[Type checker] Allow extensions of typealiases naming generic specializations #21328
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…izations.
When a (non-generic) typealias refers to a specialization of a generic
type, e.g.
```swift
typealias simd_float3 = SIMD3<Float>
```
treat an extension of the typealias as an extension of the underlying
type with same-type constraints between the generic parameters and the
specific arguments, e.g.,
```swift
extension simd_float3 { }
```
is treated as
```swift
extension SIMD where Scalar == Float { }
```
This addresses a source-compatibility problem with SE-0229, where
existing types such as simd3_float (which were separate structs)
became specializations of a generic SIMD type.
Fixes rdar://problem/46604664 and rdar://problem/46604370.
|
@swift-ci please smoke test |
|
@swift-ci please test source compatibility |
|
I assume that it's actually treated as |
|
The source-compat issue is an unrelated UPASS: |
slavapestov
reviewed
Dec 15, 2018
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
When a (non-generic) typealias refers to a specialization of a generic
type, e.g.
treat an extension of the typealias as an extension of the underlying
type with same-type constraints between the generic parameters and the
specific arguments, e.g.,
is treated as
This addresses a source-compatibility problem with SE-0229, where
existing types such as simd3_float (which were separate structs)
became specializations of a generic SIMD type.
Fixes rdar://problem/46604664 and rdar://problem/46604370.