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Merge branch 'master' into definiteAssignmentAssertions

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This commit is contained in:
Anders Hejlsberg 2017-11-20 15:09:50 -08:00
parent 02fd11e3bd e684f30d18
commit 9b9f3f25d7
5 changed files with 296 additions and 0 deletions
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2
src/compiler/checker.ts
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@ -8869,6 +8869,7 @@ namespace ts {
// An object type S is considered to be derived from an object type T if
// S is a union type and every constituent of S is derived from T,
// T is a union type and S is derived from at least one constituent of T, or
// S is a type variable with a base constraint that is derived from T,
// T is one of the global types Object and Function and S is a subtype of T, or
// T occurs directly or indirectly in an 'extends' clause of S.
// Note that this check ignores type parameters and only considers the
@ -8876,6 +8877,7 @@ namespace ts {
function isTypeDerivedFrom(source: Type, target: Type): boolean {
return source.flags & TypeFlags.Union ? every((<UnionType>source).types, t => isTypeDerivedFrom(t, target)) :
target.flags & TypeFlags.Union ? some((<UnionType>target).types, t => isTypeDerivedFrom(source, t)) :
source.flags & TypeFlags.TypeVariable ? isTypeDerivedFrom(getBaseConstraintOfType(source) || emptyObjectType, target) :
target === globalObjectType || target === globalFunctionType ? isTypeSubtypeOf(source, target) :
hasBaseType(source, getTargetType(target));
}

79
tests/baselines/reference/narrowingConstrainedTypeVariable.js Normal file
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@ -0,0 +1,79 @@
//// [narrowingConstrainedTypeVariable.ts]
// Repro from #20138
class C { }
function f1<T extends C>(v: T | string): void {
if (v instanceof C) {
const x: T = v;
}
else {
const s: string = v;
}
}
class D { }
function f2<T extends C, U extends D>(v: T | U) {
if (v instanceof C) {
const x: T = v;
}
else {
const y: U = v;
}
}
class E { x: string | undefined }
function f3<T extends E>(v: T | { x: string }) {
if (v instanceof E) {
const x: T = v;
}
else {
const y: { x: string } = v;
}
}
//// [narrowingConstrainedTypeVariable.js]
"use strict";
// Repro from #20138
var C = /** @class */ (function () {
function C() {
}
return C;
}());
function f1(v) {
if (v instanceof C) {
var x = v;
}
else {
var s = v;
}
}
var D = /** @class */ (function () {
function D() {
}
return D;
}());
function f2(v) {
if (v instanceof C) {
var x = v;
}
else {
var y = v;
}
}
var E = /** @class */ (function () {
function E() {
}
return E;
}());
function f3(v) {
if (v instanceof E) {
var x = v;
}
else {
var y = v;
}
}

88
tests/baselines/reference/narrowingConstrainedTypeVariable.symbols Normal file
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@ -0,0 +1,88 @@
=== tests/cases/conformance/types/typeRelationships/instanceOf/narrowingConstrainedTypeVariable.ts ===
// Repro from #20138
class C { }
>C : Symbol(C, Decl(narrowingConstrainedTypeVariable.ts, 0, 0))
function f1<T extends C>(v: T | string): void {
>f1 : Symbol(f1, Decl(narrowingConstrainedTypeVariable.ts, 2, 11))
>T : Symbol(T, Decl(narrowingConstrainedTypeVariable.ts, 4, 12))
>C : Symbol(C, Decl(narrowingConstrainedTypeVariable.ts, 0, 0))
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 4, 25))
>T : Symbol(T, Decl(narrowingConstrainedTypeVariable.ts, 4, 12))
if (v instanceof C) {
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 4, 25))
>C : Symbol(C, Decl(narrowingConstrainedTypeVariable.ts, 0, 0))
const x: T = v;
>x : Symbol(x, Decl(narrowingConstrainedTypeVariable.ts, 6, 13))
>T : Symbol(T, Decl(narrowingConstrainedTypeVariable.ts, 4, 12))
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 4, 25))
}
else {
const s: string = v;
>s : Symbol(s, Decl(narrowingConstrainedTypeVariable.ts, 9, 13))
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 4, 25))
}
}
class D { }
>D : Symbol(D, Decl(narrowingConstrainedTypeVariable.ts, 11, 1))
function f2<T extends C, U extends D>(v: T | U) {
>f2 : Symbol(f2, Decl(narrowingConstrainedTypeVariable.ts, 13, 11))
>T : Symbol(T, Decl(narrowingConstrainedTypeVariable.ts, 15, 12))
>C : Symbol(C, Decl(narrowingConstrainedTypeVariable.ts, 0, 0))
>U : Symbol(U, Decl(narrowingConstrainedTypeVariable.ts, 15, 24))
>D : Symbol(D, Decl(narrowingConstrainedTypeVariable.ts, 11, 1))
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 15, 38))
>T : Symbol(T, Decl(narrowingConstrainedTypeVariable.ts, 15, 12))
>U : Symbol(U, Decl(narrowingConstrainedTypeVariable.ts, 15, 24))
if (v instanceof C) {
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 15, 38))
>C : Symbol(C, Decl(narrowingConstrainedTypeVariable.ts, 0, 0))
const x: T = v;
>x : Symbol(x, Decl(narrowingConstrainedTypeVariable.ts, 17, 13))
>T : Symbol(T, Decl(narrowingConstrainedTypeVariable.ts, 15, 12))
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 15, 38))
}
else {
const y: U = v;
>y : Symbol(y, Decl(narrowingConstrainedTypeVariable.ts, 20, 13))
>U : Symbol(U, Decl(narrowingConstrainedTypeVariable.ts, 15, 24))
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 15, 38))
}
}
class E { x: string | undefined }
>E : Symbol(E, Decl(narrowingConstrainedTypeVariable.ts, 22, 1))
>x : Symbol(E.x, Decl(narrowingConstrainedTypeVariable.ts, 24, 9))
function f3<T extends E>(v: T | { x: string }) {
>f3 : Symbol(f3, Decl(narrowingConstrainedTypeVariable.ts, 24, 33))
>T : Symbol(T, Decl(narrowingConstrainedTypeVariable.ts, 26, 12))
>E : Symbol(E, Decl(narrowingConstrainedTypeVariable.ts, 22, 1))
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 26, 25))
>T : Symbol(T, Decl(narrowingConstrainedTypeVariable.ts, 26, 12))
>x : Symbol(x, Decl(narrowingConstrainedTypeVariable.ts, 26, 33))
if (v instanceof E) {
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 26, 25))
>E : Symbol(E, Decl(narrowingConstrainedTypeVariable.ts, 22, 1))
const x: T = v;
>x : Symbol(x, Decl(narrowingConstrainedTypeVariable.ts, 28, 13))
>T : Symbol(T, Decl(narrowingConstrainedTypeVariable.ts, 26, 12))
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 26, 25))
}
else {
const y: { x: string } = v;
>y : Symbol(y, Decl(narrowingConstrainedTypeVariable.ts, 31, 13))
>x : Symbol(x, Decl(narrowingConstrainedTypeVariable.ts, 31, 18))
>v : Symbol(v, Decl(narrowingConstrainedTypeVariable.ts, 26, 25))
}
}

91
tests/baselines/reference/narrowingConstrainedTypeVariable.types Normal file
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@ -0,0 +1,91 @@
=== tests/cases/conformance/types/typeRelationships/instanceOf/narrowingConstrainedTypeVariable.ts ===
// Repro from #20138
class C { }
>C : C
function f1<T extends C>(v: T | string): void {
>f1 : <T extends C>(v: string | T) => void
>T : T
>C : C
>v : string | T
>T : T
if (v instanceof C) {
>v instanceof C : boolean
>v : string | T
>C : typeof C
const x: T = v;
>x : T
>T : T
>v : T
}
else {
const s: string = v;
>s : string
>v : string
}
}
class D { }
>D : D
function f2<T extends C, U extends D>(v: T | U) {
>f2 : <T extends C, U extends D>(v: T | U) => void
>T : T
>C : C
>U : U
>D : D
>v : T | U
>T : T
>U : U
if (v instanceof C) {
>v instanceof C : boolean
>v : T | U
>C : typeof C
const x: T = v;
>x : T
>T : T
>v : T
}
else {
const y: U = v;
>y : U
>U : U
>v : U
}
}
class E { x: string | undefined }
>E : E
>x : string | undefined
function f3<T extends E>(v: T | { x: string }) {
>f3 : <T extends E>(v: T | { x: string; }) => void
>T : T
>E : E
>v : T | { x: string; }
>T : T
>x : string
if (v instanceof E) {
>v instanceof E : boolean
>v : T | { x: string; }
>E : typeof E
const x: T = v;
>x : T
>T : T
>v : T
}
else {
const y: { x: string } = v;
>y : { x: string; }
>x : string
>v : { x: string; }
}
}

36
tests/cases/conformance/types/typeRelationships/instanceOf/narrowingConstrainedTypeVariable.ts Normal file
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@ -0,0 +1,36 @@
// @strict: true
// Repro from #20138
class C { }
function f1<T extends C>(v: T | string): void {
if (v instanceof C) {
const x: T = v;
}
else {
const s: string = v;
}
}
class D { }
function f2<T extends C, U extends D>(v: T | U) {
if (v instanceof C) {
const x: T = v;
}
else {
const y: U = v;
}
}
class E { x: string | undefined }
function f3<T extends E>(v: T | { x: string }) {
if (v instanceof E) {
const x: T = v;
}
else {
const y: { x: string } = v;
}
}