Skip to content
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

Fixed an issue with not being able to use mapped type over union constraint as rest param #49947

Merged
merged 7 commits into from
Mar 20, 2023
Merged

Fixed an issue with not being able to use mapped type over union constraint as rest param #49947

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
6554965
Fixed an issue with not being able to use mapped type over union cons…
Andarist Jul 19, 2022
f94efbd
Fixed an issue when targeting non-readonly arrays with source being a…
Andarist Jul 29, 2022
ce8483c
Merge remote-tracking branch 'origin/main' into fix/rest-param-using-…
Andarist Dec 26, 2022
29d4bb9
Merge remote-tracking branch 'origin/main' into fix/rest-param-using-…
Andarist Mar 16, 2023
940e1ad
Bring back resolving apparent type for mapped types with tuple constr…
Andarist Mar 19, 2023
88764fe
Merge remote-tracking branch 'origin/main' into fix/rest-param-using-…
Andarist Mar 20, 2023
8e78414
Add extra test cases
Andarist Mar 20, 2023
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
4 changes: 2 additions & 2 deletions src/compiler/checker.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12318,7 +12318,7 @@ namespace ts {
const typeVariable = getHomomorphicTypeVariable(type);
if (typeVariable && !type.declaration.nameType) {
const constraint = getConstraintOfTypeParameter(typeVariable);
if (constraint && isArrayOrTupleType(constraint)) {
if (constraint && everyType(constraint, isArrayOrTupleType)) {
return instantiateType(type, prependTypeMapping(typeVariable, constraint, type.mapper));
}
}
Expand Down Expand Up @@ -19860,7 +19860,7 @@ namespace ts {
return varianceResult;
}
}
else if (isReadonlyArrayType(target) ? isArrayOrTupleType(source) : isArrayType(target) && isTupleType(source) && !source.target.readonly) {
else if (isReadonlyArrayType(target) ? everyType(source, isArrayOrTupleType) : isArrayType(target) && isTupleType(source) && !source.target.readonly) {
Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

There is a good chance that this should do the same thing in the whenFalse branch of this ternary expression:

Suggested change
else if (isReadonlyArrayType(target) ? everyType(source, isArrayOrTupleType) : isArrayType(target) && isTupleType(source) && !source.target.readonly) {
else if (isReadonlyArrayType(target) ? everyType(source, isArrayOrTupleType) : isArrayType(target) && everyType(source, isTupleType) && !source.target.readonly) {

but to make such a change I will have to figure out a test case validating it. I don't think it's going to be super hard but my available time is limited rn.

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The false branch is just for read-only types, so yeah, it should probably be the same, otherwise it'll work for non-readonly tuples, but not readonly ones.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I've pushed out a fix and tests for this.

if (relation !== identityRelation) {
return isRelatedTo(getIndexTypeOfType(source, numberType) || anyType, getIndexTypeOfType(target, numberType) || anyType, RecursionFlags.Both, reportErrors);
}
Expand Down
27 changes: 27 additions & 0 deletions tests/baselines/reference/restParamUsingMappedTypeOverUnionConstraint.symbols
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
=== tests/cases/compiler/restParamUsingMappedTypeOverUnionConstraint.ts ===
// repro 29919#issuecomment-470948453

type Mapped<T> = { [P in keyof T]: T[P] extends string ? [number] : [string] }
>Mapped : Symbol(Mapped, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 0, 0))
>T : Symbol(T, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 2, 12))
>P : Symbol(P, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 2, 20))
>T : Symbol(T, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 2, 12))
>T : Symbol(T, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 2, 12))
>P : Symbol(P, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 2, 20))

declare function test<T extends [number] | [string]>(
>test : Symbol(test, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 2, 78))
>T : Symbol(T, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 4, 22))

args: T,
>args : Symbol(args, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 4, 53))
>T : Symbol(T, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 4, 22))

fn: (...args: Mapped<T>) => void
>fn : Symbol(fn, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 5, 10))
>args : Symbol(args, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 6, 7))
>Mapped : Symbol(Mapped, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 0, 0))
>T : Symbol(T, Decl(restParamUsingMappedTypeOverUnionConstraint.ts, 4, 22))

): number

18 changes: 18 additions & 0 deletions tests/baselines/reference/restParamUsingMappedTypeOverUnionConstraint.types
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
=== tests/cases/compiler/restParamUsingMappedTypeOverUnionConstraint.ts ===
// repro 29919#issuecomment-470948453

type Mapped<T> = { [P in keyof T]: T[P] extends string ? [number] : [string] }
>Mapped : Mapped<T>

declare function test<T extends [number] | [string]>(
>test : <T extends [number] | [string]>(args: T, fn: (...args: Mapped<T>) => void) => number

args: T,
>args : T

fn: (...args: Mapped<T>) => void
>fn : (...args: Mapped<T>) => void
>args : Mapped<T>

): number

11 changes: 11 additions & 0 deletions tests/cases/compiler/restParamUsingMappedTypeOverUnionConstraint.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
// @noEmit: true
// @strict: true

// repro 29919#issuecomment-470948453

type Mapped<T> = { [P in keyof T]: T[P] extends string ? [number] : [string] }

declare function test<T extends [number] | [string]>(
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This repro is a lot easier to understand for me because it has fewer moving parts and fewer repeated identifier, so it's easier to tell what dependencies exist between elements:

declare function test<T extends [number] | []>(
    fn: (...args: { [_ in keyof T]: [boolean] | [string] }) => void
): number

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I agree with the fact that the proposed version is more succinct but at the same time, I don't feel like the added test case is overly verbose. For me personally, this is a little bit harder to read because it's less "usual". The inlined mapped type also doesn't make it completely obvious to me if this mapped type is still homomorphic or not (although that's just my lack of expertise).

Overall, I don't mind making a change but perhaps it would be good to have some guidelines in the CONTRIBUTING.md for how one should write tests etc. For an external contributor like me, it's not that obvious what kind of tests are preferred by the team.

Please let me know if I should adjust the test, add a new one or leave it as is.

args: T,
fn: (...args: Mapped<T>) => void
): number