Closed
Description
Describe the bug
When using a Collection method with multiple overloads in for-in loop inside a generic context, the compiler reports ambiguity where there is none.
To Reproduce
Attempt to compile the following code (also attached):
func f<C: Collection>(_ c: C) {
for _ in c.prefix(1) {}
}Compilation fails with this error message:
test.swift:3:12: error: ambiguous use of 'prefix'
for _ in c.prefix(1) {}
^
Swift.Collection:6:40: note: found this candidate
@inlinable public __consuming func prefix(_ maxLength: Int) -> Self.SubSequence
^
Swift.Sequence:7:40: note: found this candidate
@inlinable public __consuming func prefix(_ maxLength: Int) -> PrefixSequence<Self>
^
Expected behavior
Successful compilation.
Environment
The earliest snapshot that fails to compile is from 2022-06-07:
Apple Swift version 5.8-dev (LLVM fdfb8ac496e4538, Swift c9f10040f7f3838)
The code above compiles correctly using the 2022-06-02 snapshot:
Apple Swift version 5.8-dev (LLVM 278d67f38c6a910, Swift ee312bc1e20eb01)
Additional context
Assigning the result of c.prefix(1) before the loop or using it in a for-in loop in a non-generic context both succeed.
// OK
func g<C: Collection>(_ c: C) {
let pre = c.prefix(1)
for _ in pre {}
}
// OK
func h(_ c: Array<Int>) {
for _ in c.prefix(1) {}
}