// RUN: %empty-directory(%t)
// RUN: %target-swift-frontend %s -module-name Functions -target %target-swift-5.1-abi-triple -clang-header-expose-decls=all-public -typecheck -verify -emit-clang-header-path %t/functions.h
// RUN: %FileCheck %s < %t/functions.h

// RUN: %check-interop-cxx-header-in-clang(%t/functions.h)

// CHECK-NOT: SWIFT_EXTERN double $s9Functions9asyncFuncyS2dYaF(double x) SWIFT_NOEXCEPT SWIFT_CALL; // asyncFunc(_:)

// CHECK:       namespace Functions SWIFT_PRIVATE_ATTR SWIFT_SYMBOL_MODULE("Functions") {
// CHECK-EMPTY:
// CHECK-EMPTY:
// CHECK: // Unavailable in C++: Swift global function 'asyncFunc(_:)'.
// CHECK-EMPTY:
// CHECK-NEXT:  } // namespace Functions

// REQUIRES: concurrency

public func asyncFunc(_ x: Double) async -> Double { return 2 * x }