https://github.com/apple/swift/issues/43104 これかなあ？2016年から報告済みっぽい

[SR-487] Compiler fails to consider @autoclosure when satisfying tr...

Previous ID SR-487 Radar rdar://problem/22394263 Original Reporter russ (JIRA User) Type Bug Environment Apple Swift version 2.1.1 (swiftlang-700.1.101.15 clang-700.1.81) Apple Swift version 3.0-de...