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Fix type check for async function with alias return type. #5429

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Merged
merged 2 commits into from
Oct 28, 2015
Merged

Fix type check for async function with alias return type. #5429

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96504fa
Use resolvedSymbol instead of mergedSymbol.
rbuckton Oct 28, 2015
fdac86f
Linter errors
rbuckton Oct 28, 2015
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15 changes: 9 additions & 6 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -5479,7 +5479,7 @@ namespace ts {
let targetType = getIndexTypeOfType(target, IndexKind.String);
if (targetType) {
if ((targetType.flags & TypeFlags.Any) && !(originalSource.flags & TypeFlags.Primitive)) {
// non-primitive assignment to any is always allowed, eg
// non-primitive assignment to any is always allowed, eg
// `var x: { [index: string]: any } = { property: 12 };`
return Ternary.True;
}
Expand Down Expand Up @@ -5509,7 +5509,7 @@ namespace ts {
let targetType = getIndexTypeOfType(target, IndexKind.Number);
if (targetType) {
if ((targetType.flags & TypeFlags.Any) && !(originalSource.flags & TypeFlags.Primitive)) {
// non-primitive assignment to any is always allowed, eg
// non-primitive assignment to any is always allowed, eg
// `var x: { [index: number]: any } = { property: 12 };`
return Ternary.True;
}
Expand Down Expand Up @@ -6586,9 +6586,9 @@ namespace ts {
return;
}

// 1. walk from the use site up to the declaration and check
// 1. walk from the use site up to the declaration and check
// if there is anything function like between declaration and use-site (is binding/class is captured in function).
// 2. walk from the declaration up to the boundary of lexical environment and check
// 2. walk from the declaration up to the boundary of lexical environment and check
// if there is an iteration statement in between declaration and boundary (is binding/class declared inside iteration statement)

let container: Node;
Expand Down Expand Up @@ -11639,9 +11639,12 @@ namespace ts {
return unknownType;
}

let promiseConstructor = getMergedSymbol(promiseType.symbol);
let promiseConstructor = getNodeLinks(node.type).resolvedSymbol;
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I'm still trying to learn how the checker works, so this change is unsettling to me. Are there two almost-equivalent ways of getting the same information?

Why can't there be just one that always does the right thing, or at least has a default that works for almost all cases?

if (!promiseConstructor || !symbolIsValue(promiseConstructor)) {
error(node, Diagnostics.Type_0_is_not_a_valid_async_function_return_type, typeToString(promiseType));
let typeName = promiseConstructor
? symbolToString(promiseConstructor)
: typeToString(promiseType);
error(node, Diagnostics.Type_0_is_not_a_valid_async_function_return_type, typeName);
return unknownType;
}

Expand Down
4 changes: 2 additions & 2 deletions tests/baselines/reference/asyncFunctionDeclaration15_es6.errors.txt
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(6,16): error TS1055: Type '{}' is not a valid async function return type.
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(7,16): error TS1055: Type 'any' is not a valid async function return type.
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(8,16): error TS1055: Type 'number' is not a valid async function return type.
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(9,16): error TS1055: Type 'PromiseLike<void>' is not a valid async function return type.
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(9,16): error TS1055: Type 'PromiseLike' is not a valid async function return type.
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(10,16): error TS1055: Type 'typeof Thenable' is not a valid async function return type.
Type 'Thenable' is not assignable to type 'PromiseLike<any>'.
Types of property 'then' are incompatible.
Expand All @@ -28,7 +28,7 @@ tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration1
!!! error TS1055: Type 'number' is not a valid async function return type.
async function fn5(): PromiseLike<void> { } // error
~~~
!!! error TS1055: Type 'PromiseLike<void>' is not a valid async function return type.
!!! error TS1055: Type 'PromiseLike' is not a valid async function return type.
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Is this the alias case that the change is meant to fix?

async function fn6(): Thenable { } // error
~~~
!!! error TS1055: Type 'typeof Thenable' is not a valid async function return type.
Expand Down