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Template literal types for template literal expressions #41891

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Merged
ahejlsberg merged 11 commits into from
Dec 12, 2020
Merged

Template literal types for template literal expressions #41891

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eda291d
Infer template literal types for template literal expressions
ahejlsberg Dec 8, 2020
4acf495
Update test
ahejlsberg Dec 8, 2020
537fd37
Update another test
ahejlsberg Dec 9, 2020
e88ceca
Accept new baselines
ahejlsberg Dec 9, 2020
e35c42e
Minor fixes
ahejlsberg Dec 9, 2020
dfd760d
Add tests
ahejlsberg Dec 9, 2020
54c3be9
Accept new baselines
ahejlsberg Dec 9, 2020
afcfd9c
Make new TypeFlags internal
ahejlsberg Dec 9, 2020
96885c3
Accept new API baselines
ahejlsberg Dec 9, 2020
b3cdbf3
Ensure template literals assignable to String, Object, {}, etc.
ahejlsberg Dec 9, 2020
5cf670b
Add tests
ahejlsberg Dec 9, 2020
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Add tests
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@ahejlsberg
ahejlsberg committed Dec 9, 2020
commit 5cf670b69c7b85f1453550e8ef52214b8f968da8
16 changes: 16 additions & 0 deletions tests/baselines/reference/templateLiteralTypes2.js
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Original file line number Diff line number Diff line change
Expand Up @@ -63,6 +63,14 @@ function ft13(s: string, cond: boolean) {

type T0 = string | `${number}px`;

function ft14(t: `foo${number}`) {
let x1: string = t;
let x2: String = t;
let x3: Object = t;
let x4: {} = t;
let x6: { length: number } = t;
}

// Repro from #41631

declare function takesLiteral<T extends string>(literal: T): T extends `foo.bar.${infer R}` ? R : unknown;
Expand Down Expand Up @@ -146,6 +154,13 @@ function ft13(s, cond) {
var y1 = nonWidening("foo" + s);
var y2 = nonWidening(cond ? 'a' : "foo" + s);
}
function ft14(t) {
var x1 = t;
var x2 = t;
var x3 = t;
var x4 = t;
var x6 = t;
}
var t1 = takesLiteral("foo.bar.baz"); // "baz"
var id2 = "foo.bar.baz";
var t2 = takesLiteral(id2); // "baz"
Expand All @@ -169,6 +184,7 @@ declare function widening<T>(x: T): T;
declare function nonWidening<T extends string | number | symbol>(x: T): T;
declare function ft13(s: string, cond: boolean): void;
declare type T0 = string | `${number}px`;
declare function ft14(t: `foo${number}`): void;
declare function takesLiteral<T extends string>(literal: T): T extends `foo.bar.${infer R}` ? R : unknown;
declare const t1: "baz";
declare const id2 = "foo.bar.baz";
Expand Down
94 changes: 61 additions & 33 deletions tests/baselines/reference/templateLiteralTypes2.symbols
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Original file line number Diff line number Diff line change
Expand Up @@ -229,68 +229,96 @@ function ft13(s: string, cond: boolean) {
type T0 = string | `${number}px`;
>T0 : Symbol(T0, Decl(templateLiteralTypes2.ts, 60, 1))

function ft14(t: `foo${number}`) {
>ft14 : Symbol(ft14, Decl(templateLiteralTypes2.ts, 62, 33))
>t : Symbol(t, Decl(templateLiteralTypes2.ts, 64, 14))

let x1: string = t;
>x1 : Symbol(x1, Decl(templateLiteralTypes2.ts, 65, 7))
>t : Symbol(t, Decl(templateLiteralTypes2.ts, 64, 14))

let x2: String = t;
>x2 : Symbol(x2, Decl(templateLiteralTypes2.ts, 66, 7))
>String : Symbol(String, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
>t : Symbol(t, Decl(templateLiteralTypes2.ts, 64, 14))

let x3: Object = t;
>x3 : Symbol(x3, Decl(templateLiteralTypes2.ts, 67, 7))
>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
>t : Symbol(t, Decl(templateLiteralTypes2.ts, 64, 14))

let x4: {} = t;
>x4 : Symbol(x4, Decl(templateLiteralTypes2.ts, 68, 7))
>t : Symbol(t, Decl(templateLiteralTypes2.ts, 64, 14))

let x6: { length: number } = t;
>x6 : Symbol(x6, Decl(templateLiteralTypes2.ts, 69, 7))
>length : Symbol(length, Decl(templateLiteralTypes2.ts, 69, 13))
>t : Symbol(t, Decl(templateLiteralTypes2.ts, 64, 14))
}

// Repro from #41631

declare function takesLiteral<T extends string>(literal: T): T extends `foo.bar.${infer R}` ? R : unknown;
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 62, 33))
>T : Symbol(T, Decl(templateLiteralTypes2.ts, 66, 30))
>literal : Symbol(literal, Decl(templateLiteralTypes2.ts, 66, 48))
>T : Symbol(T, Decl(templateLiteralTypes2.ts, 66, 30))
>T : Symbol(T, Decl(templateLiteralTypes2.ts, 66, 30))
>R : Symbol(R, Decl(templateLiteralTypes2.ts, 66, 87))
>R : Symbol(R, Decl(templateLiteralTypes2.ts, 66, 87))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 70, 1))
>T : Symbol(T, Decl(templateLiteralTypes2.ts, 74, 30))
>literal : Symbol(literal, Decl(templateLiteralTypes2.ts, 74, 48))
>T : Symbol(T, Decl(templateLiteralTypes2.ts, 74, 30))
>T : Symbol(T, Decl(templateLiteralTypes2.ts, 74, 30))
>R : Symbol(R, Decl(templateLiteralTypes2.ts, 74, 87))
>R : Symbol(R, Decl(templateLiteralTypes2.ts, 74, 87))

const t1 = takesLiteral("foo.bar.baz"); // "baz"
>t1 : Symbol(t1, Decl(templateLiteralTypes2.ts, 68, 5))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 62, 33))
>t1 : Symbol(t1, Decl(templateLiteralTypes2.ts, 76, 5))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 70, 1))

const id2 = "foo.bar.baz";
>id2 : Symbol(id2, Decl(templateLiteralTypes2.ts, 69, 5))
>id2 : Symbol(id2, Decl(templateLiteralTypes2.ts, 77, 5))

const t2 = takesLiteral(id2); // "baz"
>t2 : Symbol(t2, Decl(templateLiteralTypes2.ts, 70, 5))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 62, 33))
>id2 : Symbol(id2, Decl(templateLiteralTypes2.ts, 69, 5))
>t2 : Symbol(t2, Decl(templateLiteralTypes2.ts, 78, 5))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 70, 1))
>id2 : Symbol(id2, Decl(templateLiteralTypes2.ts, 77, 5))

declare const someString: string;
>someString : Symbol(someString, Decl(templateLiteralTypes2.ts, 72, 13))
>someString : Symbol(someString, Decl(templateLiteralTypes2.ts, 80, 13))

const t3 = takesLiteral(`foo.bar.${someString}`); // string
>t3 : Symbol(t3, Decl(templateLiteralTypes2.ts, 73, 5))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 62, 33))
>someString : Symbol(someString, Decl(templateLiteralTypes2.ts, 72, 13))
>t3 : Symbol(t3, Decl(templateLiteralTypes2.ts, 81, 5))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 70, 1))
>someString : Symbol(someString, Decl(templateLiteralTypes2.ts, 80, 13))

const id4 = `foo.bar.${someString}`;
>id4 : Symbol(id4, Decl(templateLiteralTypes2.ts, 75, 5))
>someString : Symbol(someString, Decl(templateLiteralTypes2.ts, 72, 13))
>id4 : Symbol(id4, Decl(templateLiteralTypes2.ts, 83, 5))
>someString : Symbol(someString, Decl(templateLiteralTypes2.ts, 80, 13))

const t4 = takesLiteral(id4); // string
>t4 : Symbol(t4, Decl(templateLiteralTypes2.ts, 76, 5))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 62, 33))
>id4 : Symbol(id4, Decl(templateLiteralTypes2.ts, 75, 5))
>t4 : Symbol(t4, Decl(templateLiteralTypes2.ts, 84, 5))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 70, 1))
>id4 : Symbol(id4, Decl(templateLiteralTypes2.ts, 83, 5))

declare const someUnion: 'abc' | 'def' | 'ghi';
>someUnion : Symbol(someUnion, Decl(templateLiteralTypes2.ts, 78, 13))
>someUnion : Symbol(someUnion, Decl(templateLiteralTypes2.ts, 86, 13))

const t5 = takesLiteral(`foo.bar.${someUnion}`); // "abc" | "def" | "ghi"
>t5 : Symbol(t5, Decl(templateLiteralTypes2.ts, 79, 5))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 62, 33))
>someUnion : Symbol(someUnion, Decl(templateLiteralTypes2.ts, 78, 13))
>t5 : Symbol(t5, Decl(templateLiteralTypes2.ts, 87, 5))
>takesLiteral : Symbol(takesLiteral, Decl(templateLiteralTypes2.ts, 70, 1))
>someUnion : Symbol(someUnion, Decl(templateLiteralTypes2.ts, 86, 13))

// Repro from #41732

const pixelValue: number = 22;
>pixelValue : Symbol(pixelValue, Decl(templateLiteralTypes2.ts, 83, 5))
>pixelValue : Symbol(pixelValue, Decl(templateLiteralTypes2.ts, 91, 5))

type PixelValueType = `${number}px`;
>PixelValueType : Symbol(PixelValueType, Decl(templateLiteralTypes2.ts, 83, 30))
>PixelValueType : Symbol(PixelValueType, Decl(templateLiteralTypes2.ts, 91, 30))

const pixelString: PixelValueType = `22px`;
>pixelString : Symbol(pixelString, Decl(templateLiteralTypes2.ts, 87, 5))
>PixelValueType : Symbol(PixelValueType, Decl(templateLiteralTypes2.ts, 83, 30))
>pixelString : Symbol(pixelString, Decl(templateLiteralTypes2.ts, 95, 5))
>PixelValueType : Symbol(PixelValueType, Decl(templateLiteralTypes2.ts, 91, 30))

const pixelStringWithTemplate: PixelValueType = `${pixelValue}px`;
>pixelStringWithTemplate : Symbol(pixelStringWithTemplate, Decl(templateLiteralTypes2.ts, 89, 5))
>PixelValueType : Symbol(PixelValueType, Decl(templateLiteralTypes2.ts, 83, 30))
>pixelValue : Symbol(pixelValue, Decl(templateLiteralTypes2.ts, 83, 5))
>pixelStringWithTemplate : Symbol(pixelStringWithTemplate, Decl(templateLiteralTypes2.ts, 97, 5))
>PixelValueType : Symbol(PixelValueType, Decl(templateLiteralTypes2.ts, 91, 30))
>pixelValue : Symbol(pixelValue, Decl(templateLiteralTypes2.ts, 91, 5))

26 changes: 26 additions & 0 deletions tests/baselines/reference/templateLiteralTypes2.types
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Original file line number Diff line number Diff line change
Expand Up @@ -257,6 +257,32 @@ function ft13(s: string, cond: boolean) {
type T0 = string | `${number}px`;
>T0 : string

function ft14(t: `foo${number}`) {
>ft14 : (t: `foo${number}`) => void
>t : `foo${number}`

let x1: string = t;
>x1 : string
>t : `foo${number}`

let x2: String = t;
>x2 : String
>t : `foo${number}`

let x3: Object = t;
>x3 : Object
>t : `foo${number}`

let x4: {} = t;
>x4 : {}
>t : `foo${number}`

let x6: { length: number } = t;
>x6 : { length: number; }
>length : number
>t : `foo${number}`
}

// Repro from #41631

declare function takesLiteral<T extends string>(literal: T): T extends `foo.bar.${infer R}` ? R : unknown;
Expand Down
8 changes: 8 additions & 0 deletions tests/cases/conformance/types/literal/templateLiteralTypes2.ts
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Expand Up @@ -65,6 +65,14 @@ function ft13(s: string, cond: boolean) {

type T0 = string | `${number}px`;

function ft14(t: `foo${number}`) {
let x1: string = t;
let x2: String = t;
let x3: Object = t;
let x4: {} = t;
let x6: { length: number } = t;
}

// Repro from #41631

declare function takesLiteral<T extends string>(literal: T): T extends `foo.bar.${infer R}` ? R : unknown;
Expand Down