microsoft/TypeScript
1
0
Fork 0
mirror of https://github.com/microsoft/TypeScript.git synced 2026-05-16 07:13:45 -05:00
Code Issues Packages Projects Releases 212 Wiki Activity

Merge pull request #21782 from Microsoft/fixIdenticalConditionalTypes

Browse Source 
Compatibility of identical conditional types
This commit is contained in:
Anders Hejlsberg
2018-02-08 17:38:31 -08:00
committed by GitHub
parent e2178ecfab 6dfcbffdc1
commit 868a9ee117
6 changed files with 344 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
src/compiler/checker.ts
View File

@@ -8223,16 +8223,17 @@ namespace ts {
const erasedCheckType = getActualTypeParameter(checkType);
const trueType = instantiateType(baseTrueType, mapper);
const falseType = instantiateType(baseFalseType, mapper);
const id = target && (target.id + "," + erasedCheckType.id + "," + extendsType.id + "," + trueType.id + "," + falseType.id);
const cached = id && conditionalTypes.get(id);
// We compute the cache key from the ids of the four constituent types, plus an indicator of whether the
// type is distributive (i.e. whether the original declaration has a type parameter as the check type).
const isDistributive = (target ? target.checkType : erasedCheckType).flags & TypeFlags.TypeParameter ? 1 : 0;
const id = erasedCheckType.id + "," + extendsType.id + "," + trueType.id + "," + falseType.id + "," + isDistributive;
const cached = conditionalTypes.get(id);
if (cached) {
return cached;
}
const result = createConditionalType(erasedCheckType, extendsType, trueType, falseType,
inferTypeParameters, target, mapper, aliasSymbol, instantiateTypes(baseAliasTypeArguments, mapper));
if (id) {
conditionalTypes.set(id, result);
}
conditionalTypes.set(id, result);
return result;
}