validation-test/Sema/type_checker_perf/fast/rdar23861629.swift

// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
// REQUIRES: tools-release,no_asan

struct S { var s: String? }

func rdar23861629(_ a: [S]) {
  _ = a.reduce("") {
    ($0 == "") ? ($1.s ?? "") : ($0 + "," + ($1.s ?? "")) + ($1.s ?? "test") + ($1.s ?? "okay")
  }
}