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Allow string enum in element access #18029

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Merged
merged 4 commits into from
Aug 28, 2017
Merged

Allow string enum in element access #18029

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5534899
Allow string enums in element access
sandersn Aug 24, 2017
d7d69a1
Test:string enum in element access
sandersn Aug 24, 2017
197040d
Merge branch 'master' into allow-string-enum-in-element-access
sandersn Aug 28, 2017
8087206
Explain boolean exception in getIndexedAccessType
sandersn Aug 28, 2017
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2 changes: 1 addition & 1 deletion src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -7688,7 +7688,7 @@ namespace ts {
}
// In the following we resolve T[K] to the type of the property in T selected by K.
const apparentObjectType = getApparentType(objectType);
if (indexType.flags & TypeFlags.Union && !(indexType.flags & TypeFlags.Primitive)) {
if (indexType.flags & TypeFlags.Union && !(indexType.flags & TypeFlags.Boolean)) {
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Could you add a comment explaining that we are avoiding TypeFlags.Boolean here for stylistic reasons to ensure that we show boolean and not true in error messages? Might also want to link to keyofAndIndexedAccessErrors.errors.txt, which is the only test that fails (i.e., has slightly different error messages) if this check isn't here.

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Done

const propTypes: Type[] = [];
for (const t of (<UnionType>indexType).types) {
const propType = getPropertyTypeForIndexType(apparentObjectType, t, accessNode, /*cacheSymbol*/ false);
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26 changes: 26 additions & 0 deletions tests/baselines/reference/stringEnumInElementAccess01.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
//// [stringEnumInElementAccess01.ts]
enum E {
A = "a",
B = "b",
C = "c",
}

interface Item {
a: string;
b: number;
c: boolean;
}

declare const item: Item;
declare const e: E;
const snb: string | number | boolean = item[e];


//// [stringEnumInElementAccess01.js]
var E;
(function (E) {
E["A"] = "a";
E["B"] = "b";
E["C"] = "c";
})(E || (E = {}));
var snb = item[e];
40 changes: 40 additions & 0 deletions tests/baselines/reference/stringEnumInElementAccess01.symbols
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@@ -0,0 +1,40 @@
=== tests/cases/conformance/expressions/elementAccess/stringEnumInElementAccess01.ts ===
enum E {
>E : Symbol(E, Decl(stringEnumInElementAccess01.ts, 0, 0))

A = "a",
>A : Symbol(E.A, Decl(stringEnumInElementAccess01.ts, 0, 8))

B = "b",
>B : Symbol(E.B, Decl(stringEnumInElementAccess01.ts, 1, 12))

C = "c",
>C : Symbol(E.C, Decl(stringEnumInElementAccess01.ts, 2, 12))
}

interface Item {
>Item : Symbol(Item, Decl(stringEnumInElementAccess01.ts, 4, 1))

a: string;
>a : Symbol(Item.a, Decl(stringEnumInElementAccess01.ts, 6, 16))

b: number;
>b : Symbol(Item.b, Decl(stringEnumInElementAccess01.ts, 7, 14))

c: boolean;
>c : Symbol(Item.c, Decl(stringEnumInElementAccess01.ts, 8, 14))
}

declare const item: Item;
>item : Symbol(item, Decl(stringEnumInElementAccess01.ts, 12, 13))
>Item : Symbol(Item, Decl(stringEnumInElementAccess01.ts, 4, 1))

declare const e: E;
>e : Symbol(e, Decl(stringEnumInElementAccess01.ts, 13, 13))
>E : Symbol(E, Decl(stringEnumInElementAccess01.ts, 0, 0))

const snb: string | number | boolean = item[e];
>snb : Symbol(snb, Decl(stringEnumInElementAccess01.ts, 14, 5))
>item : Symbol(item, Decl(stringEnumInElementAccess01.ts, 12, 13))
>e : Symbol(e, Decl(stringEnumInElementAccess01.ts, 13, 13))

44 changes: 44 additions & 0 deletions tests/baselines/reference/stringEnumInElementAccess01.types
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@@ -0,0 +1,44 @@
=== tests/cases/conformance/expressions/elementAccess/stringEnumInElementAccess01.ts ===
enum E {
>E : E

A = "a",
>A : E.A
>"a" : "a"

B = "b",
>B : E.B
>"b" : "b"

C = "c",
>C : E.C
>"c" : "c"
}

interface Item {
>Item : Item

a: string;
>a : string

b: number;
>b : number

c: boolean;
>c : boolean
}

declare const item: Item;
>item : Item
>Item : Item

declare const e: E;
>e : E
>E : E

const snb: string | number | boolean = item[e];
>snb : string | number | boolean
>item[e] : string | number | boolean
>item : Item
>e : E

16 changes: 16 additions & 0 deletions tests/cases/conformance/expressions/elementAccess/stringEnumInElementAccess01.ts
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@@ -0,0 +1,16 @@
// @noImplicitAny: true
enum E {
A = "a",
B = "b",
C = "c",
}

interface Item {
a: string;
b: number;
c: boolean;
}

declare const item: Item;
declare const e: E;
const snb: string | number | boolean = item[e];