8000 Covariant checking for callback parameters by ahejlsberg · Pull Request #15104 · microsoft/TypeScript · GitHub
[go: up one dir, main page]
Skip to content

Covariant checking for callback parameters #15104

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 9 commits into from
Apr 18, 2017
Merged

Covariant checking for callback parameters #15104

Changes from 1 commit
Commits
Show all changes
9 commits
Select commit Hold shift + click to select a range
8ae3e05
Treat callback parameters as strictly covariant
ahejlsberg Apr 8, 2017
eebd67f
Fix callback types to match covariantly
ahejlsberg Apr 8, 2017
11543d7
Accept new baselines
ahejlsberg Apr 8, 2017
50f84b1
Add tests
ahejlsberg Apr 8, 2017
189fc51
Check callback return values bi-variantly
ahejlsberg Apr 10, 2017
33bc9d1
Accept new baselines
ahejlsberg Apr 10, 2017
510bc81
Add another test case
ahejlsberg Apr 10, 2017
ec35b80
Allow callbacks unioned with null and/or undefined
ahejlsberg Apr 11, 2017
3cda0ea
Update tests
ahejlsberg Apr 11, 2017
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Prev Previous commit
Next Next commit
Allow callbacks unioned with null and/or undefined
  • Loading branch information
@ahejlsberg
ahejlsberg committed Apr 11, 2017
commit ec35b800e30ec735be8946842fcfa6ef45649a2c
8 changes: 5 additions & 3 deletions src/compiler/checker.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8213,8 +8213,8 @@ namespace ts {
for (let i = 0; i < checkCount; i++) {
const sourceType = i < sourceMax ? getTypeOfParameter(sourceParams[i]) : getRestTypeOfSignature(source);
const targetType = i < targetMax ? getTypeOfParameter(targetParams[i]) : getRestTypeOfSignature(target);
const sourceSig = getSingleCallSignature(sourceType);
const targetSig = getSingleCallSignature(targetType);
const sourceSig = getSingleCallSignature(getNonNullableType(sourceType));
const targetSig = getSingleCallSignature(getNonNullableType(targetType));
// In order to ensure that any generic type Foo<T> is at least co-variant with respect to T no matter
// how Foo uses T, we need to relate parameters bi-variantly (given that parameters are input positions,
// they naturally relate only contra-variantly). However, if the source and target parameters both have
Expand All @@ -8223,7 +8223,9 @@ namespace ts {
// similar to return values, callback parameters are output positions. This means that a Promise<T>,
// where T is used only in callback parameter positions, will be co-variant (as opposed to bi-variant)
// with respect to T.
const related = sourceSig && targetSig && !sourceSig.typePredicate && !targetSig.typePredicate ?
const callbacks = sourceSig && targetSig && !sourceSig.typePredicate && !targetSig.typePredicate &&
(getFalsyFlags(sourceType) & TypeFlags.Nullable) === (getFalsyFlags(targetType) & TypeFlags.Nullable);
const related = callbacks ?
compareSignaturesRelated(targetSig, sourceSig, /*checkAsCallback*/ true, /*ignoreReturnTypes*/ false, reportErrors, errorReporter, compareTypes) :
!checkAsCallback && compareTypes(sourceType, targetType, /*reportErrors*/ false) || compareTypes(targetType, sourceType, reportErrors);
if (!related) {
Expand Down
0