diff --git a/tests/language/variance/syntax/variance_disabled_keyword_identifier_syntax_test.dart b/tests/language/variance/syntax/variance_disabled_keyword_identifier_syntax_test.dart
new file mode 100644
index 000000000000..0d6828c30022
--- /dev/null
+++ b/tests/language/variance/syntax/variance_disabled_keyword_identifier_syntax_test.dart
@@ -0,0 +1,48 @@
+// 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.
+
+// Tests identifier usage of keywords `out` and `inout`, correct usage of `in`.
+
+import "package:expect/expect.dart";
+
+class A<out> {}
+
+class B<inout> {}
+
+class C<out, inout> {}
+
+F<inout, out>() {}
+
+mixin G<out, inout> {}
+
+typedef H<inout, out> = out Function(inout);
+
+class OutParameter {
+  var out = 3;
+  int func(int out) {
+    return out;
+  }
+}
+
+class inout {
+  void out(int x) {}
+}
+
+var out = 5;
+
+main() {
+  OutParameter x = new OutParameter();
+  Expect.equals(2, x.func(2));
+  Expect.equals(3, x.out);
+
+  inout foo = inout();
+  foo.out(4);
+
+  Expect.equals(5, out);
+
+  var collection = [0, 1, 2];
+  for (var x in collection) {
+    Expect.isTrue(x is int);
+  }
+}
diff --git a/tests/language/variance/syntax/variance_disabled_syntax_test.dart b/tests/language/variance/syntax/variance_disabled_syntax_test.dart
new file mode 100644
index 000000000000..2811208a794b
--- /dev/null
+++ b/tests/language/variance/syntax/variance_disabled_syntax_test.dart
@@ -0,0 +1,76 @@
+// 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.
+
+// Tests with `variance` flag disabled
+// Correct variance modifier usage will issue an error.
+
+import 'package:expect/expect.dart';
+
+abstract class A<in X> {
+//               ^^
+// [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
+// [cfe] This requires the 'variance' language feature to be enabled.
+  int foo(X bar);
+}
+
+class B<out X, in Y, inout Z> {}
+//      ^^^
+// [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
+// [cfe] This requires the 'variance' language feature to be enabled.
+//             ^^
+// [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
+// [cfe] This requires the 'variance' language feature to be enabled.
+//                   ^^^^^
+// [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
+// [cfe] This requires the 'variance' language feature to be enabled.
+
+class C<in T> extends A<T> {
+//      ^^
+// [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
+// [cfe] This requires the 'variance' language feature to be enabled.
+  @override
+  int foo(T bar) {
+    return 2;
+  }
+}
+
+mixin D<out T> {}
+//      ^^^
+// [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
+// [cfe] This requires the 'variance' language feature to be enabled.
+
+class E1 {}
+
+mixin E<in T extends E1> {}
+//      ^^
+// [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
+// [cfe] This requires the 'variance' language feature to be enabled.
+
+class F<out T> = Object with D<T>;
+//      ^^^
+// [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
+// [cfe] This requires the 'variance' language feature to be enabled.
+
+class G<out out> {}
+//      ^^^
+// [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
+// [cfe] This requires the 'variance' language feature to be enabled.
+
+class H<out inout> {}
+//      ^^^
+// [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
+// [cfe] This requires the 'variance' language feature to be enabled.
+
+main() {
+  B<int, String, bool> b = B();
+
+  C<int> c = C();
+  Expect.equals(2, c.foo(3));
+
+  F<int> f = F();
+
+  G<int> g = G();
+
+  H<int> h = H();
+}
diff --git a/tests/language/variance/syntax/variance_keyword_identifier_syntax_test.dart b/tests/language/variance/syntax/variance_keyword_identifier_syntax_test.dart
new file mode 100644
index 000000000000..a0bf3d7b67d2
--- /dev/null
+++ b/tests/language/variance/syntax/variance_keyword_identifier_syntax_test.dart
@@ -0,0 +1,51 @@
+// 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.
+
+// Tests identifier usage of keywords `out` and `inout`, correct usage of `in`
+// with the experimental flag `variance` enabled.
+
+// SharedOptions=--enable-experiment=variance
+
+import "package:expect/expect.dart";
+
+class A<out> {}
+
+class B<inout> {}
+
+class C<out, inout> {}
+
+F<inout, out>() {}
+
+mixin G<out, inout> {}
+
+typedef H<inout, out> = out Function(inout);
+
+class OutParameter {
+  var out = 3;
+  int func(int out) {
+    return out;
+  }
+}
+
+class inout {
+  void out(int x) {}
+}
+
+var out = 5;
+
+main() {
+  OutParameter x = new OutParameter();
+  Expect.equals(2, x.func(2));
+  Expect.equals(3, x.out);
+
+  inout foo = inout();
+  foo.out(4);
+
+  Expect.equals(5, out);
+
+  var collection = [0, 1, 2];
+  for (var x in collection) {
+    Expect.isTrue(x is int);
+  }
+}
diff --git a/tests/language/variance/syntax/variance_syntax_test.dart b/tests/language/variance/syntax/variance_syntax_test.dart
new file mode 100644
index 000000000000..9a40965b6648
--- /dev/null
+++ b/tests/language/variance/syntax/variance_syntax_test.dart
@@ -0,0 +1,45 @@
+// 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=variance
+
+import 'package:expect/expect.dart';
+
+abstract class A<in X> {
+  int foo(X bar);
+}
+
+class B<out X, in Y, inout Z> {}
+
+class C<in T> extends A<T> {
+  @override
+  int foo(T bar) {
+    return 2;
+  }
+}
+
+mixin D<out T> {}
+
+class E1 {}
+
+mixin E<in T extends E1> {}
+
+class F<out T> = Object with D<T>;
+
+class G<out out> {}
+
+class H<out inout> {}
+
+main() {
+  B<int, String, bool> b = B();
+
+  C<int> c = C();
+  Expect.equals(2, c.foo(3));
+
+  F<int> f = F();
+
+  G<int> g = G();
+
+  H<int> h = H();
+}
diff --git a/tests/language/variance/syntax/variance_type_parameter_error_syntax_test.dart b/tests/language/variance/syntax/variance_type_parameter_error_syntax_test.dart
new file mode 100644
index 000000000000..28c1add7b429
--- /dev/null
+++ b/tests/language/variance/syntax/variance_type_parameter_error_syntax_test.dart
@@ -0,0 +1,68 @@
+// 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.
+
+// Tests erroneous usages of variance in unapplicable type parameters.
+
+// SharedOptions=--enable-experiment=variance
+
+void A(out int foo) {
+//     ^^^
+// [analyzer] COMPILE_TIME_ERROR.UNDEFINED_CLASS
+// [cfe] 'out' isn't a type.
+//     ^
+// [cfe] Type 'out' not found.
+//             ^^^
+// [analyzer] SYNTACTIC_ERROR.EXPECTED_TOKEN
+// [cfe] Expected ')' before this.
+  List<out String> bar;
+  //  ^
+  // [analyzer] STATIC_TYPE_WARNING.UNDEFINED_OPERATOR
+  // [cfe] The operator '<' isn't defined for the class 'Type'.
+  //   ^^^
+  // [analyzer] STATIC_WARNING.UNDEFINED_IDENTIFIER
+  // [cfe] Expected ';' after this.
+  //   ^^^
+  // [analyzer] SYNTACTIC_ERROR.EXPECTED_TOKEN
+  // [cfe] Getter not found: 'out'.
+  //             ^
+  // [analyzer] STATIC_TYPE_WARNING.UNDEFINED_OPERATOR
+  // [cfe] The operator '>' isn't defined for the class 'Type'.
+  //               ^^^
+  // [analyzer] STATIC_WARNING.UNDEFINED_IDENTIFIER
+  // [cfe] Getter not found: 'bar'.
+}
+
+void B(out foo) {}
+//     ^^^
+// [analyzer] COMPILE_TIME_ERROR.UNDEFINED_CLASS
+// [cfe] 'out' isn't a type.
+//     ^
+// [cfe] Type 'out' not found.
+
+class C<in out X, out out Y> {}
+//         ^^^
+// [analyzer] SYNTACTIC_ERROR.MULTIPLE_VARIANCE_MODIFIERS
+// [cfe] Each type parameter can have at most one variance modifier.
+//                    ^^^
+// [analyzer] SYNTACTIC_ERROR.MULTIPLE_VARIANCE_MODIFIERS
+// [cfe] Each type parameter can have at most one variance modifier.
+
+class D<in out inout in out X> {}
+//         ^^^
+// [analyzer] SYNTACTIC_ERROR.MULTIPLE_VARIANCE_MODIFIERS
+// [cfe] Each type parameter can have at most one variance modifier.
+//             ^^^^^
+// [analyzer] SYNTACTIC_ERROR.MULTIPLE_VARIANCE_MODIFIERS
+// [cfe] Each type parameter can have at most one variance modifier.
+//                   ^^
+// [analyzer] SYNTACTIC_ERROR.MULTIPLE_VARIANCE_MODIFIERS
+// [cfe] Each type parameter can have at most one variance modifier.
+//                      ^^^
+// [analyzer] SYNTACTIC_ERROR.MULTIPLE_VARIANCE_MODIFIERS
+// [cfe] Each type parameter can have at most one variance modifier.
+
+typedef E<out T> = T Function(T a);
+//            ^
+// [analyzer] SYNTACTIC_ERROR.EXPECTED_TOKEN
+// [cfe] Expected ',' before this.
diff --git a/tests/language/variance/variance_downwards_inference_test.dart b/tests/language/variance/variance_downwards_inference_test.dart
new file mode 100644
index 000000000000..b6cd329cf635
--- /dev/null
+++ b/tests/language/variance/variance_downwards_inference_test.dart
@@ -0,0 +1,53 @@
+// 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.
+
+// Tests downwards inference for explicit variance modifiers.
+
+// SharedOptions=--enable-experiment=variance
+
+class A<out T> {
+  final T _x;
+  A(T x):_x = x;
+  T get x => _x;
+  void set x(Object value) {}
+}
+
+class B<in T> {
+  B(List<T> x);
+  void set x(T val) {}
+}
+
+class C<out T, S> {
+  final T _x;
+  C(T x, S y):_x = x;
+  T get x => _x;
+  void set x(Object value) {}
+  void set y(S _value) {}
+}
+
+class D<in T> {
+  D(T x, void Function(T) y) {}
+  void set x(T val) {}
+}
+
+main() {
+  // int <: T <: Object
+  // Choose int
+  A<Object> a = new A(3)..x+=1;
+
+  // int <: T
+  // num <: T
+  // Choose num
+  B<int> b = new B(<num>[])..x=2.2;
+
+  // int <: T <: Object
+  // Choose int
+  // int <: S <: Object
+  // Choose Object
+  C<Object, Object> c = new C(3, 3)..x+=1..y="hello";
+
+  // int <: T <: num
+  // Choose num due to contravariant heuristic.
+  D<int> d = new D(3, (num x) {})..x=2.2;
+}
diff --git a/tests/language/variance/variance_in_field_error_test.dart b/tests/language/variance/variance_in_field_error_test.dart
new file mode 100644
index 000000000000..98c4af6986a1
--- /dev/null
+++ b/tests/language/variance/variance_in_field_error_test.dart
@@ -0,0 +1,91 @@
+// 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.
+
+// Tests erroneous field usage for the `in` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class A<in T> {
+  final T a = throw "uncalled";
+  //      ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  final T Function() b = () => throw "uncalled";
+  //                 ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  T get c => throw "uncalled";
+//^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//        ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  late T d;
+//       ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  covariant late T e;
+  //               ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  T? f = null;
+  // ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+}
+
+mixin BMixin<in T> {
+  final T a = throw "uncalled";
+  //      ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  final T Function() b = () => throw "uncalled";
+  //                 ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  T get c => throw "uncalled";
+//^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//        ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  late T d;
+//       ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  covariant late T e;
+  //               ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  T? f = null;
+  // ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+}
+
+abstract class C<in T> {
+  T get a;
+//^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//       ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+}
+
+class D<in T> extends C<T> {
+  var a;
+  //  ^
+  // [analyzer] COMPILE_TIME_ERROR.NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+  //  ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Field 'a' should be initialized because its type 'T' doesn't allow null.
+}
diff --git a/tests/language/variance/variance_in_field_test.dart b/tests/language/variance/variance_in_field_test.dart
new file mode 100644
index 000000000000..2b60fbbdc709
--- /dev/null
+++ b/tests/language/variance/variance_in_field_test.dart
@@ -0,0 +1,56 @@
+// 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.
+
+// Tests various fields for the `in` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+import "package:expect/expect.dart";
+
+typedef Int2Void = void Function(int);
+
+class A<in T> {
+  void set a(T value) => value;
+  final void Function(T) b = (T val) {
+    Expect.equals(2, val);
+  };
+  A<T> get c => this;
+}
+
+mixin BMixin<in T> {
+  void set a(T value) => value;
+  final void Function(T) b = (T val) {
+    Expect.equals(2, val);
+  };
+  BMixin<T> get c => this;
+}
+
+class B with BMixin<int> {}
+
+void testClass() {
+  A<int> a = new A();
+
+  a.a = 2;
+
+  Expect.type<Int2Void>(a.b);
+  a.b(2);
+
+  a.c.a = 2;
+}
+
+void testMixin() {
+  B b = new B();
+
+  b.a = 2;
+
+  Expect.type<Int2Void>(b.b);
+  b.b(2);
+
+  b.c.a = 2;
+}
+
+main() {
+  testClass();
+  testMixin();
+}
diff --git a/tests/language/variance/variance_in_inference_error_test.dart b/tests/language/variance/variance_in_inference_error_test.dart
new file mode 100644
index 000000000000..2c220ab734db
--- /dev/null
+++ b/tests/language/variance/variance_in_inference_error_test.dart
@@ -0,0 +1,101 @@
+// 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.
+
+// Tests local inference errors for the `in` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+
+class Exactly<inout T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+class ContraBound<in T> {
+  ContraBound(T x, void Function(T) y) {}
+}
+
+Exactly<T> inferCovContra<T>(Covariant<T> x, Contravariant<T> y) => new Exactly<T>();
+Exactly<T> inferContraContra<T>(Contravariant<T> x, Contravariant<T> y) => new Exactly<T>();
+Exactly<T> inferContraBound<T>(ContraBound<T> x) => new Exactly<T>();
+
+main() {
+  Exactly<Upper> upper;
+  Exactly<Lower> lower;
+
+  // T <: Upper and T <: Middle.
+  // We choose Middle.
+  var inferredMiddle = inferContraContra(Contravariant<Upper>(), Contravariant<Middle>());
+  upper = inferredMiddle;
+  //      ^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Middle>' can't be assigned to a variable of type 'Exactly<Upper>'.
+
+  // T <: Upper and T <: Lower.
+  // We choose Lower.
+  var inferredLower = inferContraContra(Contravariant<Upper>(), Contravariant<Lower>());
+  upper = inferredLower;
+  //      ^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Lower>' can't be assigned to a variable of type 'Exactly<Upper>'.
+
+  // int <: T <: String is not a valid constraint.
+  inferCovContra(Covariant<int>(), Contravariant<String>());
+//^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.COULD_NOT_INFER
+//                                 ^^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+// [cfe] The argument type 'Contravariant<String>' can't be assigned to the parameter type 'Contravariant<int>'.
+
+  // String <: T <: int is not a valid constraint.
+  inferCovContra(Covariant<String>(), Contravariant<int>());
+//^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.COULD_NOT_INFER
+//                                    ^^^^^^^^^^^^^^^^^^^^
+// [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+// [cfe] The argument type 'Contravariant<int>' can't be assigned to the parameter type 'Contravariant<String>'.
+
+  // Middle <: T <: Lower is not a valid constraint
+  inferCovContra(Covariant<Middle>(), Contravariant<Lower>());
+//^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.COULD_NOT_INFER
+//                                    ^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.INVALID_CAST_NEW_EXPR
+// [cfe] The argument type 'Contravariant<Lower>' can't be assigned to the parameter type 'Contravariant<Middle>'.
+
+  // Upper <: T <: Lower is not a valid constraint
+  inferCovContra(Covariant<Upper>(), Contravariant<Lower>());
+//^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.COULD_NOT_INFER
+//                                   ^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.INVALID_CAST_NEW_EXPR
+// [cfe] The argument type 'Contravariant<Lower>' can't be assigned to the parameter type 'Contravariant<Upper>'.
+
+  // Upper <: T <: Middle is not a valid constraint
+  inferCovContra(Covariant<Upper>(), Contravariant<Middle>());
+//^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.COULD_NOT_INFER
+//                                   ^^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.INVALID_CAST_NEW_EXPR
+// [cfe] The argument type 'Contravariant<Middle>' can't be assigned to the parameter type 'Contravariant<Upper>'.
+
+  // Inference for Contrabound(...) produces Lower <: T <: Upper.
+  // Since T is contravariant, we choose Upper as the solution.
+  var inferredContraUpper = inferContraBound(ContraBound(Lower(), (Upper x) {}));
+  lower = inferredContraUpper;
+  //      ^^^^^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Upper>' can't be assigned to a variable of type 'Exactly<Lower>'.
+
+  // Inference for Contrabound(...) produces Lower <: T <: Middle.
+  // Since T is contravariant, we choose Middle as the solution.
+  var inferredContraMiddle = inferContraBound(ContraBound(Lower(), (Middle x) {}));
+  lower = inferredContraMiddle;
+  //      ^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Middle>' can't be assigned to a variable of type 'Exactly<Lower>'.
+}
diff --git a/tests/language/variance/variance_in_inference_test.dart b/tests/language/variance/variance_in_inference_test.dart
new file mode 100644
index 000000000000..03277fb01ee8
--- /dev/null
+++ b/tests/language/variance/variance_in_inference_test.dart
@@ -0,0 +1,76 @@
+// 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.
+
+// Tests local inference for the `in` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+
+class Exactly<inout T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+class ContraBound<in T> {
+  ContraBound(T x, void Function(T) y) {}
+}
+
+Exactly<T> inferCovContra<T>(Covariant<T> x, Contravariant<T> y) => new Exactly<T>();
+Exactly<T> inferContraContra<T>(Contravariant<T> x, Contravariant<T> y) => new Exactly<T>();
+Exactly<T> inferContraBound<T>(ContraBound<T> x) => new Exactly<T>();
+
+main() {
+  Exactly<Upper> upper;
+  Exactly<Middle> middle;
+  Exactly<Lower> lower;
+
+  // Lower <: T
+  // T <: Lower
+  // Choose Lower for Lower <: T <: Lower
+  var inferredLower = inferCovContra(Covariant<Lower>(), Contravariant<Lower>());
+  lower = inferredLower;
+
+  // Lower <: T
+  // T <: Middle
+  // Choose Lower for Lower <: T <: Middle
+  var inferredLower2 = inferCovContra(Covariant<Lower>(), Contravariant<Middle>());
+  lower = inferredLower2;
+
+  // Lower <: T
+  // T <: Upper
+  // Choose Lower for Lower <: T <: Upper
+  var inferredLower3 = inferCovContra(Covariant<Lower>(), Contravariant<Upper>());
+  lower = inferredLower3;
+
+  // T <: Upper
+  // T <: Middle
+  // Choose Middle since it is the greatest lower bound of Upper and Middle.
+  var inferredMiddle = inferContraContra(Contravariant<Upper>(), Contravariant<Middle>());
+  middle = inferredMiddle;
+
+  // T <: Upper
+  // T <: Lower
+  // Choose Lower since it is the greatest lower bound of Upper and Lower.
+  var inferredLower4 = inferContraContra(Contravariant<Lower>(), Contravariant<Upper>());
+  lower = inferredLower4;
+
+  // T <: Middle
+  // T <: Lower
+  // Choose Lower since it is the greatest lower bound of Middle and Lower.
+  var inferredLower5 = inferContraContra(Contravariant<Lower>(), Contravariant<Middle>());
+  lower = inferredLower5;
+
+  // Lower <: T <: Upper
+  // Choose Upper.
+  var inferredContraUpper = inferContraBound(ContraBound(Lower(), (Upper x) {}));
+  upper = inferredContraUpper;
+
+  // Lower <: T <: Middle
+  // Choose Middle.
+  var inferredContraMiddle = inferContraBound(ContraBound(Lower(), (Middle x) {}));
+  middle = inferredContraMiddle;
+}
diff --git a/tests/language/variance/variance_in_method_error_test.dart b/tests/language/variance/variance_in_method_error_test.dart
new file mode 100644
index 000000000000..b06567c3955d
--- /dev/null
+++ b/tests/language/variance/variance_in_method_error_test.dart
@@ -0,0 +1,349 @@
+// 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.
+
+// Tests erroneous method signatures and return types for the `in` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+typedef Inv<T> = void Function<X extends T>();
+typedef Cov<T> = T Function();
+typedef Contra<T> = void Function(T);
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+class Invariant<inout T> {}
+
+class A<in T> {
+  T method1() => throw "uncalled";
+//^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//         ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  void method2(Contra<T> x) {}
+  //           ^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                     ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  Cov<T> method3() {
+//^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//              ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+    return () => throw "uncalled";
+  }
+
+  void method4(Contra<Cov<T>> x) {}
+  //           ^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                          ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  void method5(Cov<Contra<T>> x) {}
+  //           ^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                          ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  Contra<Contra<T>> method6() => (Contra<T> x) {};
+//^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                         ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  Cov<Cov<T>> method7() {
+//^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                   ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+    return () {
+      return () => throw "uncalled";
+    };
+  }
+
+  Inv<T> method8() => throw "uncalled";
+//^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//              ^
+// [cfe] Can't use 'in' type variable 'T' in an 'inout' position in the return type.
+
+  void method9(Inv<T> x) {}
+  //           ^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                  ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  Covariant<T> method10() => throw "uncalled";
+//^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                     ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  void method11(Contravariant<T> x) {}
+  //            ^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                             ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  Invariant<T> method12() => throw "uncalled";
+//^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                     ^
+// [cfe] Can't use 'in' type variable 'T' in an 'inout' position in the return type.
+
+  void method13(Invariant<T> x) {}
+  //            ^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                         ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  void method14(Contravariant<Covariant<T>> x) {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                        ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  void method15(Covariant<Contravariant<T>> x) {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                        ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  Contravariant<Contravariant<T>> method16() => Contravariant<Contravariant<T>>();
+//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                                        ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  Covariant<Covariant<T>> method17() => Covariant<Covariant<T>>();
+//^^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                                ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  void method18<X extends T>() {}
+  //            ^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  void method19<X extends Cov<T>>() {}
+  //            ^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  void method20<X extends Covariant<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  void method21({required Contra<T> x}) {}
+  //             ^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  void method22({required Contravariant<T> x}) {}
+  //             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                       ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  void method23({required Covariant<T> x, required Contravariant<T> y}) {}
+  //                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                                                ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  void method24<X extends Contra<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  void method25<X extends Contravariant<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+}
+
+mixin BMixin<in T> {
+  T method1() => throw "uncalled";
+//^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//         ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  void method2(Contra<T> x) {}
+  //           ^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                     ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  Cov<T> method3() {
+//^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//              ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+    return () => throw "uncalled";
+  }
+
+  void method4(Contra<Cov<T>> x) {}
+  //           ^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                          ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  void method5(Cov<Contra<T>> x) {}
+  //           ^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                          ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  Contra<Contra<T>> method6() => (Contra<T> x) {};
+//^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                         ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  Cov<Cov<T>> method7() {
+//^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                   ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+    return () {
+      return () => throw "uncalled";
+    };
+  }
+
+  Inv<T> method8() => throw "uncalled";
+//^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//              ^
+// [cfe] Can't use 'in' type variable 'T' in an 'inout' position in the return type.
+
+  void method9(Inv<T> x) {}
+  //           ^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                  ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  Covariant<T> method10() => throw "uncalled";
+//^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                     ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  void method11(Contravariant<T> x) {}
+  //            ^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                             ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  Invariant<T> method12() => throw "uncalled";
+//^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                     ^
+// [cfe] Can't use 'in' type variable 'T' in an 'inout' position in the return type.
+
+  void method13(Invariant<T> x) {}
+  //            ^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                         ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  void method14(Contravariant<Covariant<T>> x) {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                        ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  void method15(Covariant<Contravariant<T>> x) {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                        ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  Contravariant<Contravariant<T>> method16() => Contravariant<Contravariant<T>>();
+//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                                        ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  Covariant<Covariant<T>> method17() => Covariant<Covariant<T>>();
+//^^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                                ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+
+  void method18<X extends T>() {}
+  //            ^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  void method19<X extends Cov<T>>() {}
+  //            ^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  void method20<X extends Covariant<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  void method21({required Contra<T> x}) {}
+  //             ^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  void method22({required Contravariant<T> x}) {}
+  //             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                       ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  void method23({required Covariant<T> x, required Contravariant<T> y}) {}
+  //                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                                                ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+
+  void method24<X extends Contra<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+
+  void method25<X extends Contravariant<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'in' type variable 'T' in an 'inout' position.
+}
+
+class B<in T> {
+  void method1(A<T> x) {}
+  //           ^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+  Contra<A<T>> method2() {
+//^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in the return type.
+    throw "uncalled";
+  }
+}
+
+class C<T> {
+  void method(T x) {}
+}
+
+class D<in T> extends C<void Function(T)> {
+  @override
+  void method(void Function(T) x) {}
+  //          ^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                           ^
+  // [cfe] Can't use 'in' type variable 'T' in an 'out' position.
+}
diff --git a/tests/language/variance/variance_in_method_test.dart b/tests/language/variance/variance_in_method_test.dart
new file mode 100644
index 000000000000..a0949756fdaa
--- /dev/null
+++ b/tests/language/variance/variance_in_method_test.dart
@@ -0,0 +1,246 @@
+// 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.
+
+// Tests method signatures and return types for the `in` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+import "package:expect/expect.dart";
+
+typedef Cov<T> = T Function();
+typedef Contra<T> = void Function(T);
+
+Cov<int> covFunction = () => 2;
+Contra<int> contraFunction = (int val) {};
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+
+class A<in T> {
+  void method1(T x) {}
+  void method2(Cov<T> x) {}
+  Contra<T> method3() {
+    return (T val) {
+      Expect.equals(2, val);
+    };
+  }
+
+  void method4(Cov<Cov<T>> x) {}
+  Contra<Cov<T>> method5() {
+    return (Cov<T> method) {
+      Expect.type<Cov<T>>(method);
+    };
+  }
+  Cov<Contra<T>> method6() {
+    return () {
+      return (T x) {
+        Expect.equals(2, x);
+      };
+    };
+  }
+  void method7(Contra<Contra<T>> x) {}
+
+  void method8(Covariant<T> x) {}
+  Contravariant<T>? method9() => null;
+  void method10(Covariant<Covariant<T>> x) {}
+  Contravariant<Covariant<T>>? method11() => null;
+  void method12(Contravariant<Contravariant<T>> x) {}
+  Covariant<Contravariant<T>>? method13() => null;
+
+  void method14(covariant T x) {}
+  void method15(covariant Contra<T> x) {}
+  void method16(covariant Cov<T> x) {}
+  void method17(covariant Contravariant<T> x) {}
+  void method18(covariant Covariant<T> x) {}
+
+  void method19({T? x}) {}
+  void method20({Covariant<T>? x}) {}
+  void method21({Cov<T>? x}) {}
+}
+
+mixin BMixin<in T> {
+  void method1(T x) {}
+  void method2(Cov<T> x) {}
+  Contra<T> method3() {
+    return (T val) {
+      Expect.equals(2, val);
+    };
+  }
+
+  void method4(Cov<Cov<T>> x) {}
+  Contra<Cov<T>> method5() {
+    return (Cov<T> method) {
+      Expect.type<Cov<T>>(method);
+    };
+  }
+  Cov<Contra<T>> method6() {
+    return () {
+      return (T x) {
+        Expect.equals(2, x);
+      };
+    };
+  }
+  void method7(Contra<Contra<T>> x) {}
+
+  void method8(Covariant<T> x) {}
+  Contravariant<T>? method9() => null;
+  void method10(Covariant<Covariant<T>> x) {}
+  Contravariant<Covariant<T>>? method11() => null;
+  void method12(Contravariant<Contravariant<T>> x) {}
+  Covariant<Contravariant<T>>? method13() => null;
+
+  void method14(covariant T x) {}
+  void method15(covariant Contra<T> x) {}
+  void method16(covariant Cov<T> x) {}
+  void method17(covariant Contravariant<T> x) {}
+  void method18(covariant Covariant<T> x) {}
+
+  void method19({T? x}) {}
+  void method20({Covariant<T>? x}) {}
+  void method21({Cov<T>? x}) {}
+}
+
+class B with BMixin<int> {}
+
+class C<in T> {
+  void method1(Contra<A<T>> x) {}
+  A<T> method2() {
+    return A<T>();
+  }
+}
+
+class D<T> {
+  late T x;
+  T? method() => null;
+  void method2(T x) {}
+  void method3(covariant T x) {}
+}
+
+class E<in T> extends D<void Function(T)> {
+  @override
+  void Function(T) method() => (T x) {};
+
+  @override
+  void method3(covariant void Function(T) x) {}
+}
+
+void testClass() {
+  A<int> a = new A();
+
+  a.method1(2);
+
+  a.method2(covFunction);
+
+  Expect.type<Contra<int>>(a.method3());
+  Contra<int> method3Function = a.method3();
+  method3Function(2);
+
+  a.method4(() {
+    return covFunction;
+  });
+
+  Expect.type<Contra<Cov<int>>>(a.method5());
+  Contra<Cov<int>> method5Function = a.method5();
+  method5Function(covFunction);
+
+  Expect.type<Cov<Contra<int>>>(a.method6());
+  Cov<Contra<int>> method6Function = a.method6();
+  Expect.type<Contra<int>>(method6Function());
+  Contra<int> method6NestedFunction = method6Function();
+  method6NestedFunction(2);
+
+  a.method7((Contra<int> x) {});
+
+  a.method8(Covariant<int>());
+  Expect.isNull(a.method9());
+  a.method10(Covariant<Covariant<int>>());
+  Expect.isNull(a.method11());
+  a.method12(Contravariant<Contravariant<int>>());
+  Expect.isNull(a.method13());
+
+  a.method14(3);
+  a.method15(contraFunction);
+  a.method16(covFunction);
+  a.method17(Contravariant<int>());
+  a.method18(Covariant<int>());
+
+  a.method19();
+  a.method20();
+  a.method21();
+}
+
+void testMixin() {
+  B b = new B();
+
+  b.method1(2);
+
+  b.method2(covFunction);
+
+  Expect.type<Contra<int>>(b.method3());
+  Contra<int> method3Return = b.method3();
+  method3Return(2);
+
+  b.method4(() {
+    return covFunction;
+  });
+
+  Expect.type<Contra<Cov<int>>>(b.method5());
+  Contra<Cov<int>> method5Return = b.method5();
+  method5Return(covFunction);
+
+  Expect.type<Cov<Contra<int>>>(b.method6());
+  Cov<Contra<int>> method6Function = b.method6();
+  Expect.type<Contra<int>>(method6Function());
+  Contra<int> method6NestedFunction = method6Function();
+  method6NestedFunction(2);
+
+  b.method7((Contra<int> x) {});
+
+  b.method8(Covariant<int>());
+  Expect.isNull(b.method9());
+  b.method10(Covariant<Covariant<int>>());
+  Expect.isNull(b.method11());
+  b.method12(Contravariant<Contravariant<int>>());
+  Expect.isNull(b.method13());
+
+  b.method14(3);
+  b.method15(contraFunction);
+  b.method16(covFunction);
+  b.method17(Contravariant<int>());
+  b.method18(Covariant<int>());
+
+  b.method19();
+  b.method20();
+  b.method21();
+}
+
+void testClassInMethods() {
+  C<int> c = new C();
+
+  c.method1((A<int> x) {});
+
+  Expect.type<A<int>>(c.method2());
+}
+
+void testOverrideLegacyMethods() {
+  E<int> e = new E();
+  Expect.isTrue(e.method() is Function);
+  e.method2(contraFunction);
+  e.method3(contraFunction);
+  e.x = contraFunction;
+
+  D<Object> d = e;
+  Expect.throws(() => d.x = "test");
+
+  e = new E<Object>();
+  Expect.throws(() => e.method2(contraFunction));
+  Expect.throws(() => e.method3(contraFunction));
+}
+
+main() {
+  testClass();
+  testMixin();
+  testClassInMethods();
+  testOverrideLegacyMethods();
+}
diff --git a/tests/language/variance/variance_in_subclass_error_test.dart b/tests/language/variance/variance_in_subclass_error_test.dart
new file mode 100644
index 000000000000..123b3e568565
--- /dev/null
+++ b/tests/language/variance/variance_in_subclass_error_test.dart
@@ -0,0 +1,144 @@
+// 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.
+
+// Tests erroneous subclass usage for the `in` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+typedef CovFunction<T> = T Function();
+typedef ContraFunction<T> = void Function(T);
+typedef InvFunction<T> = T Function(T);
+
+class LegacyCovariant<T> {}
+class Covariant<out T> {}
+class Contravariant<in T> {}
+class Invariant<inout T> {}
+mixin MLegacyCovariant<T> {}
+mixin MCovariant<out T> {}
+mixin MContravariant<in T> {}
+mixin MInvariant<inout T> {}
+
+class A<in T> extends LegacyCovariant<T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'LegacyCovariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class B<in T> implements LegacyCovariant<T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'LegacyCovariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class C<in T> with MLegacyCovariant<T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'MLegacyCovariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class D<in T> extends Covariant<T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Covariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class E<in T> implements Covariant<T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Covariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class F<in T> with MCovariant<T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'MCovariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class G<in T> extends Invariant<T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'inout' position in supertype 'Invariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class H<in T> implements Invariant<T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'inout' position in supertype 'Invariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class I<in T> with MInvariant<T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'inout' position in supertype 'MInvariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class J<in T> extends Covariant<Covariant<T>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Covariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class K<in T> extends Contravariant<Contravariant<T>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Contravariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class L<in T> extends Covariant<CovFunction<T>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Covariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class M<in T> extends Covariant<ContraFunction<ContraFunction<T>>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Covariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class N<in T> extends Contravariant<CovFunction<Contravariant<T>>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Contravariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class O<in T> extends Covariant<CovFunction<Covariant<T>>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Covariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class P<in T> extends Covariant<Covariant<Covariant<T>>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Covariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class Q<in T> extends Invariant<InvFunction<T>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'inout' position in supertype 'Invariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class R<in T> = Covariant<T> with MContravariant<T>;
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Covariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class S<in T> = Contravariant<T> with MCovariant<T>;
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'MCovariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class T<in X> = Invariant<X> with MInvariant<X>;
+//    ^
+// [cfe] Can't use 'in' type variable 'X' in an 'inout' position in supertype 'Invariant'.
+//    ^
+// [cfe] Can't use 'in' type variable 'X' in an 'inout' position in supertype 'MInvariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
diff --git a/tests/language/variance/variance_in_subclass_test.dart b/tests/language/variance/variance_in_subclass_test.dart
new file mode 100644
index 000000000000..f7a314a9b22a
--- /dev/null
+++ b/tests/language/variance/variance_in_subclass_test.dart
@@ -0,0 +1,49 @@
+// 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.
+
+// Tests subclass usage for the `in` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+typedef CovFunction<T> = T Function();
+typedef ContraFunction<T> = void Function(T);
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+mixin MContravariant<in T> {}
+
+class A<in T> extends Contravariant<T> {}
+class B<in T> implements Contravariant<T> {}
+class C<in T> with MContravariant<T> {}
+
+class D<in T> extends Covariant<Contravariant<T>> {}
+class E<in T> extends Contravariant<Covariant<T>> {}
+
+class F<in T> extends Covariant<ContraFunction<T>> {}
+class G<in T> extends Covariant<ContraFunction<CovFunction<T>>> {}
+class H<in T> extends Covariant<CovFunction<ContraFunction<T>>> {}
+
+class I<in T> extends Covariant<ContraFunction<Covariant<T>>> {}
+
+class J<in T> extends Contravariant<Contravariant<Contravariant<T>>> {}
+
+class K<in T> = Contravariant<T> with MContravariant<T>;
+class L<in T> = Covariant<Contravariant<T>> with MContravariant<T>;
+class M<in T> = Contravariant<T> with MContravariant<Covariant<T>>;
+
+main() {
+  A<num> a = A();
+  B<num> b = B();
+  C<num> c = C();
+  D<num> d = D();
+  E<num> e = E();
+  F<num> f = F();
+  G<num> g = G();
+  H<num> h = H();
+  I<num> i = I();
+  J<num> j = J();
+  K<num> k = K();
+  L<num> l = L();
+  M<num> m = M();
+}
diff --git a/tests/language/variance/variance_in_subtyping_error_test.dart b/tests/language/variance/variance_in_subtyping_error_test.dart
new file mode 100644
index 000000000000..d5697c76c975
--- /dev/null
+++ b/tests/language/variance/variance_in_subtyping_error_test.dart
@@ -0,0 +1,80 @@
+// 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.
+
+// Tests erroneous subtyping for the `in` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class Contravariant<in T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+class A {
+  Contravariant<Middle> method1() {
+    return new Contravariant<Middle>();
+  }
+
+  void method2(Contravariant<Middle> x) {}
+}
+
+class B extends A {
+  @override
+  Contravariant<Lower> method1() {
+  //                   ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.INVALID_OVERRIDE
+  // [cfe] The return type of the method 'B.method1' is 'Contravariant<Lower>', which does not match the return type, 'Contravariant<Middle>', of the overridden method, 'A.method1'.
+    return new Contravariant<Lower>();
+  }
+
+  @override
+  void method2(Contravariant<Upper> x) {}
+  //   ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.INVALID_OVERRIDE
+  //                                ^
+  // [cfe] The parameter 'x' of the method 'B.method2' has type 'Contravariant<Upper>', which does not match the corresponding type, 'Contravariant<Middle>', in the overridden method, 'A.method2'.
+}
+
+class C<out T extends Contravariant<Middle>> {}
+
+class D {
+  C<Contravariant<Lower>> method1() {
+  //^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  //                             ^
+  // [cfe] Type argument 'Contravariant<Lower>' doesn't conform to the bound 'Contravariant<Middle>' of the type variable 'T' on 'C' in the return type.
+    return C<Contravariant<Lower>>();
+    //     ^
+    // [cfe] Type argument 'Contravariant<Lower>' doesn't conform to the bound 'Contravariant<Middle>' of the type variable 'T' on 'C'.
+    //       ^^^^^^^^^^^^^^^^^^^^
+    // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  }
+}
+
+void testCall(Iterable<Contravariant<Middle>> x) {}
+
+main() {
+  C<Contravariant<Lower>> c = new C<Contravariant<Lower>>();
+  //^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  //                      ^
+  // [cfe] Type argument 'Contravariant<Lower>' doesn't conform to the bound 'Contravariant<Middle>' of the type variable 'T' on 'C'.
+  //                              ^
+  // [cfe] Type argument 'Contravariant<Lower>' doesn't conform to the bound 'Contravariant<Middle>' of the type variable 'T' on 'C'.
+  //                                ^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+
+  Iterable<Contravariant<Middle>> iterableMiddle = [new Contravariant<Middle>()];
+  List<Contravariant<Lower>> listLower = [new Contravariant<Lower>()];
+  iterableMiddle = listLower;
+  //               ^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'List<Contravariant<Lower>>' can't be assigned to a variable of type 'Iterable<Contravariant<Middle>>'.
+
+  testCall(listLower);
+  //       ^^^^^^^^^
+  // [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+  // [cfe] The argument type 'List<Contravariant<Lower>>' can't be assigned to the parameter type 'Iterable<Contravariant<Middle>>'.
+}
diff --git a/tests/language/variance/variance_in_subtyping_test.dart b/tests/language/variance/variance_in_subtyping_test.dart
new file mode 100644
index 000000000000..df89b2ba2b48
--- /dev/null
+++ b/tests/language/variance/variance_in_subtyping_test.dart
@@ -0,0 +1,102 @@
+// 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.
+
+// Tests subtyping for the `in` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+import "package:expect/expect.dart";
+
+class Contravariant<in T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+class A {
+  Contravariant<Middle> method1() {
+    return Contravariant<Middle>();
+  }
+
+  void method2(Contravariant<Middle> x) {}
+}
+
+class B extends A {
+  @override
+  Contravariant<Upper> method1() {
+    return new Contravariant<Upper>();
+  }
+
+  @override
+  void method2(Contravariant<Lower> x) {}
+}
+
+class C extends A {
+  @override
+  Contravariant<Middle> method1() {
+    return new Contravariant<Middle>();
+  }
+
+  @override
+  void method2(Contravariant<Middle> x) {}
+}
+
+class D<out T extends Contravariant<Middle>> {}
+
+class E {
+  D<Contravariant<Upper>> method1() {
+    return D<Contravariant<Upper>>();
+  }
+}
+
+class F {
+  D<Contravariant<Middle>> method1() {
+    return D<Contravariant<Middle>>();
+  }
+}
+
+void testCall(Iterable<Contravariant<Lower>> x) {}
+
+main() {
+  A a = new A();
+  Expect.type<Contravariant<Middle>>(a.method1());
+  Expect.type<Contravariant<Lower>>(a.method1());
+  Expect.notType<Contravariant<Upper>>(a.method1());
+  a.method2(new Contravariant<Middle>());
+  a.method2(new Contravariant<Upper>());
+
+  B b = new B();
+  Expect.type<Contravariant<Upper>>(b.method1());
+  Expect.type<Contravariant<Middle>>(b.method1());
+  Expect.type<Contravariant<Lower>>(b.method1());
+  b.method2(new Contravariant<Lower>());
+  b.method2(new Contravariant<Middle>());
+
+  C c = new C();
+  Expect.type<Contravariant<Middle>>(c.method1());
+  Expect.type<Contravariant<Lower>>(c.method1());
+  Expect.notType<Contravariant<Upper>>(c.method1());
+  c.method2(new Contravariant<Middle>());
+  c.method2(new Contravariant<Upper>());
+
+  D<Contravariant<Upper>> dUpper = new D<Contravariant<Upper>>();
+  D<Contravariant<Middle>> dMiddle = new D<Contravariant<Middle>>();
+
+  E e = new E();
+  Expect.type<D<Contravariant<Upper>>>(e.method1());
+  Expect.type<D<Contravariant<Middle>>>(e.method1());
+
+  F f = new F();
+  Expect.type<D<Contravariant<Middle>>>(e.method1());
+
+  Iterable<Contravariant<Lower>> iterableLower = [new Contravariant<Lower>()];
+  List<Contravariant<Middle>> listMiddle = [new Contravariant<Middle>()];
+  iterableLower = listMiddle;
+
+  testCall(listMiddle);
+
+  Expect.subtype<Contravariant<Upper>, Contravariant<Middle>>();
+  Expect.subtype<Contravariant<Middle>, Contravariant<Middle>>();
+  Expect.notSubtype<Contravariant<Lower>, Contravariant<Middle>>();
+}
diff --git a/tests/language/variance/variance_inout_field_test.dart b/tests/language/variance/variance_inout_field_test.dart
new file mode 100644
index 000000000000..4e436d48eb95
--- /dev/null
+++ b/tests/language/variance/variance_inout_field_test.dart
@@ -0,0 +1,99 @@
+// 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.
+
+// Tests various fields for the `inout` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+import "package:expect/expect.dart";
+
+typedef Void2Int = int? Function();
+typedef Int2Void = void Function(int);
+
+class A<inout T> {
+  late T a;
+  final T? b = null;
+  final T? Function() c = () => null;
+  final void Function(T) d = (T val) {
+    Expect.equals(2, val);
+  };
+  A<T> get e => this;
+  covariant late T f;
+  T? get g => null;
+  void set h(T value) => value;
+  void set i(covariant T value) => value;
+}
+
+mixin BMixin<inout T> {
+  late T a;
+  final T? b = null;
+  final T? Function() c = () => null;
+  final void Function(T) d = (T val) {
+    Expect.equals(2, val);
+  };
+  BMixin<T> get e => this;
+  covariant late T f;
+  T? get g => null;
+  void set h(T value) => value;
+  void set i(covariant T value) => value;
+}
+
+class B with BMixin<int> {}
+
+void testClass() {
+  A<int> a = new A();
+
+  a.a = 2;
+  Expect.equals(2, a.a);
+
+  Expect.isNull(a.b);
+
+  Expect.type<Void2Int>(a.c);
+  Expect.isNull(a.c());
+
+  Expect.type<Int2Void>(a.d);
+  a.d(2);
+
+  a.e.a = 3;
+
+  a.f = 2;
+  Expect.equals(2, a.f);
+
+  Expect.isNull(a.g);
+
+  a.h = 2;
+
+  a.i = 2;
+}
+
+void testMixin() {
+  B b = new B();
+
+  b.a = 2;
+  Expect.equals(2, b.a);
+
+  Expect.isNull(b.b);
+
+  Expect.type<Void2Int>(b.c);
+  Expect.isNull(b.c());
+
+  Expect.type<Int2Void>(b.d);
+  b.d(2);
+
+  b.e.a = 3;
+
+  b.f = 2;
+  Expect.equals(2, b.f);
+
+  Expect.isNull(b.g);
+
+  b.h = 2;
+
+  b.i = 2;
+}
+
+main() {
+  testClass();
+  testMixin();
+}
diff --git a/tests/language/variance/variance_inout_inference_error_test.dart b/tests/language/variance/variance_inout_inference_error_test.dart
new file mode 100644
index 000000000000..763265801abc
--- /dev/null
+++ b/tests/language/variance/variance_inout_inference_error_test.dart
@@ -0,0 +1,60 @@
+// 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.
+
+// Tests local inference errors for the `inout` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+class Invariant<inout T> {}
+
+class Exactly<inout T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+Exactly<T> inferInvInv<T>(Invariant<T> x, Invariant<T> y) => new Exactly<T>();
+Exactly<T> inferInvCov<T>(Invariant<T> x, Covariant<T> y) => new Exactly<T>();
+Exactly<T> inferInvContra<T>(Invariant<T> x, Contravariant<T> y) => new Exactly<T>();
+
+main() {
+  // Middle <: T <: Middle and int <: T <: int are not valid constraints.
+  inferInvInv(Invariant<Middle>(), Invariant<int>());
+//            ^^^^^^^^^^^^^^^^^^^
+// [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+// [cfe] The argument type 'Invariant<Middle>' can't be assigned to the parameter type 'Invariant<Object>'.
+//                                 ^^^^^^^^^^^^^^^^
+// [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+// [cfe] The argument type 'Invariant<int>' can't be assigned to the parameter type 'Invariant<Object>'.
+
+  // Middle <: T <: Middle and Upper <: T <: Upper are not valid constraints.
+  inferInvInv(Invariant<Middle>(), Invariant<Upper>());
+//            ^^^^^^^^^^^^^^^^^^^
+// [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+// [cfe] The argument type 'Invariant<Middle>' can't be assigned to the parameter type 'Invariant<Upper>'.
+
+  // Middle <: T <: Middle and Lower <: T <: Lower are not valid constraints.
+  inferInvInv(Invariant<Middle>(), Invariant<Lower>());
+//                                 ^^^^^^^^^^^^^^^^^^
+// [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+// [cfe] The argument type 'Invariant<Lower>' can't be assigned to the parameter type 'Invariant<Middle>'.
+
+  // Upper <: T
+  // Middle <: T <: Middle
+  // Upper <: T <: Middle is not a valid constraint.
+  inferInvCov(Invariant<Middle>(), Covariant<Upper>());
+//            ^^^^^^^^^^^^^^^^^^^
+// [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+// [cfe] The argument type 'Invariant<Middle>' can't be assigned to the parameter type 'Invariant<Upper>'.
+
+  // T <: Lower
+  // Middle <: T <: Lower
+  // Middle <: T <: Lower is not a valid constraint
+  inferInvContra(Invariant<Middle>(), Contravariant<Lower>());
+//                                    ^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+// [cfe] The argument type 'Contravariant<Lower>' can't be assigned to the parameter type 'Contravariant<Middle>'.
+}
diff --git a/tests/language/variance/variance_inout_inference_test.dart b/tests/language/variance/variance_inout_inference_test.dart
new file mode 100644
index 000000000000..8a5e3c527059
--- /dev/null
+++ b/tests/language/variance/variance_inout_inference_test.dart
@@ -0,0 +1,54 @@
+// 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.
+
+// Tests local inference for the `inout` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+class Invariant<inout T> {}
+
+class Exactly<inout T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+Exactly<T> inferInvInv<T>(Invariant<T> x, Invariant<T> y) => new Exactly<T>();
+Exactly<T> inferInvCov<T>(Invariant<T> x, Covariant<T> y) => new Exactly<T>();
+Exactly<T> inferInvContra<T>(Invariant<T> x, Contravariant<T> y) => new Exactly<T>();
+
+main() {
+  Exactly<Middle> middle;
+
+  // Middle <: T <: Middle
+  // Choose Middle
+  var inferredMiddle = inferInvInv(Invariant<Middle>(), Invariant<Middle>());
+  middle = inferredMiddle;
+
+  // Lower <: T
+  // Middle <: T <: Middle
+  // Choose Middle since this merges to Middle <: T <: Middle
+  var inferredMiddle2 = inferInvCov(Invariant<Middle>(), Covariant<Lower>());
+  middle = inferredMiddle2;
+
+  // Middle <: T
+  // Middle <: T <: Middle
+  // Choose Middle since this merges to Middle <: T <: Middle
+  var inferredMiddle3 = inferInvCov(Invariant<Middle>(), Covariant<Middle>());
+  middle = inferredMiddle3;
+
+  // T <: Upper
+  // Middle <: T <: Middle
+  // Choose Middle since this merges to Middle <: T <: Middle
+  var inferredMiddle4 = inferInvContra(Invariant<Middle>(), Contravariant<Upper>());
+  middle = inferredMiddle4;
+
+  // T <: Middle
+  // Middle <: T <: Middle
+  // Choose Middle since this merges to Middle <: T <: Middle
+  var inferredMiddle5 = inferInvContra(Invariant<Middle>(), Contravariant<Middle>());
+  middle = inferredMiddle5;
+}
diff --git a/tests/language/variance/variance_inout_method_test.dart b/tests/language/variance/variance_inout_method_test.dart
new file mode 100644
index 000000000000..e76f19ee32d8
--- /dev/null
+++ b/tests/language/variance/variance_inout_method_test.dart
@@ -0,0 +1,288 @@
+// 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.
+
+// Tests method signatures and return types for the `inout` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+import "package:expect/expect.dart";
+
+typedef Cov<T> = T Function();
+typedef Contra<T> = void Function(T);
+
+Cov<int> covFunction = () => 2;
+Contra<int> contraFunction = (int val) {};
+Cov<num> covFunctionNum = () => 2;
+Contra<num> contraFunctionNum = (num val) {};
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+class Invariant<inout T> {}
+
+class A<inout T> {
+  void method1(T x) {}
+  void method2(Cov<T> x) {}
+  Contra<T> method3() {
+    return (T val) {
+      Expect.equals(2, val);
+    };
+  }
+
+  T? method4() => null;
+  void method5(Contra<T> x) {}
+  Cov<T?> method6() {
+    return () => null;
+  }
+
+  T method7(T x) => x;
+  Contra<T> method8(Contra<T> x) => x;
+  Cov<T> method9(Cov<T> x) => x;
+
+  T method10<S extends T>(S x) => x;
+
+  void method11(Covariant<T> x) {}
+  Covariant<T>? method12() => null;
+  void method13(Contravariant<T> x) {}
+  Contravariant<T>? method14() => null;
+  void method15(Invariant<T> x) {}
+  Invariant<T>? method16() => null;
+
+  void method17(covariant T x) {}
+  void method18(covariant Contra<T> x) {}
+  void method19(covariant Cov<T> x) {}
+  void method20(covariant Contravariant<T> x) {}
+  void method21(covariant Covariant<T> x) {}
+
+  void method22<S extends Contravariant<T>>() {}
+  void method23<S extends Covariant<T>>() {}
+  void method24<S extends Contra<T>>() {}
+  void method25<S extends Cov<T>>() {}
+
+  void method26({Contra<T>? a, Cov<T>? b, T? c}) {}
+  void method27({Contravariant<T>? a, Covariant<T>? b}) {}
+}
+
+mixin BMixin<inout T> {
+  void method1(T x) {}
+  void method2(Cov<T> x) {}
+  Contra<T> method3() {
+    return (T val) {
+      Expect.equals(2, val);
+    };
+  }
+
+  T? method4() => null;
+  void method5(Contra<T> x) {}
+  Cov<T?> method6() {
+    return () => null;
+  }
+
+  T method7(T x) => x;
+  Contra<T> method8(Contra<T> x) => x;
+  Cov<T> method9(Cov<T> x) => x;
+
+  T method10<S extends T>(S x) => x;
+
+  void method11(Covariant<T> x) {}
+  Covariant<T>? method12() => null;
+  void method13(Contravariant<T> x) {}
+  Contravariant<T>? method14() => null;
+  void method15(Invariant<T> x) {}
+  Invariant<T>? method16() => null;
+
+  void method17(covariant T x) {}
+  void method18(covariant Contra<T> x) {}
+  void method19(covariant Cov<T> x) {}
+  void method20(covariant Contravariant<T> x) {}
+  void method21(covariant Covariant<T> x) {}
+
+  void method22<S extends Contravariant<T>>() {}
+  void method23<S extends Covariant<T>>() {}
+  void method24<S extends Contra<T>>() {}
+  void method25<S extends Cov<T>>() {}
+
+  void method26({Contra<T>? a, Cov<T>? b, T? c}) {}
+  void method27({Contravariant<T>? a, Covariant<T>? b}) {}
+}
+
+class B with BMixin<num> {}
+
+class C<inout T> {
+  void method1(Contra<A<T>> x) {}
+  void method2(Cov<A<T>> x) {}
+  A<T> method3() {
+    return A<T>();
+  }
+}
+
+class D<T> {
+  T? method() => null;
+  void method2(T x) {}
+  void method3(covariant T x) {}
+}
+
+class E<inout T> extends D<T> {
+  @override
+  T? method() => null;
+
+  @override
+  void method2(T x) {}
+
+  @override
+  void method3(covariant T x) {}
+}
+
+abstract class F<T> {
+  int method(T x);
+}
+
+class G<inout T> {
+  final void Function(T) f;
+  G(this.f);
+  int method(T x) {
+    f(x);
+    return -1;
+  }
+}
+
+class H<inout T> extends G<T> implements F<T> {
+  H(void Function(T) f) : super(f);
+}
+
+void testClass() {
+  A<int> a = new A();
+
+  a.method1(2);
+
+  a.method2(() => 2);
+
+  Expect.type<Contra<int>>(a.method3());
+  Contra<int> method3Function = a.method3();
+  method3Function(2);
+
+  Expect.isNull(a.method4());
+
+  a.method5((int val) {});
+
+  Expect.type<Cov<int?>>(a.method6());
+  Cov<int?> method6Function = a.method6();
+  Expect.isNull(method6Function());
+
+  Expect.equals(3, a.method7(3));
+
+  Expect.type<Contra<int>>(a.method8(contraFunction));
+  Expect.equals(contraFunction, a.method8(contraFunction));
+
+  Expect.type<Cov<int>>(a.method9(covFunction));
+  Expect.equals(covFunction, a.method9(covFunction));
+
+  A<num> aa = new A();
+  Expect.type<num>(aa.method10(3));
+
+  a.method11(Covariant<int>());
+  Expect.isNull(a.method12());
+  a.method13(Contravariant<int>());
+  Expect.isNull(a.method14());
+  a.method15(Invariant<int>());
+  Expect.isNull(a.method16());
+
+  a.method17(3);
+  a.method18(contraFunction);
+  a.method19(covFunction);
+  a.method20(Contravariant<int>());
+  a.method21(Covariant<int>());
+
+  a.method22<Contravariant<int>>();
+  a.method23<Covariant<int>>();
+  a.method24<Contra<int>>();
+  a.method25<Cov<int>>();
+
+  a.method26();
+  a.method27();
+}
+
+void testMixin() {
+  B b = new B();
+
+  b.method1(2);
+
+  b.method2(() => 2);
+
+  Expect.type<Contra<num>>(b.method3());
+  Contra<num> method3Function = b.method3();
+  method3Function(2);
+
+  Expect.isNull(b.method4());
+
+  b.method5((num val) {});
+
+  Expect.type<Cov<num?>>(b.method6());
+  Cov<num?> method6Function = b.method6();
+  Expect.isNull(method6Function());
+
+  Expect.equals(3, b.method7(3));
+
+  Expect.type<Contra<num>>(b.method8(contraFunctionNum));
+  Expect.equals(contraFunctionNum, b.method8(contraFunctionNum));
+
+  Expect.type<Cov<num>>(b.method9(covFunctionNum));
+  Expect.equals(covFunctionNum, b.method9(covFunctionNum));
+
+  Expect.type<num>(b.method10(3));
+
+  b.method11(Covariant<num>());
+  Expect.isNull(b.method12());
+  b.method13(Contravariant<num>());
+  Expect.isNull(b.method14());
+  b.method15(Invariant<num>());
+  Expect.isNull(b.method16());
+
+  b.method17(3);
+  b.method18(contraFunctionNum);
+  b.method19(covFunctionNum);
+  b.method20(Contravariant<num>());
+  b.method21(Covariant<num>());
+
+  b.method22<Contravariant<num>>();
+  b.method23<Covariant<num>>();
+  b.method24<Contra<num>>();
+  b.method25<Cov<num>>();
+
+  b.method26();
+  b.method27();
+}
+
+void testClassInMethods() {
+  C<int> c = new C();
+
+  c.method1((A<int> x) {});
+  c.method2(() => throw "uncalled");
+
+  Expect.type<A<int>>(c.method3());
+}
+
+void testOverrideLegacyMethods() {
+  E<int> e = new E();
+  Expect.isNull(e.method());
+  e.method2(3);
+  e.method3(3);
+
+  D<Object> d = e;
+  Expect.throws(() => d.method2("test"));
+  Expect.throws(() => d.method3("test"));
+
+  F<Object> f = new H<String>((String s) {});
+  Expect.throws(() => f.method(3));
+
+  // Tests reified type is the type expected for F and not G.
+  Expect.type<int Function(Object)>(f.method);
+  Expect.type<int Function(Object)>(new H<String>((String s){}).method);
+}
+
+main() {
+  testClass();
+  testMixin();
+  testClassInMethods();
+  testOverrideLegacyMethods();
+}
diff --git a/tests/language/variance/variance_inout_subclass_test.dart b/tests/language/variance/variance_inout_subclass_test.dart
new file mode 100644
index 000000000000..e1b7122c8052
--- /dev/null
+++ b/tests/language/variance/variance_inout_subclass_test.dart
@@ -0,0 +1,90 @@
+// 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.
+
+// Tests subclass usage for the `inout` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+typedef CovFunction<T> = T Function();
+typedef ContraFunction<T> = void Function(T);
+typedef InvFunction<T> = T Function(T);
+
+class LegacyCovariant<T> {}
+class Invariant<inout T>{}
+class Covariant<out T> {}
+class Contravariant<in T> {}
+mixin MLegacyCovariant<T> {}
+mixin MContravariant<in T> {}
+mixin MCovariant<out T> {}
+mixin MInvariant<inout T> {}
+
+class A<inout T> extends LegacyCovariant<T> {}
+class B<inout T> extends Invariant<T> {}
+class C<inout T> extends Covariant<T> {}
+class D<inout T> extends Contravariant<T> {}
+
+class E<inout T> implements LegacyCovariant<T> {}
+class F<inout T> implements Invariant<T> {}
+class G<inout T> implements Covariant<T> {}
+class H<inout T> implements Contravariant<T> {}
+
+class I<inout T> with MLegacyCovariant<T> {}
+class J<inout T> with MInvariant<T> {}
+class K<inout T> with MCovariant<T> {}
+class L<inout T> with MContravariant<T> {}
+
+class M<inout T> extends Covariant<Contravariant<T>> {}
+class N<inout T> extends Contravariant<Covariant<T>> {}
+class O<inout T> extends Covariant<ContraFunction<T>> {}
+class P<inout T> extends Covariant<ContraFunction<CovFunction<T>>> {}
+class Q<inout T> extends Covariant<CovFunction<ContraFunction<T>>> {}
+class R<inout T> extends Covariant<ContraFunction<Covariant<T>>> {}
+class S<inout T> extends Contravariant<Contravariant<Contravariant<T>>> {}
+
+class T<inout X> extends Covariant<Covariant<X>> {}
+class U<inout T> extends Contravariant<Contravariant<T>> {}
+class V<inout T> extends Covariant<CovFunction<T>> {}
+class W<inout T> extends Covariant<ContraFunction<ContraFunction<T>>> {}
+class X<inout T> extends Contravariant<CovFunction<Contravariant<T>>> {}
+class Y<inout T> extends Covariant<CovFunction<Covariant<T>>> {}
+class Z<inout T> extends Covariant<Covariant<Covariant<T>>> {}
+
+class AA<inout T> extends Covariant<InvFunction<T>> {}
+
+class AB<inout T> = Invariant<T> with MInvariant<T>;
+class AC<inout T> = Covariant<T> with MCovariant<T>;
+class AD<inout T> = Contravariant<T> with MContravariant<T>;
+
+main() {
+  A<num> a = A();
+  B<num> b = B();
+  C<num> c = C();
+  D<num> d = D();
+  E<num> e = E();
+  F<num> f = F();
+  G<num> g = G();
+  H<num> h = H();
+  I<num> i = I();
+  J<num> j = J();
+  K<num> k = K();
+  L<num> l = L();
+  M<num> m = M();
+  N<num> n = N();
+  O<num> o = O();
+  P<num> p = P();
+  Q<num> q = Q();
+  R<num> r = R();
+  S<num> s = S();
+  T<num> t = T();
+  U<num> u = U();
+  V<num> v = V();
+  W<num> w = W();
+  X<num> x = X();
+  Y<num> y = Y();
+  Z<num> z = Z();
+  AA<num> aa = AA();
+  AB<num> ab = AB();
+  AC<num> ac = AC();
+  AD<num> ad = AD();
+}
diff --git a/tests/language/variance/variance_inout_subtyping_error_test.dart b/tests/language/variance/variance_inout_subtyping_error_test.dart
new file mode 100644
index 000000000000..d06f3365ed2b
--- /dev/null
+++ b/tests/language/variance/variance_inout_subtyping_error_test.dart
@@ -0,0 +1,130 @@
+// 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.
+
+// Tests erroneous subtyping for the `inout` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class Invariant<inout T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+class A {
+  Invariant<Middle> method1() {
+    return Invariant<Middle>();
+  }
+
+  void method2(Invariant<Middle> x) {}
+}
+
+class B extends A {
+  @override
+  Invariant<Upper> method1() {
+  //               ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.INVALID_OVERRIDE
+  // [cfe] The return type of the method 'B.method1' is 'Invariant<Upper>', which does not match the return type, 'Invariant<Middle>', of the overridden method, 'A.method1'.
+    return new Invariant<Upper>();
+  }
+
+  @override
+  void method2(Invariant<Lower> x) {}
+  //   ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.INVALID_OVERRIDE
+  //                            ^
+  // [cfe] The parameter 'x' of the method 'B.method2' has type 'Invariant<Lower>', which does not match the corresponding type, 'Invariant<Middle>', in the overridden method, 'A.method2'.
+}
+
+class C extends A {
+  @override
+  Invariant<Lower> method1() {
+  //               ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.INVALID_OVERRIDE
+  // [cfe] The return type of the method 'C.method1' is 'Invariant<Lower>', which does not match the return type, 'Invariant<Middle>', of the overridden method, 'A.method1'.
+    return new Invariant<Lower>();
+  }
+
+  @override
+  void method2(Invariant<Upper> x) {}
+  //   ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.INVALID_OVERRIDE
+  //                            ^
+  // [cfe] The parameter 'x' of the method 'C.method2' has type 'Invariant<Upper>', which does not match the corresponding type, 'Invariant<Middle>', in the overridden method, 'A.method2'.
+}
+
+class D<out T extends Invariant<Middle>> {}
+
+class E {
+  D<Invariant<Upper>> method1() {
+  //^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  //                         ^
+  // [cfe] Type argument 'Invariant<Upper>' doesn't conform to the bound 'Invariant<Middle>' of the type variable 'T' on 'D' in the return type.
+    return D<Invariant<Upper>>();
+    //     ^
+    // [cfe] Type argument 'Invariant<Upper>' doesn't conform to the bound 'Invariant<Middle>' of the type variable 'T' on 'D'.
+    //       ^^^^^^^^^^^^^^^^
+    // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  }
+
+  D<Invariant<Lower>> method2() {
+  //^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  //                         ^
+  // [cfe] Type argument 'Invariant<Lower>' doesn't conform to the bound 'Invariant<Middle>' of the type variable 'T' on 'D' in the return type.
+    return D<Invariant<Lower>>();
+    //     ^
+    // [cfe] Type argument 'Invariant<Lower>' doesn't conform to the bound 'Invariant<Middle>' of the type variable 'T' on 'D'.
+    //       ^^^^^^^^^^^^^^^^
+    // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  }
+}
+
+void testCall<T>(Iterable<Invariant<T>> x) {}
+
+main() {
+  D<Invariant<Upper>> dUpper = new D<Invariant<Upper>>();
+  //^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  //                  ^
+  // [cfe] Type argument 'Invariant<Upper>' doesn't conform to the bound 'Invariant<Middle>' of the type variable 'T' on 'D'.
+  //                               ^
+  // [cfe] Type argument 'Invariant<Upper>' doesn't conform to the bound 'Invariant<Middle>' of the type variable 'T' on 'D'.
+  //                                 ^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  D<Invariant<Lower>> dLower = new D<Invariant<Lower>>();
+  //^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  //                  ^
+  // [cfe] Type argument 'Invariant<Lower>' doesn't conform to the bound 'Invariant<Middle>' of the type variable 'T' on 'D'.
+  //                               ^
+  // [cfe] Type argument 'Invariant<Lower>' doesn't conform to the bound 'Invariant<Middle>' of the type variable 'T' on 'D'.
+  //                                 ^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+
+  Iterable<Invariant<Lower>> iterableLower = [new Invariant<Lower>()];
+  List<Invariant<Middle>> listMiddle = [new Invariant<Middle>()];
+  iterableLower = listMiddle;
+  //              ^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'List<Invariant<Middle>>' can't be assigned to a variable of type 'Iterable<Invariant<Lower>>'.
+
+  Iterable<Invariant<Middle>> iterableMiddle = [new Invariant<Middle>()];
+  List<Invariant<Lower>> listLower = [new Invariant<Lower>()];
+  iterableMiddle = listLower;
+  //               ^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'List<Invariant<Lower>>' can't be assigned to a variable of type 'Iterable<Invariant<Middle>>'.
+
+  testCall<Lower>(listMiddle);
+  //              ^^^^^^^^^^
+  // [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+  // [cfe] The argument type 'List<Invariant<Middle>>' can't be assigned to the parameter type 'Iterable<Invariant<Lower>>'.
+
+  testCall<Middle>(listLower);
+  //               ^^^^^^^^^
+  // [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+  // [cfe] The argument type 'List<Invariant<Lower>>' can't be assigned to the parameter type 'Iterable<Invariant<Middle>>'.
+}
diff --git a/tests/language/variance/variance_inout_subtyping_test.dart b/tests/language/variance/variance_inout_subtyping_test.dart
new file mode 100644
index 000000000000..e4252f49a1ad
--- /dev/null
+++ b/tests/language/variance/variance_inout_subtyping_test.dart
@@ -0,0 +1,170 @@
+// 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.
+
+// Tests subtyping for the `inout` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+import 'dart:async';
+
+import "package:expect/expect.dart";
+
+class Invariant<inout T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+class A {
+  Invariant<Middle> method1() {
+    return new Invariant<Middle>();
+  }
+
+  void method2(Invariant<Middle> x) {}
+}
+
+class B extends A {
+  @override
+  Invariant<Middle> method1() {
+    return new Invariant<Middle>();
+  }
+
+  @override
+  void method2(Invariant<Middle> x) {}
+}
+
+class C<out X extends Invariant<Middle>> {}
+
+class D {
+  C<Invariant<Middle>> method1() {
+    return C<Invariant<Middle>>();
+  }
+}
+
+class E {
+  Invariant<dynamic> method1() {
+    return new Invariant<dynamic>();
+  }
+
+  void method2(Invariant<Object?> x) {}
+}
+
+class F extends E {
+  @override
+  Invariant<Object?> method1() {
+    return new Invariant<Object?>();
+  }
+
+  @override
+  void method2(Invariant<dynamic> x) {}
+}
+
+class G {
+  Invariant<dynamic> method1() {
+    return new Invariant<dynamic>();
+  }
+
+  void method2(Invariant<FutureOr<dynamic>> x) {}
+}
+
+class H extends G {
+  @override
+  Invariant<FutureOr<dynamic>> method1() {
+    return new Invariant<FutureOr<dynamic>>();
+  }
+
+  @override
+  void method2(Invariant<dynamic> x) {}
+}
+
+class I {
+  Invariant<FutureOr<Never>> method1() {
+    return new Invariant<FutureOr<Never>>();
+  }
+
+  void method2(Invariant<Future<Never>> x) {}
+}
+
+class J extends I {
+  @override
+  Invariant<Future<Never>> method1() {
+    return new Invariant<Future<Never>>();
+  }
+
+  @override
+  void method2(Invariant<FutureOr<Never>> x) {}
+}
+
+void testCall(Iterable<Invariant<Middle>> x) {}
+
+main() {
+  A a = new A();
+  Expect.type<Invariant<Middle>>(a.method1());
+  Expect.notType<Invariant<Upper>>(a.method1());
+  Expect.notType<Invariant<Lower>>(a.method1());
+  a.method2(new Invariant<Middle>());
+
+  B b = new B();
+  Expect.type<Invariant<Middle>>(b.method1());
+  Expect.notType<Invariant<Upper>>(b.method1());
+  Expect.notType<Invariant<Lower>>(b.method1());
+  b.method2(new Invariant<Middle>());
+
+  C<Invariant<Middle>> c = new C<Invariant<Middle>>();
+
+  D d = new D();
+  Expect.type<C<Invariant<Middle>>>(d.method1());
+
+  E e = new E();
+  Expect.type<Invariant<dynamic>>(e.method1());
+  e.method2(new Invariant<Object?>());
+
+  // Invariant<dynamic> <:> Invariant<Object?>
+  F f = new F();
+  Expect.type<Invariant<Object?>>(f.method1());
+  Expect.type<Invariant<dynamic>>(f.method1());
+  f.method2(new Invariant<Object?>());
+  f.method2(new Invariant<dynamic>());
+
+  G g = new G();
+  Expect.type<Invariant<dynamic>>(g.method1());
+  g.method2(new Invariant<FutureOr<dynamic>>());
+
+  // Invariant<FutureOr<dynamic>> <:> Invariant<dynamic>
+  H h = new H();
+  Expect.type<Invariant<FutureOr<dynamic>>>(h.method1());
+  Expect.type<Invariant<dynamic>>(h.method1());
+  h.method2(new Invariant<FutureOr<dynamic>>());
+  h.method2(new Invariant<dynamic>());
+
+  I i = new I();
+  Expect.type<Invariant<FutureOr<Never>>>(i.method1());
+  i.method2(new Invariant<Future<Never>>());
+
+  // Invariant<FutureOr<Never>> <:> Invariant<Future<Never>>
+  J j = new J();
+  Expect.type<Invariant<FutureOr<Never>>>(j.method1());
+  Expect.type<Invariant<Future<Never>>>(j.method1());
+  j.method2(new Invariant<FutureOr<Never>>());
+  j.method2(new Invariant<Future<Never>>());
+
+  Iterable<Invariant<Middle>> iterableMiddle = [new Invariant<Middle>()];
+  List<Invariant<Middle>> listMiddle = [new Invariant<Middle>()];
+  iterableMiddle = listMiddle;
+
+  testCall(listMiddle);
+
+  Expect.subtype<Invariant<Middle>, Invariant<Middle>>();
+  Expect.notSubtype<Invariant<Lower>, Invariant<Middle>>();
+  Expect.notSubtype<Invariant<Upper>, Invariant<Middle>>();
+
+  Expect.subtype<Invariant<dynamic>, Invariant<Object?>>();
+  Expect.subtype<Invariant<Object?>, Invariant<dynamic>>();
+
+  Expect.subtype<Invariant<FutureOr<dynamic>>, Invariant<dynamic>>();
+  Expect.subtype<Invariant<dynamic>, Invariant<FutureOr<dynamic>>>();
+
+  Expect.subtype<Invariant<FutureOr<Never>>, Invariant<Future<Never>>>();
+  Expect.subtype<Invariant<Future<Never>>, Invariant<FutureOr<Never>>>();
+}
diff --git a/tests/language/variance/variance_method_tearoff_test.dart b/tests/language/variance/variance_method_tearoff_test.dart
new file mode 100644
index 000000000000..1e69d797c745
--- /dev/null
+++ b/tests/language/variance/variance_method_tearoff_test.dart
@@ -0,0 +1,52 @@
+// 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.
+
+// Tests reified types of torn-off methods with type parameters that have
+// explicit variance modifiers.
+
+// SharedOptions=--enable-experiment=variance
+
+import "package:expect/expect.dart";
+
+class Contravariant<in T> {
+  int method(T x) { return -1; }
+}
+
+class Invariant<inout T> {
+  T method(T x) { return x; }
+}
+
+class LegacyCovariant<T> {
+  int method(T x) { return -1; }
+}
+
+class NoSuchMethod<inout T> implements Invariant<T> {
+  noSuchMethod(_) => 3;
+}
+
+main() {
+  Contravariant<int> contraDiff = new Contravariant<num>();
+  Expect.notType<int Function(Object)>(contraDiff.method);
+  Expect.type<int Function(num)>(contraDiff.method);
+
+  Contravariant<num> contraSame = new Contravariant<num>();
+  Expect.notType<int Function(Object)>(contraSame.method);
+  Expect.type<int Function(num)>(contraSame.method);
+
+  Invariant<num> invSame = new Invariant<num>();
+  Expect.notType<num Function(Object)>(invSame.method);
+  Expect.type<num Function(num)>(invSame.method);
+
+  LegacyCovariant<num> legacyDiff = new LegacyCovariant<int>();
+  Expect.type<int Function(Object)>(legacyDiff.method);
+  Expect.type<int Function(num)>(legacyDiff.method);
+
+  LegacyCovariant<num> legacySame = new LegacyCovariant<num>();
+  Expect.type<int Function(Object)>(legacySame.method);
+  Expect.type<int Function(num)>(legacySame.method);
+
+  NoSuchMethod<num> nsm = new NoSuchMethod<num>();
+  Expect.notType<num Function(Object)>(nsm.method);
+  Expect.type<num Function(num)>(nsm.method);
+}
diff --git a/tests/language/variance/variance_multi_subclass_error_test.dart b/tests/language/variance/variance_multi_subclass_error_test.dart
new file mode 100644
index 000000000000..ed790c7394d6
--- /dev/null
+++ b/tests/language/variance/variance_multi_subclass_error_test.dart
@@ -0,0 +1,84 @@
+// 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.
+
+// Tests erroneous variance usage multiple type parameters.
+
+// SharedOptions=--enable-experiment=variance
+
+typedef CovFunction<T> = T Function();
+typedef ContraFunction<T> = void Function(T);
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+
+class MultiTwo<in T, out U> {}
+class MultiThree<in T, out U, inout V> {}
+
+class A<in T, out U, inout V> extends Covariant<T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'Covariant'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class B<in T> extends MultiThree<T, T, T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'inout' position in supertype 'MultiThree'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class C<in T, out U, inout V> extends MultiTwo<U, T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'MultiTwo'.
+//    ^
+// [cfe] Can't use 'out' type variable 'U' in an 'in' position in supertype 'MultiTwo'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+//                ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class D<in T, out U, inout V> extends MultiThree<V, U, T> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'inout' position in supertype 'MultiThree'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class E<in T, out U, inout V> extends MultiThree<Covariant<U>, Covariant<T>, Covariant<U>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'MultiThree'.
+//    ^
+// [cfe] Can't use 'out' type variable 'U' in an 'inout' position in supertype 'MultiThree'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+//                ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class F<in T, out U, inout V> extends MultiTwo<Contravariant<T>, Contravariant<U>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'MultiTwo'.
+//    ^
+// [cfe] Can't use 'out' type variable 'U' in an 'in' position in supertype 'MultiTwo'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+//                ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class G<in T, out U, inout V> extends MultiThree<CovFunction<U>, CovFunction<T>, CovFunction<U>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'MultiThree'.
+//    ^
+// [cfe] Can't use 'out' type variable 'U' in an 'inout' position in supertype 'MultiThree'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+//                ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class H<in T, out U, inout V> extends MultiTwo<ContraFunction<T>, ContraFunction<U>> {}
+//    ^
+// [cfe] Can't use 'in' type variable 'T' in an 'out' position in supertype 'MultiTwo'.
+//    ^
+// [cfe] Can't use 'out' type variable 'U' in an 'in' position in supertype 'MultiTwo'.
+//         ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+//                ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
diff --git a/tests/language/variance/variance_multi_subclass_test.dart b/tests/language/variance/variance_multi_subclass_test.dart
new file mode 100644
index 000000000000..ae4f57ae5ab2
--- /dev/null
+++ b/tests/language/variance/variance_multi_subclass_test.dart
@@ -0,0 +1,42 @@
+// 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.
+
+// Tests variance usage multiple type parameters.
+
+// SharedOptions=--enable-experiment=variance
+
+typedef CovFunction<T> = T Function();
+typedef ContraFunction<T> = void Function(T);
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+
+class A<in T, out U> {}
+class B<in T, out U, inout V> {}
+
+class C<inout T, in U, out V> extends A<T, V> {}
+class D<inout T, in U, out V> extends B<U, V, T> {}
+class E<inout T, in U, out V> extends B<T, T, T> {}
+
+class F<inout T, in U, out V> extends A<Contravariant<V>, Contravariant<U>> {}
+class G<inout T, in U, out V> extends A<Covariant<Contravariant<V>>, Contravariant<Covariant<U>>> {}
+class H<inout T, in U, out V> extends B<Covariant<U>, Covariant<V>, Covariant<T>> {}
+
+class I<inout T, in U, out V> extends A<ContraFunction<V>, ContraFunction<U>> {}
+class J<inout T, in U, out V> extends A<CovFunction<ContraFunction<V>>, ContraFunction<CovFunction<U>>> {}
+class K<inout T, in U, out V> extends B<CovFunction<U>, CovFunction<V>, CovFunction<T>> {}
+
+main() {
+  A<num, bool> a = A();
+  B<num, bool, String> b = B();
+  C<num, bool, String> c = C();
+  D<num, bool, String> d = D();
+  E<num, bool, String> e = E();
+  F<num, bool, String> f = F();
+  G<num, bool, String> g = G();
+  H<num, bool, String> h = H();
+  I<num, bool, String> i = I();
+  J<num, bool, String> j = J();
+  K<num, bool, String> k = K();
+}
diff --git a/tests/language/variance/variance_out_field_error_test.dart b/tests/language/variance/variance_out_field_error_test.dart
new file mode 100644
index 000000000000..8fc79a91e8e8
--- /dev/null
+++ b/tests/language/variance/variance_out_field_error_test.dart
@@ -0,0 +1,64 @@
+// 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.
+
+// Tests erroneous field usage for the `out` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class A<out T> {
+  void set a(T value) => value;
+  //         ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //           ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+  final void Function(T) b = (T val) {};
+  //                     ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+  late T c;
+//       ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  T? d = null;
+  // ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+}
+
+mixin BMixin<out T> {
+  void set a(T value) => value;
+  //         ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //           ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+  final void Function(T) b = (T val) {};
+  //                     ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+  late T c;
+//       ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  T? d = null;
+  // ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+}
+
+abstract class C<out T> {
+  void set a(T value) => value;
+  //         ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //           ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+}
+
+class D<out T> extends C<T> {
+  late var a;
+  //       ^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+}
diff --git a/tests/language/variance/variance_out_field_test.dart b/tests/language/variance/variance_out_field_test.dart
new file mode 100644
index 000000000000..3059cb8259e1
--- /dev/null
+++ b/tests/language/variance/variance_out_field_test.dart
@@ -0,0 +1,72 @@
+// 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.
+
+// Tests various fields for the `out` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+import "package:expect/expect.dart";
+
+typedef Void2Int = int? Function();
+
+class A<out T> {
+  final T? a = null;
+  final T? Function() b = () => null;
+  T? get c => null;
+  A<T> get d => this;
+  covariant late T e;
+  void set f(covariant T value) => value;
+}
+
+mixin BMixin<out T> {
+  final T? a = null;
+  final T? Function() b = () => null;
+  T? get c => null;
+  BMixin<T> get d => this;
+  covariant late T e;
+  void set f(covariant T value) => value;
+}
+
+class B with BMixin<int> {}
+
+void testClass() {
+  A<int> a = new A();
+
+  Expect.isNull(a.a);
+
+  Expect.type<Void2Int>(a.b);
+  Expect.isNull(a.b());
+
+  Expect.isNull(a.c);
+
+  Expect.isNull(a.d.a);
+
+  a.e = 2;
+  Expect.equals(2, a.e);
+
+  a.f = 2;
+}
+
+void testMixin() {
+  B b = new B();
+
+  Expect.isNull(b.a);
+
+  Expect.type<Void2Int>(b.b);
+  Expect.isNull(b.b());
+
+  Expect.isNull(b.c);
+
+  Expect.isNull(b.d.a);
+
+  b.e = 2;
+  Expect.equals(2, b.e);
+
+  b.f = 2;
+}
+
+main() {
+  testClass();
+  testMixin();
+}
diff --git a/tests/language/variance/variance_out_inference_error_test.dart b/tests/language/variance/variance_out_inference_error_test.dart
new file mode 100644
index 000000000000..809cdfb44fd7
--- /dev/null
+++ b/tests/language/variance/variance_out_inference_error_test.dart
@@ -0,0 +1,60 @@
+// 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.
+
+// Tests local inference errors for the `out` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class Covariant<out T> {}
+
+class Exactly<inout T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+class CovBound<out T> {
+  CovBound(T x, void Function(T) y) {}
+}
+
+Exactly<T> inferCovCov<T>(Covariant<T> x, Covariant<T> y) => new Exactly<T>();
+Exactly<T> inferCovBound<T>(CovBound<T> x) => new Exactly<T>();
+
+main() {
+  Exactly<Upper> upper;
+  Exactly<Middle> middle;
+  Exactly<Lower> lower;
+
+  // Lower <: T <: Middle.
+  // We choose Middle.
+  var inferredMiddle = inferCovCov(Covariant<Lower>(), Covariant<Middle>());
+  lower = inferredMiddle;
+  //      ^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Middle>' can't be assigned to a variable of type 'Exactly<Lower>'.
+
+  // Lower <: T <: Upper.
+  // We choose Upper.
+  var inferredUpper = inferCovCov(Covariant<Lower>(), Covariant<Upper>());
+  lower = inferredUpper;
+  //      ^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Upper>' can't be assigned to a variable of type 'Exactly<Lower>'.
+
+  // Inference for Covbound(...) produces Lower <: T <: Upper.
+  // Since T is covariant, we choose Lower as the solution.
+  var inferredCovLower = inferCovBound(CovBound(Lower(), (Upper x) {}));
+  upper = inferredCovLower;
+  //      ^^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Lower>' can't be assigned to a variable of type 'Exactly<Upper>'.
+
+  // Inference for Covbound(...) produces Lower <: T <: Middle.
+  // Since T is covariant, we choose Lower as the solution.
+  var inferredCovLower2 = inferCovBound(CovBound(Lower(), (Middle x) {}));
+  middle = inferredCovLower2;
+  //       ^^^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Lower>' can't be assigned to a variable of type 'Exactly<Middle>'.
+}
diff --git a/tests/language/variance/variance_out_inference_test.dart b/tests/language/variance/variance_out_inference_test.dart
new file mode 100644
index 000000000000..14b49e165e36
--- /dev/null
+++ b/tests/language/variance/variance_out_inference_test.dart
@@ -0,0 +1,55 @@
+// 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.
+
+// Tests local inference for the `out` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class Covariant<out T> {}
+
+class Exactly<inout T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+class CovBound<out T> {
+  CovBound(T x, void Function(T) y) {}
+}
+
+Exactly<T> inferCovCov<T>(Covariant<T> x, Covariant<T> y) => new Exactly<T>();
+Exactly<T> inferCovBound<T>(CovBound<T> x) => new Exactly<T>();
+
+main() {
+  Exactly<Upper> upper;
+  Exactly<Lower> lower;
+
+  // Upper <: T
+  // Upper <: T
+  // Choose Upper
+  var inferredUpper = inferCovCov(Covariant<Upper>(), Covariant<Upper>());
+  upper = inferredUpper;
+
+  // Upper <: T
+  // Middle <: T
+  // Choose Upper since it is the lowest upper bound of Upper and Middle.
+  var inferredUpper2 = inferCovCov(Covariant<Upper>(), Covariant<Middle>());
+  upper = inferredUpper2;
+
+  // Upper <: T
+  // Lower <: T
+  // Choose Upper since it is the lowest upper bound of Upper and Lower.
+  var inferredUpper3 = inferCovCov(Covariant<Upper>(), Covariant<Lower>());
+  upper = inferredUpper3;
+
+  // Lower <: T <: Upper
+  // Choose Lower.
+  var inferredCovLower = inferCovBound(CovBound(Lower(), (Upper x) {}));
+  lower = inferredCovLower;
+
+  // Lower <: T <: Middle
+  // Choose Lower.
+  var inferredCovLower2 = inferCovBound(CovBound(Lower(), (Middle x) {}));
+  lower = inferredCovLower2;
+}
diff --git a/tests/language/variance/variance_out_method_error_test.dart b/tests/language/variance/variance_out_method_error_test.dart
new file mode 100644
index 000000000000..54ebd174e26f
--- /dev/null
+++ b/tests/language/variance/variance_out_method_error_test.dart
@@ -0,0 +1,357 @@
+// 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.
+
+// Tests erroneous method signatures and return types for the `out` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+typedef Inv<T> = void Function<X extends T>();
+typedef Cov<T> = T Function();
+typedef Contra<T> = void Function(T);
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+class Invariant<inout T> {}
+
+class A<out T> {
+  void method1(T x) {}
+  //           ^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //             ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method2(Cov<T> x) {}
+  //           ^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                  ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  Contra<T> method3() => (T val) {};
+//^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                 ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+
+  void method4(Cov<Cov<T>> x) {}
+  //           ^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                       ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  Contra<Cov<T>> method5() => (Cov<T> method) {};
+//^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                      ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+
+  Cov<Contra<T>> method6() {
+//^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                      ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+    return () {
+      return (T x) {};
+    };
+  }
+
+  void method7(Contra<Contra<T>> x) {}
+  //           ^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                             ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  Inv<T> method8() => throw "uncalled";
+//^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//              ^
+// [cfe] Can't use 'out' type variable 'T' in an 'inout' position in the return type.
+
+  void method9(Inv<T> x) {}
+  //           ^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                  ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  Contravariant<T> method10() => throw "uncalled";
+//^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                         ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+
+  void method11(Covariant<T> x) {}
+  //            ^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                         ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  Invariant<T> method12() => throw "uncalled";
+//^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                     ^
+// [cfe] Can't use 'out' type variable 'T' in an 'inout' position in the return type.
+
+  void method13(Invariant<T> x) {}
+  //            ^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                         ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  void method14(Covariant<Covariant<T>> x) {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                    ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method15(Contravariant<Contravariant<T>> x) {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                            ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  Contravariant<Covariant<T>> method16() => Contravariant<Covariant<T>>();
+//^^^^^^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                                    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+
+  Covariant<Contravariant<T>> method17() => Covariant<Contravariant<T>>();
+//^^^^^^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                                    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+
+  void method18<X extends Contra<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  void method19<X extends Contravariant<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  void method20({required T x}) {}
+  //             ^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                        ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method21({required Cov<T> x}) {}
+  //             ^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                             ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method22({required Covariant<T> x}) {}
+  //             ^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                   ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method23({required Covariant<T> x, required Contravariant<T> y}) {}
+  //             ^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                   ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method24<X extends T>() {}
+  //            ^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  void method25<X extends Contra<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  void method26<X extends Contravariant<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+}
+
+mixin BMixin<out T> {
+  void method1(T x) {}
+  //           ^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //             ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method2(Cov<T> x) {}
+  //           ^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                  ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  Contra<T> method3() => (T val) {};
+//^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                 ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+
+  void method4(Cov<Cov<T>> x) {}
+  //           ^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                       ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  Contra<Cov<T>> method5() => (Cov<T> method) {};
+//^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                      ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+
+  Cov<Contra<T>> method6() {
+//^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                      ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+    return () {
+      return (T x) {};
+    };
+  }
+
+  void method7(Contra<Contra<T>> x) {}
+  //           ^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                             ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  Inv<T> method8() => throw "uncalled";
+//^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//              ^
+// [cfe] Can't use 'out' type variable 'T' in an 'inout' position in the return type.
+
+  void method9(Inv<T> x) {}
+  //           ^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                  ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  Contravariant<T> method10() => throw "uncalled";
+//^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                         ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+
+  void method11(Covariant<T> x) {}
+  //            ^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                         ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  Invariant<T> method12() => throw "uncalled";
+//^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                     ^
+// [cfe] Can't use 'out' type variable 'T' in an 'inout' position in the return type.
+
+  void method13(Invariant<T> x) {}
+  //            ^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                         ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  void method14(Covariant<Covariant<T>> x) {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                    ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method15(Contravariant<Contravariant<T>> x) {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                            ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  Contravariant<Covariant<T>> method16() => Contravariant<Covariant<T>>();
+//^^^^^^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                                    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+
+  Covariant<Contravariant<T>> method17() => Covariant<Contravariant<T>>();
+//^^^^^^^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                                    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+
+  void method18<X extends Contra<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  void method19<X extends Contravariant<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  void method20({required T x}) {}
+  //             ^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                        ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method21({required Cov<T> x}) {}
+  //             ^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                             ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method22({required Covariant<T> x}) {}
+  //             ^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                   ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method23({required Covariant<T> x, required Contravariant<T> y}) {}
+  //             ^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                                   ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+
+  void method24<X extends T>() {}
+  //            ^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  void method25<X extends Contra<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+
+  void method26<X extends Contravariant<T>>() {}
+  //            ^^^^^^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  // [cfe] Can't use 'out' type variable 'T' in an 'inout' position.
+}
+
+class B<out T> {
+  void method1(Cov<A<T>> x) {}
+  //           ^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //                     ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+  Contra<A<T>> method2() {
+//^^^^^^^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+//                    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in the return type.
+    throw "uncalled";
+  }
+}
+
+class C<T> {
+  void method(T x) {}
+}
+
+class D<out T> extends C<T> {
+  @override
+  void method(T x) {}
+  //          ^^^
+  // [analyzer] COMPILE_TIME_ERROR.WRONG_TYPE_PARAMETER_VARIANCE_POSITION
+  //            ^
+  // [cfe] Can't use 'out' type variable 'T' in an 'in' position.
+}
diff --git a/tests/language/variance/variance_out_method_test.dart b/tests/language/variance/variance_out_method_test.dart
new file mode 100644
index 000000000000..6d3a9a5bbbfe
--- /dev/null
+++ b/tests/language/variance/variance_out_method_test.dart
@@ -0,0 +1,231 @@
+// 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.
+
+// Tests method signatures and return types for the `out` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+import "package:expect/expect.dart";
+
+typedef Cov<T> = T Function();
+typedef Contra<T> = void Function(T);
+
+Cov<int> covFunction = () => 2;
+Contra<int> contraFunction = (int val) {};
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+
+class A<out T> {
+  T? method1() => null;
+  void method2(Contra<T> x) {}
+  Cov<T?> method3() {
+    return () => null;
+  }
+
+  void method4(Contra<Cov<T>> x) {}
+  void method5(Cov<Contra<T>> x) {}
+  Contra<Contra<T>> method6() {
+    return (Contra<T> x) {
+      Expect.type<Contra<T>>(x);
+    };
+  }
+
+  Cov<Cov<T?>> method7() {
+    return () {
+      return () => null;
+    };
+  }
+
+  void method8(Contravariant<T> x) {}
+  Covariant<T>? method9() => null;
+  void method10(Contravariant<Covariant<T>> x) {}
+  Covariant<Covariant<T>>? method11() => null;
+  void method12(Covariant<Contravariant<T>> x) {}
+  Contravariant<Contravariant<T>>? method13() => null;
+
+  void method14(covariant T x) {}
+  void method15(covariant Contra<T> x) {}
+  void method16(covariant Cov<T> x) {}
+  void method17(covariant Contravariant<T> x) {}
+  void method18(covariant Covariant<T> x) {}
+
+  void method19({Contravariant<T>? x}) {}
+  void method20({Contra<T>? x}) {}
+}
+
+mixin BMixin<out T> {
+  T? method1() => null;
+  void method2(Contra<T> x) {}
+  Cov<T?> method3() {
+    return () => null;
+  }
+
+  void method4(Contra<Cov<T>> x) {}
+  void method5(Cov<Contra<T>> x) {}
+  Contra<Contra<T>> method6() {
+    return (Contra<T> x) {
+      Expect.type<Contra<T>>(x);
+    };
+  }
+
+  Cov<Cov<T?>> method7() {
+    return () {
+      return () => null;
+    };
+  }
+
+  void method8(Contravariant<T> x) {}
+  Covariant<T>? method9() => null;
+  void method10(Contravariant<Covariant<T>> x) {}
+  Covariant<Covariant<T>>? method11() => null;
+  void method12(Covariant<Contravariant<T>> x) {}
+  Contravariant<Contravariant<T>>? method13() => null;
+
+  void method14(covariant T x) {}
+  void method15(covariant Contra<T> x) {}
+  void method16(covariant Cov<T> x) {}
+  void method17(covariant Contravariant<T> x) {}
+  void method18(covariant Covariant<T> x) {}
+
+  void method19({Contravariant<T>? x}) {}
+  void method20({Contra<T>? x}) {}
+}
+
+class B with BMixin<int> {}
+
+class C<out T> {
+  void method1(Contra<A<T>> x) {}
+  A<T> method2() {
+    return A<T>();
+  }
+}
+
+class D<T> {
+  T? method() => null;
+  void method2(T x) {}
+  void method3(covariant T x) {}
+}
+
+class E<out T> extends D<T> {
+  @override
+  T? method() => null;
+
+  @override
+  void method3(covariant T x) {}
+}
+
+void testClass() {
+  A<int> a = new A();
+
+  Expect.isNull(a.method1());
+
+  a.method2(contraFunction);
+
+  Expect.type<Cov<int?>>(a.method3());
+  Cov<int?> method3Function = a.method3();
+  Expect.isNull(method3Function());
+
+  a.method4((Cov<int> x) {});
+
+  a.method5(() {
+    return contraFunction;
+  });
+
+  Expect.type<Contra<Contra<int>>>(a.method6());
+  Contra<Contra<int>> method6Function = a.method6();
+  method6Function(contraFunction);
+
+  Expect.type<Cov<Cov<int?>>>(a.method7());
+  Cov<Cov<int?>> method7Function = a.method7();
+  Expect.type<Cov<int?>>(method7Function());
+  Cov<int?> method7NestedFunction = method7Function();
+  Expect.isNull(method7NestedFunction());
+
+  a.method8(Contravariant<int>());
+  Expect.isNull(a.method9());
+  a.method10(Contravariant<Covariant<int>>());
+  Expect.isNull(a.method11());
+  a.method12(Covariant<Contravariant<int>>());
+  Expect.isNull(a.method13());
+
+  a.method14(3);
+  a.method15(contraFunction);
+  a.method16(covFunction);
+  a.method17(Contravariant<int>());
+  a.method18(Covariant<int>());
+
+  a.method19();
+  a.method20();
+}
+
+void testMixin() {
+  B b = new B();
+
+  Expect.isNull(b.method1());
+
+  b.method2(contraFunction);
+
+  Expect.type<Cov<int?>>(b.method3());
+  Cov<int?> method3Function = b.method3();
+  Expect.isNull(method3Function());
+
+  b.method4((Cov<int> x) {});
+
+  b.method5(() {
+    return contraFunction;
+  });
+
+  Expect.type<Contra<Contra<int>>>(b.method6());
+  Contra<Contra<int>> method6Function = b.method6();
+  method6Function(contraFunction);
+
+  Expect.type<Cov<Cov<int?>>>(b.method7());
+  Cov<Cov<int?>> method7Function = b.method7();
+  Expect.type<Cov<int?>>(method7Function());
+  Cov<int?> method7NestedFunction = method7Function();
+  Expect.isNull(method7NestedFunction());
+
+  b.method8(Contravariant<int>());
+  Expect.isNull(b.method9());
+  b.method10(Contravariant<Covariant<int>>());
+  Expect.isNull(b.method11());
+  b.method12(Covariant<Contravariant<int>>());
+  Expect.isNull(b.method13());
+
+  b.method14(3);
+  b.method15(contraFunction);
+  b.method16(covFunction);
+  b.method17(Contravariant<int>());
+  b.method18(Covariant<int>());
+
+  b.method19();
+  b.method20();
+}
+
+void testClassInMethods() {
+  C<int> c = new C();
+
+  c.method1((A<int> x) {});
+
+  Expect.type<A<int>>(c.method2());
+}
+
+void testOverrideLegacyMethods() {
+  E<int> e = new E();
+  Expect.isNull(e.method());
+  e.method2(3);
+  e.method3(3);
+
+  D<Object> d = e;
+  Expect.throws(() => d.method2("test"));
+  Expect.throws(() => d.method3("test"));
+}
+
+main() {
+  testClass();
+  testMixin();
+  testClassInMethods();
+  testOverrideLegacyMethods();
+}
diff --git a/tests/language/variance/variance_out_subclass_error_test.dart b/tests/language/variance/variance_out_subclass_error_test.dart
new file mode 100644
index 000000000000..046395c6b3a6
--- /dev/null
+++ b/tests/language/variance/variance_out_subclass_error_test.dart
@@ -0,0 +1,124 @@
+// 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.
+
+// Tests erroneous subclass usage for the `out` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+typedef CovFunction<T> = T Function();
+typedef ContraFunction<T> = void Function(T);
+typedef InvFunction<T> = T Function(T);
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+class Invariant<inout T> {}
+mixin MCovariant<out T> {}
+mixin MContravariant<in T> {}
+mixin MInvariant<in T> {}
+
+class A<out T> extends Contravariant<T> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'Contravariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class B<out T> implements Contravariant<T> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'Contravariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class C<out T> with MContravariant<T> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'MContravariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class D<out T> extends Invariant<T> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'inout' position in supertype 'Invariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class E<out T> implements Invariant<T> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'inout' position in supertype 'Invariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class F<out T> with MInvariant<T> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'MInvariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class G<out T> extends Covariant<Contravariant<T>> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'Covariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class H<out T> extends Contravariant<Covariant<T>> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'Contravariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class I<out T> extends Covariant<ContraFunction<T>> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'Covariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class J<out T> extends Covariant<ContraFunction<CovFunction<T>>> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'Covariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class K<out T> extends Covariant<CovFunction<ContraFunction<T>>> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'Covariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class L<out T> extends Covariant<ContraFunction<Covariant<T>>> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'Covariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class M<out T> extends Contravariant<Contravariant<Contravariant<T>>> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'Contravariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class N<out T> extends Covariant<InvFunction<T>> {}
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'inout' position in supertype 'Covariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class O<out T> = Covariant<T> with MContravariant<T>;
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'MContravariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class P<out T> = Contravariant<T> with MCovariant<T>;
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'Contravariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+
+class Q<out T> = Invariant<T> with MInvariant<T>;
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'in' position in supertype 'MInvariant'.
+//    ^
+// [cfe] Can't use 'out' type variable 'T' in an 'inout' position in supertype 'Invariant'.
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
+//          ^
+// [analyzer] COMPILE_TIME_ERROR.WRONG_EXPLICIT_TYPE_PARAMETER_VARIANCE_IN_SUPERINTERFACE
diff --git a/tests/language/variance/variance_out_subclass_test.dart b/tests/language/variance/variance_out_subclass_test.dart
new file mode 100644
index 000000000000..0c8861df7b61
--- /dev/null
+++ b/tests/language/variance/variance_out_subclass_test.dart
@@ -0,0 +1,58 @@
+// 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.
+
+// Tests subclass usage for the `out` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+typedef CovFunction<T> = T Function();
+typedef ContraFunction<T> = void Function(T);
+
+class LegacyCovariant<T> {}
+class Covariant<out T> {}
+class Contravariant<in T> {}
+mixin MLegacyCovariant<T> {}
+mixin MCovariant<out T> {}
+
+class A<out T> extends LegacyCovariant<T> {}
+class B<out T> implements LegacyCovariant<T> {}
+class C<out T> with MLegacyCovariant<T> {}
+
+class D<out T> extends Covariant<T> {}
+class E<out T> implements Covariant<T> {}
+class F<out T> with MCovariant<T> {}
+
+class G<out T> extends Covariant<Covariant<T>> {}
+class H<out T> extends Contravariant<Contravariant<T>> {}
+
+class I<out T> extends Covariant<CovFunction<T>> {}
+class J<out T> extends Covariant<ContraFunction<ContraFunction<T>>> {}
+class K<out T> extends Contravariant<CovFunction<Contravariant<T>>> {}
+
+class L<out T> extends Covariant<CovFunction<Covariant<T>>> {}
+
+class M<out T> extends Covariant<Covariant<Covariant<T>>> {}
+
+class N<out T> = Covariant<T> with MCovariant<T>;
+class O<out T> = Contravariant<Contravariant<T>> with MCovariant<T>;
+class P<out T> = Covariant<T> with MCovariant<Covariant<T>>;
+
+main() {
+  A<num> a = A();
+  B<num> b = B();
+  C<num> c = C();
+  D<num> d = D();
+  E<num> e = E();
+  F<num> f = F();
+  G<num> g = G();
+  H<num> h = H();
+  I<num> i = I();
+  J<num> j = J();
+  K<num> k = K();
+  L<num> l = L();
+  M<num> m = M();
+  N<num> n = N();
+  O<num> o = O();
+  P<num> p = P();
+}
diff --git a/tests/language/variance/variance_out_subtyping_error_test.dart b/tests/language/variance/variance_out_subtyping_error_test.dart
new file mode 100644
index 000000000000..a85f4cb945b7
--- /dev/null
+++ b/tests/language/variance/variance_out_subtyping_error_test.dart
@@ -0,0 +1,80 @@
+// 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.
+
+// Tests erroneous subtyping for the `out` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+class Covariant<out T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower {}
+
+class A {
+  Covariant<Middle> method1() {
+    return Covariant<Middle>();
+  }
+
+  void method2(Covariant<Middle> x) {}
+}
+
+class B extends A {
+  @override
+  Covariant<Upper> method1() {
+  //               ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.INVALID_OVERRIDE
+  // [cfe] The return type of the method 'B.method1' is 'Covariant<Upper>', which does not match the return type, 'Covariant<Middle>', of the overridden method, 'A.method1'.
+    return new Covariant<Upper>();
+  }
+
+  @override
+  void method2(Covariant<Lower> x) {}
+  //   ^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.INVALID_OVERRIDE
+  //                            ^
+  // [cfe] The parameter 'x' of the method 'B.method2' has type 'Covariant<Lower>', which does not match the corresponding type, 'Covariant<Middle>', in the overridden method, 'A.method2'.
+}
+
+class C<out T extends Covariant<Middle>> {}
+
+class D {
+  C<Covariant<Upper>> method1() {
+  //^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  //                         ^
+  // [cfe] Type argument 'Covariant<Upper>' doesn't conform to the bound 'Covariant<Middle>' of the type variable 'T' on 'C' in the return type.
+    return C<Covariant<Upper>>();
+    //     ^
+    // [cfe] Type argument 'Covariant<Upper>' doesn't conform to the bound 'Covariant<Middle>' of the type variable 'T' on 'C'.
+    //       ^^^^^^^^^^^^^^^^
+    // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  }
+}
+
+void testCall(Iterable<Covariant<Lower>> x) {}
+
+main() {
+  C<Covariant<Upper>> c = new C<Covariant<Upper>>();
+  //^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+  //                  ^
+  // [cfe] Type argument 'Covariant<Upper>' doesn't conform to the bound 'Covariant<Middle>' of the type variable 'T' on 'C'.
+  //                          ^
+  // [cfe] Type argument 'Covariant<Upper>' doesn't conform to the bound 'Covariant<Middle>' of the type variable 'T' on 'C'.
+  //                            ^^^^^^^^^^^^^^^^
+  // [analyzer] COMPILE_TIME_ERROR.TYPE_ARGUMENT_NOT_MATCHING_BOUNDS
+
+  Iterable<Covariant<Lower>> iterableLower = [new Covariant<Lower>()];
+  List<Covariant<Middle>> listMiddle = [new Covariant<Middle>()];
+  iterableLower = listMiddle;
+  //              ^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'List<Covariant<Middle>>' can't be assigned to a variable of type 'Iterable<Covariant<Lower>>'.
+
+  testCall(listMiddle);
+  //       ^^^^^^^^^^
+  // [analyzer] STATIC_WARNING.ARGUMENT_TYPE_NOT_ASSIGNABLE
+  // [cfe] The argument type 'List<Covariant<Middle>>' can't be assigned to the parameter type 'Iterable<Covariant<Lower>>'.
+}
diff --git a/tests/language/variance/variance_out_subtyping_test.dart b/tests/language/variance/variance_out_subtyping_test.dart
new file mode 100644
index 000000000000..00f5ed3cf928
--- /dev/null
+++ b/tests/language/variance/variance_out_subtyping_test.dart
@@ -0,0 +1,102 @@
+// 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.
+
+// Tests subtyping for the `out` variance modifier.
+
+// SharedOptions=--enable-experiment=variance
+
+import "package:expect/expect.dart";
+
+class Covariant<out T> {}
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+class A {
+  Covariant<Middle> method1() {
+    return new Covariant<Middle>();
+  }
+
+  void method2(Covariant<Middle> x) {}
+}
+
+class B extends A {
+  @override
+  Covariant<Lower> method1() {
+    return new Covariant<Lower>();
+  }
+
+  @override
+  void method2(Covariant<Upper> x) {}
+}
+
+class C extends A {
+  @override
+  Covariant<Middle> method1() {
+    return new Covariant<Middle>();
+  }
+
+  @override
+  void method2(Covariant<Middle> x) {}
+}
+
+class D<out T extends Covariant<Middle>> {}
+
+class E {
+  D<Covariant<Lower>> method1() {
+    return D<Covariant<Lower>>();
+  }
+}
+
+class F {
+  D<Covariant<Middle>> method1() {
+    return D<Covariant<Middle>>();
+  }
+}
+
+void testCall(Iterable<Covariant<Middle>> x) {}
+
+main() {
+  A a = new A();
+  Expect.type<Covariant<Middle>>(a.method1());
+  Expect.type<Covariant<Upper>>(a.method1());
+  Expect.notType<Covariant<Lower>>(a.method1());
+  a.method2(new Covariant<Middle>());
+  a.method2(new Covariant<Lower>());
+
+  B b = new B();
+  Expect.type<Covariant<Upper>>(b.method1());
+  Expect.type<Covariant<Middle>>(b.method1());
+  Expect.type<Covariant<Lower>>(b.method1());
+  b.method2(new Covariant<Upper>());
+  b.method2(new Covariant<Middle>());
+
+  C c = new C();
+  Expect.type<Covariant<Middle>>(c.method1());
+  Expect.type<Covariant<Upper>>(c.method1());
+  Expect.notType<Covariant<Lower>>(c.method1());
+  c.method2(new Covariant<Middle>());
+  c.method2(new Covariant<Lower>());
+
+  D<Covariant<Lower>> dLower = new D<Covariant<Lower>>();
+  D<Covariant<Middle>> dMiddle = new D<Covariant<Middle>>();
+
+  E e = new E();
+  Expect.type<D<Covariant<Lower>>>(e.method1());
+  Expect.type<D<Covariant<Middle>>>(e.method1());
+
+  F f = new F();
+  Expect.type<D<Covariant<Middle>>>(f.method1());
+
+  Iterable<Covariant<Middle>> iterableMiddle = [new Covariant<Middle>()];
+  List<Covariant<Lower>> listLower = [new Covariant<Lower>()];
+  iterableMiddle = listLower;
+
+  testCall(listLower);
+
+  Expect.subtype<Covariant<Lower>, Covariant<Middle>>();
+  Expect.subtype<Covariant<Middle>, Covariant<Middle>>();
+  Expect.notSubtype<Covariant<Upper>, Covariant<Middle>>();
+}
diff --git a/tests/language/variance/variance_unconstrained_inference_test.dart b/tests/language/variance/variance_unconstrained_inference_test.dart
new file mode 100644
index 000000000000..fed460b564a0
--- /dev/null
+++ b/tests/language/variance/variance_unconstrained_inference_test.dart
@@ -0,0 +1,26 @@
+// 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.
+
+// Tests unconstrained inferencing with sound variance.
+
+// SharedOptions=--enable-experiment=variance
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+class Invariant<inout T> {}
+
+void covariantListInfer<T>(Covariant<List<T>> x) {}
+void contravariantListInfer<T>(Contravariant<List<T>> x) {}
+void invariantListInfer<T>(Invariant<List<T>> x) {}
+
+main() {
+  var cov = new Covariant();
+  covariantListInfer(Covariant());
+
+  var contra = new Contravariant();
+  contravariantListInfer(Contravariant());
+
+  var inv = new Invariant();
+  invariantListInfer(Invariant());
+}
diff --git a/tests/language/variance/variance_upper_lower_bounds_error_test.dart b/tests/language/variance/variance_upper_lower_bounds_error_test.dart
new file mode 100644
index 000000000000..2c69097d9cf4
--- /dev/null
+++ b/tests/language/variance/variance_upper_lower_bounds_error_test.dart
@@ -0,0 +1,102 @@
+// 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.
+
+// Tests erroneous upper and lower bounds computation with respect to
+// variance modifiers.
+
+// SharedOptions=--enable-experiment=variance
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+class Invariant<inout T> {}
+class LegacyCovariant<T> {}
+
+class Multi<out T, inout U, in V> {}
+
+class Exactly<inout T> {}
+Exactly<T> exactly<T>(T x) => new Exactly<T>();
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+main() {
+  bool condition = true;
+
+  var contraLowerActual =
+      exactly(condition ? Contravariant<Upper>() : Contravariant<Lower>());
+  Exactly<Contravariant<Upper>> contraUpperExpected = contraLowerActual;
+  //                                                  ^^^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Contravariant<Lower>>' can't be assigned to a variable of type 'Exactly<Contravariant<Upper>>'.
+
+  var contraMiddleActual =
+      exactly(condition ? Contravariant<Upper>() : Contravariant<Middle>());
+  contraUpperExpected = contraMiddleActual;
+  //                    ^^^^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Contravariant<Middle>>' can't be assigned to a variable of type 'Exactly<Contravariant<Upper>>'.
+
+  var covMiddleActual =
+      exactly(condition ? Covariant<Middle>() : Covariant<Lower>());
+  Exactly<Covariant<Lower>> covLowerExpected = covMiddleActual;
+  //                                           ^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Covariant<Middle>>' can't be assigned to a variable of type 'Exactly<Covariant<Lower>>'.
+
+  var covUpperActual =
+      exactly(condition ? Covariant<Upper>() : Covariant<Lower>());
+  covLowerExpected = covUpperActual;
+  //                 ^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Covariant<Upper>>' can't be assigned to a variable of type 'Exactly<Covariant<Lower>>'.
+
+  var invObjectActual =
+      exactly(condition ? Invariant<Upper>() : Invariant<Middle>());
+  Exactly<Invariant<Middle>> invMiddleExpected = invObjectActual;
+  //                                             ^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Object>' can't be assigned to a variable of type 'Exactly<Invariant<Middle>>'.
+  Exactly<Invariant<Upper>> invUpperExpected = invObjectActual;
+  //                                           ^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Object>' can't be assigned to a variable of type 'Exactly<Invariant<Upper>>'.
+
+  var legacyCovMiddleActual =
+      exactly(condition ? LegacyCovariant<Middle>() : LegacyCovariant<Lower>());
+  Exactly<LegacyCovariant<Lower>> legacyCovLowerExpected =
+      legacyCovMiddleActual;
+  //  ^^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<LegacyCovariant<Middle>>' can't be assigned to a variable of type 'Exactly<LegacyCovariant<Lower>>'.
+
+  var legacyCovUpperActual =
+      exactly(condition ? LegacyCovariant<Upper>() : LegacyCovariant<Lower>());
+  legacyCovLowerExpected = legacyCovUpperActual;
+  //                       ^^^^^^^^^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<LegacyCovariant<Upper>>' can't be assigned to a variable of type 'Exactly<LegacyCovariant<Lower>>'.
+
+  var multiActual = exactly(condition
+      ? Multi<Middle, Middle, Middle>()
+      : Multi<Lower, Middle, Lower>());
+  Exactly<Multi<Lower, Middle, Lower>> multiExpected = multiActual;
+  //                                                   ^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Multi<Middle, Middle, Lower>>' can't be assigned to a variable of type 'Exactly<Multi<Lower, Middle, Lower>>'.
+
+  var multiActual2 = exactly(
+      condition ? Multi<Middle, int, Middle>() : Multi<Lower, Middle, Lower>());
+  Exactly<Multi<Middle, Object, Lower>> multiObjectExpected = multiActual2;
+  //                                                          ^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Object>' can't be assigned to a variable of type 'Exactly<Multi<Middle, Object, Lower>>'.
+
+  var multiActual3 = exactly(
+      condition ? Multi<int, Middle, Middle>() : Multi<Lower, Middle, Lower>());
+  Exactly<Object> multiObjectExpected2 = multiActual3;
+  //                                     ^^^^^^^^^^^^
+  // [analyzer] STATIC_TYPE_WARNING.INVALID_ASSIGNMENT
+  // [cfe] A value of type 'Exactly<Multi<Object, Middle, Lower>>' can't be assigned to a variable of type 'Exactly<Object>'.
+}
diff --git a/tests/language/variance/variance_upper_lower_bounds_test.dart b/tests/language/variance/variance_upper_lower_bounds_test.dart
new file mode 100644
index 000000000000..ceb9ac88b915
--- /dev/null
+++ b/tests/language/variance/variance_upper_lower_bounds_test.dart
@@ -0,0 +1,71 @@
+// 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.
+
+// Tests upper and lower bounds computation with respect to variance modifiers.
+
+// SharedOptions=--enable-experiment=variance
+
+class Covariant<out T> {}
+class Contravariant<in T> {}
+class Invariant<inout T> {}
+class LegacyCovariant<T> {}
+
+class Multi<out T, inout U, in V> {}
+
+class Exactly<inout T> {}
+Exactly<T> exactly<T>(T x) => new Exactly<T>();
+
+class Upper {}
+class Middle extends Upper {}
+class Lower extends Middle {}
+
+main() {
+  bool condition = true;
+
+  var contraLowerActual =
+      exactly(condition ? Contravariant<Upper>() : Contravariant<Lower>());
+  Exactly<Contravariant<Lower>> contraLowerExpected = contraLowerActual;
+
+  var contraMiddleActual =
+      exactly(condition ? Contravariant<Upper>() : Contravariant<Middle>());
+  Exactly<Contravariant<Middle>> contraMiddleExpected = contraMiddleActual;
+
+  var covMiddleActual =
+      exactly(condition ? Covariant<Middle>() : Covariant<Lower>());
+  Exactly<Covariant<Middle>> covMiddleExpected = covMiddleActual;
+
+  var covUpperActual =
+      exactly(condition ? Covariant<Upper>() : Covariant<Lower>());
+  Exactly<Covariant<Upper>> covUpperExpected = covUpperActual;
+
+  var invMiddleActual =
+      exactly(condition ? Invariant<Middle>() : Invariant<Middle>());
+  Exactly<Invariant<Middle>> invMiddleExpected = invMiddleActual;
+
+  var invObjectActual =
+      exactly(condition ? Invariant<Upper>() : Invariant<Middle>());
+  Exactly<Object> invObjectExpected = invObjectActual;
+
+  var legacyCovMiddleActual =
+      exactly(condition ? LegacyCovariant<Middle>() : LegacyCovariant<Lower>());
+  Exactly<LegacyCovariant<Middle>> legacyCovMiddleExpected =
+      legacyCovMiddleActual;
+
+  var legacyCovUpperActual =
+      exactly(condition ? LegacyCovariant<Upper>() : LegacyCovariant<Lower>());
+  Exactly<LegacyCovariant<Upper>> legacyCovUpperExpected = legacyCovUpperActual;
+
+  var multiActual = exactly(condition
+      ? Multi<Middle, Middle, Middle>()
+      : Multi<Lower, Middle, Lower>());
+  Exactly<Multi<Middle, Middle, Lower>> multiExpected = multiActual;
+
+  var multiActual2 = exactly(
+      condition ? Multi<Middle, int, Middle>() : Multi<Lower, Middle, Lower>());
+  Exactly<Object> multiObjectExpected = multiActual2;
+
+  var multiActual3 = exactly(
+      condition ? Multi<int, Middle, Middle>() : Multi<Lower, Middle, Lower>());
+  Exactly<Multi<Object, Middle, Lower>> multiObjectExpected2 = multiActual3;
+}