcases/extensions/annotations.dart.outline.expect
new file mode 100644
index 00000000000..1c723318e51
--- /dev/null
+++ b/pkg/front_end/testcases/extensions/annotations.dart.outline.expect
@@ -0,0 +1,32 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class Class extends core::Object {
+  synthetic constructor •() → self::Class*
+    ;
+  @core::pragma::_("dart2js:noInline")
+  method instanceMethod() → dynamic
+    ;
+  @core::pragma::_("dart2js:noInline")
+  static method staticMethod() → dynamic
+    ;
+}
+extension Extension on self::Class* {
+  method extensionInstanceMethod = self::Extension|extensionInstanceMethod;
+  tearoff extensionInstanceMethod = self::Extension|get#extensionInstanceMethod;
+  static method extensionStaticMethod = self::Extension|extensionStaticMethod;
+}
+@core::pragma::_("dart2js:noInline")
+static method Extension|extensionInstanceMethod(final self::Class* #this) → dynamic
+  ;
+static method Extension|get#extensionInstanceMethod(final self::Class* #this) → () →* dynamic
+  return () → dynamic => self::Extension|extensionInstanceMethod(#this);
+@core::pragma::_("dart2js:noInline")
+static method Extension|extensionStaticMethod() → dynamic
+  ;
+@core::pragma::_("dart2js:noInline")
+static method topLevelMethod() → dynamic
+  ;
+static method main() → dynamic
+  ;
diff --git a/pkg/front_end/testcases/extensions/annotations.dart.strong.expect b/pkg/front_end/testcases/extensions/annotations.dart.strong.expect
new file mode 100644
index 00000000000..73aac112389
--- /dev/null
+++ b/pkg/front_end/testcases/extensions/annotations.dart.strong.expect
@@ -0,0 +1,33 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class Class extends core::Object {
+  synthetic constructor •() → self::Class*
+    : super core::Object::•()
+    ;
+  @#C3
+  method instanceMethod() → dynamic {}
+  @#C3
+  static method staticMethod() → dynamic {}
+}
+extension Extension on self::Class* {
+  method extensionInstanceMethod = self::Extension|extensionInstanceMethod;
+  tearoff extensionInstanceMethod = self::Extension|get#extensionInstanceMethod;
+  static method extensionStaticMethod = self::Extension|extensionStaticMethod;
+}
+@#C3
+static method Extension|extensionInstanceMethod(final self::Class* #this) → dynamic {}
+static method Extension|get#extensionInstanceMethod(final self::Class* #this) → () →* dynamic
+  return () → dynamic => self::Extension|extensionInstanceMethod(#this);
+@#C3
+static method Extension|extensionStaticMethod() → dynamic {}
+@#C3
+static method topLevelMethod() → dynamic {}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = "dart2js:noInline"
+  #C2 = null
+  #C3 = core::pragma {name:#C1, options:#C2}
+}
diff --git a/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect
new file mode 100644
index 00000000000..73aac112389
--- /dev/null
+++ b/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect
@@ -0,0 +1,33 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class Class extends core::Object {
+  synthetic constructor •() → self::Class*
+    : super core::Object::•()
+    ;
+  @#C3
+  method instanceMethod() → dynamic {}
+  @#C3
+  static method staticMethod() → dynamic {}
+}
+extension Extension on self::Class* {
+  method extensionInstanceMethod = self::Extension|extensionInstanceMethod;
+  tearoff extensionInstanceMethod = self::Extension|get#extensionInstanceMethod;
+  static method extensionStaticMethod = self::Extension|extensionStaticMethod;
+}
+@#C3
+static method Extension|extensionInstanceMethod(final self::Class* #this) → dynamic {}
+static method Extension|get#extensionInstanceMethod(final self::Class* #this) → () →* dynamic
+  return () → dynamic => self::Extension|extensionInstanceMethod(#this);
+@#C3
+static method Extension|extensionStaticMethod() → dynamic {}
+@#C3
+static method topLevelMethod() → dynamic {}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = "dart2js:noInline"
+  #C2 = null
+  #C3 = core::pragma {name:#C1, options:#C2}
+}
diff --git a/pkg/front_end/testcases/text_serialization.status b/pkg/front_end/testcases/text_serialization.status
index 678a2f49f03..8d5b8d11f87 100644
--- a/pkg/front_end/testcases/text_serialization.status
+++ b/pkg/front_end/testcases/text_serialization.status
@@ -9,6 +9,7 @@
 all_variances: TextSerializationFailure
 expression/eval: TextSerializationFailure # Was: Pass
 expression/main: TextSerializationFailure # Was: Pass
+extensions/annotations: TextSerializationFailure
 extensions/compounds: TextSerializationFailure
 extensions/conflicts: TextSerializationFailure
 extensions/direct_instance_access: TextSerializationFailure