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Preserve literal types in contextual unions (microsoft#19966)
* Cherrypick non-comparability related changes from prolific literals PR * Renames and other style changes * Accept changes to new tests * Exclude the domain root from contextual typing literals except for type variables * Readd simple preservation fix * Add huge map test * Revert changes to widening on destructuring initalizers * Use tristate for subtype-reduction type * Rename type and argument * Move longer-running test to user suite
1 parent d01f4d1 commit eba15b5

14 files changed

Lines changed: 11007 additions & 49 deletions

‎src/compiler/checker.ts‎

Lines changed: 47 additions & 43 deletions
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‎src/compiler/types.ts‎

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2787,7 +2787,7 @@ namespace ts {
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/* @internal */ getNullType(): Type;
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/* @internal */ getESSymbolType(): Type;
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/* @internal */ getNeverType(): Type;
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/* @internal */ getUnionType(types: Type[], subtypeReduction?: boolean): Type;
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/* @internal */ getUnionType(types: Type[], subtypeReduction?: UnionReduction): Type;
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/* @internal */ createArrayType(elementType: Type): Type;
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/* @internal */ createPromiseType(type: Type): Type;
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@@ -2842,6 +2842,13 @@ namespace ts {
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/* @internal */ getAccessibleSymbolChain(symbol: Symbol, enclosingDeclaration: Node | undefined, meaning: SymbolFlags, useOnlyExternalAliasing: boolean): Symbol[] | undefined;
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}
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2845+
/* @internal */
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export const enum UnionReduction {
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None = 0,
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Literal,
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Subtype
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}
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export enum NodeBuilderFlags {
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None = 0,
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// Options

‎src/services/codefixes/inferFromUsage.ts‎

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -305,7 +305,7 @@ namespace ts.codefix {
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}
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}
307307
if (types.length) {
308-
const type = checker.getWidenedType(checker.getUnionType(types, /*subtypeReduction*/ true));
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const type = checker.getWidenedType(checker.getUnionType(types, UnionReduction.Subtype));
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paramTypes[parameterIndex] = isRestParameter ? checker.createArrayType(type) : type;
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}
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}
@@ -542,12 +542,12 @@ namespace ts.codefix {
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return checker.getStringType();
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}
544544
else if (usageContext.candidateTypes) {
545-
return checker.getWidenedType(checker.getUnionType(map(usageContext.candidateTypes, t => checker.getBaseTypeOfLiteralType(t)), /*subtypeReduction*/ true));
545+
return checker.getWidenedType(checker.getUnionType(map(usageContext.candidateTypes, t => checker.getBaseTypeOfLiteralType(t)), UnionReduction.Subtype));
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}
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else if (usageContext.properties && hasCallContext(usageContext.properties.get("then" as __String))) {
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const paramType = getParameterTypeFromCallContexts(0, usageContext.properties.get("then" as __String).callContexts, /*isRestParameter*/ false, checker);
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const types = paramType.getCallSignatures().map(c => c.getReturnType());
550-
return checker.createPromiseType(types.length ? checker.getUnionType(types, /*subtypeReduction*/ true) : checker.getAnyType());
550+
return checker.createPromiseType(types.length ? checker.getUnionType(types, UnionReduction.Subtype) : checker.getAnyType());
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}
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else if (usageContext.properties && hasCallContext(usageContext.properties.get("push" as __String))) {
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return checker.createArrayType(getParameterTypeFromCallContexts(0, usageContext.properties.get("push" as __String).callContexts, /*isRestParameter*/ false, checker));
@@ -610,7 +610,7 @@ namespace ts.codefix {
610610
}
611611

612612
if (types.length) {
613-
const type = checker.getWidenedType(checker.getUnionType(types, /*subtypeReduction*/ true));
613+
const type = checker.getWidenedType(checker.getUnionType(types, UnionReduction.Subtype));
614614
return isRestParameter ? checker.createArrayType(type) : type;
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}
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return undefined;

‎tests/baselines/reference/contextualTypeShouldBeLiteral.js‎

Lines changed: 136 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,136 @@
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//// [contextualTypeShouldBeLiteral.ts]
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interface X {
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type: 'x';
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value: string;
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method(): void;
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}
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interface Y {
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type: 'y';
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value: 'none' | 'done';
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method(): void;
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}
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function foo(bar: X | Y) { }
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foo({
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type: 'y',
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value: 'done',
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method() {
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this;
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this.type;
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this.value;
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}
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});
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interface X2 {
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type1: 'x';
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value: string;
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method(): void;
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}
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interface Y2 {
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type2: 'y';
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value: 'none' | 'done';
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method(): void;
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}
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function foo2(bar: X2 | Y2) { }
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foo2({
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type2: 'y',
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value: 'done',
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method() {
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this;
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this.value;
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}
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});
48+
49+
interface X3 {
50+
type: 'x';
51+
value: 1 | 2 | 3;
52+
xtra: number;
53+
}
54+
55+
interface Y3 {
56+
type: 'y';
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value: 11 | 12 | 13;
58+
ytra: number;
59+
}
60+
61+
let xy: X3 | Y3 = {
62+
type: 'y',
63+
value: 11,
64+
ytra: 12
65+
};
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xy;
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69+
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interface LikeA {
71+
x: 'x';
72+
y: 'y';
73+
value: string;
74+
method(): void;
75+
}
76+
77+
interface LikeB {
78+
x: 'xx';
79+
y: 'yy';
80+
value: number;
81+
method(): void;
82+
}
83+
84+
let xyz: LikeA | LikeB = {
85+
x: 'x',
86+
y: 'y',
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value: "foo",
88+
method() {
89+
this;
90+
this.x;
91+
this.y;
92+
this.value;
93+
}
94+
};
95+
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xyz;
97+
98+
//// [contextualTypeShouldBeLiteral.js]
99+
"use strict";
100+
function foo(bar) { }
101+
foo({
102+
type: 'y',
103+
value: 'done',
104+
method: function () {
105+
this;
106+
this.type;
107+
this.value;
108+
}
109+
});
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function foo2(bar) { }
111+
foo2({
112+
type2: 'y',
113+
value: 'done',
114+
method: function () {
115+
this;
116+
this.value;
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}
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});
119+
var xy = {
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type: 'y',
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value: 11,
122+
ytra: 12
123+
};
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xy;
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var xyz = {
126+
x: 'x',
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y: 'y',
128+
value: "foo",
129+
method: function () {
130+
this;
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this.x;
132+
this.y;
133+
this.value;
134+
}
135+
};
136+
xyz;

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