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Only check constraints after type argument inference is complete

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This commit is contained in:
Anders Hejlsberg
2019-01-30 06:38:13 -08:00
parent ae6c9cd051
commit 7a31706a9f
1 changed files with 14 additions and 9 deletions
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23
src/compiler/checker.ts
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@@ -14788,7 +14788,7 @@ namespace ts {
return getWidenedType(unwidenedType);
}
function getInferredType(context: InferenceContext, index: number): Type {
function getInferredType(context: InferenceContext, index: number, ignoreConstraints = false): Type {
const inference = context.inferences[index];
let inferredType = inference.inferredType;
if (!inferredType) {
@@ -14836,11 +14836,13 @@ namespace ts {
inference.inferredType = inferredType;
const constraint = getConstraintOfTypeParameter(inference.typeParameter);
if (constraint) {
const instantiatedConstraint = instantiateType(constraint, context);
if (!context.compareTypes(inferredType, getTypeWithThisArgument(instantiatedConstraint, inferredType))) {
inference.inferredType = inferredType = instantiatedConstraint;
if (!ignoreConstraints) {
const constraint = getConstraintOfTypeParameter(inference.typeParameter);
if (constraint) {
const instantiatedConstraint = instantiateType(constraint, context);
if (!context.compareTypes(inferredType, getTypeWithThisArgument(instantiatedConstraint, inferredType))) {
inference.inferredType = inferredType = instantiatedConstraint;
}
}
}
}
@@ -14852,10 +14854,10 @@ namespace ts {
return isInJavaScriptFile ? anyType : emptyObjectType;
}
function getInferredTypes(context: InferenceContext): Type[] {
function getInferredTypes(context: InferenceContext, ignoreConstraints = false): Type[] {
const result: Type[] = [];
for (let i = 0; i < context.inferences.length; i++) {
result.push(getInferredType(context, i));
result.push(getInferredType(context, i, ignoreConstraints));
}
return result;
}
@@ -19925,7 +19927,10 @@ namespace ts {
inferTypes(context.inferences, spreadType, restType);
}
return getInferredTypes(context);
// If we are excluding context sensitive arguments we know there is another round of type inference
// coming, so we omit constraint checking. Otherwise, when a type parameter's constraint is self-
// referential, checking the constraint would cause inferences to be fixed prematurely.
return getInferredTypes(context, !!excludeArgument);
}
function getArrayifiedType(type: Type) {