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More complete check in isConstTypeVariable (#53341)

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This commit is contained in:
Anders Hejlsberg
2023-04-01 14:45:31 -07:00
committed by GitHub
parent b40385b595
commit 3f675b60bf
6 changed files with 138 additions and 10 deletions
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19
src/compiler/checker.ts
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@@ -13557,10 +13557,14 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
return hasNonCircularBaseConstraint(typeParameter) ? getConstraintFromTypeParameter(typeParameter) : undefined;
}
function isConstTypeVariable(type: Type): boolean {
return !!(type.flags & TypeFlags.TypeParameter && some((type as TypeParameter).symbol?.declarations, d => hasSyntacticModifier(d, ModifierFlags.Const)) ||
isGenericTupleType(type) && findIndex(getTypeArguments(type), (t, i) => !!(type.target.elementFlags[i] & ElementFlags.Variadic) && isConstTypeVariable(t)) >= 0 ||
type.flags & TypeFlags.IndexedAccess && isConstTypeVariable((type as IndexedAccessType).objectType));
function isConstTypeVariable(type: Type | undefined): boolean {
return !!(type && (
type.flags & TypeFlags.TypeParameter && some((type as TypeParameter).symbol?.declarations, d => hasSyntacticModifier(d, ModifierFlags.Const)) ||
type.flags & TypeFlags.Union && some((type as UnionType).types, isConstTypeVariable) ||
type.flags & TypeFlags.IndexedAccess && isConstTypeVariable((type as IndexedAccessType).objectType) ||
type.flags & TypeFlags.Conditional && isConstTypeVariable(getConstraintOfConditionalType(type as ConditionalType)) ||
type.flags & TypeFlags.Substitution && isConstTypeVariable((type as SubstitutionType).baseType) ||
isGenericTupleType(type) && findIndex(getTypeArguments(type), (t, i) => !!(type.target.elementFlags[i] & ElementFlags.Variadic) && isConstTypeVariable(t)) >= 0));
}
function getConstraintOfIndexedAccess(type: IndexedAccessType) {
@@ -37385,16 +37389,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
const parent = node.parent;
return isAssertionExpression(parent) && isConstTypeReference(parent.type) ||
isJSDocTypeAssertion(parent) && isConstTypeReference(getJSDocTypeAssertionType(parent)) ||
isValidConstAssertionArgument(node) && isConstTypeParameterContext(node) ||
isValidConstAssertionArgument(node) && isConstTypeVariable(getContextualType(node, ContextFlags.None)) ||
(isParenthesizedExpression(parent) || isArrayLiteralExpression(parent) || isSpreadElement(parent)) && isConstContext(parent) ||
(isPropertyAssignment(parent) || isShorthandPropertyAssignment(parent) || isTemplateSpan(parent)) && isConstContext(parent.parent);
}
function isConstTypeParameterContext(node: Expression) {
const contextualType = getContextualType(node, ContextFlags.None);
return !!contextualType && someType(contextualType, isConstTypeVariable);
}
function checkExpressionForMutableLocation(node: Expression, checkMode: CheckMode | undefined, forceTuple?: boolean): Type {
const type = checkExpression(node, checkMode, forceTuple);
return isConstContext(node) || isCommonJsExportedExpression(node) ? getRegularTypeOfLiteralType(type) :