1 //===- TypeTraitsTest.cpp - type_traits unit tests ------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "llvm/ADT/STLExtras.h"
10 #include "gtest/gtest.h"
11
12 using namespace llvm;
13
14 //===----------------------------------------------------------------------===//
15 // function_traits
16 //===----------------------------------------------------------------------===//
17
18 namespace {
19 /// Check a callable type of the form `bool(const int &)`.
20 template <typename CallableT> struct CheckFunctionTraits {
21 static_assert(
22 std::is_same_v<typename function_traits<CallableT>::result_t, bool>,
23 "expected result_t to be `bool`");
24 static_assert(
25 std::is_same_v<typename function_traits<CallableT>::template arg_t<0>,
26 const int &>,
27 "expected arg_t<0> to be `const int &`");
28 static_assert(function_traits<CallableT>::num_args == 1,
29 "expected num_args to be 1");
30 };
31
32 /// Test function pointers.
33 using FuncType = bool (*)(const int &);
34 struct CheckFunctionPointer : CheckFunctionTraits<FuncType> {};
35
36 /// Test method pointers.
37 struct Foo {
38 bool func(const int &v);
39 };
40 struct CheckMethodPointer : CheckFunctionTraits<decltype(&Foo::func)> {};
41
42 /// Test lambda references.
__anon49e6b1000202(const int &v) 43 LLVM_ATTRIBUTE_UNUSED auto lambdaFunc = [](const int &v) -> bool {
44 return true;
45 };
46 struct CheckLambda : CheckFunctionTraits<decltype(lambdaFunc)> {};
47
48 } // end anonymous namespace
49
50 //===----------------------------------------------------------------------===//
51 // is_detected
52 //===----------------------------------------------------------------------===//
53
54 namespace {
55 struct HasFooMethod {
foo__anon49e6b1000311::HasFooMethod56 void foo() {}
57 };
58 struct NoFooMethod {};
59
60 template <class T> using has_foo_method_t = decltype(std::declval<T &>().foo());
61
62 static_assert(is_detected<has_foo_method_t, HasFooMethod>::value,
63 "expected foo method to be detected");
64 static_assert(!is_detected<has_foo_method_t, NoFooMethod>::value,
65 "expected no foo method to be detected");
66 } // end anonymous namespace
67