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Remove allowComplexConstraintInference in inferTypes (#54815)

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Jake Bailey 2023-08-15 08:54:21 -07:00 committed by GitHub
parent f37d2ad669
commit defb504be6
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1 changed files with 1 additions and 10 deletions
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src/compiler/checker.ts
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@ -24491,7 +24491,6 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
let bivariant = false;
let propagationType: Type;
let inferencePriority: number = InferencePriority.MaxValue;
let allowComplexConstraintInference = true;
let visited: Map<string, number>;
let sourceStack: Type[];
let targetStack: Type[];
@ -24697,15 +24696,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
// getApparentType can return _any_ type, since an indexed access or conditional may simplify to any other type.
// If that occurs and it doesn't simplify to an object or intersection, we'll need to restart `inferFromTypes`
// with the simplified source.
if (apparentSource !== source && allowComplexConstraintInference && !(apparentSource.flags & (TypeFlags.Object | TypeFlags.Intersection))) {
// TODO: The `allowComplexConstraintInference` flag is a hack! This forbids inference from complex constraints within constraints!
// This isn't required algorithmically, but rather is used to lower the memory burden caused by performing inference
// that is _too good_ in projects with complicated constraints (eg, fp-ts). In such cases, if we did not limit ourselves
// here, we might produce more valid inferences for types, causing us to do more checks and perform more instantiations
// (in addition to the extra stack depth here) which, in turn, can push the already close process over its limit.
// TL;DR: If we ever become generally more memory efficient (or our resource budget ever increases), we should just
// remove this `allowComplexConstraintInference` flag.
allowComplexConstraintInference = false;
if (apparentSource !== source && !(apparentSource.flags & (TypeFlags.Object | TypeFlags.Intersection))) {
return inferFromTypes(apparentSource, target);
}
source = apparentSource;