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Merge pull request #10920 from Microsoft/fixLiteralUnionInference
Fix literal union type inference
2 parents 21c2c89 + 832295d commit bbf80a7

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6 files changed

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lines changed

6 files changed

+277
-12
lines changed

‎src/compiler/checker.ts

Lines changed: 14 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -7603,16 +7603,24 @@ namespace ts {
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}
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return;
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}
7606-
// Find each target constituent type that has an identically matching source
7607-
// constituent type, and for each such target constituent type infer from the type to
7608-
// itself. When inferring from a type to itself we effectively find all type parameter
7609-
// occurrences within that type and infer themselves as their type arguments.
7606+
// Find each source constituent type that has an identically matching target constituent
7607+
// type, and for each such type infer from the type to itself. When inferring from a
7608+
// type to itself we effectively find all type parameter occurrences within that type
7609+
// and infer themselves as their type arguments. We have special handling for numeric
7610+
// and string literals because the number and string types are not represented as unions
7611+
// of all their possible values.
76107612
let matchingTypes: Type[];
7611-
for (const t of (<UnionOrIntersectionType>target).types) {
7612-
if (typeIdenticalToSomeType(t, (<UnionOrIntersectionType>source).types)) {
7613+
for (const t of (<UnionOrIntersectionType>source).types) {
7614+
if (typeIdenticalToSomeType(t, (<UnionOrIntersectionType>target).types)) {
76137615
(matchingTypes || (matchingTypes = [])).push(t);
76147616
inferFromTypes(t, t);
76157617
}
7618+
else if (t.flags & (TypeFlags.NumberLiteral | TypeFlags.StringLiteral)) {
7619+
const b = getBaseTypeOfLiteralType(t);
7620+
if (typeIdenticalToSomeType(b, (<UnionOrIntersectionType>target).types)) {
7621+
(matchingTypes || (matchingTypes = [])).push(t, b);
7622+
}
7623+
}
76167624
}
76177625
// Next, to improve the quality of inferences, reduce the source and target types by
76187626
// removing the identically matched constituents. For example, when inferring from

‎tests/baselines/reference/typeInferenceLiteralUnion.js

Lines changed: 59 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,59 @@
1+
//// [typeInferenceLiteralUnion.ts]
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// Repro from #10901
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/**
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* Administrivia: JavaScript primitive types and Date
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*/
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export type Primitive = number | string | boolean | Date;
7+
8+
/**
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* Administrivia: anything with a valueOf(): number method is comparable, so we allow it in numeric operations
10+
*/
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interface Numeric {
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valueOf(): number;
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}
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// Not very useful, but meets Numeric
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class NumCoercible {
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public a: number;
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constructor(a: number) {
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this.a = a;
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}
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public valueOf() {
23+
return this.a;
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}
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}
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/**
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* Return the min and max simultaneously.
29+
*/
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export function extent<T extends Numeric>(array: Array<T | Primitive>): [T | Primitive, T | Primitive] | [undefined, undefined] {
31+
return [undefined, undefined];
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}
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34+
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let extentMixed: [Primitive | NumCoercible, Primitive | NumCoercible] | [undefined, undefined];
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extentMixed = extent([new NumCoercible(10), 13, '12', true]);
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38+
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//// [typeInferenceLiteralUnion.js]
40+
"use strict";
41+
// Not very useful, but meets Numeric
42+
var NumCoercible = (function () {
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function NumCoercible(a) {
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this.a = a;
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}
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NumCoercible.prototype.valueOf = function () {
47+
return this.a;
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};
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return NumCoercible;
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}());
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/**
52+
* Return the min and max simultaneously.
53+
*/
54+
function extent(array) {
55+
return [undefined, undefined];
56+
}
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exports.extent = extent;
58+
var extentMixed;
59+
extentMixed = extent([new NumCoercible(10), 13, '12', true]);

‎tests/baselines/reference/typeInferenceLiteralUnion.symbols

Lines changed: 79 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,79 @@
1+
=== tests/cases/compiler/typeInferenceLiteralUnion.ts ===
2+
// Repro from #10901
3+
/**
4+
* Administrivia: JavaScript primitive types and Date
5+
*/
6+
export type Primitive = number | string | boolean | Date;
7+
>Primitive : Symbol(Primitive, Decl(typeInferenceLiteralUnion.ts, 0, 0))
8+
>Date : Symbol(Date, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
9+
10+
/**
11+
* Administrivia: anything with a valueOf(): number method is comparable, so we allow it in numeric operations
12+
*/
13+
interface Numeric {
14+
>Numeric : Symbol(Numeric, Decl(typeInferenceLiteralUnion.ts, 4, 57))
15+
16+
valueOf(): number;
17+
>valueOf : Symbol(Numeric.valueOf, Decl(typeInferenceLiteralUnion.ts, 9, 19))
18+
}
19+
20+
// Not very useful, but meets Numeric
21+
class NumCoercible {
22+
>NumCoercible : Symbol(NumCoercible, Decl(typeInferenceLiteralUnion.ts, 11, 1))
23+
24+
public a: number;
25+
>a : Symbol(NumCoercible.a, Decl(typeInferenceLiteralUnion.ts, 14, 20))
26+
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constructor(a: number) {
28+
>a : Symbol(a, Decl(typeInferenceLiteralUnion.ts, 17, 16))
29+
30+
this.a = a;
31+
>this.a : Symbol(NumCoercible.a, Decl(typeInferenceLiteralUnion.ts, 14, 20))
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>this : Symbol(NumCoercible, Decl(typeInferenceLiteralUnion.ts, 11, 1))
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>a : Symbol(NumCoercible.a, Decl(typeInferenceLiteralUnion.ts, 14, 20))
34+
>a : Symbol(a, Decl(typeInferenceLiteralUnion.ts, 17, 16))
35+
}
36+
public valueOf() {
37+
>valueOf : Symbol(NumCoercible.valueOf, Decl(typeInferenceLiteralUnion.ts, 19, 5))
38+
39+
return this.a;
40+
>this.a : Symbol(NumCoercible.a, Decl(typeInferenceLiteralUnion.ts, 14, 20))
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>this : Symbol(NumCoercible, Decl(typeInferenceLiteralUnion.ts, 11, 1))
42+
>a : Symbol(NumCoercible.a, Decl(typeInferenceLiteralUnion.ts, 14, 20))
43+
}
44+
}
45+
46+
/**
47+
* Return the min and max simultaneously.
48+
*/
49+
export function extent<T extends Numeric>(array: Array<T | Primitive>): [T | Primitive, T | Primitive] | [undefined, undefined] {
50+
>extent : Symbol(extent, Decl(typeInferenceLiteralUnion.ts, 23, 1))
51+
>T : Symbol(T, Decl(typeInferenceLiteralUnion.ts, 28, 23))
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>Numeric : Symbol(Numeric, Decl(typeInferenceLiteralUnion.ts, 4, 57))
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>array : Symbol(array, Decl(typeInferenceLiteralUnion.ts, 28, 42))
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>Array : Symbol(Array, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
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>T : Symbol(T, Decl(typeInferenceLiteralUnion.ts, 28, 23))
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>Primitive : Symbol(Primitive, Decl(typeInferenceLiteralUnion.ts, 0, 0))
57+
>T : Symbol(T, Decl(typeInferenceLiteralUnion.ts, 28, 23))
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>Primitive : Symbol(Primitive, Decl(typeInferenceLiteralUnion.ts, 0, 0))
59+
>T : Symbol(T, Decl(typeInferenceLiteralUnion.ts, 28, 23))
60+
>Primitive : Symbol(Primitive, Decl(typeInferenceLiteralUnion.ts, 0, 0))
61+
62+
return [undefined, undefined];
63+
>undefined : Symbol(undefined)
64+
>undefined : Symbol(undefined)
65+
}
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67+
68+
let extentMixed: [Primitive | NumCoercible, Primitive | NumCoercible] | [undefined, undefined];
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>extentMixed : Symbol(extentMixed, Decl(typeInferenceLiteralUnion.ts, 33, 3))
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>Primitive : Symbol(Primitive, Decl(typeInferenceLiteralUnion.ts, 0, 0))
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>NumCoercible : Symbol(NumCoercible, Decl(typeInferenceLiteralUnion.ts, 11, 1))
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>Primitive : Symbol(Primitive, Decl(typeInferenceLiteralUnion.ts, 0, 0))
73+
>NumCoercible : Symbol(NumCoercible, Decl(typeInferenceLiteralUnion.ts, 11, 1))
74+
75+
extentMixed = extent([new NumCoercible(10), 13, '12', true]);
76+
>extentMixed : Symbol(extentMixed, Decl(typeInferenceLiteralUnion.ts, 33, 3))
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>extent : Symbol(extent, Decl(typeInferenceLiteralUnion.ts, 23, 1))
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>NumCoercible : Symbol(NumCoercible, Decl(typeInferenceLiteralUnion.ts, 11, 1))
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‎tests/baselines/reference/typeInferenceLiteralUnion.types

Lines changed: 89 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,89 @@
1+
=== tests/cases/compiler/typeInferenceLiteralUnion.ts ===
2+
// Repro from #10901
3+
/**
4+
* Administrivia: JavaScript primitive types and Date
5+
*/
6+
export type Primitive = number | string | boolean | Date;
7+
>Primitive : Primitive
8+
>Date : Date
9+
10+
/**
11+
* Administrivia: anything with a valueOf(): number method is comparable, so we allow it in numeric operations
12+
*/
13+
interface Numeric {
14+
>Numeric : Numeric
15+
16+
valueOf(): number;
17+
>valueOf : () => number
18+
}
19+
20+
// Not very useful, but meets Numeric
21+
class NumCoercible {
22+
>NumCoercible : NumCoercible
23+
24+
public a: number;
25+
>a : number
26+
27+
constructor(a: number) {
28+
>a : number
29+
30+
this.a = a;
31+
>this.a = a : number
32+
>this.a : number
33+
>this : this
34+
>a : number
35+
>a : number
36+
}
37+
public valueOf() {
38+
>valueOf : () => number
39+
40+
return this.a;
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>this.a : number
42+
>this : this
43+
>a : number
44+
}
45+
}
46+
47+
/**
48+
* Return the min and max simultaneously.
49+
*/
50+
export function extent<T extends Numeric>(array: Array<T | Primitive>): [T | Primitive, T | Primitive] | [undefined, undefined] {
51+
>extent : <T extends Numeric>(array: (string | number | boolean | Date | T)[]) => [string | number | boolean | Date | T, string | number | boolean | Date | T] | [undefined, undefined]
52+
>T : T
53+
>Numeric : Numeric
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>array : (string | number | boolean | Date | T)[]
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>Array : T[]
56+
>T : T
57+
>Primitive : Primitive
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>T : T
59+
>Primitive : Primitive
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>T : T
61+
>Primitive : Primitive
62+
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return [undefined, undefined];
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>[undefined, undefined] : [undefined, undefined]
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>undefined : undefined
66+
>undefined : undefined
67+
}
68+
69+
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let extentMixed: [Primitive | NumCoercible, Primitive | NumCoercible] | [undefined, undefined];
71+
>extentMixed : [undefined, undefined] | [string | number | boolean | Date | NumCoercible, string | number | boolean | Date | NumCoercible]
72+
>Primitive : Primitive
73+
>NumCoercible : NumCoercible
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>Primitive : Primitive
75+
>NumCoercible : NumCoercible
76+
77+
extentMixed = extent([new NumCoercible(10), 13, '12', true]);
78+
>extentMixed = extent([new NumCoercible(10), 13, '12', true]) : [undefined, undefined] | [string | number | boolean | Date | NumCoercible, string | number | boolean | Date | NumCoercible]
79+
>extentMixed : [undefined, undefined] | [string | number | boolean | Date | NumCoercible, string | number | boolean | Date | NumCoercible]
80+
>extent([new NumCoercible(10), 13, '12', true]) : [undefined, undefined] | [string | number | boolean | Date | NumCoercible, string | number | boolean | Date | NumCoercible]
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>extent : <T extends Numeric>(array: (string | number | boolean | Date | T)[]) => [string | number | boolean | Date | T, string | number | boolean | Date | T] | [undefined, undefined]
82+
>[new NumCoercible(10), 13, '12', true] : (true | NumCoercible | 13 | "12")[]
83+
>new NumCoercible(10) : NumCoercible
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>NumCoercible : typeof NumCoercible
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>10 : 10
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>13 : 13
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>'12' : "12"
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>true : true
89+

‎tests/baselines/reference/unionTypeInference.errors.txt

Lines changed: 1 addition & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1,9 +1,7 @@
11
tests/cases/conformance/types/typeRelationships/typeInference/unionTypeInference.ts(9,15): error TS2345: Argument of type '2' is not assignable to parameter of type 'string | 1'.
2-
tests/cases/conformance/types/typeRelationships/typeInference/unionTypeInference.ts(13,15): error TS2345: Argument of type 'number | "hello"' is not assignable to parameter of type 'string | 1'.
3-
Type 'number' is not assignable to type 'string | 1'.
42

53

6-
==== tests/cases/conformance/types/typeRelationships/typeInference/unionTypeInference.ts (2 errors) ====
4+
==== tests/cases/conformance/types/typeRelationships/typeInference/unionTypeInference.ts (1 errors) ====
75
// Verify that inferences made *to* a type parameter in a union type are secondary
86
// to inferences made directly to that type parameter
97

@@ -19,9 +17,6 @@ tests/cases/conformance/types/typeRelationships/typeInference/unionTypeInference
1917
var a2 = f(1, "hello");
2018
var a3: number;
2119
var a3 = f(1, a1 || "hello");
22-
~~~~~~~~~~~~~
23-
!!! error TS2345: Argument of type 'number | "hello"' is not assignable to parameter of type 'string | 1'.
24-
!!! error TS2345: Type 'number' is not assignable to type 'string | 1'.
2520
var a4: any;
2621
var a4 = f(undefined, "abc");
2722

‎tests/cases/compiler/typeInferenceLiteralUnion.ts

Lines changed: 35 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,35 @@
1+
// Repro from #10901
2+
/**
3+
* Administrivia: JavaScript primitive types and Date
4+
*/
5+
export type Primitive = number | string | boolean | Date;
6+
7+
/**
8+
* Administrivia: anything with a valueOf(): number method is comparable, so we allow it in numeric operations
9+
*/
10+
interface Numeric {
11+
valueOf(): number;
12+
}
13+
14+
// Not very useful, but meets Numeric
15+
class NumCoercible {
16+
public a: number;
17+
18+
constructor(a: number) {
19+
this.a = a;
20+
}
21+
public valueOf() {
22+
return this.a;
23+
}
24+
}
25+
26+
/**
27+
* Return the min and max simultaneously.
28+
*/
29+
export function extent<T extends Numeric>(array: Array<T | Primitive>): [T | Primitive, T | Primitive] | [undefined, undefined] {
30+
return [undefined, undefined];
31+
}
32+
33+
34+
let extentMixed: [Primitive | NumCoercible, Primitive | NumCoercible] | [undefined, undefined];
35+
extentMixed = extent([new NumCoercible(10), 13, '12', true]);

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