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Fix contextual typing for post-spread tuple elements (#52769)

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This commit is contained in:
Anders Hejlsberg
2023-02-18 09:35:24 -08:00
committed by GitHub
parent d87d0adcd3
commit 5c92af1dcc
6 changed files with 440 additions and 12 deletions
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26
src/compiler/checker.ts
View File

@@ -23201,7 +23201,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
return restType && createArrayType(restType);
}
function getElementTypeOfSliceOfTupleType(type: TupleTypeReference, index: number, endSkipCount = 0, writing = false) {
function getElementTypeOfSliceOfTupleType(type: TupleTypeReference, index: number, endSkipCount = 0, writing = false, noReductions = false) {
const length = getTypeReferenceArity(type) - endSkipCount;
if (index < length) {
const typeArguments = getTypeArguments(type);
@@ -23210,7 +23210,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
const t = typeArguments[i];
elementTypes.push(type.target.elementFlags[i] & ElementFlags.Variadic ? getIndexedAccessType(t, numberType) : t);
}
return writing ? getIntersectionType(elementTypes) : getUnionType(elementTypes);
return writing ? getIntersectionType(elementTypes) : getUnionType(elementTypes, noReductions ? UnionReduction.None : UnionReduction.Literal);
}
return undefined;
}
@@ -28956,9 +28956,9 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
if (prop) {
return isCircularMappedProperty(prop) ? undefined : getTypeOfSymbol(prop);
}
if (isTupleType(t)) {
const restType = getRestTypeOfTupleType(t);
if (restType && isNumericLiteralName(name) && +name >= 0) {
if (isTupleType(t) && isNumericLiteralName(name) && +name >= 0) {
const restType = getElementTypeOfSliceOfTupleType(t, t.target.fixedLength, /*endSkipCount*/ 0, /*writing*/ false, /*noReductions*/ true);
if (restType) {
return restType;
}
}
@@ -29010,10 +29010,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
// type of T.
function getContextualTypeForElementExpression(arrayContextualType: Type | undefined, index: number): Type | undefined {
return arrayContextualType && (
getTypeOfPropertyOfContextualType(arrayContextualType, "" + index as __String)
|| mapType(
arrayContextualType,
t => getIteratedTypeOrElementType(IterationUse.Element, t, undefinedType, /*errorNode*/ undefined, /*checkAssignability*/ false),
index >= 0 && getTypeOfPropertyOfContextualType(arrayContextualType, "" + index as __String) ||
mapType(arrayContextualType, t =>
isTupleType(t) ?
getElementTypeOfSliceOfTupleType(t, 0, /*endSkipCount*/ 0, /*writing*/ false, /*noReductions*/ true) :
getIteratedTypeOrElementType(IterationUse.Element, t, undefinedType, /*errorNode*/ undefined, /*checkAssignability*/ false),
/*noReductions*/ true));
}
@@ -29245,7 +29246,12 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
case SyntaxKind.ArrayLiteralExpression: {
const arrayLiteral = parent as ArrayLiteralExpression;
const type = getApparentTypeOfContextualType(arrayLiteral, contextFlags);
return getContextualTypeForElementExpression(type, indexOfNode(arrayLiteral.elements, node));
// The index of an array literal element doesn't necessarily line up with the index of the corresponding
// element in a contextual tuple type when there are preceding spread elements in the array literal. For
// this reason we only pass indices for elements that precede the first spread element.
const spreadIndex = getNodeLinks(arrayLiteral).firstSpreadIndex ??= findIndex(arrayLiteral.elements, isSpreadElement);
const elementIndex = indexOfNode(arrayLiteral.elements, node);
return getContextualTypeForElementExpression(type, spreadIndex < 0 || elementIndex < spreadIndex ? elementIndex : -1);
}
case SyntaxKind.ConditionalExpression:
return getContextualTypeForConditionalOperand(node, contextFlags);

1
src/compiler/types.ts
View File

@@ -5996,6 +5996,7 @@ export interface NodeLinks {
declarationRequiresScopeChange?: boolean; // Set by `useOuterVariableScopeInParameter` in checker when downlevel emit would change the name resolution scope inside of a parameter.
serializedTypes?: Map<string, SerializedTypeEntry>; // Collection of types serialized at this location
decoratorSignature?: Signature; // Signature for decorator as if invoked by the runtime.
firstSpreadIndex?: number; // Index of first spread element in array literal (-1 for none)
parameterInitializerContainsUndefined?: boolean; // True if this is a parameter declaration whose type annotation contains "undefined".
fakeScopeForSignatureDeclaration?: boolean; // True if this is a fake scope injected into an enclosing declaration chain.
}