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Merged
merged 6 commits into from
Jun 2, 2019
Merged

Implicit index signatures for enum object types #31687

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b688e25
Implement inferrable index signatures for enum types
ahejlsberg May 23, 2019
a95d18e
Accept new baselines
ahejlsberg May 23, 2019
0b53b8e
Merge branch 'master' into enumImplicitIndexSignatures
ahejlsberg May 30, 2019
cf1bceb
Add tests
ahejlsberg May 31, 2019
8bd6fd8
Accept new baselines
ahejlsberg May 31, 2019
bb15df3
Fix lint error
ahejlsberg May 31, 2019
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8 changes: 6 additions & 2 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -7316,7 +7316,8 @@ namespace ts {
stringIndexInfo = createIndexInfo(anyType, /*isReadonly*/ false);
}
}
const numberIndexInfo = symbol.flags & SymbolFlags.Enum ? enumNumberIndexInfo : undefined;
const numberIndexInfo = symbol.flags & SymbolFlags.Enum && (getDeclaredTypeOfSymbol(symbol).flags & TypeFlags.Enum ||
some(type.properties, prop => !!(getTypeOfSymbol(prop).flags & TypeFlags.NumberLike))) ? enumNumberIndexInfo : undefined;
setStructuredTypeMembers(type, members, emptyArray, emptyArray, stringIndexInfo, numberIndexInfo);
// We resolve the members before computing the signatures because a signature may use
// typeof with a qualified name expression that circularly references the type we are
Expand Down Expand Up @@ -8191,6 +8192,9 @@ namespace ts {
propTypes.push(getTypeOfSymbol(prop));
}
}
if (kind === IndexKind.String) {
append(propTypes, getIndexTypeOfType(type, IndexKind.Number));
}
if (propTypes.length) {
return getUnionType(propTypes, UnionReduction.Subtype);
}
Expand Down Expand Up @@ -14596,7 +14600,7 @@ namespace ts {
* with no call or construct signatures.
*/
function isObjectTypeWithInferableIndex(type: Type) {
return type.symbol && (type.symbol.flags & (SymbolFlags.ObjectLiteral | SymbolFlags.TypeLiteral | SymbolFlags.ValueModule)) !== 0 &&
return type.symbol && (type.symbol.flags & (SymbolFlags.ObjectLiteral | SymbolFlags.TypeLiteral | SymbolFlags.Enum | SymbolFlags.ValueModule)) !== 0 &&
!typeHasCallOrConstructSignatures(type);
}

Expand Down
35 changes: 35 additions & 0 deletions tests/baselines/reference/implicitIndexSignatures.js
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Expand Up @@ -44,6 +44,18 @@ function f4() {
const v3 = getNumberIndexValue(o1);
const v4 = getNumberIndexValue(o2);
}

function f5() {
enum E1 { A, B }
enum E2 { A = "A", B = "B" }
enum E3 { A = 0, B = "B" }
const v1 = getStringIndexValue(E1);
const v2 = getStringIndexValue(E2);
const v3 = getStringIndexValue(E3);
const v4 = getNumberIndexValue(E1);
const v5 = getNumberIndexValue(E2);
const v6 = getNumberIndexValue(E3);
}


//// [implicitIndexSignatures.js]
Expand Down Expand Up @@ -83,3 +95,26 @@ function f4() {
var v3 = getNumberIndexValue(o1);
var v4 = getNumberIndexValue(o2);
}
function f5() {
var E1;
(function (E1) {
E1[E1["A"] = 0] = "A";
E1[E1["B"] = 1] = "B";
})(E1 || (E1 = {}));
var E2;
(function (E2) {
E2["A"] = "A";
E2["B"] = "B";
})(E2 || (E2 = {}));
var E3;
(function (E3) {
E3[E3["A"] = 0] = "A";
E3["B"] = "B";
})(E3 || (E3 = {}));
var v1 = getStringIndexValue(E1);
var v2 = getStringIndexValue(E2);
var v3 = getStringIndexValue(E3);
var v4 = getNumberIndexValue(E1);
var v5 = getNumberIndexValue(E2);
var v6 = getNumberIndexValue(E3);
}
49 changes: 49 additions & 0 deletions tests/baselines/reference/implicitIndexSignatures.symbols
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Expand Up @@ -168,3 +168,52 @@ function f4() {
>o2 : Symbol(o2, Decl(implicitIndexSignatures.ts, 39, 7))
}

function f5() {
>f5 : Symbol(f5, Decl(implicitIndexSignatures.ts, 44, 1))

enum E1 { A, B }
>E1 : Symbol(E1, Decl(implicitIndexSignatures.ts, 46, 15))
>A : Symbol(E1.A, Decl(implicitIndexSignatures.ts, 47, 13))
>B : Symbol(E1.B, Decl(implicitIndexSignatures.ts, 47, 16))

enum E2 { A = "A", B = "B" }
>E2 : Symbol(E2, Decl(implicitIndexSignatures.ts, 47, 20))
>A : Symbol(E2.A, Decl(implicitIndexSignatures.ts, 48, 13))
>B : Symbol(E2.B, Decl(implicitIndexSignatures.ts, 48, 22))

enum E3 { A = 0, B = "B" }
>E3 : Symbol(E3, Decl(implicitIndexSignatures.ts, 48, 32))
>A : Symbol(E3.A, Decl(implicitIndexSignatures.ts, 49, 13))
>B : Symbol(E3.B, Decl(implicitIndexSignatures.ts, 49, 20))

const v1 = getStringIndexValue(E1);
>v1 : Symbol(v1, Decl(implicitIndexSignatures.ts, 50, 9))
>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
>E1 : Symbol(E1, Decl(implicitIndexSignatures.ts, 46, 15))

const v2 = getStringIndexValue(E2);
>v2 : Symbol(v2, Decl(implicitIndexSignatures.ts, 51, 9))
>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
>E2 : Symbol(E2, Decl(implicitIndexSignatures.ts, 47, 20))

const v3 = getStringIndexValue(E3);
>v3 : Symbol(v3, Decl(implicitIndexSignatures.ts, 52, 9))
>getStringIndexValue : Symbol(getStringIndexValue, Decl(implicitIndexSignatures.ts, 11, 13))
>E3 : Symbol(E3, Decl(implicitIndexSignatures.ts, 48, 32))

const v4 = getNumberIndexValue(E1);
>v4 : Symbol(v4, Decl(implicitIndexSignatures.ts, 53, 9))
>getNumberIndexValue : Symbol(getNumberIndexValue, Decl(implicitIndexSignatures.ts, 13, 68))
>E1 : Symbol(E1, Decl(implicitIndexSignatures.ts, 46, 15))

const v5 = getNumberIndexValue(E2);
>v5 : Symbol(v5, Decl(implicitIndexSignatures.ts, 54, 9))
>getNumberIndexValue : Symbol(getNumberIndexValue, Decl(implicitIndexSignatures.ts, 13, 68))
>E2 : Symbol(E2, Decl(implicitIndexSignatures.ts, 47, 20))

const v6 = getNumberIndexValue(E3);
>v6 : Symbol(v6, Decl(implicitIndexSignatures.ts, 55, 9))
>getNumberIndexValue : Symbol(getNumberIndexValue, Decl(implicitIndexSignatures.ts, 13, 68))
>E3 : Symbol(E3, Decl(implicitIndexSignatures.ts, 48, 32))
}

59 changes: 59 additions & 0 deletions tests/baselines/reference/implicitIndexSignatures.types
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Expand Up @@ -196,3 +196,62 @@ function f4() {
>o2 : { 0: string; 1: string; count: number; }
}

function f5() {
>f5 : () => void

enum E1 { A, B }
>E1 : E1
>A : E1.A
>B : E1.B

enum E2 { A = "A", B = "B" }
>E2 : E2
>A : E2.A
>"A" : "A"
>B : E2.B
>"B" : "B"

enum E3 { A = 0, B = "B" }
>E3 : E3
>A : E3.A
>0 : 0
>B : E3.B
>"B" : "B"

const v1 = getStringIndexValue(E1);
>v1 : string | E1
>getStringIndexValue(E1) : string | E1
>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
>E1 : typeof E1

const v2 = getStringIndexValue(E2);
>v2 : E2
>getStringIndexValue(E2) : E2
>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
>E2 : typeof E2

const v3 = getStringIndexValue(E3);
>v3 : string | E3.A
>getStringIndexValue(E3) : string | E3.A
>getStringIndexValue : <T>(map: { [x: string]: T; }) => T
>E3 : typeof E3

const v4 = getNumberIndexValue(E1);
>v4 : string
>getNumberIndexValue(E1) : string
>getNumberIndexValue : <T>(map: { [x: number]: T; }) => T
>E1 : typeof E1

const v5 = getNumberIndexValue(E2);
>v5 : unknown
>getNumberIndexValue(E2) : unknown
>getNumberIndexValue : <T>(map: { [x: number]: T; }) => T
>E2 : typeof E2

const v6 = getNumberIndexValue(E3);
>v6 : string
>getNumberIndexValue(E3) : string
>getNumberIndexValue : <T>(map: { [x: number]: T; }) => T
>E3 : typeof E3
}

8 changes: 4 additions & 4 deletions tests/baselines/reference/useObjectValuesAndEntries1.types
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Expand Up @@ -121,16 +121,16 @@ enum E { A, B }
>B : E.B

var entries5 = Object.entries(E); // [string, any][]
>entries5 : [string, any][]
>Object.entries(E) : [string, any][]
>entries5 : [string, string | E][]
>Object.entries(E) : [string, string | E][]
>Object.entries : { <T>(o: { [s: string]: T; } | ArrayLike<T>): [string, T][]; (o: {}): [string, any][]; }
>Object : ObjectConstructor
>entries : { <T>(o: { [s: string]: T; } | ArrayLike<T>): [string, T][]; (o: {}): [string, any][]; }
>E : typeof E

var values5 = Object.values(E); // any[]
>values5 : any[]
>Object.values(E) : any[]
>values5 : (string | E)[]
>Object.values(E) : (string | E)[]
>Object.values : { <T>(o: { [s: string]: T; } | ArrayLike<T>): T[]; (o: {}): any[]; }
>Object : ObjectConstructor
>values : { <T>(o: { [s: string]: T; } | ArrayLike<T>): T[]; (o: {}): any[]; }
Expand Down
12 changes: 12 additions & 0 deletions tests/cases/compiler/implicitIndexSignatures.ts
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Expand Up @@ -43,3 +43,15 @@ function f4() {
const v3 = getNumberIndexValue(o1);
const v4 = getNumberIndexValue(o2);
}

function f5() {
enum E1 { A, B }
enum E2 { A = "A", B = "B" }
enum E3 { A = 0, B = "B" }
const v1 = getStringIndexValue(E1);
const v2 = getStringIndexValue(E2);
const v3 = getStringIndexValue(E3);
const v4 = getNumberIndexValue(E1);
const v5 = getNumberIndexValue(E2);
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Why is this unknown and not an error? (Is it just because inference fails and "a thing with an inferrable index" is assignable to a {[x: number]: unknown}?) I'd think that yeah, E2 has an inferrable index type, sure, but we know that it has no numbers in it at all. But, from the stance that the number index signature (were it present in the type) would need to be assignable to the string index, this'd need to be E2.

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Because we infer nothing for T in the call to getNumberIndexValue. Keep in mind we're not doing an assignment here, we're just doing inference.

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Well, we are doing an assignment - we're saying that a {[x: string]: E2} is assignable to a {[x: number]: unknown}. I guess the output type here just irks me a tad - it could only possibly be an E2 or keyof typeof E2, rather than an unknown.

Like, if I write enum StrNum { Zero = "0", One = "1" }, indexing by 0 or 1 is gunna get me Zero or One, likewise if I write enum NumStr { "0" = "Zero", "1" = "One" }, indexing by Zero or One is gunna get me "0" or "1".

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No, indexing your StrNum by 0 or 1 is going to get you undefined (there's no reverse mapping for string valued members), and NumStr is an error because members can't have numeric names.

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Anyway, the unknown type is consistent with what we infer for object literal types that have no numerically named members. In some sense it would be more consistent to return undefined since that's what you're going to get, but that really is an orthogonal issue.

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there's no reverse mapping for string valued member

I always forget about that.

Anyway, the unknown type is consistent with what we infer for object literal types that have no numerically named members

Oh, ick. Ok.

const v6 = getNumberIndexValue(E3);
}