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Collect type from return statment in generator function

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This commit is contained in:
Kanchalai Tanglertsampan 2017-02-22 10:23:47 -08:00
parent 359823b4be
commit f55167e565
1 changed files with 9 additions and 7 deletions
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16
src/compiler/checker.ts
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@ -14963,10 +14963,12 @@ namespace ts {
}
}
else {
let types: Type[];
let yieldTypes: Type[];
let returnTypes: Type[];
if (functionFlags & FunctionFlags.Generator) { // Generator or AsyncGenerator function
types = checkAndAggregateYieldOperandTypes(func, contextualMapper);
if (types.length === 0) {
yieldTypes = checkAndAggregateYieldOperandTypes(func, contextualMapper);
returnTypes = checkAndAggregateReturnExpressionTypes(func, contextualMapper);
if (yieldTypes.length === 0 && (!returnTypes || returnTypes.length === 0)) {
const iterableIteratorAny = functionFlags & FunctionFlags.Async
? createAsyncIterableIteratorType(anyType) // AsyncGenerator function
: createIterableIteratorType(anyType); // Generator function
@ -14978,14 +14980,14 @@ namespace ts {
}
}
else {
types = checkAndAggregateReturnExpressionTypes(func, contextualMapper);
if (!types) {
returnTypes = checkAndAggregateReturnExpressionTypes(func, contextualMapper);
if (!returnTypes) {
// For an async function, the return type will not be never, but rather a Promise for never.
return functionFlags & FunctionFlags.Async
? createPromiseReturnType(func, neverType) // Async function
: neverType; // Normal function
}
if (types.length === 0) {
if (returnTypes.length === 0) {
// For an async function, the return type will not be void, but rather a Promise for void.
return functionFlags & FunctionFlags.Async
? createPromiseReturnType(func, voidType) // Async function
@ -14993,7 +14995,7 @@ namespace ts {
}
}
// Return a union of the return expression types.
type = getUnionType(types, /*subtypeReduction*/ true);
type = getUnionType(yieldTypes ? yieldTypes.concat(returnTypes) : returnTypes, /*subtypeReduction*/ true);
if (functionFlags & FunctionFlags.Generator) { // AsyncGenerator function or Generator function
type = functionFlags & FunctionFlags.Async