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Move more logic to cached side of relation checks

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This commit is contained in:
Anders Hejlsberg
2022-02-07 10:17:31 -05:00
parent 4866ce562d
commit 2670b26187
1 changed files with 30 additions and 28 deletions
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58
src/compiler/checker.ts
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@@ -18361,31 +18361,6 @@ namespace ts {
}
}
if (!result && source.flags & (TypeFlags.Intersection | TypeFlags.TypeParameter)) {
// The combined constraint of an intersection type is the intersection of the constraints of
// the constituents. When an intersection type contains instantiable types with union type
// constraints, there are situations where we need to examine the combined constraint. One is
// when the target is a union type. Another is when the intersection contains types belonging
// to one of the disjoint domains. For example, given type variables T and U, each with the
// constraint 'string | number', the combined constraint of 'T & U' is 'string | number' and
// we need to check this constraint against a union on the target side. Also, given a type
// variable V constrained to 'string | number', 'V & number' has a combined constraint of
// 'string & number | number & number' which reduces to just 'number'.
// This also handles type parameters, as a type parameter with a union constraint compared against a union
// needs to have its constraint hoisted into an intersection with said type parameter, this way
// the type param can be compared with itself in the target (with the influence of its constraint to match other parts)
// For example, if `T extends 1 | 2` and `U extends 2 | 3` and we compare `T & U` to `T & U & (1 | 2 | 3)`
const constraint = getEffectiveConstraintOfIntersection(source.flags & TypeFlags.Intersection ? (source as IntersectionType).types: [source], !!(target.flags & TypeFlags.Union));
if (constraint && (source.flags & TypeFlags.Intersection || target.flags & TypeFlags.Union)) {
if (everyType(constraint, c => c !== source)) { // Skip comparison if expansion contains the source itself
// TODO: Stack errors so we get a pyramid for the "normal" comparison above, _and_ a second for this
if (result = isRelatedTo(constraint, target, RecursionFlags.Source, /*reportErrors*/ false, /*headMessage*/ undefined, intersectionState)) {
resetErrorInfo(saveErrorInfo);
}
}
}
}
// For certain combinations involving intersections and optional, excess, or mismatched properties we need
// an extra property check where the intersection is viewed as a single object. The following are motivating
// examples that all should be errors, but aren't without this extra property check:
@@ -18970,17 +18945,44 @@ namespace ts {
}
}
else if (sourceFlags & TypeFlags.UnionOrIntersection || targetFlags & TypeFlags.UnionOrIntersection) {
result = unionOrIntersectionRelatedTo(source, target, reportErrors, intersectionState);
if (result = unionOrIntersectionRelatedTo(source, target, reportErrors, intersectionState)) {
return result;
}
if (source.flags & TypeFlags.Intersection || source.flags & TypeFlags.TypeParameter && target.flags & TypeFlags.Union) {
// (T extends 1 | 2) & 1 <=> 1
// (T extends 1 | 2) <=> T & 1 | T & 2
// The combined constraint of an intersection type is the intersection of the constraints of
// the constituents. When an intersection type contains instantiable types with union type
// constraints, there are situations where we need to examine the combined constraint. One is
// when the target is a union type. Another is when the intersection contains types belonging
// to one of the disjoint domains. For example, given type variables T and U, each with the
// constraint 'string | number', the combined constraint of 'T & U' is 'string | number' and
// we need to check this constraint against a union on the target side. Also, given a type
// variable V constrained to 'string | number', 'V & number' has a combined constraint of
// 'string & number | number & number' which reduces to just 'number'.
// This also handles type parameters, as a type parameter with a union constraint compared against a union
// needs to have its constraint hoisted into an intersection with said type parameter, this way
// the type param can be compared with itself in the target (with the influence of its constraint to match other parts)
// For example, if `T extends 1 | 2` and `U extends 2 | 3` and we compare `T & U` to `T & U & (1 | 2 | 3)`
const constraint = getEffectiveConstraintOfIntersection(source.flags & TypeFlags.Intersection ? (source as IntersectionType).types: [source], !!(target.flags & TypeFlags.Union));
if (constraint && everyType(constraint, c => c !== source)) { // Skip comparison if expansion contains the source itself
// TODO: Stack errors so we get a pyramid for the "normal" comparison above, _and_ a second for this
if (result = isRelatedTo(constraint, target, RecursionFlags.Source, /*reportErrors*/ false, /*headMessage*/ undefined, intersectionState)) {
resetErrorInfo(saveErrorInfo);
return result;
}
}
}
// The ordered decomposition above doesn't handle all cases. Specifically, we also need to handle:
// Source is instantiable (e.g. source has union or intersection constraint).
// Source is an object, target is a union (e.g. { a, b: boolean } <=> { a, b: true } | { a, b: false }).
// Source is an intersection, target is an object (e.g. { a } & { b } <=> { a, b }).
// Source is an intersection, target is a union (e.g. { a } & { b: boolean } <=> { a, b: true } | { a, b: false }).
// Source is an intersection, target instantiable (e.g. string & { tag } <=> T["a"] constrained to string & { tag }).
if (result || !(sourceFlags & TypeFlags.Instantiable ||
if (!(sourceFlags & TypeFlags.Instantiable ||
sourceFlags & TypeFlags.Object && targetFlags & TypeFlags.Union ||
sourceFlags & TypeFlags.Intersection && targetFlags & (TypeFlags.Object | TypeFlags.Union | TypeFlags.Instantiable))) {
return result;
return Ternary.False;
}
}