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Clean up return type checking logic

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This commit is contained in:
Anders Hejlsberg 2018-08-05 08:47:55 -07:00
parent faed2d2c33
commit ab7defa5ea
1 changed files with 28 additions and 36 deletions
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64
src/compiler/checker.ts
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@ -7676,7 +7676,8 @@ namespace ts {
}
let type = signature.target ? instantiateType(getReturnTypeOfSignature(signature.target), signature.mapper!) :
signature.unionSignatures ? getUnionType(map(signature.unionSignatures, getReturnTypeOfSignature), UnionReduction.Subtype) :
getReturnTypeFromAnnotationOrBody(signature.declaration!);
getReturnTypeFromAnnotation(signature.declaration!) ||
(nodeIsMissing((<FunctionLikeDeclaration>signature.declaration).body) ? anyType : getReturnTypeFromBody(<FunctionLikeDeclaration>signature.declaration));
if (!popTypeResolution()) {
if (signature.declaration) {
const typeNode = getEffectiveReturnTypeNode(signature.declaration);
@ -7701,7 +7702,7 @@ namespace ts {
return signature.resolvedReturnType;
}
function getReturnTypeFromAnnotationOrBody(declaration: SignatureDeclaration | JSDocSignature) {
function getReturnTypeFromAnnotation(declaration: SignatureDeclaration | JSDocSignature) {
if (declaration.kind === SyntaxKind.Constructor) {
return getDeclaredTypeOfClassOrInterface(getMergedSymbol((<ClassDeclaration>declaration.parent).symbol));
}
@ -7713,20 +7714,17 @@ namespace ts {
return getTypeFromTypeNode(typeNode);
}
if (declaration.kind === SyntaxKind.GetAccessor && !hasNonBindableDynamicName(declaration)) {
const jsDocType = isInJavaScriptFile(declaration) && getTypeForDeclarationFromJSDocComment(declaration);
if (jsDocType) {
return jsDocType;
}
const setter = getDeclarationOfKind<AccessorDeclaration>(getSymbolOfNode(declaration), SyntaxKind.SetAccessor);
const setterType = getAnnotatedAccessorType(setter);
if (setterType) {
return setterType;
}
}
const typeFromTag = getReturnTypeOfTypeTag(declaration);
if (typeFromTag) {
return typeFromTag;
}
if (nodeIsMissing((<FunctionLikeDeclaration>declaration).body)) {
return anyType;
}
return getReturnTypeFromBody(<FunctionLikeDeclaration>declaration);
return getReturnTypeOfTypeTag(declaration);
}
function isResolvingReturnTypeOfSignature(signature: Signature) {
@ -20674,7 +20672,7 @@ namespace ts {
contextualSignature : instantiateSignature(contextualSignature, contextualMapper);
assignContextualParameterTypes(signature, instantiatedContextualSignature);
}
if (!getReturnOrPromisedType(node, getFunctionFlags(node)) && !signature.resolvedReturnType) {
if (!getReturnTypeFromAnnotation(node) && !signature.resolvedReturnType) {
const returnType = getReturnTypeFromBody(node, checkMode);
if (!signature.resolvedReturnType) {
signature.resolvedReturnType = returnType;
@ -20690,12 +20688,9 @@ namespace ts {
}
function getReturnOrPromisedType(node: FunctionLikeDeclaration | MethodSignature, functionFlags: FunctionFlags) {
const returnTypeNode = getEffectiveReturnTypeNode(node);
return returnTypeNode &&
((functionFlags & FunctionFlags.AsyncGenerator) === FunctionFlags.Async ?
checkAsyncFunctionReturnType(node, returnTypeNode) : // Async function
getTypeFromTypeNode(returnTypeNode)) || // AsyncGenerator function, Generator function, or normal function
getReturnTypeOfTypeTag(node); // type from JSDoc @type tag
const type = getReturnTypeFromAnnotation(node);
return type && ((functionFlags & FunctionFlags.AsyncGenerator) === FunctionFlags.Async) ?
getAwaitedType(type) || errorType : type;
}
function checkFunctionExpressionOrObjectLiteralMethodDeferred(node: ArrowFunction | FunctionExpression | MethodDeclaration) {
@ -23218,16 +23213,15 @@ namespace ts {
* Checks the return type of an async function to ensure it is a compatible
* Promise implementation.
*
* This checks that an async function has a valid Promise-compatible return type,
* and returns the *awaited type* of the promise. An async function has a valid
* Promise-compatible return type if the resolved value of the return type has a
* construct signature that takes in an `initializer` function that in turn supplies
* a `resolve` function as one of its arguments and results in an object with a
* callable `then` signature.
* This checks that an async function has a valid Promise-compatible return type.
* An async function has a valid Promise-compatible return type if the resolved value
* of the return type has a construct signature that takes in an `initializer` function
* that in turn supplies a `resolve` function as one of its arguments and results in an
* object with a callable `then` signature.
*
* @param node The signature to check
*/
function checkAsyncFunctionReturnType(node: FunctionLikeDeclaration | MethodSignature, returnTypeNode: TypeNode): Type {
function checkAsyncFunctionReturnType(node: FunctionLikeDeclaration | MethodSignature, returnTypeNode: TypeNode) {
// As part of our emit for an async function, we will need to emit the entity name of
// the return type annotation as an expression. To meet the necessary runtime semantics
// for __awaiter, we must also check that the type of the declaration (e.g. the static
@ -23256,14 +23250,14 @@ namespace ts {
if (languageVersion >= ScriptTarget.ES2015) {
if (returnType === errorType) {
return errorType;
return;
}
const globalPromiseType = getGlobalPromiseType(/*reportErrors*/ true);
if (globalPromiseType !== emptyGenericType && !isReferenceToType(returnType, globalPromiseType)) {
// The promise type was not a valid type reference to the global promise type, so we
// report an error and return the unknown type.
error(returnTypeNode, Diagnostics.The_return_type_of_an_async_function_or_method_must_be_the_global_Promise_T_type);
return errorType;
return;
}
}
else {
@ -23271,13 +23265,13 @@ namespace ts {
markTypeNodeAsReferenced(returnTypeNode);
if (returnType === errorType) {
return errorType;
return;
}
const promiseConstructorName = getEntityNameFromTypeNode(returnTypeNode);
if (promiseConstructorName === undefined) {
error(returnTypeNode, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, typeToString(returnType));
return errorType;
return;
}
const promiseConstructorSymbol = resolveEntityName(promiseConstructorName, SymbolFlags.Value, /*ignoreErrors*/ true);
@ -23289,7 +23283,7 @@ namespace ts {
else {
error(returnTypeNode, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
}
return errorType;
return;
}
const globalPromiseConstructorLikeType = getGlobalPromiseConstructorLikeType(/*reportErrors*/ true);
@ -23297,12 +23291,12 @@ namespace ts {
// If we couldn't resolve the global PromiseConstructorLike type we cannot verify
// compatibility with __awaiter.
error(returnTypeNode, Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value, entityNameToString(promiseConstructorName));
return errorType;
return;
}
if (!checkTypeAssignableTo(promiseConstructorType, globalPromiseConstructorLikeType, returnTypeNode,
Diagnostics.Type_0_is_not_a_valid_async_function_return_type_in_ES5_SlashES3_because_it_does_not_refer_to_a_Promise_compatible_constructor_value)) {
return errorType;
return;
}
// Verify there is no local declaration that could collide with the promise constructor.
@ -23312,12 +23306,10 @@ namespace ts {
error(collidingSymbol.valueDeclaration, Diagnostics.Duplicate_identifier_0_Compiler_uses_declaration_1_to_support_async_functions,
idText(rootName),
entityNameToString(promiseConstructorName));
return errorType;
return;
}
}
// Get and return the awaited type of the return type.
return checkAwaitedType(returnType, node, Diagnostics.The_return_type_of_an_async_function_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
checkAwaitedType(returnType, node, Diagnostics.The_return_type_of_an_async_function_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);
}
/** Check a decorator */
@ -24978,7 +24970,7 @@ namespace ts {
error(node, Diagnostics.Return_type_of_constructor_signature_must_be_assignable_to_the_instance_type_of_the_class);
}
}
else if (getEffectiveReturnTypeNode(func) || isGetAccessorWithAnnotatedSetAccessor(func) || getReturnTypeOfTypeTag(func)) {
else if (getReturnTypeFromAnnotation(func)) {
if (functionFlags & FunctionFlags.Async) { // Async function
const promisedType = getPromisedTypeOfPromise(returnType);
const awaitedType = checkAwaitedType(exprType, node, Diagnostics.The_return_type_of_an_async_function_must_either_be_a_valid_promise_or_must_not_contain_a_callable_then_member);