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Examine all constraints of indexed access types in relations

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This commit is contained in:
Anders Hejlsberg 2018-08-27 15:50:26 -07:00
parent b50c37de78
commit eeabd527ca
1 changed files with 16 additions and 13 deletions
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29
src/compiler/checker.ts
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@ -6899,10 +6899,15 @@ namespace ts {
}
function getConstraintOfIndexedAccess(type: IndexedAccessType) {
const objectType = getBaseConstraintOfType(type.objectType) || type.objectType;
const indexType = getBaseConstraintOfType(type.indexType) || type.indexType;
const constraint = !isGenericObjectType(objectType) && !isGenericIndexType(indexType) ? getIndexedAccessType(objectType, indexType, /*accessNode*/ undefined, errorType) : undefined;
return constraint && constraint !== errorType ? constraint : undefined;
const objectType = getConstraintOfType(type.objectType) || type.objectType;
if (objectType !== type.objectType) {
const constraint = getIndexedAccessType(objectType, type.indexType, /*accessNode*/ undefined, errorType);
if (constraint && constraint !== errorType) {
return constraint;
}
}
const baseConstraint = getBaseConstraintOfType(type);
return baseConstraint && baseConstraint !== type ? baseConstraint : undefined;
}
function getDefaultConstraintOfConditionalType(type: ConditionalType) {
@ -7074,9 +7079,6 @@ namespace ts {
if (t.flags & TypeFlags.Substitution) {
return getBaseConstraint((<SubstitutionType>t).substitute);
}
if (isGenericMappedType(t)) {
return emptyObjectType;
}
return t;
}
}
@ -11642,12 +11644,13 @@ namespace ts {
}
}
else if (target.flags & TypeFlags.IndexedAccess) {
// A type S is related to a type T[K] if S is related to C, where C is the
// constraint of T[K]
const constraint = getConstraintForRelation(target);
if (constraint) {
if (result = isRelatedTo(source, constraint, reportErrors)) {
return result;
// A type S is related to a type T[K] if S is related to C, where C is the base constraint of T[K]
if (relation !== identityRelation) {
const constraint = getBaseConstraintOfType(target);
if (constraint && constraint !== target) {
if (result = isRelatedTo(source, constraint, reportErrors)) {
return result;
}
}
}
}