// Copyright (c) 2015, 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.

library analyzer.test.src.task.strong.checker_test;

import 'package:test_reflective_loader/test_reflective_loader.dart';

import 'strong_test_helper.dart';

void main() {
  defineReflectiveSuite(() {
    defineReflectiveTests(CheckerTest);
  });
}

void _addMetaLibrary() {
  addFile(
      r'''
library meta;
class _Checked { const _Checked(); }
const Object checked = const _Checked();

class _Virtual { const _Virtual(); }
const Object virtual = const _Virtual();
    ''',
      name: '/meta.dart');
}

@reflectiveTest
class CheckerTest {
  void setUp() {
    doSetUp();
  }

  void tearDown() {
    doTearDown();
  }

  void test_awaitForInCastsStreamElementToVariable() {
    checkFile('''
import 'dart:async';
main() async {
  // Don't choke if sequence is not stream.
  await for (var i in /*error:FOR_IN_OF_INVALID_TYPE*/1234) {}

  // Dynamic cast.
  await for (String /*info:DYNAMIC_CAST*/s in new Stream<dynamic>()) {}

  // Identity cast.
  await for (String s in new Stream<String>()) {}

  // Untyped.
  await for (var s in new Stream<String>()) {}

  // Downcast.
  await for (int /*info:DOWN_CAST_IMPLICIT*/i in new Stream<num>()) {}
}
''');
  }

  void test_awaitForInCastsSupertypeSequenceToStream() {
    checkFile('''
main() async {
  dynamic d;
  await for (var i in /*info:DYNAMIC_CAST*/d) {}

  Object o;
  await for (var i in /*info:DOWN_CAST_IMPLICIT*/o) {}
}
''');
  }

  void test_binaryAndIndexOperators() {
    checkFile('''
class A {
  A operator *(B b) => null;
  A operator /(B b) => null;
  A operator ~/(B b) => null;
  A operator %(B b) => null;
  A operator +(B b) => null;
  A operator -(B b) => null;
  A operator <<(B b) => null;
  A operator >>(B b) => null;
  A operator &(B b) => null;
  A operator ^(B b) => null;
  A operator |(B b) => null;
  A operator[](B b) => null;
}

class B {
  A operator -(B b) => null;
}

foo() => new A();

test() {
  A a = new A();
  B b = new B();
  var c = foo();
  a = a * b;
  a = a * /*info:DYNAMIC_CAST*/c;
  a = a / b;
  a = a ~/ b;
  a = a % b;
  a = a + b;
  a = a + /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/a;
  a = a - b;
  b = /*error:INVALID_ASSIGNMENT*/b - b;
  a = a << b;
  a = a >> b;
  a = a & b;
  a = a ^ b;
  a = a | b;
  c = (/*info:DYNAMIC_INVOKE*/c + b);

  String x = 'hello';
  int y = 42;
  x = x + x;
  x = x + /*info:DYNAMIC_CAST*/c;
  x = x + /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/y;

  bool p = true;
  p = p && p;
  p = p && /*info:DYNAMIC_CAST*/c;
  p = (/*info:DYNAMIC_CAST*/c) && p;
  p = (/*info:DYNAMIC_CAST*/c) && /*info:DYNAMIC_CAST*/c;
  p = /*error:NON_BOOL_OPERAND*/y && p;
  p = c == y;

  a = a[b];
  a = a[/*info:DYNAMIC_CAST*/c];
  c = (/*info:DYNAMIC_INVOKE*/c[b]);
  a[/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/y];
}
''');
  }

  void test_callMethodOnFunctions() {
    checkFile(r'''
void f(int x) => print(x);
main() {
  f.call(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/'hi');
}
    ''');
  }

  void test_castsInConditions() {
    checkFile('''
main() {
  bool b = true;
  num x = b ? 1 : 2.3;
  int y = /*info:ASSIGNMENT_CAST*/b ? 1 : 2.3;
  String z = !b ? "hello" : null;
  z = b ? null : "hello";
}
''');
  }

  void test_castsInConstantContexts() {
    checkFile('''
class A {
  static const num n = 3.0;
  // The severe error is from constant evaluation where we know the
  // concrete type.
  static const int /*error:VARIABLE_TYPE_MISMATCH*/i = /*info:ASSIGNMENT_CAST*/n;
  final int fi;
  const A(num a) : this.fi = /*info:DOWN_CAST_IMPLICIT*/a;
}
class B extends A {
  const B(Object a) : super(/*info:DOWN_CAST_IMPLICIT*/a);
}
void foo(Object o) {
  var a = const A(/*info:DOWN_CAST_IMPLICIT, error:CONST_WITH_NON_CONSTANT_ARGUMENT, error:INVALID_CONSTANT*/o);
}
''');
  }

  void test_classOverrideOfGrandInterface_interfaceOfAbstractSuperclass() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}
abstract class Base implements I1 {}

class T1 extends Base {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}
''');
  }

  void test_classOverrideOfGrandInterface_interfaceOfConcreteSuperclass() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}

class /*error:NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE*/Base
    implements I1 {}

class T1 extends Base {
    // not reported technically because if the class is concrete,
    // it should implement all its interfaces and hence it is
    // sufficient to check overrides against it.
    m(B a) {}
}
''');
  }

  void test_classOverrideOfGrandInterface_interfaceOfInterfaceOfChild() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}
abstract class I2 implements I1 {}

class T1 implements I2 {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}
''');
  }

  void test_classOverrideOfGrandInterface_mixinOfInterfaceOfChild() {
    checkFile('''
class A {}
class B {}

abstract class M1 {
    m(A a);
}
abstract class I2 extends Object with M1 {}

class T1 implements I2 {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}
''');
  }

  void test_classOverrideOfGrandInterface_superclassOfInterfaceOfChild() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}
abstract class I2 extends I1 {}

class T1 implements I2 {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}
''');
  }

  void test_compoundAssignment_returnsDynamic() {
    checkFile(r'''
class Foo {
  operator +(other) => null;
}

main() {
  var foo = new Foo();
  foo = /*info:DYNAMIC_CAST*/foo + 1;
  /*info:DYNAMIC_CAST*/foo += 1;
}
    ''');
  }

  void test_compoundAssignments() {
    checkFile('''
class A {
  A operator *(B b) => null;
  A operator /(B b) => null;
  A operator ~/(B b) => null;
  A operator %(B b) => null;
  A operator +(B b) => null;
  A operator -(B b) => null;
  A operator <<(B b) => null;
  A operator >>(B b) => null;
  A operator &(B b) => null;
  A operator ^(B b) => null;
  A operator |(B b) => null;
  D operator [](B index) => null;
  void operator []=(B index, D value) => null;
}

class B {
  A operator -(B b) => null;
}

class D {
  D operator +(D d) => null;
}

class SubA extends A {}
class SubSubA extends SubA {}

foo() => new A();

test() {
  int x = 0;
  x += 5;
  x += /*error:INVALID_ASSIGNMENT*/3.14;

  double y = 0.0;
  y += 5;
  y += 3.14;

  num z = 0;
  z += 5;
  z += 3.14;

  x = /*info:DOWN_CAST_IMPLICIT*/x + z;
  /*info:DOWN_CAST_IMPLICIT_ASSIGN*/x += z;
  y = y + z;
  y += z;

  dynamic w = 42;
  /*info:DOWN_CAST_IMPLICIT_ASSIGN*/x += /*info:DYNAMIC_CAST*/w;
  y += /*info:DYNAMIC_CAST*/w;
  z += /*info:DYNAMIC_CAST*/w;

  A a = new A();
  B b = new B();
  var c = foo();
  a = a * b;
  a *= b;
  a *= /*info:DYNAMIC_CAST*/c;
  a /= b;
  a ~/= b;
  a %= b;
  a += b;
  a += /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/a;
  a -= b;
  b -= /*error:INVALID_ASSIGNMENT*/b;
  a <<= b;
  a >>= b;
  a &= b;
  a ^= b;
  a |= b;
  /*info:DYNAMIC_INVOKE*/c += b;

  SubA sa;
  /*info:DOWN_CAST_IMPLICIT_ASSIGN*/sa += b;
  SubSubA ssa = /*info:ASSIGNMENT_CAST,info:DOWN_CAST_IMPLICIT_ASSIGN*/sa += b;

  var d = new D();
  a[b] += d;
  a[/*info:DYNAMIC_CAST*/c] += d;
  a[/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/z] += d;
  a[b] += /*info:DYNAMIC_CAST*/c;
  a[b] += /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/z;
  /*info:DYNAMIC_INVOKE,info:DYNAMIC_INVOKE*/c[b] += d;
}
''');
  }

  void test_constantGenericTypeArg_explict() {
    // Regression test for https://github.com/dart-lang/sdk/issues/26141
    checkFile('''
abstract class Equality<R> {}
abstract class EqualityBase<R> implements Equality<R> {
  final C<R> c = const C<R>();
  const EqualityBase();
}
class DefaultEquality<S> extends EqualityBase<S> {
  const DefaultEquality();
}
class SetEquality<T> implements Equality<T> {
  final Equality<T> field = const DefaultEquality<T>();
  const SetEquality([Equality<T> inner = const DefaultEquality<T>()]);
}
class C<Q> {
  final List<Q> list = const <Q>[];
  final Map<Q, Iterable<Q>> m =  const <Q, Iterable<Q>>{};
  const C();
}
main() {
  const SetEquality<String>();
}
    ''');
  }

  void test_constantGenericTypeArg_infer() {
    // Regression test for https://github.com/dart-lang/sdk/issues/26141
    checkFile('''
abstract class Equality<Q> {}
abstract class EqualityBase<R> implements Equality<R> {
  final C<R> c = /*info:INFERRED_TYPE_ALLOCATION*/const C();
  const EqualityBase();
}
class DefaultEquality<S> extends EqualityBase<S> {
  const DefaultEquality();
}
class SetEquality<T> implements Equality<T> {
  final Equality<T> field = const DefaultEquality();
  const SetEquality([Equality<T> inner = const DefaultEquality()]);
}
class C<Q> {
  final List<Q> list = /*info:INFERRED_TYPE_LITERAL*/const [];
  final Map<Q, Iterable<Q>> m =  /*info:INFERRED_TYPE_LITERAL*/const {};
  const C();
}
main() {
  const SetEquality<String>();
}
    ''');
  }

  void test_constructorInvalid() {
    // Regression test for https://github.com/dart-lang/sdk/issues/26695
    checkFile('''
class A {
  B({ /*error:FIELD_INITIALIZER_OUTSIDE_CONSTRUCTOR*/this.test: 1.0 }) {}
  final double test = 0.0;
}
''');
  }

  void test_constructors() {
    checkFile('''
const num z = 25;
Object obj = "world";

class A {
  int x;
  String y;

  A(this.x) : this.y = /*error:FIELD_INITIALIZER_NOT_ASSIGNABLE*/42;

  A.c1(p): this.x = /*info:DOWN_CAST_IMPLICIT*/z, this.y = /*info:DYNAMIC_CAST*/p;

  A.c2(this.x, this.y);

  A.c3(/*error:INVALID_PARAMETER_DECLARATION*/num this.x, String this.y);
}

class B extends A {
  B() : super(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/"hello");

  B.c2(int x, String y) : super.c2(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/y,
                                   /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/x);

  B.c3(num x, Object y) : super.c3(x, /*info:DOWN_CAST_IMPLICIT*/y);
}

void main() {
   A a = new A.c2(/*info:DOWN_CAST_IMPLICIT*/z, /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/z);
   var b = new B.c2(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/"hello", /*info:DOWN_CAST_IMPLICIT*/obj);
}
''');
  }

  void test_conversionAndDynamicInvoke() {
    addFile(
        '''
dynamic toString = (int x) => x + 42;
dynamic hashCode = "hello";
''',
        name: '/helper.dart');
    checkFile('''
import 'helper.dart' as helper;

class A {
  String x = "hello world";

  void baz1(y) { x + /*info:DYNAMIC_CAST*/y; }
  static baz2(y) => /*info:DYNAMIC_INVOKE*/y + y;
}

void foo(String str) {
  print(str);
}

class B {
  String toString([int arg]) => arg.toString();
}

void bar(a) {
  foo(/*info:DYNAMIC_CAST,info:DYNAMIC_INVOKE*/a.x);
}

baz() => new B();

typedef DynFun(x);
typedef StrFun(String x);

var bar1 = bar;

void main() {
  var a = new A();
  bar(a);
  (/*info:DYNAMIC_INVOKE*/bar1(a));
  var b = bar;
  (/*info:DYNAMIC_INVOKE*/b(a));
  var f1 = foo;
  f1("hello");
  dynamic f2 = foo;
  (/*info:DYNAMIC_INVOKE*/f2("hello"));
  DynFun f3 = foo;
  (/*info:DYNAMIC_INVOKE*/f3("hello"));
  (/*info:DYNAMIC_INVOKE*/f3(42));
  StrFun f4 = foo;
  f4("hello");
  a.baz1("hello");
  var b1 = a.baz1;
  (/*info:DYNAMIC_INVOKE*/b1("hello"));
  A.baz2("hello");
  var b2 = A.baz2;
  (/*info:DYNAMIC_INVOKE*/b2("hello"));

  dynamic a1 = new B();
  (/*info:DYNAMIC_INVOKE*/a1.x);
  a1.toString();
  (/*info:DYNAMIC_INVOKE*/a1.toString(42));
  var toStringClosure = a1.toString;
  (/*info:DYNAMIC_INVOKE*/a1.toStringClosure());
  (/*info:DYNAMIC_INVOKE*/a1.toStringClosure(42));
  (/*info:DYNAMIC_INVOKE*/a1.toStringClosure("hello"));
  a1.hashCode;

  dynamic toString = () => null;
  (/*info:DYNAMIC_INVOKE*/toString());

  (/*info:DYNAMIC_INVOKE*/helper.toString());
  var toStringClosure2 = helper.toString;
  (/*info:DYNAMIC_INVOKE*/toStringClosure2());
  int hashCode = /*info:DYNAMIC_CAST*/helper.hashCode;

  baz().toString();
  baz().hashCode;
}
''');
  }

  void test_covariantOverride() {
    _addMetaLibrary();
    checkFile(r'''
import 'meta.dart';
class C {
  num f(num x) => x;
}
class D extends C {
  int f(@checked int x) => x;
}
class E extends D {
  int f(Object x) => /*info:DOWN_CAST_IMPLICIT*/x;
}
class F extends E {
  int f(@checked int x) => x;
}
class G extends E implements D {}

class D_error extends C {
  /*error:INVALID_METHOD_OVERRIDE*/int f(int x) => x;
}
class E_error extends D {
  /*error:INVALID_METHOD_OVERRIDE*/int f(@checked double x) => 0;
}
class F_error extends E {
  /*error:INVALID_METHOD_OVERRIDE*/int f(@checked double x) => 0;
}
class G_error extends E implements D {
  /*error:INVALID_METHOD_OVERRIDE*/int f(@checked double x) => 0;
}
    ''');
  }

  void test_covariantOverride_fields() {
    _addMetaLibrary();
    checkFile(r'''
import 'meta.dart';
class A {
  get foo => '';
  set foo(_) {}
}

class B extends A {
  @checked num foo;
}
class C extends A {
  @checked @virtual num foo;
}
class D extends C {
  @virtual int foo;
}
class E extends D {
  @virtual /*error:INVALID_METHOD_OVERRIDE*/num foo;
}
    ''');
  }

  void test_covariantOverride_leastUpperBound() {
    _addMetaLibrary();
    checkFile(r'''
import "meta.dart";
abstract class Top {}
abstract class Left implements Top {}
abstract class Right implements Top {}
abstract class Bottom implements Left, Right {}

abstract class TakesLeft {
  m(Left x);
}
abstract class TakesRight {
  m(Right x);
}
abstract class TakesTop implements TakesLeft, TakesRight {
  m(Top x); // works today
}
abstract class TakesBottom implements TakesLeft, TakesRight {
  // LUB(Left, Right) == Top, so this is an implicit cast from Top to Bottom.
  m(@checked Bottom x);
}
    ''');
  }

  void test_covariantOverride_markerIsInherited() {
    _addMetaLibrary();
    checkFile(r'''
import 'meta.dart';
class C {
  num f(@checked num x) => x;
}
class D extends C {
  int f(int x) => x;
}
class E extends D {
  int f(Object x) => /*info:DOWN_CAST_IMPLICIT*/x;
}
class F extends E {
  int f(int x) => x;
}
class G extends E implements D {}

class D_error extends C {
  /*error:INVALID_METHOD_OVERRIDE*/int f(String x) => 0;
}
class E_error extends D {
  /*error:INVALID_METHOD_OVERRIDE*/int f(double x) => 0;
}
class F_error extends E {
  /*error:INVALID_METHOD_OVERRIDE*/int f(double x) => 0;
}
class G_error extends E implements D {
  /*error:INVALID_METHOD_OVERRIDE*/int f(double x) => 0;
}
    ''');
  }

  void test_dynamicInvocation() {
    checkFile('''
typedef dynamic A(dynamic x);
class B {
  int call(int x) => x;
  double col(double x) => x;
}
void main() {
  {
    B f = new B();
    int x;
    double y;
    x = f(3);
    x = /*error:INVALID_ASSIGNMENT*/f.col(3.0);
    y = /*error:INVALID_ASSIGNMENT*/f(3);
    y = f.col(3.0);
    f(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/3.0);
    f.col(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/3);
  }
  {
    Function f = new B();
    int x;
    double y;
    x = /*info:DYNAMIC_CAST, info:DYNAMIC_INVOKE*/f(3);
    x = /*info:DYNAMIC_CAST, info:DYNAMIC_INVOKE*/f.col(3.0);
    y = /*info:DYNAMIC_CAST, info:DYNAMIC_INVOKE*/f(3);
    y = /*info:DYNAMIC_CAST, info:DYNAMIC_INVOKE*/f.col(3.0);
    /*info:DYNAMIC_INVOKE*/f(3.0);
    // Through type propagation, we know f is actually a B, hence the
    // hint.
    /*info:DYNAMIC_INVOKE*/f.col(3);
  }
  {
    A f = new B();
    int x;
    double y;
    x = /*info:DYNAMIC_CAST, info:DYNAMIC_INVOKE*/f(3);
    y = /*info:DYNAMIC_CAST, info:DYNAMIC_INVOKE*/f(3);
    /*info:DYNAMIC_INVOKE*/f(3.0);
  }
  {
    dynamic g = new B();
    /*info:DYNAMIC_INVOKE*/g.call(32.0);
    /*info:DYNAMIC_INVOKE*/g.col(42.0);
    /*info:DYNAMIC_INVOKE*/g.foo(42.0);
    /*info:DYNAMIC_INVOKE*/g.x;
    A f = new B();
    /*info:DYNAMIC_INVOKE*/f.col(42.0);
    /*info:DYNAMIC_INVOKE*/f.foo(42.0);
    /*info:DYNAMIC_INVOKE*/f./*error:UNDEFINED_GETTER*/x;
  }
}
''');
  }

  void test_factoryConstructorDowncast() {
    checkFile(r'''
class Animal {
  Animal();
  factory Animal.cat() => new Cat();
}

class Cat extends Animal {}

void main() {
  Cat c = /*info:ASSIGNMENT_CAST*/new Animal.cat();
  c = /*error:INVALID_CAST_NEW_EXPR*/new Animal();
}''');
  }

  void test_fieldFieldOverride() {
    checkFile('''
class A {}
class B extends A {}
class C extends B {}

class Base {
  B f1;
  B f2;
  B f3;
  B f4;
}

class Child extends Base {
  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/A f1; // invalid for getter
  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/C f2; // invalid for setter
  /*error:INVALID_FIELD_OVERRIDE*/var f3;
  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/dynamic f4;
}

class Child2 implements Base {
  /*error:INVALID_METHOD_OVERRIDE*/A f1; // invalid for getter
  /*error:INVALID_METHOD_OVERRIDE*/C f2; // invalid for setter
  var f3;
  /*error:INVALID_METHOD_OVERRIDE*/dynamic f4;
}
''');
  }

  void test_fieldGetterOverride() {
    checkFile('''
class A {}
class B extends A {}
class C extends B {}

abstract class Base {
  B f1;
  B f2;
  B f3;
  B f4;
}

class Child extends Base {
  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/A get f1 => null;
  /*error:INVALID_FIELD_OVERRIDE*/C get f2 => null;
  /*error:INVALID_FIELD_OVERRIDE*/get f3 => null;
  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/dynamic get f4 => null;
}

class /*error:NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_FOUR*/Child2 implements Base {
  /*error:INVALID_METHOD_OVERRIDE*/A get f1 => null;
  C get f2 => null;
  get f3 => null;
  /*error:INVALID_METHOD_OVERRIDE*/dynamic get f4 => null;
}
''');
  }

  void test_fieldOverride_fuzzyArrows() {
    checkFile('''
typedef void ToVoid<T>(T x);
class F {
  final ToVoid<dynamic> f = null;
  final ToVoid<int> g = null;
}

class G extends F {
  /*error:INVALID_FIELD_OVERRIDE*/final ToVoid<int> f = null;
  /*error:INVALID_FIELD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/final ToVoid<dynamic> g = null;
}

class H implements F {
  final ToVoid<int> f = null;
  /*error:INVALID_METHOD_OVERRIDE*/final ToVoid<dynamic> g = null;
}
 ''');
  }

  void test_fieldOverride_virtual() {
    _addMetaLibrary();
    checkFile(r'''
import 'meta.dart';
class C {
  @virtual int x;
}
class OverrideGetter extends C {
  int get x => 42;
}
class OverrideSetter extends C {
  set x(int v) {}
}
class OverrideBoth extends C {
  int get x => 42;
  set x(int v) {}
}
class OverrideWithField extends C {
  int x;

  // expose the hidden storage slot
  int get superX => super.x;
  set superX(int v) { super.x = v; }
}
class VirtualNotInherited extends OverrideWithField {
  /*error:INVALID_FIELD_OVERRIDE*/int x;
}
    ''');
  }

  void test_fieldSetterOverride() {
    checkFile('''
class A {}
class B extends A {}
class C extends B {}

class Base {
  B f1;
  B f2;
  B f3;
  B f4;
  B f5;
}

class Child extends Base {
  /*error:INVALID_FIELD_OVERRIDE*/B get f1 => null;
  /*error:INVALID_FIELD_OVERRIDE*/B get f2 => null;
  /*error:INVALID_FIELD_OVERRIDE*/B get f3 => null;
  /*error:INVALID_FIELD_OVERRIDE*/B get f4 => null;
  /*error:INVALID_FIELD_OVERRIDE*/B get f5 => null;

  /*error:INVALID_FIELD_OVERRIDE*/void set f1(A value) {}
  /*error:INVALID_FIELD_OVERRIDE,error:INVALID_METHOD_OVERRIDE*/void set f2(C value) {}
  /*error:INVALID_FIELD_OVERRIDE*/void set f3(value) {}
  /*error:INVALID_FIELD_OVERRIDE*/void set f4(dynamic value) {}
  /*error:INVALID_FIELD_OVERRIDE*/set f5(B value) {}
}

class Child2 implements Base {
  B get f1 => null;
  B get f2 => null;
  B get f3 => null;
  B get f4 => null;
  B get f5 => null;

  void set f1(A value) {}
  /*error:INVALID_METHOD_OVERRIDE*/void set f2(C value) {}
  void set f3(value) {}
  void set f4(dynamic value) {}
  set f5(B value) {}
}
''');
  }

  void test_forInCastsIterateElementToVariable() {
    checkFile('''
main() {
  // Don't choke if sequence is not iterable.
  for (var i in /*error:FOR_IN_OF_INVALID_TYPE*/1234) {}

  // Dynamic cast.
  for (String /*info:DYNAMIC_CAST*/s in <dynamic>[]) {}

  // Identity cast.
  for (String s in <String>[]) {}

  // Untyped.
  for (var s in <String>[]) {}

  // Downcast.
  for (int /*info:DOWN_CAST_IMPLICIT*/i in <num>[]) {}
}
''');
  }

  void test_forInCastsSupertypeSequenceToIterate() {
    checkFile('''
main() {
  dynamic d;
  for (var i in /*info:DYNAMIC_CAST*/d) {}

  Object o;
  for (var i in /*info:DOWN_CAST_IMPLICIT*/o) {}
}
''');
  }

  void test_forLoopVariable() {
    checkFile('''
foo() {
  for (int i = 0; i < 10; i++) {
    i = /*error:INVALID_ASSIGNMENT*/"hi";
  }
}
bar() {
  for (var i = 0; i < 10; i++) {
    int j = i + 1;
  }
}
''');
  }

  void test_functionModifiers_async() {
    checkFile('''
import 'dart:async';
import 'dart:math' show Random;

dynamic x;

foo1() async => x;
Future foo2() async => x;
Future<int> foo3() async => x;
Future<int> foo4() async => new Future<int>.value(/*info:DYNAMIC_CAST*/x);
Future<int> foo5() async =>
    /*error:RETURN_OF_INVALID_TYPE*/new Future<String>.value(/*info:DYNAMIC_CAST*/x);

bar1() async { return x; }
Future bar2() async { return x; }
Future<int> bar3() async { return x; }
Future<int> bar4() async { return new Future<int>.value(/*info:DYNAMIC_CAST*/x); }
Future<int> bar5() async {
  return /*error:RETURN_OF_INVALID_TYPE*/new Future<String>.value(/*info:DYNAMIC_CAST*/x);
}

int y;
Future<int> z;

baz() async {
  int a = /*info:DYNAMIC_CAST*/await x;
  int b = await y;
  int c = await z;
  String d = /*error:INVALID_ASSIGNMENT*/await z;
}

Future<bool> get issue_ddc_264 async {
  await 42;
  if (new Random().nextBool()) {
    return true;
  } else {
    return new Future<bool>.value(false);
  }
}


Future<String> issue_sdk_26404() async {
  return (1 > 0) ? new Future<String>.value('hello') : "world";
}
''');
  }

  void test_functionModifiers_asyncStar() {
    checkFile('''
import 'dart:async';

dynamic x;

bar1() async* { yield x; }
Stream bar2() async* { yield x; }
Stream<int> bar3() async* { yield /*info:DYNAMIC_CAST*/x; }
Stream<int> bar4() async* { yield /*error:YIELD_OF_INVALID_TYPE*/new Stream<int>(); }

baz1() async* { yield* /*info:DYNAMIC_CAST*/x; }
Stream baz2() async* { yield* /*info:DYNAMIC_CAST*/x; }
Stream<int> baz3() async* { yield* /*info:DYNAMIC_CAST*/x; }
Stream<int> baz4() async* { yield* new Stream<int>(); }
Stream<int> baz5() async* { yield* /*info:INFERRED_TYPE_ALLOCATION*/new Stream(); }
''');
  }

  void test_functionModifiers_syncStar() {
    checkFile('''
dynamic x;

bar1() sync* { yield x; }
Iterable bar2() sync* { yield x; }
Iterable<int> bar3() sync* { yield /*info:DYNAMIC_CAST*/x; }
Iterable<int> bar4() sync* { yield /*error:YIELD_OF_INVALID_TYPE*/bar3(); }

baz1() sync* { yield* /*info:DYNAMIC_CAST*/x; }
Iterable baz2() sync* { yield* /*info:DYNAMIC_CAST*/x; }
Iterable<int> baz3() sync* { yield* /*info:DYNAMIC_CAST*/x; }
Iterable<int> baz4() sync* { yield* bar3(); }
Iterable<int> baz5() sync* { yield* /*info:INFERRED_TYPE_ALLOCATION*/new List(); }
''');
  }

  void test_functionTypingAndSubtyping_classes() {
    checkFile('''
class A {}
class B extends A {}

typedef A Top(B x);   // Top of the lattice
typedef B Left(B x);  // Left branch
typedef B Left2(B x); // Left branch
typedef A Right(A x); // Right branch
typedef B Bot(A x);   // Bottom of the lattice

B left(B x) => x;
B bot_(A x) => /*info:DOWN_CAST_IMPLICIT*/x;
B bot(A x) => x as B;
A top(B x) => x;
A right(A x) => x;

void main() {
  { // Check typedef equality
    Left f = left;
    Left2 g = f;
  }
  {
    Top f;
    f = top;
    f = left;
    f = right;
    f = bot;
  }
  {
    Left f;
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = left;
    f = /*error:INVALID_ASSIGNMENT*/right;
    f = bot;
  }
  {
    Right f;
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = /*error:INVALID_ASSIGNMENT*/left;
    f = right;
    f = bot;
  }
  {
    Bot f;
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = /*error:INVALID_CAST_FUNCTION*/left;
    f = /*error:INVALID_CAST_FUNCTION*/right;
    f = bot;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_dynamic() {
    checkFile('''
class A {}

typedef dynamic Top(dynamic x);     // Top of the lattice
typedef dynamic Left(A x);          // Left branch
typedef A Right(dynamic x);         // Right branch
typedef A Bottom(A x);              // Bottom of the lattice

void main() {
  Top top;
  Left left;
  Right right;
  Bottom bot;
  {
    Top f;
    f = top;
    f = left;
    f = right;
    f = bot;
  }
  {
    Left f;
    f = /*warning:DOWN_CAST_COMPOSITE*/top;
    f = left;
    f = /*error:INVALID_ASSIGNMENT*/right;
    f = bot;
  }
  {
    Right f;
    f = /*warning:DOWN_CAST_COMPOSITE*/top;
    f = /*error:INVALID_ASSIGNMENT*/left;
    f = right;
    f = bot;
  }
  {
    Bottom f;
    f = /*warning:DOWN_CAST_COMPOSITE*/top;
    f = /*warning:DOWN_CAST_COMPOSITE*/left;
    f = /*warning:DOWN_CAST_COMPOSITE*/right;
    f = bot;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_dynamic_knownFunctions() {
    // Our lattice should look like this:
    //
    //
    //           Bot -> Top
    //          /        \
    //      A -> Top    Bot -> A
    //       /     \      /
    // Top -> Top   A -> A
    //         \      /
    //         Top -> A
    //
    // Note that downcasts of known functions are promoted to
    // static type errors, since they cannot succeed.
    // This makes some of what look like downcasts turn into
    // type errors below.
    checkFile('''
class A {}

typedef dynamic BotTop(dynamic x);
typedef dynamic ATop(A x);
typedef A BotA(dynamic x);
typedef A AA(A x);
typedef A TopA(Object x);
typedef dynamic TopTop(Object x);

dynamic aTop(A x) => x;
A aa(A x) => x;
dynamic topTop(dynamic x) => x;
A topA(dynamic x) => /*info:DYNAMIC_CAST*/x;
void apply/*<T>*/(/*=T*/ f0, /*=T*/ f1, /*=T*/ f2,
                  /*=T*/ f3, /*=T*/ f4, /*=T*/ f5) {}
void main() {
  BotTop botTop;
  BotA botA;
  {
    BotTop f;
    f = topA;
    f = topTop;
    f = aa;
    f = aTop;
    f = botA;
    f = botTop;
    apply/*<BotTop>*/(
        topA,
        topTop,
        aa,
        aTop,
        botA,
        botTop
                      );
    apply/*<BotTop>*/(
        (dynamic x) => new A(),
        (dynamic x) => (x as Object),
        (A x) => x,
        (A x) => null,
        botA,
        botTop
                      );
  }
  {
    ATop f;
    f = topA;
    f = topTop;
    f = aa;
    f = aTop;
    f = /*error:INVALID_ASSIGNMENT*/botA;
    f = /*warning:DOWN_CAST_COMPOSITE*/botTop;
    apply/*<ATop>*/(
        topA,
        topTop,
        aa,
        aTop,
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/botA,
        /*warning:DOWN_CAST_COMPOSITE*/botTop
                    );
    apply/*<ATop>*/(
        (dynamic x) => new A(),
        (dynamic x) => (x as Object),
        (A x) => x,
        (A x) => null,
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/botA,
        /*warning:DOWN_CAST_COMPOSITE*/botTop
                    );
  }
  {
    BotA f;
    f = topA;
    f = /*error:INVALID_ASSIGNMENT*/topTop;
    f = aa;
    f = /*error:INVALID_ASSIGNMENT*/aTop;
    f = botA;
    f = /*warning:DOWN_CAST_COMPOSITE*/botTop;
    apply/*<BotA>*/(
        topA,
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/topTop,
        aa,
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/aTop,
        botA,
        /*warning:DOWN_CAST_COMPOSITE*/botTop
                    );
    apply/*<BotA>*/(
        (dynamic x) => new A(),
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/(dynamic x) => (x as Object),
        (A x) => x,
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/(A x) => (/*info:UNNECESSARY_CAST*/x as Object),
        botA,
        /*warning:DOWN_CAST_COMPOSITE*/botTop
                    );
  }
  {
    AA f;
    f = topA;
    f = /*error:INVALID_ASSIGNMENT*/topTop;
    f = aa;
    f = /*error:INVALID_CAST_FUNCTION*/aTop; // known function
    f = /*warning:DOWN_CAST_COMPOSITE*/botA;
    f = /*warning:DOWN_CAST_COMPOSITE*/botTop;
    apply/*<AA>*/(
        topA,
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/topTop,
        aa,
        /*error:INVALID_CAST_FUNCTION*/aTop, // known function
        /*warning:DOWN_CAST_COMPOSITE*/botA,
        /*warning:DOWN_CAST_COMPOSITE*/botTop
                  );
    apply/*<AA>*/(
        (dynamic x) => new A(),
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/(dynamic x) => (x as Object),
        (A x) => x,
        /*error:INVALID_CAST_FUNCTION_EXPR*/(A x) => (/*info:UNNECESSARY_CAST*/x as Object), // known function
        /*warning:DOWN_CAST_COMPOSITE*/botA,
        /*warning:DOWN_CAST_COMPOSITE*/botTop
                  );
  }
  {
    TopTop f;
    f = topA;
    f = topTop;
    f = /*error:INVALID_ASSIGNMENT*/aa;
    f = /*error:INVALID_CAST_FUNCTION*/aTop; // known function
    f = /*error:INVALID_ASSIGNMENT*/botA;
    f = /*warning:DOWN_CAST_COMPOSITE*/botTop;
    apply/*<TopTop>*/(
        topA,
        topTop,
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/aa,
        /*error:INVALID_CAST_FUNCTION*/aTop, // known function
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/botA,
        /*warning:DOWN_CAST_COMPOSITE*/botTop
                      );
    apply/*<TopTop>*/(
        (dynamic x) => new A(),
        (dynamic x) => (x as Object),
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/(A x) => x,
        /*error:INVALID_CAST_FUNCTION_EXPR*/(A x) => (/*info:UNNECESSARY_CAST*/x as Object), // known function
        /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/botA,
        /*warning:DOWN_CAST_COMPOSITE*/botTop
                      );
  }
  {
    TopA f;
    f = topA;
    f = /*error:INVALID_CAST_FUNCTION*/topTop; // known function
    f = /*error:INVALID_CAST_FUNCTION*/aa; // known function
    f = /*error:INVALID_CAST_FUNCTION*/aTop; // known function
    f = /*warning:DOWN_CAST_COMPOSITE*/botA;
    f = /*warning:DOWN_CAST_COMPOSITE*/botTop;
    apply/*<TopA>*/(
        topA,
        /*error:INVALID_CAST_FUNCTION*/topTop, // known function
        /*error:INVALID_CAST_FUNCTION*/aa, // known function
        /*error:INVALID_CAST_FUNCTION*/aTop, // known function
        /*warning:DOWN_CAST_COMPOSITE*/botA,
        /*warning:DOWN_CAST_COMPOSITE*/botTop
                    );
    apply/*<TopA>*/(
        (dynamic x) => new A(),
        /*error:INVALID_CAST_FUNCTION_EXPR*/(dynamic x) => (x as Object), // known function
        /*error:INVALID_CAST_FUNCTION_EXPR*/(A x) => x, // known function
        /*error:INVALID_CAST_FUNCTION_EXPR*/(A x) => (/*info:UNNECESSARY_CAST*/x as Object), // known function
        /*warning:DOWN_CAST_COMPOSITE*/botA,
        /*warning:DOWN_CAST_COMPOSITE*/botTop
                    );
  }
}
''');
  }

  void test_functionTypingAndSubtyping_dynamicFunctions_closuresAreNotFuzzy() {
    // Regression test for
    // https://github.com/dart-lang/sdk/issues/26118
    // https://github.com/dart-lang/sdk/issues/26156
    checkFile('''
void takesF(void f(int x)) {}

typedef void TakesInt(int x);

void update(_) {}
void updateOpt([_]) {}
void updateOptNum([num x]) {}

class A {
  TakesInt f;
  A(TakesInt g) {
    f = update;
    f = updateOpt;
    f = updateOptNum;
  }
  TakesInt g(bool a, bool b) {
    if (a) {
      return update;
    } else if (b) {
      return updateOpt;
    } else {
      return updateOptNum;
    }
  }
}

void test0() {
  takesF(update);
  takesF(updateOpt);
  takesF(updateOptNum);
  TakesInt f;
  f = update;
  f = updateOpt;
  f = updateOptNum;
  new A(update);
  new A(updateOpt);
  new A(updateOptNum);
}

void test1() {
  void takesF(f(int x)) => null;
  takesF((dynamic y) => 3);
}

void test2() {
  int x;
  int f/*<T>*/(/*=T*/ t, callback(/*=T*/ x)) { return 3; }
  f(x, (y) => 3);
}
''');
  }

  void test_functionTypingAndSubtyping_functionLiteralVariance() {
    checkFile('''
class A {}
class B extends A {}

typedef T Function2<S, T>(S z);

A top(B x) => x;
B left(B x) => x;
A right(A x) => x;
B bot(A x) => x as B;

void main() {
  {
    Function2<B, A> f;
    f = top;
    f = left;
    f = right;
    f = bot;
  }
  {
    Function2<B, B> f; // left
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = left;
    f = /*error:INVALID_ASSIGNMENT*/right;
    f = bot;
  }
  {
    Function2<A, A> f; // right
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = /*error:INVALID_ASSIGNMENT*/left;
    f = right;
    f = bot;
  }
  {
    Function2<A, B> f;
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = /*error:INVALID_CAST_FUNCTION*/left;
    f = /*error:INVALID_CAST_FUNCTION*/right;
    f = bot;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_functionVariableVariance() {
    checkFile('''
class A {}
class B extends A {}

typedef T Function2<S, T>(S z);

void main() {
  {
    Function2<B, A> top;
    Function2<B, B> left;
    Function2<A, A> right;
    Function2<A, B> bot;

    top = right;
    top = bot;
    top = top;
    top = left;

    left = /*warning:DOWN_CAST_COMPOSITE*/top;
    left = left;
    left = /*error:INVALID_ASSIGNMENT*/right;
    left = bot;

    right = /*warning:DOWN_CAST_COMPOSITE*/top;
    right = /*error:INVALID_ASSIGNMENT*/left;
    right = right;
    right = bot;

    bot = /*warning:DOWN_CAST_COMPOSITE*/top;
    bot = /*warning:DOWN_CAST_COMPOSITE*/left;
    bot = /*warning:DOWN_CAST_COMPOSITE*/right;
    bot = bot;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_higherOrderFunctionLiteral1() {
    checkFile('''
class A {}
class B extends A {}

typedef T Function2<S, T>(S z);

typedef A BToA(B x);  // Top of the base lattice
typedef B AToB(A x);  // Bot of the base lattice

BToA top(AToB f) => f;
AToB left(AToB f) => f;
BToA right(BToA f) => f;
AToB bot_(BToA f) => /*warning:DOWN_CAST_COMPOSITE*/f;
AToB bot(BToA f) => f as AToB;

void main() {
  {
    Function2<AToB, BToA> f; // Top
    f = top;
    f = left;
    f = right;
    f = bot;
  }
  {
    Function2<AToB, AToB> f; // Left
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = left;
    f = /*error:INVALID_ASSIGNMENT*/right;
    f = bot;
  }
  {
    Function2<BToA, BToA> f; // Right
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = /*error:INVALID_ASSIGNMENT*/left;
    f = right;
    f = bot;
  }
  {
    Function2<BToA, AToB> f; // Bot
    f = bot;
    f = /*error:INVALID_CAST_FUNCTION*/left;
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = /*error:INVALID_CAST_FUNCTION*/right;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_higherOrderFunctionLiteral2() {
    checkFile('''
class A {}
class B extends A {}

typedef T Function2<S, T>(S z);

typedef A BToA(B x);  // Top of the base lattice
typedef B AToB(A x);  // Bot of the base lattice

Function2<B, A> top(AToB f) => f;
Function2<A, B> left(AToB f) => f;
Function2<B, A> right(BToA f) => f;
Function2<A, B> bot_(BToA f) => /*warning:DOWN_CAST_COMPOSITE*/f;
Function2<A, B> bot(BToA f) => f as Function2<A, B>;

void main() {
  {
    Function2<AToB, BToA> f; // Top
    f = top;
    f = left;
    f = right;
    f = bot;
  }
  {
    Function2<AToB, AToB> f; // Left
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = left;
    f = /*error:INVALID_ASSIGNMENT*/right;
    f = bot;
  }
  {
    Function2<BToA, BToA> f; // Right
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = /*error:INVALID_ASSIGNMENT*/left;
    f = right;
    f = bot;
  }
  {
    Function2<BToA, AToB> f; // Bot
    f = bot;
    f = /*error:INVALID_CAST_FUNCTION*/left;
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = /*error:INVALID_CAST_FUNCTION*/right;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_higherOrderFunctionLiteral3() {
    checkFile('''
class A {}
class B extends A {}

typedef T Function2<S, T>(S z);

typedef A BToA(B x);  // Top of the base lattice
typedef B AToB(A x);  // Bot of the base lattice

BToA top(Function2<A, B> f) => f;
AToB left(Function2<A, B> f) => f;
BToA right(Function2<B, A> f) => f;
AToB bot_(Function2<B, A> f) => /*warning:DOWN_CAST_COMPOSITE*/f;
AToB bot(Function2<B, A> f) => f as AToB;

void main() {
  {
    Function2<AToB, BToA> f; // Top
    f = top;
    f = left;
    f = right;
    f = bot;
  }
  {
    Function2<AToB, AToB> f; // Left
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = left;
    f = /*error:INVALID_ASSIGNMENT*/right;
    f = bot;
  }
  {
    Function2<BToA, BToA> f; // Right
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = /*error:INVALID_ASSIGNMENT*/left;
    f = right;
    f = bot;
  }
  {
    Function2<BToA, AToB> f; // Bot
    f = bot;
    f = /*error:INVALID_CAST_FUNCTION*/left;
    f = /*error:INVALID_CAST_FUNCTION*/top;
    f = /*error:INVALID_CAST_FUNCTION*/right;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_higherOrderFunctionVariables() {
    checkFile('''
class A {}
class B extends A {}

typedef T Function2<S, T>(S z);

void main() {
  {
    Function2<Function2<A, B>, Function2<B, A>> top;
    Function2<Function2<B, A>, Function2<B, A>> right;
    Function2<Function2<A, B>, Function2<A, B>> left;
    Function2<Function2<B, A>, Function2<A, B>> bot;

    top = right;
    top = bot;
    top = top;
    top = left;

    left = /*warning:DOWN_CAST_COMPOSITE*/top;
    left = left;
    left =
        /*error:INVALID_ASSIGNMENT*/right;
    left = bot;

    right = /*warning:DOWN_CAST_COMPOSITE*/top;
    right =
        /*error:INVALID_ASSIGNMENT*/left;
    right = right;
    right = bot;

    bot = /*warning:DOWN_CAST_COMPOSITE*/top;
    bot = /*warning:DOWN_CAST_COMPOSITE*/left;
    bot = /*warning:DOWN_CAST_COMPOSITE*/right;
    bot = bot;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_instanceMethodVariance() {
    checkFile('''
class A {}
class B extends A {}

class C {
  A top(B x) => x;
  B left(B x) => x;
  A right(A x) => x;
  B bot(A x) => x as B;
}

typedef T Function2<S, T>(S z);

void main() {
  C c = new C();
  {
    Function2<B, A> f;
    f = c.top;
    f = c.left;
    f = c.right;
    f = c.bot;
  }
  {
    Function2<B, B> f;
    f = /*warning:DOWN_CAST_COMPOSITE*/c.top;
    f = c.left;
    f = /*error:INVALID_ASSIGNMENT*/c.right;
    f = c.bot;
  }
  {
    Function2<A, A> f;
    f = /*warning:DOWN_CAST_COMPOSITE*/c.top;
    f = /*error:INVALID_ASSIGNMENT*/c.left;
    f = c.right;
    f = c.bot;
  }
  {
    Function2<A, B> f;
    f = /*warning:DOWN_CAST_COMPOSITE*/c.top;
    f = /*warning:DOWN_CAST_COMPOSITE*/c.left;
    f = /*warning:DOWN_CAST_COMPOSITE*/c.right;
    f = c.bot;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_intAndObject() {
    checkFile('''
typedef Object Top(int x);      // Top of the lattice
typedef int Left(int x);        // Left branch
typedef int Left2(int x);       // Left branch
typedef Object Right(Object x); // Right branch
typedef int Bot(Object x);      // Bottom of the lattice

Object globalTop(int x) => x;
int globalLeft(int x) => x;
Object globalRight(Object x) => x;
int bot_(Object x) => /*info:DOWN_CAST_IMPLICIT*/x;
int globalBot(Object x) => x as int;

void main() {
  // Note: use locals so we only know the type, not that it's a specific
  // function declaration. (we can issue better errors in that case.)
  var top = globalTop;
  var left = globalLeft;
  var right = globalRight;
  var bot = globalBot;

  { // Check typedef equality
    Left f = left;
    Left2 g = f;
  }
  {
    Top f;
    f = top;
    f = left;
    f = right;
    f = bot;
  }
  {
    Left f;
    f = /*warning:DOWN_CAST_COMPOSITE*/top;
    f = left;
    f = /*error:INVALID_ASSIGNMENT*/right;
    f = bot;
  }
  {
    Right f;
    f = /*warning:DOWN_CAST_COMPOSITE*/top;
    f = /*error:INVALID_ASSIGNMENT*/left;
    f = right;
    f = bot;
  }
  {
    Bot f;
    f = /*warning:DOWN_CAST_COMPOSITE*/top;
    f = /*warning:DOWN_CAST_COMPOSITE*/left;
    f = /*warning:DOWN_CAST_COMPOSITE*/right;
    f = bot;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_namedAndOptionalParameters() {
    checkFile('''
class A {}

typedef A FR(A x);
typedef A FO([A x]);
typedef A FN({A x});
typedef A FRR(A x, A y);
typedef A FRO(A x, [A y]);
typedef A FRN(A x, {A n});
typedef A FOO([A x, A y]);
typedef A FNN({A x, A y});
typedef A FNNN({A z, A y, A x});

void main() {
   FR r;
   FO o;
   FN n;
   FRR rr;
   FRO ro;
   FRN rn;
   FOO oo;
   FNN nn;
   FNNN nnn;

   r = r;
   r = o;
   r = /*error:INVALID_ASSIGNMENT*/n;
   r = /*error:INVALID_ASSIGNMENT*/rr;
   r = ro;
   r = rn;
   r = oo;
   r = /*error:INVALID_ASSIGNMENT*/nn;
   r = /*error:INVALID_ASSIGNMENT*/nnn;

   o = /*warning:DOWN_CAST_COMPOSITE*/r;
   o = o;
   o = /*error:INVALID_ASSIGNMENT*/n;
   o = /*error:INVALID_ASSIGNMENT*/rr;
   o = /*error:INVALID_ASSIGNMENT*/ro;
   o = /*error:INVALID_ASSIGNMENT*/rn;
   o = oo;
   o = /*error:INVALID_ASSIGNMENT*/nn;
   o = /*error:INVALID_ASSIGNMENT*/nnn;

   n = /*error:INVALID_ASSIGNMENT*/r;
   n = /*error:INVALID_ASSIGNMENT*/o;
   n = n;
   n = /*error:INVALID_ASSIGNMENT*/rr;
   n = /*error:INVALID_ASSIGNMENT*/ro;
   n = /*error:INVALID_ASSIGNMENT*/rn;
   n = /*error:INVALID_ASSIGNMENT*/oo;
   n = nn;
   n = nnn;

   rr = /*error:INVALID_ASSIGNMENT*/r;
   rr = /*error:INVALID_ASSIGNMENT*/o;
   rr = /*error:INVALID_ASSIGNMENT*/n;
   rr = rr;
   rr = ro;
   rr = /*error:INVALID_ASSIGNMENT*/rn;
   rr = oo;
   rr = /*error:INVALID_ASSIGNMENT*/nn;
   rr = /*error:INVALID_ASSIGNMENT*/nnn;

   ro = /*warning:DOWN_CAST_COMPOSITE*/r;
   ro = /*error:INVALID_ASSIGNMENT*/o;
   ro = /*error:INVALID_ASSIGNMENT*/n;
   ro = /*warning:DOWN_CAST_COMPOSITE*/rr;
   ro = ro;
   ro = /*error:INVALID_ASSIGNMENT*/rn;
   ro = oo;
   ro = /*error:INVALID_ASSIGNMENT*/nn;
   ro = /*error:INVALID_ASSIGNMENT*/nnn;

   rn = /*warning:DOWN_CAST_COMPOSITE*/r;
   rn = /*error:INVALID_ASSIGNMENT*/o;
   rn = /*error:INVALID_ASSIGNMENT*/n;
   rn = /*error:INVALID_ASSIGNMENT*/rr;
   rn = /*error:INVALID_ASSIGNMENT*/ro;
   rn = rn;
   rn = /*error:INVALID_ASSIGNMENT*/oo;
   rn = /*error:INVALID_ASSIGNMENT*/nn;
   rn = /*error:INVALID_ASSIGNMENT*/nnn;

   oo = /*warning:DOWN_CAST_COMPOSITE*/r;
   oo = /*warning:DOWN_CAST_COMPOSITE*/o;
   oo = /*error:INVALID_ASSIGNMENT*/n;
   oo = /*warning:DOWN_CAST_COMPOSITE*/rr;
   oo = /*warning:DOWN_CAST_COMPOSITE*/ro;
   oo = /*error:INVALID_ASSIGNMENT*/rn;
   oo = oo;
   oo = /*error:INVALID_ASSIGNMENT*/nn;
   oo = /*error:INVALID_ASSIGNMENT*/nnn;

   nn = /*error:INVALID_ASSIGNMENT*/r;
   nn = /*error:INVALID_ASSIGNMENT*/o;
   nn = /*warning:DOWN_CAST_COMPOSITE*/n;
   nn = /*error:INVALID_ASSIGNMENT*/rr;
   nn = /*error:INVALID_ASSIGNMENT*/ro;
   nn = /*error:INVALID_ASSIGNMENT*/rn;
   nn = /*error:INVALID_ASSIGNMENT*/oo;
   nn = nn;
   nn = nnn;

   nnn = /*error:INVALID_ASSIGNMENT*/r;
   nnn = /*error:INVALID_ASSIGNMENT*/o;
   nnn = /*warning:DOWN_CAST_COMPOSITE*/n;
   nnn = /*error:INVALID_ASSIGNMENT*/rr;
   nnn = /*error:INVALID_ASSIGNMENT*/ro;
   nnn = /*error:INVALID_ASSIGNMENT*/rn;
   nnn = /*error:INVALID_ASSIGNMENT*/oo;
   nnn = /*warning:DOWN_CAST_COMPOSITE*/nn;
   nnn = nnn;
}
''');
  }

  void test_functionTypingAndSubtyping_objectsWithCallMethods() {
    checkFile('''
typedef int I2I(int x);
typedef num N2N(num x);
class A {
   int call(int x) => x;
}
class B {
   num call(num x) => x;
}
int i2i(int x) => x;
num n2n(num x) => x;
void main() {
   {
     I2I f;
     f = new A();
     f = /*error:INVALID_ASSIGNMENT*/new B();
     f = i2i;
     f = /*error:INVALID_ASSIGNMENT*/n2n;
     f = /*info:UNNECESSARY_CAST,warning:DOWN_CAST_COMPOSITE*/i2i as Object;
     f = /*info:UNNECESSARY_CAST,warning:DOWN_CAST_COMPOSITE*/n2n as Function;
   }
   {
     N2N f;
     f = /*error:INVALID_ASSIGNMENT*/new A();
     f = new B();
     f = /*error:INVALID_ASSIGNMENT*/i2i;
     f = n2n;
     f = /*info:UNNECESSARY_CAST,warning:DOWN_CAST_COMPOSITE*/i2i as Object;
     f = /*info:UNNECESSARY_CAST,warning:DOWN_CAST_COMPOSITE*/n2n as Function;
   }
   {
     A f;
     f = new A();
     f = /*error:INVALID_ASSIGNMENT*/new B();
     f = /*error:INVALID_ASSIGNMENT*/i2i;
     f = /*error:INVALID_ASSIGNMENT*/n2n;
     f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_IMPLICIT*/i2i as Object;
     f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_IMPLICIT*/n2n as Function;
   }
   {
     B f;
     f = /*error:INVALID_ASSIGNMENT*/new A();
     f = new B();
     f = /*error:INVALID_ASSIGNMENT*/i2i;
     f = /*error:INVALID_ASSIGNMENT*/n2n;
     f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_IMPLICIT*/i2i as Object;
     f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_IMPLICIT*/n2n as Function;
   }
   {
     Function f;
     f = new A();
     f = new B();
     f = i2i;
     f = n2n;
     f = /*info:UNNECESSARY_CAST,info:DOWN_CAST_IMPLICIT*/i2i as Object;
     f = /*info:UNNECESSARY_CAST*/n2n as Function;
   }
}
''');
  }

  void test_functionTypingAndSubtyping_staticMethodVariance() {
    checkFile('''
class A {}
class B extends A {}

class C {
  static A top(B x) => x;
  static B left(B x) => x;
  static A right(A x) => x;
  static B bot(A x) => x as B;
}

typedef T Function2<S, T>(S z);

void main() {
  {
    Function2<B, A> f;
    f = C.top;
    f = C.left;
    f = C.right;
    f = C.bot;
  }
  {
    Function2<B, B> f;
    f = /*error:INVALID_CAST_METHOD*/C.top;
    f = C.left;
    f = /*error:INVALID_ASSIGNMENT*/C.right;
    f = C.bot;
  }
  {
    Function2<A, A> f;
    f = /*error:INVALID_CAST_METHOD*/C.top;
    f = /*error:INVALID_ASSIGNMENT*/C.left;
    f = C.right;
    f = C.bot;
  }
  {
    Function2<A, B> f;
    f = /*error:INVALID_CAST_METHOD*/C.top;
    f = /*error:INVALID_CAST_METHOD*/C.left;
    f = /*error:INVALID_CAST_METHOD*/C.right;
    f = C.bot;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_subtypeOfUniversalType() {
    checkFile('''
void main() {
  nonGenericFn(x) => null;
  {
    /*=R*/ f/*<P, R>*/(/*=P*/ p) => null;
    /*=T*/ g/*<S, T>*/(/*=S*/ s) => null;

    var local = f;
    local = g; // valid

    // Non-generic function cannot subtype a generic one.
    local = /*error:INVALID_ASSIGNMENT*/(x) => null;
    local = /*error:INVALID_ASSIGNMENT*/nonGenericFn;
  }
  {
    Iterable/*<R>*/ f/*<P, R>*/(List/*<P>*/ p) => null;
    List/*<T>*/ g/*<S, T>*/(Iterable/*<S>*/ s) => null;

    var local = f;
    local = g; // valid

    var local2 = g;
    local = local2;
    local2 = /*error:INVALID_CAST_FUNCTION*/f;
    local2 = /*warning:DOWN_CAST_COMPOSITE*/local;

    // Non-generic function cannot subtype a generic one.
    local = /*error:INVALID_ASSIGNMENT*/(x) => null;
    local = /*error:INVALID_ASSIGNMENT*/nonGenericFn;
  }
}
''');
  }

  void test_functionTypingAndSubtyping_uninferredClosure() {
    checkFile('''
typedef num Num2Num(num x);
void main() {
  Num2Num g = /*info:INFERRED_TYPE_CLOSURE,error:INVALID_ASSIGNMENT*/(int x) { return x; };
  print(g(42));
}
''');
  }

  void test_functionTypingAndSubtyping_void() {
    checkFile('''
class A {
  void bar() => null;
  void foo() => bar(); // allowed
}
''');
  }

  void test_genericClassMethodOverride() {
    checkFile('''
class A {}
class B extends A {}

class Base<T extends B> {
  T foo() => null;
}

class Derived<S extends A> extends Base<B> {
  /*error:INVALID_METHOD_OVERRIDE*/S foo() => null;
}

class Derived2<S extends B> extends Base<B> {
  S foo() => null;
}
''');
  }

  void test_genericFunctionWrongNumberOfArguments() {
    checkFile(r'''
/*=T*/ foo/*<T>*/(/*=T*/ x, /*=T*/ y) => x;
/*=T*/ bar/*<T>*/({/*=T*/ x, /*=T*/ y}) => x;

main() {
  String x;
  // resolving these shouldn't crash.
  foo/*error:EXTRA_POSITIONAL_ARGUMENTS*/(1, 2, 3);
  x = foo/*error:EXTRA_POSITIONAL_ARGUMENTS*/('1', '2', '3');
  foo/*error:NOT_ENOUGH_REQUIRED_ARGUMENTS*/(1);
  x = foo/*error:NOT_ENOUGH_REQUIRED_ARGUMENTS*/('1');
  x = /*error:COULD_NOT_INFER*/foo/*error:EXTRA_POSITIONAL_ARGUMENTS*/(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/1, /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/2, 3);
  x = /*error:COULD_NOT_INFER*/foo/*error:NOT_ENOUGH_REQUIRED_ARGUMENTS*/(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/1);

  // named arguments
  bar(y: 1, x: 2, /*error:UNDEFINED_NAMED_PARAMETER*/z: 3);
  x = bar(/*error:UNDEFINED_NAMED_PARAMETER*/z: '1', x: '2', y: '3');
  bar(y: 1);
  x = bar(x: '1', /*error:UNDEFINED_NAMED_PARAMETER*/z: 42);
  x = /*error:COULD_NOT_INFER*/bar(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/y: 1, /*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/x: 2, /*error:UNDEFINED_NAMED_PARAMETER*/z: 3);
  x = /*error:COULD_NOT_INFER*/bar(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/x: 1);
}
''');
  }

  void test_genericMethodOverride() {
    checkFile('''
class Future<T> {
  /*=S*/ then/*<S>*/(/*=S*/ onValue(T t)) => null;
}

class DerivedFuture<T> extends Future<T> {
  /*=S*/ then/*<S>*/(/*=S*/ onValue(T t)) => null;
}

class DerivedFuture2<A> extends Future<A> {
  /*=B*/ then/*<B>*/(/*=B*/ onValue(A a)) => null;
}

class DerivedFuture3<T> extends Future<T> {
  /*=S*/ then/*<S>*/(Object onValue(T t)) => null;
}

class DerivedFuture4<A> extends Future<A> {
  /*=B*/ then/*<B>*/(Object onValue(A a)) => null;
}
''');
  }

  void test_getterGetterOverride() {
    checkFile('''
class A {}
class B extends A {}
class C extends B {}

abstract class Base {
  B get f1;
  B get f2;
  B get f3;
  B get f4;
}

class Child extends Base {
  /*error:INVALID_METHOD_OVERRIDE*/A get f1 => null;
  C get f2 => null;
  get f3 => null;
  /*error:INVALID_METHOD_OVERRIDE*/dynamic get f4 => null;
}
''');
  }

  void test_getterOverride_fuzzyArrows() {
    checkFile('''
typedef void ToVoid<T>(T x);

class F {
  ToVoid<dynamic> get f => null;
  ToVoid<int> get g => null;
}

class G extends F {
  ToVoid<int> get f => null;
  /*error:INVALID_METHOD_OVERRIDE*/ToVoid<dynamic> get g => null;
}

class H implements F {
  ToVoid<int> get f => null;
  /*error:INVALID_METHOD_OVERRIDE*/ToVoid<dynamic> get g => null;
}
''');
  }

  void test_ifForDoWhileStatementsUseBooleanConversion() {
    checkFile('''
main() {
  dynamic dyn = 42;
  Object obj = 42;
  int i = 42;
  bool b = false;

  if (b) {}
  if (/*info:DYNAMIC_CAST*/dyn) {}
  if (/*info:DOWN_CAST_IMPLICIT*/obj) {}
  if (/*error:NON_BOOL_CONDITION*/i) {}

  while (b) {}
  while (/*info:DYNAMIC_CAST*/dyn) {}
  while (/*info:DOWN_CAST_IMPLICIT*/obj) {}
  while (/*error:NON_BOOL_CONDITION*/i) {}

  do {} while (b);
  do {} while (/*info:DYNAMIC_CAST*/dyn);
  do {} while (/*info:DOWN_CAST_IMPLICIT*/obj);
  do {} while (/*error:NON_BOOL_CONDITION*/i);

  for (;b;) {}
  for (;/*info:DYNAMIC_CAST*/dyn;) {}
  for (;/*info:DOWN_CAST_IMPLICIT*/obj;) {}
  for (;/*error:NON_BOOL_CONDITION*/i;) {}
}
''');
  }

  void test_implicitCasts() {
    addFile('num n; int i = /*info:ASSIGNMENT_CAST*/n;');
    check();
    // TODO(jmesserly): should not be emitting the hint as well as the error.
    // It is a "strong mode hint" however, so it will not be user visible.
    addFile(
        'num n; int i = /*info:ASSIGNMENT_CAST,error:INVALID_ASSIGNMENT*/n;');
    check(implicitCasts: false);
  }

  void test_implicitCasts_genericMethods() {
    addFile('var x = <String>[].map((x) => "");');
    check(implicitCasts: false);
  }

  void test_implicitCasts_numericOps() {
    // Regression test for https://github.com/dart-lang/sdk/issues/26912
    addFile(r'''
void f() {
  int x = 0;
  int y = 0;
  x += y;
}
    ''');
    check(implicitCasts: false);
  }

  void test_implicitDynamic_field() {
    addFile(r'''
class C {
  var /*error:IMPLICIT_DYNAMIC_FIELD*/x0;
  var /*error:IMPLICIT_DYNAMIC_FIELD*/x1 = (<dynamic>[])[0];
  var /*error:IMPLICIT_DYNAMIC_FIELD*/x2,
      x3 = 42,
      /*error:IMPLICIT_DYNAMIC_FIELD*/x4;
  dynamic y0;
  dynamic y1 = (<dynamic>[])[0];
}
    ''');
    check(implicitDynamic: false);
  }

  void test_implicitDynamic_function() {
    addFile(r'''
/*=T*/ a/*<T>*/(/*=T*/ t) => t;
/*=T*/ b/*<T>*/() => null;

void main/*<S>*/() {
  dynamic d;
  int i;
  /*error:IMPLICIT_DYNAMIC_FUNCTION*/a(d);
  a(42);
  /*error:IMPLICIT_DYNAMIC_FUNCTION*/b();
  d = /*error:IMPLICIT_DYNAMIC_FUNCTION*/b();
  i = b();

  void f/*<T>*/(/*=T*/ t) {};
  /*=T*/ g/*<T>*/() => null;

  /*error:IMPLICIT_DYNAMIC_FUNCTION*/f(d);
  f(42);
  /*error:IMPLICIT_DYNAMIC_FUNCTION*/g();
  d = /*error:IMPLICIT_DYNAMIC_FUNCTION*/g();
  i = g();

  /*error:IMPLICIT_DYNAMIC_INVOKE*/(/*<T>*/(/*=T*/ t) => t)(d);
  (/*<T>*/(/*=T*/ t) => t)(42);
  (/*<T>*/() => /*info:UNNECESSARY_CAST*/null as dynamic/*=T*/)/*<int>*/();
}
    ''');
    check(implicitDynamic: false);
  }

  void test_implicitDynamic_listLiteral() {
    addFile(r'''

var l0 = /*error:IMPLICIT_DYNAMIC_LIST_LITERAL*/[];
List l1 = /*error:IMPLICIT_DYNAMIC_LIST_LITERAL*/[];
List<dynamic> l2 = /*error:IMPLICIT_DYNAMIC_LIST_LITERAL*/[];
dynamic d = 42;
var l3 = /*error:IMPLICIT_DYNAMIC_LIST_LITERAL*/[d, d];

var l4 = <dynamic>[];
var l5 = <int>[];
List<int> l6 = /*info:INFERRED_TYPE_LITERAL*/[];
var l7 = /*info:INFERRED_TYPE_LITERAL*/[42];
    ''');
    check(implicitDynamic: false);
  }

  void test_implicitDynamic_mapLiteral() {
    addFile(r'''
var m0 = /*error:IMPLICIT_DYNAMIC_MAP_LITERAL*/{};
Map m1 = /*error:IMPLICIT_DYNAMIC_MAP_LITERAL*/{};
Map<dynamic, dynamic> m2 = /*error:IMPLICIT_DYNAMIC_MAP_LITERAL*/{};
dynamic d = 42;
var m3 = /*error:IMPLICIT_DYNAMIC_MAP_LITERAL*/{d: d};
var m4 = /*info:INFERRED_TYPE_LITERAL,error:IMPLICIT_DYNAMIC_MAP_LITERAL*/{'x': d, 'y': d};
var m5 = /*info:INFERRED_TYPE_LITERAL,error:IMPLICIT_DYNAMIC_MAP_LITERAL*/{d: 'x'};

var m6 = <dynamic, dynamic>{};
var m7 = <String, String>{};
Map<String, String> m8 = /*info:INFERRED_TYPE_LITERAL*/{};
var m9 = /*info:INFERRED_TYPE_LITERAL*/{'hi': 'there'};
    ''');
    check(implicitDynamic: false);
  }

  void test_implicitDynamic_method() {
    addFile(r'''
class C {
  /*=T*/ m/*<T>*/(/*=T*/ s) => s;
  /*=T*/ n/*<T>*/() => null;
}
class D<E> {
  /*=T*/ m/*<T>*/(/*=T*/ s) => s;
  /*=T*/ n/*<T>*/() => null;
}
void f() {
  dynamic d;
  int i;
  new C()./*error:IMPLICIT_DYNAMIC_METHOD*/m(d);
  new C().m(42);
  new C()./*error:IMPLICIT_DYNAMIC_METHOD*/n();
  d = new C()./*error:IMPLICIT_DYNAMIC_METHOD*/n();
  i = new C().n();

  new D<int>()./*error:IMPLICIT_DYNAMIC_METHOD*/m(d);
  new D<int>().m(42);
  new D<int>()./*error:IMPLICIT_DYNAMIC_METHOD*/n();
  d = new D<int>()./*error:IMPLICIT_DYNAMIC_METHOD*/n();
  i = new D<int>().n();
}
    ''');
    check(implicitDynamic: false);
  }

  void test_implicitDynamic_parameter() {
    addFile(r'''
const dynamic DYNAMIC_VALUE = 42;

// simple formal
void f0(/*error:IMPLICIT_DYNAMIC_PARAMETER*/x) {}
void f1(dynamic x) {}

// default formal
void df0([/*error:IMPLICIT_DYNAMIC_PARAMETER*/x = DYNAMIC_VALUE]) {}
void df1([dynamic x = DYNAMIC_VALUE]) {}

// https://github.com/dart-lang/sdk/issues/25794
void df2([/*error:IMPLICIT_DYNAMIC_PARAMETER*/x = 42]) {}

// default formal (named)
void nf0({/*error:IMPLICIT_DYNAMIC_PARAMETER*/x: DYNAMIC_VALUE}) {}
void nf1({dynamic x: DYNAMIC_VALUE}) {}

// https://github.com/dart-lang/sdk/issues/25794
void nf2({/*error:IMPLICIT_DYNAMIC_PARAMETER*/x: 42}) {}

// field formal
class C {
  var /*error:IMPLICIT_DYNAMIC_FIELD*/x;
  C(this.x);
}

// function typed formal
void ftf0(void x(/*error:IMPLICIT_DYNAMIC_PARAMETER*/y)) {}
void ftf1(void x(int y)) {}
    ''');
    check(implicitDynamic: false);
  }

  void test_implicitDynamic_return() {
    addFile(r'''
// function
/*error:IMPLICIT_DYNAMIC_RETURN*/f0() {}
dynamic f1() { return 42; }

// nested function
void main() {
  /*error:IMPLICIT_DYNAMIC_RETURN*/g0() {}
  dynamic g1() { return 42; }
}

// methods
class B {
  int m1() => 42;
}
class C extends B {
  /*error:IMPLICIT_DYNAMIC_RETURN*/m0() => 123;
  m1() => 123;
  dynamic m2() => 'hi';
}

// accessors
set x(int value) {}
/*error:IMPLICIT_DYNAMIC_RETURN*/get y0 => 42;
dynamic get y1 => 42;

// function typed formals
void ftf0(/*error:IMPLICIT_DYNAMIC_RETURN*/f(int x)) {}
void ftf1(dynamic f(int x)) {}

// function expressions
var fe0 = (int x) => x as dynamic;
var fe1 = (int x) => x;
    ''');
    check(implicitDynamic: false);
  }

  void test_implicitDynamic_type() {
    addFile(r'''
class C<T> {}
class M1<T extends /*error:IMPLICIT_DYNAMIC_TYPE*/List> {}
class M2<T> {}
class I<T> {}
class D<T, S> extends /*error:IMPLICIT_DYNAMIC_TYPE*/C
    with M1, /*error:IMPLICIT_DYNAMIC_TYPE*/M2
    implements /*error:IMPLICIT_DYNAMIC_TYPE*/I {}

C f(D d) {
  D x = new /*error:IMPLICIT_DYNAMIC_TYPE*/D();
  D<int, dynamic> y = /*info:INFERRED_TYPE_ALLOCATION*/new /*error:IMPLICIT_DYNAMIC_TYPE*/D();
  D<dynamic, int> z = /*info:INFERRED_TYPE_ALLOCATION*/new /*error:IMPLICIT_DYNAMIC_TYPE*/D();
  return new /*error:IMPLICIT_DYNAMIC_TYPE*/C();
}

class A<T extends num> {}
class N1<T extends List<int>> {}
class N2<T extends Object> {}
class J<T extends Object> {}
class B<T extends Object> extends A with N1, N2 implements J {}
A g(B b) {
  B y = /*info:INFERRED_TYPE_ALLOCATION*/new B();
  return /*info:INFERRED_TYPE_ALLOCATION*/new A();
}
    ''');
    check(implicitDynamic: false);
  }

  void test_implicitDynamic_variable() {
    addFile(r'''
var /*error:IMPLICIT_DYNAMIC_VARIABLE*/x0;
var /*error:IMPLICIT_DYNAMIC_VARIABLE*/x1 = (<dynamic>[])[0];
var /*error:IMPLICIT_DYNAMIC_VARIABLE*/x2,
    x3 = 42,
    /*error:IMPLICIT_DYNAMIC_VARIABLE*/x4;
dynamic y0;
dynamic y1 = (<dynamic>[])[0];
    ''');
    check(implicitDynamic: false);
  }

  void test_invalidOverrides_baseClassOverrideToChildInterface() {
    checkFile('''
class A {}
class B {}

abstract class I {
    m(A a);
}

class Base {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    /*error:INVALID_METHOD_OVERRIDE_FROM_BASE*/extends Base implements I {}
''');
  }

  void test_invalidOverrides_childOverride() {
    checkFile('''
class A {}
class B {}

class Base {
    A f;
}

class T1 extends Base {
  /*warning:MISMATCHED_GETTER_AND_SETTER_TYPES_FROM_SUPERTYPE, error:INVALID_FIELD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/B get f => null;
}

class T2 extends Base {
  /*warning:MISMATCHED_GETTER_AND_SETTER_TYPES_FROM_SUPERTYPE, error:INVALID_FIELD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/set f(
      B b) => null;
}

class T3 extends Base {
  /*error:INVALID_FIELD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/final B
      /*warning:FINAL_NOT_INITIALIZED*/f;
}
class T4 extends Base {
  // two: one for the getter one for the setter.
  /*error:INVALID_FIELD_OVERRIDE, error:INVALID_METHOD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/B f;
}

class /*error:NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE*/T5 implements Base {
  /*warning:MISMATCHED_GETTER_AND_SETTER_TYPES_FROM_SUPERTYPE, error:INVALID_METHOD_OVERRIDE*/B get f => null;
}

class /*error:NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE*/T6 implements Base {
  /*warning:MISMATCHED_GETTER_AND_SETTER_TYPES_FROM_SUPERTYPE, error:INVALID_METHOD_OVERRIDE*/set f(B b) => null;
}

class /*error:NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE*/T7 implements Base {
  /*error:INVALID_METHOD_OVERRIDE*/final B f = null;
}
class T8 implements Base {
  // two: one for the getter one for the setter.
  /*error:INVALID_METHOD_OVERRIDE, error:INVALID_METHOD_OVERRIDE*/B f;
}
''');
  }

  void test_invalidOverrides_childOverride2() {
    checkFile('''
class A {}
class B {}

class Base {
    m(A a) {}
}

class Test extends Base {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}
''');
  }

  void test_invalidOverrides_classOverrideOfInterface() {
    checkFile('''
class A {}
class B {}

abstract class I {
    m(A a);
}

class T1 implements I {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}
''');
  }

  void test_invalidOverrides_doubleOverride() {
    checkFile('''
class A {}
class B {}

class Grandparent {
    m(A a) {}
}
class Parent extends Grandparent {
    m(A a) {}
}

class Test extends Parent {
    // Reported only once
    /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}
''');
  }

  void test_invalidOverrides_doubleOverride2() {
    checkFile('''
class A {}
class B {}

class Grandparent {
    m(A a) {}
}
class Parent extends Grandparent {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}

class Test extends Parent {
    m(B a) {}
}
''');
  }

  void test_invalidOverrides_grandChildOverride() {
    checkFile('''
class A {}
class B {}

class Grandparent {
    m(A a) {}
    int x;
}
class Parent extends Grandparent {
}

class Test extends Parent {
    /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
    /*error:INVALID_FIELD_OVERRIDE*/int x;
}
''');
  }

  void test_invalidOverrides_mixinOverrideOfInterface() {
    checkFile('''
class A {}
class B {}

abstract class I {
    m(A a);
}

class M {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    extends Object with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M
    implements I {}
''');
  }

  void test_invalidOverrides_mixinOverrideToBase() {
    checkFile('''
class A {}
class B {}

class Base {
    m(A a) {}
    int x;
}

class M1 {
    m(B a) {}
}

class M2 {
    int x;
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1 extends Base
    with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M1 {}
class /*error:INCONSISTENT_METHOD_INHERITANCE*/T2 extends Base
    with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M1, /*error:INVALID_FIELD_OVERRIDE*/M2 {}
class /*error:INCONSISTENT_METHOD_INHERITANCE*/T3 extends Base
    with /*error:INVALID_FIELD_OVERRIDE*/M2, /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M1 {}
''');
  }

  void test_invalidOverrides_mixinOverrideToMixin() {
    checkFile('''
class A {}
class B {}

class Base {
}

class M1 {
    m(B a) {}
    int x;
}

class M2 {
    m(A a) {}
    int x;
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1 extends Base
    with M1,
    /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN,error:INVALID_FIELD_OVERRIDE*/M2 {}
''');
  }

  void test_invalidOverrides_noDuplicateMixinOverride() {
    // This is a regression test for a bug in an earlier implementation were
    // names were hiding errors if the first mixin override looked correct,
    // but subsequent ones did not.
    checkFile('''
class A {}
class B {}

class Base {
    m(A a) {}
}

class M1 {
    m(A a) {}
}

class M2 {
    m(B a) {}
}

class M3 {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1 extends Base
    with M1, /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M2, M3 {}
''');
  }

  void
      test_invalidOverrides_noErrorsIfSubclassCorrectlyOverrideBaseAndInterface() {
    // This is a case were it is incorrect to say that the base class
    // incorrectly overrides the interface.
    checkFile('''
class A {}
class B {}

class Base {
    m(A a) {}
}

class I1 {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    /*error:INVALID_METHOD_OVERRIDE_FROM_BASE*/extends Base
    implements I1 {}

class T2 extends Base implements I1 {
    m(a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T3
    extends Object with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/Base
    implements I1 {}

class T4 extends Object with Base implements I1 {
    m(a) {}
}
''');
  }

  void test_invalidRuntimeChecks() {
    checkFile('''
typedef int I2I(int x);
typedef int D2I(x);
typedef int II2I(int x, int y);
typedef int DI2I(x, int y);
typedef int ID2I(int x, y);
typedef int DD2I(x, y);

typedef I2D(int x);
typedef D2D(x);
typedef II2D(int x, int y);
typedef DI2D(x, int y);
typedef ID2D(int x, y);
typedef DD2D(x, y);

int foo(int x) => x;
int bar(int x, int y) => x + y;

void main() {
  bool b;
  b = /*info:NON_GROUND_TYPE_CHECK_INFO*/foo is I2I;
  b = /*info:NON_GROUND_TYPE_CHECK_INFO*/foo is D2I;
  b = /*info:NON_GROUND_TYPE_CHECK_INFO*/foo is I2D;
  b = foo is D2D;

  b = /*info:NON_GROUND_TYPE_CHECK_INFO*/bar is II2I;
  b = /*info:NON_GROUND_TYPE_CHECK_INFO*/bar is DI2I;
  b = /*info:NON_GROUND_TYPE_CHECK_INFO*/bar is ID2I;
  b = /*info:NON_GROUND_TYPE_CHECK_INFO*/bar is II2D;
  b = /*info:NON_GROUND_TYPE_CHECK_INFO*/bar is DD2I;
  b = /*info:NON_GROUND_TYPE_CHECK_INFO*/bar is DI2D;
  b = /*info:NON_GROUND_TYPE_CHECK_INFO*/bar is ID2D;
  b = bar is DD2D;

  // For as, the validity of checks is deferred to runtime.
  Function f;
  f = /*info:UNNECESSARY_CAST*/foo as I2I;
  f = /*info:UNNECESSARY_CAST*/foo as D2I;
  f = /*info:UNNECESSARY_CAST*/foo as I2D;
  f = /*info:UNNECESSARY_CAST*/foo as D2D;

  f = /*info:UNNECESSARY_CAST*/bar as II2I;
  f = /*info:UNNECESSARY_CAST*/bar as DI2I;
  f = /*info:UNNECESSARY_CAST*/bar as ID2I;
  f = /*info:UNNECESSARY_CAST*/bar as II2D;
  f = /*info:UNNECESSARY_CAST*/bar as DD2I;
  f = /*info:UNNECESSARY_CAST*/bar as DI2D;
  f = /*info:UNNECESSARY_CAST*/bar as ID2D;
  f = /*info:UNNECESSARY_CAST*/bar as DD2D;
}
''');
  }

  void test_leastUpperBounds() {
    checkFile('''
typedef T Returns<T>();

// regression test for https://github.com/dart-lang/sdk/issues/26094
class A <S extends Returns<S>, T extends Returns<T>> {
  int test(bool b) {
    S s;
    T t;
    if (b) {
      return /*error:RETURN_OF_INVALID_TYPE*/b ? s : t;
    } else {
      return /*error:RETURN_OF_INVALID_TYPE*/s ?? t;
    }
  }
}

class B<S, T extends S> {
  T t;
  S s;
  int test(bool b) {
    return /*error:RETURN_OF_INVALID_TYPE*/b ? t : s;
  }
}

class C {
  // Check that the least upper bound of two types with the same
  // class but different type arguments produces the pointwise
  // least upper bound of the type arguments
  int test1(bool b) {
    List<int> li;
    List<double> ld;
    return /*error:RETURN_OF_INVALID_TYPE*/b ? li : ld;
  }
  // TODO(leafp): This case isn't handled yet.  This test checks
  // the case where two related classes are instantiated with related
  // but different types.
  Iterable<num> test2(bool b) {
    List<int> li;
    Iterable<double> id;
    int x =
        /*info:ASSIGNMENT_CAST should be error:INVALID_ASSIGNMENT*/
        b ? li : id;
    return /*warning:DOWN_CAST_COMPOSITE should be pass*/b ? li : id;
  }
}
''');
  }

  void test_leastUpperBounds_fuzzyArrows() {
    checkFile(r'''
typedef String TakesA<T>(T item);

void main() {
  TakesA<int> f;
  TakesA<dynamic> g;
  TakesA<String> h;
  g = h;
  f = /*warning:DOWN_CAST_COMPOSITE*/f ?? g;
}
''');
  }

  void test_loadLibrary() {
    addFile('''library lib1;''', name: '/lib1.dart');
    checkFile(r'''
import 'lib1.dart' deferred as lib1;
import 'dart:async' show Future;
main() {
  Future f = lib1.loadLibrary();
}''');
  }

  void test_methodOverride() {
    checkFile('''
class A {}
class B extends A {}
class C extends B {}

class Base {
  B m1(B a) => null;
  B m2(B a) => null;
  B m3(B a) => null;
  B m4(B a) => null;
  B m5(B a) => null;
  B m6(B a) => null;
}

class Child extends Base {
  /*error:INVALID_METHOD_OVERRIDE*/A m1(A value) => null;
  /*error:INVALID_METHOD_OVERRIDE*/C m2(C value) => null;
  /*error:INVALID_METHOD_OVERRIDE*/A m3(C value) => null;
  C m4(A value) => null;
  m5(value) => null;
  /*error:INVALID_METHOD_OVERRIDE*/dynamic m6(dynamic value) => null;
}
''');
  }

  void test_methodOverride_fuzzyArrows() {
    checkFile('''
abstract class A {
  bool operator ==(Object object);
}

class B implements A {}

class F {
  void f(x) {}
  void g(int x) {}
}

class G extends F {
  /*error:INVALID_METHOD_OVERRIDE*/void f(int x) {}
  void g(dynamic x) {}
}

class H implements F {
  /*error:INVALID_METHOD_OVERRIDE*/void f(int x) {}
  void g(dynamic x) {}
}
''');
  }

  void test_methodTearoffStrictArrow() {
    // Regression test for https://github.com/dart-lang/sdk/issues/26393
    checkFile(r'''
class A {
  void foo(dynamic x) {}
  void test(void f(int x)) {
    test(foo);
  }
}
    ''');
  }

  void test_mixinOverrideOfGrandInterface_interfaceOfAbstractSuperclass() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}
abstract class Base implements I1 {}

class M {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1 extends Base
    with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M {}
''');
  }

  void test_mixinOverrideOfGrandInterface_interfaceOfConcreteSuperclass() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}

class /*error:NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE*/Base
    implements I1 {}

class M {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1 extends Base
    with M {}
''');
  }

  void test_mixinOverrideOfGrandInterface_interfaceOfInterfaceOfChild() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}
abstract class I2 implements I1 {}

class M {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    extends Object with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M
    implements I2 {}
''');
  }

  void test_mixinOverrideOfGrandInterface_mixinOfInterfaceOfChild() {
    checkFile('''
class A {}
class B {}

abstract class M1 {
    m(A a);
}
abstract class I2 extends Object with M1 {}

class M {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    extends Object with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M
    implements I2 {}
''');
  }

  void test_mixinOverrideOfGrandInterface_superclassOfInterfaceOfChild() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}
abstract class I2 extends I1 {}

class M {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    extends Object with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M
    implements I2 {}
''');
  }

  void
      test_noDuplicateReportsFromOverridingInterfaces_baseTypeAndMixinOverrideSameMethodInInterface() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}

class Base {
    m(B a) {}
}

class M {
    m(B a) {}
}

// Here we want to report both, because the error location is
// different.
// TODO(sigmund): should we merge these as well?
class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    /*error:INVALID_METHOD_OVERRIDE_FROM_BASE*/extends Base
    with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M
    implements I1 {}
''');
  }

  void
      test_noDuplicateReportsFromOverridingInterfaces_twoGrandTypesOverrideSameMethodInInterface() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}

class Grandparent {
    m(B a) {}
}

class Parent1 extends Grandparent {
    m(B a) {}
}
class Parent2 extends Grandparent {}

// Note: otherwise both errors would be reported on this line
class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    /*error:INVALID_METHOD_OVERRIDE_FROM_BASE*/extends Parent1
    implements I1 {}
class /*error:INCONSISTENT_METHOD_INHERITANCE*/T2
    /*error:INVALID_METHOD_OVERRIDE_FROM_BASE*/extends Parent2
    implements I1 {}
''');
  }

  void
      test_noDuplicateReportsFromOverridingInterfaces_twoMixinsOverrideSameMethodInInterface() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}

class M1 {
    m(B a) {}
}

class M2 {
    m(B a) {}
}

// Here we want to report both, because the error location is
// different.
// TODO(sigmund): should we merge these as well?
class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1 extends Object
    with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M1,
    /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M2
    implements I1 {}
''');
  }

  void
      test_noDuplicateReportsFromOverridingInterfaces_typeAndBaseTypeOverrideSameMethodInInterface() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}

class Base {
    m(B a) {}
}

// Note: no error reported in `extends Base` to avoid duplicating
// the error in T1.
class T1 extends Base implements I1 {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}

// If there is no error in the class, we do report the error at
// the base class:
class /*error:INCONSISTENT_METHOD_INHERITANCE*/T2
    /*error:INVALID_METHOD_OVERRIDE_FROM_BASE*/extends Base
    implements I1 {}
''');
  }

  void
      test_noDuplicateReportsFromOverridingInterfaces_typeAndMixinOverrideSameMethodInInterface() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}

class M {
    m(B a) {}
}

class T1 extends Object with M implements I1 {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T2
    extends Object with /*error:INVALID_METHOD_OVERRIDE_FROM_MIXIN*/M
    implements I1 {}
''');
  }

  void
      test_noDuplicateReportsFromOverridingInterfaces_typeOverridesSomeMethodInMultipleInterfaces() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}
abstract class I2 implements I1 {
    m(A a);
}

class Base {}

class T1 implements I2 {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}
''');
  }

  void test_nullCoalescingOperator() {
    checkFile('''
class A {}
class C<T> {}
main() {
  A a, b;
  a ??= new A();
  b = b ?? new A();

  // downwards inference
  C<int> c, d;
  c ??= /*info:INFERRED_TYPE_ALLOCATION*/new C();
  d = d ?? /*info:INFERRED_TYPE_ALLOCATION*/new C();
}
''');
  }

  void test_nullCoalescingStrictArrow() {
    checkFile(r'''
bool _alwaysTrue(x) => true;
typedef bool TakesA<T>(T t);
class C<T> {
  TakesA<T> g;
  C(TakesA<T> f)
    : g = f ?? _alwaysTrue;
  C.a() : g = _alwaysTrue;
}
    ''');
  }

  void test_optionalParams() {
    // Regression test for https://github.com/dart-lang/sdk/issues/26155
    checkFile(r'''
void takesF(void f(int x)) {
  takesF(/*info:INFERRED_TYPE_CLOSURE,info:INFERRED_TYPE_CLOSURE*/([x]) { bool z = x.isEven; });
  takesF(/*info:INFERRED_TYPE_CLOSURE*/(y) { bool z = y.isEven; });
}
    ''');
  }

  void test_overrideNarrowsType() {
    addFile(r'''
class A {}
class B extends A {}

abstract class C {
  m(A a);
  n(B b);
}
abstract class D extends C {
  /*error:INVALID_METHOD_OVERRIDE*/m(B b);
  n(A a);
}
    ''');
    check(implicitCasts: false);
  }

  void test_overrideNarrowsType_legalWithChecked() {
    // Regression test for https://github.com/dart-lang/sdk/issues/25232
    _addMetaLibrary();
    checkFile(r'''
import 'meta.dart';
abstract class A { void test(A arg) { } }
abstract class B extends A { void test(@checked B arg) { } }
abstract class X implements A { }
class C extends B with X { }
class D extends B implements A { }
    ''');
  }

  void test_overrideNarrowsType_noDuplicateError() {
    // Regression test for https://github.com/dart-lang/sdk/issues/25232
    _addMetaLibrary();
    checkFile(r'''
import 'meta.dart';
abstract class A { void test(A arg) { } }
abstract class B extends A {
  /*error:INVALID_METHOD_OVERRIDE*/void test(B arg) { }
}
abstract class X implements A { }
class C extends B with X { }

// We treat "implements A" as asking for another check.
// This feels inconsistent to me.
class D /*error:INVALID_METHOD_OVERRIDE_FROM_BASE*/extends B implements A { }
    ''');
  }

  void test_privateOverride() {
    addFile(
        '''
import 'main.dart' as main;

class Base {
  var f1;
  var _f2;
  var _f3;
  get _f4 => null;

  int _m1() => null;
}

class GrandChild extends main.Child {
  /*error:INVALID_FIELD_OVERRIDE*/var _f2;
  /*error:INVALID_FIELD_OVERRIDE*/var _f3;
  var _f4;

  /*error:INVALID_METHOD_OVERRIDE*/String _m1() => null;
}
''',
        name: '/helper.dart');
    checkFile('''
import 'helper.dart' as helper;

class Child extends helper.Base {
  /*error:INVALID_FIELD_OVERRIDE*/var f1;
  var _f2;
  var _f4;

  String _m1() => null;
}
''');
  }

  void test_proxy() {
    checkFile(r'''
@proxy class C {}
@proxy class D {
  var f;
  m() => null;
  operator -() => null;
  operator +(int other) => null;
  operator [](int index) => null;
  call() => null;
}
@proxy class F implements Function { noSuchMethod(i) => 42; }


m() {
  D d = new D();
  d.m();
  d.m;
  d.f;
  -d;
  d + 7;
  d[7];
  d();

  C c = new C();
  /*info:DYNAMIC_INVOKE*/c.m();
  /*info:DYNAMIC_INVOKE*/c.m;
  /*info:DYNAMIC_INVOKE*/-c;
  /*info:DYNAMIC_INVOKE*/c + 7;
  /*info:DYNAMIC_INVOKE*/c[7];
  /*error:INVOCATION_OF_NON_FUNCTION,info:DYNAMIC_INVOKE*/c();

  F f = new F();
  /*info:DYNAMIC_INVOKE*/f();
}
    ''');
  }

  void test_redirectingConstructor() {
    checkFile('''
class A {
  A(A x) {}
  A.two() : this(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/3);
}
''');
  }

  void test_relaxedCasts() {
    checkFile('''
class A {}

class L<T> {}
class M<T> extends L<T> {}
//     L<dynamic|Object>
//    /              \
// M<dynamic|Object>  L<A>
//    \              /
//          M<A>
// In normal Dart, there are additional edges
//  from M<A> to M<dynamic>
//  from L<A> to M<dynamic>
//  from L<A> to L<dynamic>
void main() {
  L lOfDs;
  L<Object> lOfOs;
  L<A> lOfAs;

  M mOfDs;
  M<Object> mOfOs;
  M<A> mOfAs;

  {
    lOfDs = mOfDs;
    lOfDs = mOfOs;
    lOfDs = mOfAs;
    lOfDs = lOfDs;
    lOfDs = lOfOs;
    lOfDs = lOfAs;
    lOfDs = new L(); // Reset type propagation.
  }
  {
    lOfOs = mOfDs;
    lOfOs = mOfOs;
    lOfOs = mOfAs;
    lOfOs = lOfDs;
    lOfOs = lOfOs;
    lOfOs = lOfAs;
    lOfOs = new L<Object>(); // Reset type propagation.
  }
  {
    lOfAs = /*error:INVALID_ASSIGNMENT*/mOfDs;
    lOfAs = /*error:INVALID_ASSIGNMENT*/mOfOs;
    lOfAs = mOfAs;
    lOfAs = /*warning:DOWN_CAST_COMPOSITE*/lOfDs;
    lOfAs = /*info:DOWN_CAST_IMPLICIT*/lOfOs;
    lOfAs = lOfAs;
    lOfAs = new L<A>(); // Reset type propagation.
  }
  {
    mOfDs = mOfDs;
    mOfDs = mOfOs;
    mOfDs = mOfAs;
    mOfDs = /*info:DOWN_CAST_IMPLICIT*/lOfDs;
    mOfDs = /*info:DOWN_CAST_IMPLICIT*/lOfOs;
    mOfDs = /*error:INVALID_ASSIGNMENT*/lOfAs;
    mOfDs = new M(); // Reset type propagation.
  }
  {
    mOfOs = mOfDs;
    mOfOs = mOfOs;
    mOfOs = mOfAs;
    mOfOs = /*info:DOWN_CAST_IMPLICIT*/lOfDs;
    mOfOs = /*info:DOWN_CAST_IMPLICIT*/lOfOs;
    mOfOs = /*error:INVALID_ASSIGNMENT*/lOfAs;
    mOfOs = new M<Object>(); // Reset type propagation.
  }
  {
    mOfAs = /*warning:DOWN_CAST_COMPOSITE*/mOfDs;
    mOfAs = /*info:DOWN_CAST_IMPLICIT*/mOfOs;
    mOfAs = mOfAs;
    mOfAs = /*warning:DOWN_CAST_COMPOSITE*/lOfDs;
    mOfAs = /*info:DOWN_CAST_IMPLICIT*/lOfOs;
    mOfAs = /*info:DOWN_CAST_IMPLICIT*/lOfAs;
  }
}
''');
  }

  void test_setterOverride_fuzzyArrows() {
    checkFile('''
typedef void ToVoid<T>(T x);
class F {
  void set f(ToVoid<dynamic> x) {}
  void set g(ToVoid<int> x) {}
  void set h(dynamic x) {}
  void set i(int x) {}
}

class G extends F {
  /*error:INVALID_METHOD_OVERRIDE*/void set f(ToVoid<int> x) {}
  void set g(ToVoid<dynamic> x) {}
  /*error:INVALID_METHOD_OVERRIDE*/void set h(int x) {}
  void set i(dynamic x) {}
}

class H implements F {
  /*error:INVALID_METHOD_OVERRIDE*/void set f(ToVoid<int> x) {}
  void set g(ToVoid<dynamic> x) {}
  /*error:INVALID_METHOD_OVERRIDE*/void set h(int x) {}
  void set i(dynamic x) {}
}
 ''');
  }

  void test_setterReturnTypes() {
    checkFile('''
void voidFn() => null;
class A {
  set a(y) => 4;
  set b(y) => voidFn();
  void set c(y) => /*error:RETURN_OF_INVALID_TYPE*/4;
  void set d(y) => voidFn();
  /*warning:NON_VOID_RETURN_FOR_SETTER*/int set e(y) => 4;
  /*warning:NON_VOID_RETURN_FOR_SETTER*/int set f(y) =>
      /*error:RETURN_OF_INVALID_TYPE*/voidFn();
  set g(y) {return /*error:RETURN_OF_INVALID_TYPE*/4;}
  void set h(y) {return /*error:RETURN_OF_INVALID_TYPE*/4;}
  /*warning:NON_VOID_RETURN_FOR_SETTER*/int set i(y) {return 4;}
}
''');
  }

  void test_setterSetterOverride() {
    checkFile('''
class A {}
class B extends A {}
class C extends B {}

abstract class Base {
  void set f1(B value);
  void set f2(B value);
  void set f3(B value);
  void set f4(B value);
  void set f5(B value);
}

class Child extends Base {
  void set f1(A value) {}
  /*error:INVALID_METHOD_OVERRIDE*/void set f2(C value) {}
  void set f3(value) {}
  void set f4(dynamic value) {}
  set f5(B value) {}
}
''');
  }

  void test_superCallPlacement() {
    checkFile('''
class Base {
  var x;
  Base() : x = print('Base.1') { print('Base.2'); }
}

class Derived extends Base {
  var y, z;
  Derived()
      : y = print('Derived.1'),
        /*error:INVALID_SUPER_INVOCATION*/super(),
        z = print('Derived.2') {
    print('Derived.3');
  }
}

class Valid extends Base {
  var y, z;
  Valid()
      : y = print('Valid.1'),
        z = print('Valid.2'),
        super() {
    print('Valid.3');
  }
}

class AlsoValid extends Base {
  AlsoValid() : super();
}

main() => new Derived();
''');
  }

  void test_superclassOverrideOfGrandInterface_interfaceOfAbstractSuperclass() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}

abstract class Base implements I1 {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}

class T1 extends Base {
    // we consider the base class incomplete because it is
    // abstract, so we report the error here too.
    // TODO(sigmund): consider tracking overrides in a fine-grain
    // manner, then this and the double-overrides would not be
    // reported.
    /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}
''');
  }

  void test_superclassOverrideOfGrandInterface_interfaceOfConcreteSuperclass() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}

class Base implements I1 {
  /*error:INVALID_METHOD_OVERRIDE*/m(B a) {}
}

class T1 extends Base {
    m(B a) {}
}
''');
  }

  void test_superclassOverrideOfGrandInterface_interfaceOfInterfaceOfChild() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}
abstract class I2 implements I1 {}

class Base {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    /*error:INVALID_METHOD_OVERRIDE_FROM_BASE*/extends Base implements I2 {}
''');
  }

  void test_superclassOverrideOfGrandInterface_mixinOfInterfaceOfChild() {
    checkFile('''
class A {}
class B {}

abstract class M1 {
    m(A a);
}
abstract class I2 extends Object with M1 {}

class Base {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    /*error:INVALID_METHOD_OVERRIDE_FROM_BASE*/extends Base
    implements I2 {}
''');
  }

  void test_superclassOverrideOfGrandInterface_superclassOfInterfaceOfChild() {
    checkFile('''
class A {}
class B {}

abstract class I1 {
    m(A a);
}
abstract class I2 extends I1 {}

class Base {
    m(B a) {}
}

class /*error:INCONSISTENT_METHOD_INHERITANCE*/T1
    /*error:INVALID_METHOD_OVERRIDE_FROM_BASE*/extends Base
    implements I2 {}
''');
  }

  void test_superConstructor() {
    checkFile('''
class A { A(A x) {} }
class B extends A {
  B() : super(/*error:ARGUMENT_TYPE_NOT_ASSIGNABLE*/3);
}
''');
  }

  void test_ternaryOperator() {
    checkFile('''
abstract class Comparable<T> {
  int compareTo(T other);
  static int compare(Comparable a, Comparable b) => a.compareTo(b);
}
typedef int Comparator<T>(T a, T b);

typedef bool _Predicate<T>(T value);

class SplayTreeMap<K, V> {
  Comparator<K> _comparator;
  _Predicate _validKey;

  // The warning on assigning to _comparator is legitimate. Since K has
  // no bound, all we know is that it's object. _comparator's function
  // type is effectively:              (Object, Object) -> int
  // We are assigning it a fn of type: (Comparable, Comparable) -> int
  // There's no telling if that will work. For example, consider:
  //
  //     new SplayTreeMap<Uri>();
  //
  // This would end up calling .compareTo() on a Uri, which doesn't
  // define that since it doesn't implement Comparable.
  SplayTreeMap([int compare(K key1, K key2),
                bool isValidKey(potentialKey)])
    : _comparator = /*warning:DOWN_CAST_COMPOSITE*/(compare == null) ? Comparable.compare : compare,
      _validKey = (isValidKey != null) ? isValidKey : ((v) => true) {

    // NOTE: this is a down cast because isValidKey has fuzzy arrow type.
    _Predicate<Object> v = /*warning:DOWN_CAST_COMPOSITE*/(isValidKey != null)
        ? isValidKey : (/*info:INFERRED_TYPE_CLOSURE*/(_) => true);

    v = (isValidKey != null)
         ? v : (/*info:INFERRED_TYPE_CLOSURE*/(_) => true);
  }
}
void main() {
  Object obj = 42;
  dynamic dyn = 42;
  int i = 42;

  // Check the boolean conversion of the condition.
  print(/*error:NON_BOOL_CONDITION*/i ? false : true);
  print((/*info:DOWN_CAST_IMPLICIT*/obj) ? false : true);
  print((/*info:DYNAMIC_CAST*/dyn) ? false : true);
}
''');
  }

  void test_typeCheckingLiterals() {
    checkFile('''
test() {
  num n = 3;
  int i = 3;
  String s = "hello";
  {
     List<int> l = <int>[i];
     l = <int>[/*error:LIST_ELEMENT_TYPE_NOT_ASSIGNABLE*/s];
     l = <int>[/*info:DOWN_CAST_IMPLICIT*/n];
     l = <int>[i, /*info:DOWN_CAST_IMPLICIT*/n, /*error:LIST_ELEMENT_TYPE_NOT_ASSIGNABLE*/s];
  }
  {
     List l = /*info:INFERRED_TYPE_LITERAL*/[i];
     l = /*info:INFERRED_TYPE_LITERAL*/[s];
     l = /*info:INFERRED_TYPE_LITERAL*/[n];
     l = /*info:INFERRED_TYPE_LITERAL*/[i, n, s];
  }
  {
     Map<String, int> m = <String, int>{s: i};
     m = <String, int>{s: /*error:MAP_VALUE_TYPE_NOT_ASSIGNABLE*/s};
     m = <String, int>{s: /*info:DOWN_CAST_IMPLICIT*/n};
     m = <String, int>{s: i,
                       s: /*info:DOWN_CAST_IMPLICIT*/n,
                       s: /*error:MAP_VALUE_TYPE_NOT_ASSIGNABLE*/s};
  }
 // TODO(leafp): We can't currently test for key errors since the
 // error marker binds to the entire entry.
  {
     Map m = /*info:INFERRED_TYPE_LITERAL*/{s: i};
     m = /*info:INFERRED_TYPE_LITERAL*/{s: s};
     m = /*info:INFERRED_TYPE_LITERAL*/{s: n};
     m = /*info:INFERRED_TYPE_LITERAL*/
         {s: i,
          s: n,
          s: s};
     m = /*info:INFERRED_TYPE_LITERAL*/
         {i: s,
          n: s,
          s: s};
  }
}
''');
  }

  void test_typePromotionFromDynamic() {
    checkFile(r'''
f() {
  dynamic x;
  if (x is int) {
    int y = x;
    String z = /*error:INVALID_ASSIGNMENT*/x;
  }
}
g() {
  Object x;
  if (x is int) {
    int y = x;
    String z = /*error:INVALID_ASSIGNMENT*/x;
  }
}
''');
  }

  void test_typePromotionFromTypeParameter() {
    // Regression test for:
    // https://github.com/dart-lang/sdk/issues/26965
    // https://github.com/dart-lang/sdk/issues/27040
    checkFile(r'''
void f/*<T>*/(/*=T*/ object) {
  if (object is String) print(object.substring(1));
}
void g/*<T extends num>*/(/*=T*/ object) {
  if (object is int) print(object.isEven);
  if (object is String) print(/*info:DYNAMIC_INVOKE*/object.substring(1));
}
class Clonable<T> {}
class SubClonable<T> extends Clonable<T> {
  T m(T t) => t;
}
void takesSubClonable/*<A>*/(SubClonable/*<A>*/ t) {}

void h/*<T extends Clonable<T>>*/(/*=T*/ object) {
  if (/*info:NON_GROUND_TYPE_CHECK_INFO*/object is SubClonable/*<T>*/) {
    print(object.m(object));

    SubClonable/*<T>*/ s = object;
    takesSubClonable/*<T>*/(object);
    h(object);
  }
}
''');
  }

  void test_typePromotionFromTypeParameterAndInference() {
    // Regression test for:
    // https://github.com/dart-lang/sdk/issues/27040
    checkFile(r'''
void f/*<T extends num>*/(T x, T y) {
  var z = x;
  var f = () => x;
  f = () => y;
  if (x is int) {
    /*info:DYNAMIC_INVOKE*/z./*error:UNDEFINED_GETTER*/isEven;
    var q = x;
    q = /*warning:DOWN_CAST_COMPOSITE*/z;
    /*info:DYNAMIC_INVOKE*/f()./*error:UNDEFINED_GETTER*/isEven;

    // This does not capture the type `T extends int`. Instead the return type
    // is `T extends num`. What happens is we substitute {T/T} on the function
    // type, and the way it is implemented, this leads back to `T extends num`.
    // See https://github.com/dart-lang/sdk/issues/27725
    var g = () => x;
    g = f;
    /*info:DYNAMIC_INVOKE*/g()./*error:UNDEFINED_GETTER*/isEven;
    q = /*warning:DOWN_CAST_COMPOSITE*/g();
    int r = x;
  }
}
    ''');
  }

  void test_typeSubtyping_assigningClass() {
    checkFile('''
class A {}
class B extends A {}

void main() {
   dynamic y;
   Object o;
   int i = 0;
   double d = 0.0;
   num n;
   A a;
   B b;
   y = a;
   o = a;
   i = /*error:INVALID_ASSIGNMENT*/a;
   d = /*error:INVALID_ASSIGNMENT*/a;
   n = /*error:INVALID_ASSIGNMENT*/a;
   a = a;
   b = /*info:DOWN_CAST_IMPLICIT*/a;
}
''');
  }

  void test_typeSubtyping_assigningSubclass() {
    checkFile('''
class A {}
class B extends A {}
class C extends A {}

void main() {
   dynamic y;
   Object o;
   int i = 0;
   double d = 0.0;
   num n;
   A a;
   B b;
   C c;
   y = b;
   o = b;
   i = /*error:INVALID_ASSIGNMENT*/b;
   d = /*error:INVALID_ASSIGNMENT*/b;
   n = /*error:INVALID_ASSIGNMENT*/b;
   a = b;
   b = b;
   c = /*error:INVALID_ASSIGNMENT*/b;
}
''');
  }

  void test_typeSubtyping_dynamicDowncasts() {
    checkFile('''
class A {}
class B extends A {}

void main() {
   dynamic y;
   Object o;
   int i = 0;
   double d = 0.0;
   num n;
   A a;
   B b;
   o = y;
   i = /*info:DYNAMIC_CAST*/y;
   d = /*info:DYNAMIC_CAST*/y;
   n = /*info:DYNAMIC_CAST*/y;
   a = /*info:DYNAMIC_CAST*/y;
   b = /*info:DYNAMIC_CAST*/y;
}
''');
  }

  void test_typeSubtyping_dynamicIsTop() {
    checkFile('''
class A {}
class B extends A {}

void main() {
   dynamic y;
   Object o;
   int i = 0;
   double d = 0.0;
   num n;
   A a;
   B b;
   y = o;
   y = i;
   y = d;
   y = n;
   y = a;
   y = b;
}
''');
  }

  void test_typeSubtyping_interfaces() {
    checkFile('''
class A {}
class B extends A {}
class C extends A {}
class D extends B implements C {}

void main() {
   A top;
   B left;
   C right;
   D bot;
   {
     top = top;
     top = left;
     top = right;
     top = bot;
   }
   {
     left = /*info:DOWN_CAST_IMPLICIT*/top;
     left = left;
     left = /*error:INVALID_ASSIGNMENT*/right;
     left = bot;
   }
   {
     right = /*info:DOWN_CAST_IMPLICIT*/top;
     right = /*error:INVALID_ASSIGNMENT*/left;
     right = right;
     right = bot;
   }
   {
     bot = /*info:DOWN_CAST_IMPLICIT*/top;
     bot = /*info:DOWN_CAST_IMPLICIT*/left;
     bot = /*info:DOWN_CAST_IMPLICIT*/right;
     bot = bot;
   }
}
''');
  }

  void test_unaryOperators() {
    checkFile('''
class A {
  A operator ~() => null;
  A operator +(int x) => null;
  A operator -(int x) => null;
  A operator -() => null;
}
class B extends A {}
class C extends B {}

foo() => new A();

test() {
  A a = new A();
  B b = new B();
  var c = foo();
  dynamic d;

  ~a;
  (/*info:DYNAMIC_INVOKE*/~d);

  !/*error:NON_BOOL_NEGATION_EXPRESSION*/a;
  !/*info:DYNAMIC_CAST*/d;

  -a;
  (/*info:DYNAMIC_INVOKE*/-d);

  ++a;
  --a;
  (/*info:DYNAMIC_INVOKE*/++d);
  (/*info:DYNAMIC_INVOKE*/--d);

  a++;
  a--;
  (/*info:DYNAMIC_INVOKE*/d++);
  (/*info:DYNAMIC_INVOKE*/d--);

  ++/*info:DOWN_CAST_IMPLICIT_ASSIGN*/b;
  --/*info:DOWN_CAST_IMPLICIT_ASSIGN*/b;
  /*info:DOWN_CAST_IMPLICIT_ASSIGN*/b++;
  /*info:DOWN_CAST_IMPLICIT_ASSIGN*/b--;

  takesC(C c) => null;
  takesC(/*info:DOWN_CAST_IMPLICIT*/++/*info:DOWN_CAST_IMPLICIT_ASSIGN*/b);
  takesC(/*info:DOWN_CAST_IMPLICIT*/--/*info:DOWN_CAST_IMPLICIT_ASSIGN*/b);
  takesC(/*info:DOWN_CAST_IMPLICIT,info:DOWN_CAST_IMPLICIT_ASSIGN*/b++);
  takesC(/*info:DOWN_CAST_IMPLICIT,info:DOWN_CAST_IMPLICIT_ASSIGN*/b--);
}''');
  }

  void test_unboundRedirectingConstructor() {
    // This is a regression test for https://github.com/dart-lang/sdk/issues/25071
    checkFile('''
class Foo {
  Foo() : /*error:REDIRECT_GENERATIVE_TO_MISSING_CONSTRUCTOR*/this.init();
}
 ''');
  }

  void test_unboundTypeName() {
    checkFile('''
void main() {
   /*error:UNDEFINED_CLASS*/AToB y;
}
''');
  }

  void test_unboundVariable() {
    checkFile('''
void main() {
   dynamic y = /*error:UNDEFINED_IDENTIFIER*/unboundVariable;
}
''');
  }

  void test_voidSubtyping() {
    // Regression test for https://github.com/dart-lang/sdk/issues/25069
    checkFile('''
typedef int Foo();
void foo() {}
void main () {
  Foo x = /*error:INVALID_ASSIGNMENT,info:USE_OF_VOID_RESULT*/foo();
}
''');
  }
}