Merge pull request #75395 from swiftlang/egorzhdan/std-function-test

[cxx-interop] Add one more test for `std::function`

Author: egorzhdan

test/Interop/Cxx/stdlib/Inputs/std-function.h

@@ -5,7 +5,8 @@
 #include <string>
 
 using FunctionIntToInt = std::function<int(int)>;
-using FunctionStringToString = std::function<std::string(const std::string&)>;
+using FunctionStringToString = std::function<std::string(std::string)>;
+using FunctionStringToStringConstRef = std::function<std::string(const std::string&)>;
 
 inline FunctionIntToInt getIdentityFunction() {
   return [](int x) { return x; };
@@ -19,4 +20,8 @@ std::string invokeFunctionTwice(FunctionStringToString f, std::string s) {
   return f(f(s));
 }
 
+std::string invokeFunctionTwiceConstRef(FunctionStringToStringConstRef f, std::string s) {
+  return f(f(s));
+}
+
 #endif // TEST_INTEROP_CXX_STDLIB_INPUTS_STD_FUNCTION_H

test/Interop/Cxx/stdlib/use-std-function.swift

@@ -57,10 +57,16 @@ StdFunctionTestSuite.test("FunctionIntToInt init from closure and pass as parame
   expectEqual(222, res)
 }
 
+StdFunctionTestSuite.test("FunctionStringToString init from closure and pass as parameter") {
+  let res = invokeFunctionTwice(.init({ $0 + std.string("abc") }),
+                                std.string("prefix"))
+  expectEqual(std.string("prefixabcabc"), res)
+}
+
 // FIXME: assertion for address-only closure params (rdar://124501345)
-//StdFunctionTestSuite.test("FunctionStringToString init from closure and pass as parameter") {
-//  let res = invokeFunctionTwice(.init({ $0 + std.string("abc") }),
-//                                std.string("prefix"))
+//StdFunctionTestSuite.test("FunctionStringToStringConstRef init from closure and pass as parameter") {
+//  let res = invokeFunctionTwiceConstRef(.init({ $0 + std.string("abc") }),
+//                                        std.string("prefix"))
 //  expectEqual(std.string("prefixabcabc"), res)
 //}
 #endif