microsoft/TypeScript
1
0
Fork 0
mirror of https://github.com/microsoft/TypeScript.git synced 2026-05-22 12:03:44 -05:00
Code Issues Packages Projects Releases 212 Wiki Activity

Merge pull request #19774 from Microsoft/fixInvariantGenericErrors

Browse Source 
Fix invariant generic error elaboration logic
This commit is contained in:
Anders Hejlsberg
2017-11-06 10:42:32 -08:00
committed by GitHub
parent 445001e171 baafe5157e
commit 7a4808a89e
6 changed files with 273 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
src/compiler/checker.ts
View File

@@ -9451,6 +9451,7 @@ namespace ts {
function structuredTypeRelatedTo(source: Type, target: Type, reportErrors: boolean): Ternary {
let result: Ternary;
let originalErrorInfo: DiagnosticMessageChain;
const saveErrorInfo = errorInfo;
if (target.flags & TypeFlags.TypeParameter) {
// A source type { [P in keyof T]: X } is related to a target type T if X is related to T[P].
@@ -9530,6 +9531,7 @@ namespace ts {
// if we have indexed access types with identical index types, see if relationship holds for
// the two object types.
if (result = isRelatedTo((<IndexedAccessType>source).objectType, (<IndexedAccessType>target).objectType, reportErrors)) {
errorInfo = saveErrorInfo;
return result;
}
}
@@ -9561,6 +9563,10 @@ namespace ts {
if (!(reportErrors && some(variances, v => v === Variance.Invariant))) {
return Ternary.False;
}
// We remember the original error information so we can restore it in case the structural
// comparison unexpectedly succeeds. This can happen when the structural comparison result
// is a Ternary.Maybe for example caused by the recursion depth limiter.
originalErrorInfo = errorInfo;
errorInfo = saveErrorInfo;
}
}
@@ -9599,8 +9605,11 @@ namespace ts {
}
}
if (result) {
errorInfo = saveErrorInfo;
return result;
if (!originalErrorInfo) {
errorInfo = saveErrorInfo;
return result;
}
errorInfo = originalErrorInfo;
}
}
}