[6.2] Allow existential parameterized compositions: any P<A> & Q
#81750
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slavapestov
changed the title
any P<A> & Q
slavapestov
changed the title
any P<A> & Qany P<A> & Q
|
@swift-ci Please test |
AnthonyLatsis
approved these changes
May 27, 2025
Comment on lines
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| auto found = primaryAssociatedTypes.find(assocTy->getName()); | ||
| if (found == primaryAssociatedTypes.end()) | ||
| return protoTy; |
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I like how this return appears to be correct regardless of args.empty(). Might be worth a test:
protocol P<A> {
associatedtype A
}
protocol Q<A, B> {
associatedtype A
associatedtype B
}
func test(_: any P & Q<Int, Float>) {}There was a problem hiding this comment.
I didn't even think of that. I'll add the test case on main in a separate PR.
hborla
approved these changes
May 27, 2025
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6.2 cherry-pick of: #76705
Description: While technically a new feature, in reality we didn't always reject compositions involving parameterized protocol types, and users discovered they could work around the restriction with a type alias. I've been fixing the missing support needed to make this work gradually over time, so now the only missing piece was ASTDemangler support for such types. Implement the ASTDemangler support and remove the Sema diagnostic that bans this construction.
Scope of the issue: This has been coming up more and more with people wanting to write stuff like
any Sequence<Int> & Sendable, etc.Tested: New tests added.
Risk: Low.
Radar: rdar://96960993
Issue: Enable constrained existential types in protocol compositions #63877
Reviewed by: @AnthonyLatsis