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Don't use a cached union/intersection type if there is an aliasSymbol #17349

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Don't use a cached union/intersection type if there is an aliasSymbol #17349

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32 changes: 26 additions & 6 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -7344,17 +7344,27 @@ namespace ts {
if (types.length === 1) {
return types[0];
}
if (aliasSymbol) {
// Don't reuse types that would have different `aliasSymbol`s.
return create();
}

const id = getTypeListId(types);
let type = unionTypes.get(id);
if (!type) {
const propagatedFlags = getPropagatingFlagsOfTypes(types, /*excludeKinds*/ TypeFlags.Nullable);
type = <UnionType>createType(TypeFlags.Union | propagatedFlags);
type = create();
unionTypes.set(id, type);
}
return type;

function create() {
const propagatedFlags = getPropagatingFlagsOfTypes(types, /*excludeKinds*/ TypeFlags.Nullable);
const type = <UnionType>createType(TypeFlags.Union | propagatedFlags);
type.types = types;
type.aliasSymbol = aliasSymbol;
type.aliasTypeArguments = aliasTypeArguments;
return type;
}
return type;
}

function getTypeFromUnionTypeNode(node: UnionTypeNode): Type {
Expand Down Expand Up @@ -7437,17 +7447,27 @@ namespace ts {
return getUnionType(map(unionType.types, t => getIntersectionType(replaceElement(typeSet, unionIndex, t))),
/*subtypeReduction*/ false, aliasSymbol, aliasTypeArguments);
}
if (aliasSymbol) {
// Don't reuse types that would have different `aliasSymbol`s.
return create();
}

const id = getTypeListId(typeSet);
let type = intersectionTypes.get(id);
if (!type) {
const propagatedFlags = getPropagatingFlagsOfTypes(typeSet, /*excludeKinds*/ TypeFlags.Nullable);
type = <IntersectionType>createType(TypeFlags.Intersection | propagatedFlags);
type = create();
intersectionTypes.set(id, type);
}
return type;

function create(): IntersectionType {
const propagatedFlags = getPropagatingFlagsOfTypes(typeSet, /*excludeKinds*/ TypeFlags.Nullable);
const type = <IntersectionType>createType(TypeFlags.Intersection | propagatedFlags);
type.types = typeSet;
type.aliasSymbol = aliasSymbol;
type.aliasTypeArguments = aliasTypeArguments;
return type;
}
return type;
}

function getTypeFromIntersectionTypeNode(node: IntersectionTypeNode): Type {
Expand Down
16 changes: 8 additions & 8 deletions tests/baselines/reference/booleanLiteralTypes1.types
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@@ -1,32 +1,32 @@
=== tests/cases/conformance/types/literal/booleanLiteralTypes1.ts ===
type A1 = true | false;
>A1 : boolean
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This behaviour is intended. I don't know that it's super important. It's probably even less important that

type A = { a }
type B = { b }
type T = A | B
type U = A | B
declare var t: T
declare var u: U

should also print either T or U (or A | B) for both t and u.

It's more important that:

declare var x: true | false

prints 'boolean' for the type of x

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@ahejlsberg can you weigh in on true | false and boolean being equivalent to type B = true | false ?

>A1 : A1
>true : true
>false : false

type A2 = false | true;
>A2 : boolean
>A2 : A2
>false : false
>true : true

function f1() {
>f1 : () => void

var a: A1;
>a : boolean
>A1 : boolean
>a : A1
>A1 : A1

var a: A2;
>a : boolean
>A2 : boolean
>a : A1
>A2 : A2

var a: true | false;
>a : boolean
>a : A1
>true : true
>false : false

var a: false | true;
>a : boolean
>a : A1
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@ghost ghost Jul 25, 2017 •
edited by ghost
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This change looked wrong until I realized that this is the fourth declaration of a, and the first declaration has type A1, which is the type shown here.
There is a test below showing that a variable whose only declaration is of type true | false will still print as boolean.

>false : false
>true : true
}
Expand Down
16 changes: 8 additions & 8 deletions tests/baselines/reference/booleanLiteralTypes2.types
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@@ -1,32 +1,32 @@
=== tests/cases/conformance/types/literal/booleanLiteralTypes2.ts ===
type A1 = true | false;
>A1 : boolean
>A1 : A1
>true : true
>false : false

type A2 = false | true;
>A2 : boolean
>A2 : A2
>false : false
>true : true

function f1() {
>f1 : () => void

var a: A1;
>a : boolean
>A1 : boolean
>a : A1
>A1 : A1

var a: A2;
>a : boolean
>A2 : boolean
>a : A1
>A2 : A2

var a: true | false;
>a : boolean
>a : A1
>true : true
>false : false

var a: false | true;
>a : boolean
>a : A1
>false : false
>true : true
}
Expand Down
3 changes: 1 addition & 2 deletions tests/baselines/reference/declarationEmitInferedTypeAlias5.js
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Expand Up @@ -25,6 +25,5 @@ exports.v = v;
//// [0.d.ts]
export declare type Data = string | boolean;
//// [1.d.ts]
import * as Z from "./0";
declare let v: Z.Data;
declare let v: string | boolean;
export { v };
4 changes: 2 additions & 2 deletions tests/baselines/reference/declarationEmitInferedTypeAlias5.types
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Expand Up @@ -13,11 +13,11 @@ import * as Z from "./0"

//let v2: Z.Data;
let v = "str" || true;
>v : Z.Data
>v : string | boolean
>"str" || true : true | "str"
>"str" : "str"
>true : true

export { v }
>v : Z.Data
>v : string | boolean

54 changes: 27 additions & 27 deletions tests/baselines/reference/enumLiteralTypes1.types
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Expand Up @@ -13,14 +13,14 @@ type YesNo = Choice.Yes | Choice.No;
>No : Choice.No

type NoYes = Choice.No | Choice.Yes;
>NoYes : YesNo
>NoYes : NoYes
>Choice : any
>No : Choice.No
>Choice : any
>Yes : Choice.Yes

type UnknownYesNo = Choice.Unknown | Choice.Yes | Choice.No;
>UnknownYesNo : Choice
>UnknownYesNo : UnknownYesNo
>Choice : any
>Unknown : Choice.Unknown
>Choice : any
Expand All @@ -37,7 +37,7 @@ function f1() {

var a: NoYes;
>a : YesNo
>NoYes : YesNo
>NoYes : NoYes

var a: Choice.Yes | Choice.No;
>a : YesNo
Expand All @@ -55,17 +55,17 @@ function f1() {
}

function f2(a: YesNo, b: UnknownYesNo, c: Choice) {
>f2 : (a: YesNo, b: Choice, c: Choice) => void
>f2 : (a: YesNo, b: UnknownYesNo, c: Choice) => void
>a : YesNo
>YesNo : YesNo
>b : Choice
>UnknownYesNo : Choice
>b : UnknownYesNo
>UnknownYesNo : UnknownYesNo
>c : Choice
>Choice : Choice

b = a;
>b = a : YesNo
>b : Choice
>b : UnknownYesNo
>a : YesNo

c = a;
Expand All @@ -74,9 +74,9 @@ function f2(a: YesNo, b: UnknownYesNo, c: Choice) {
>a : YesNo

c = b;
>c = b : YesNo
>c = b : Choice.Yes | Choice.No
>c : Choice
>b : YesNo
>b : Choice.Yes | Choice.No
}

function f3(a: Choice.Yes, b: YesNo) {
Expand Down Expand Up @@ -234,11 +234,11 @@ declare function g(x: Choice): number;
>Choice : Choice

function f5(a: YesNo, b: UnknownYesNo, c: Choice) {
>f5 : (a: YesNo, b: Choice, c: Choice) => void
>f5 : (a: YesNo, b: UnknownYesNo, c: Choice) => void
>a : YesNo
>YesNo : YesNo
>b : Choice
>UnknownYesNo : Choice
>b : UnknownYesNo
>UnknownYesNo : UnknownYesNo
>c : Choice
>Choice : Choice

Expand Down Expand Up @@ -268,7 +268,7 @@ function f5(a: YesNo, b: UnknownYesNo, c: Choice) {
>z4 : number
>g(b) : number
>g : { (x: Choice.Yes): string; (x: Choice.No): boolean; (x: Choice): number; }
>b : Choice
>b : UnknownYesNo

var z5 = g(c);
>z5 : number
Expand Down Expand Up @@ -336,30 +336,30 @@ function f11(x: YesNo) {
}

function f12(x: UnknownYesNo) {
>f12 : (x: Choice) => void
>x : Choice
>UnknownYesNo : Choice
>f12 : (x: UnknownYesNo) => void
>x : UnknownYesNo
>UnknownYesNo : UnknownYesNo

if (x) {
>x : Choice
>x : UnknownYesNo

x;
>x : YesNo
>x : Choice.Yes | Choice.No
}
else {
x;
>x : Choice
>x : UnknownYesNo
}
}

function f13(x: UnknownYesNo) {
>f13 : (x: Choice) => void
>x : Choice
>UnknownYesNo : Choice
>f13 : (x: UnknownYesNo) => void
>x : UnknownYesNo
>UnknownYesNo : UnknownYesNo

if (x === Choice.Yes) {
>x === Choice.Yes : boolean
>x : Choice
>x : UnknownYesNo
>Choice.Yes : Choice.Yes
>Choice : typeof Choice
>Yes : Choice.Yes
Expand Down Expand Up @@ -394,9 +394,9 @@ function f20(x: Item) {
>Item : Item

switch (x.kind) {
>x.kind : YesNo
>x.kind : Choice.Yes | Choice.No
>x : Item
>kind : YesNo
>kind : Choice.Yes | Choice.No

case Choice.Yes: return x.a;
>Choice.Yes : Choice.Yes
Expand All @@ -422,9 +422,9 @@ function f21(x: Item) {
>Item : Item

switch (x.kind) {
>x.kind : YesNo
>x.kind : Choice.Yes | Choice.No
>x : Item
>kind : YesNo
>kind : Choice.Yes | Choice.No

case Choice.Yes: return x.a;
>Choice.Yes : Choice.Yes
Expand Down
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