Merge pull request #71443 from Azoy/fix-specialize-function

Azoy · web-flow · commit 3923e2e621a6 · 2024-02-07T15:46:38.000-08:00
[stdlib] Fix _specialize implementation
diff --git a/stdlib/public/core/Builtin.swift b/stdlib/public/core/Builtin.swift
@@ -115,12 +115,14 @@ public func _identityCast<T, U>(_ x: T, to expectedType: U.Type) -> U {
 /// This cast can be useful for dispatching to specializations of generic
 /// functions.
 @_alwaysEmitIntoClient
+@_transparent
 public func _specialize<T, U>(_ x: T, for: U.Type) -> U? {
   guard T.self == U.self else {
     return nil
   }
 
-  return Builtin.reinterpretCast(x)
+  let result: U = Builtin.reinterpretCast(x)
+  return result
 }
 
 /// `unsafeBitCast` something to `AnyObject`.

Original file line number	Diff line number	Diff line change
`@@ -115,12 +115,14 @@ public func _identityCast<T, U>(_ x: T, to expectedType: U.Type) -> U {`
`115`	`115`	`/// This cast can be useful for dispatching to specializations of generic`
`116`	`116`	`/// functions.`
`117`	`117`	`@_alwaysEmitIntoClient`
	`118`	`+@_transparent`
`118`	`119`	`public func _specialize<T, U>(_ x: T, for: U.Type) -> U? {`
`119`	`120`	`guard T.self == U.self else {`
`120`	`121`	`return nil`
`121`	`122`	`}`
`122`	`123`
`123`		`- return Builtin.reinterpretCast(x)`
	`124`	`+ let result: U = Builtin.reinterpretCast(x)`
	`125`	`+ return result`
`124`	`126`	`}`
`125`	`127`
`126`	`128`	/// `unsafeBitCast` something to `AnyObject`.