swiftc selects UnsafePointer == when resolving overload in generic context involving arrays
| Originator: | rix.rob | ||
| Number: | rdar://22996431 | Date Originated: | 06-Oct-2015 04:07 PM |
| Status: | Open | Resolved: | |
| Product: | Developer Tools | Product Version: | Xcode 7.0.1 (7A1001) |
| Classification: | Enhancement | Reproducible: | Always |
Summary:
swiftc coerces arrays to UnsafePointer and thus also allows == in generic contexts when the arguments in question are arrays not returned from closure literals. Note that this _only_ works in generic contexts; you can’t let-bind == if the arguments are arrays.
Steps to Reproduce:
1. This code:
struct A {} // not Equatable!
func callsToThisShouldNotCompileButTotallyDo<A>(a: A, _ test: (A, A) -> Bool, _ b: A) -> Bool {
return test(a, b)
}
func doesNotEvenCompile<A>(a: () -> A, _ test: (A, A) -> Bool, _ b: () -> A) -> Bool {
return test(a(), b())
}
for i in 0..<1000000 {
assert(callsToThisShouldNotCompileButTotallyDo([ A(), A() ], ==, [ A(), A() ]), "failed at comparison \(i)")
}
Expected Results:
should not compile
Actual Results:
but totally does.
Regression:
If you call callsToThisShouldNotCompileButTotallyDo, it compiles, and should not. At runtime, it fails deterministically.
If you call doesNotEvenCompile, it does not even compile. This is correct.
Notes:
N/A
Comments
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