Swift 5: Compiler crashes on SILGen for subscript with autoclosure argument

This code crashes the compiler when code coverage is enabled:

struct S {
  subscript(i: Int, autoclosure: @autoclosure () ->  Int) -> Int {
    get {
      return 0
    }
    set {

    }
  }
}

I am using the latest (5.0-DEVELOPMENT-SNAPSHOT-2019-01-13-a) snapshot.

The SPM project to reproduce the issue: https://github.com/broadwaylamb/CompilerCrasherAutoclosureSubscript

Run:

$ swift build
$ swift test --enable-code-coverage

--enable-code-coverage is important.