在C++中使用 Catch 测试框架编译错误"error: expected ';' at end of declaration list"

我试图通过在其中实现一些简单的算法来学习C++。为了测试这些算法，我想使用 Catch2。这是我为二进制搜索提出的一个程序：

#define CATCH_CONFIG_MAIN
#include "catch.hpp"
#include <iostream>
using namespace std;
int binary_search_recursive(int A[], int key, int low, int high) {
if (low > high) {
return -1;
}
int mid = (low + high)/2;
if (A[mid] == key) {
return mid;
} else if (key < A[mid]) {
return binary_search_recursive(A, key, low, mid-1);
} else {
return binary_search_recursive(A, key, mid+1, high);
}
}
int binary_search(int A[], int key, int len) {
return binary_search_recursive(A, key, 0, len - 1);
}

// int main() {
//  int A[] = {1, 2, 4};
//  int key = 4;
//  int len = 3;
//  cout << binary_search(A, key, len);
//  return 0;
// }
TEST_CASE("Binary search works", "[binary_search]") {
REQUIRE(1 == 1);
}

我将catch.hpp单个头文件复制到同一目录中的地方。问题是当我尝试在Mac上使用g++命令编译它时，出现以下错误：

$ g++ BinarySearch.cpp
In file included from BinarySearch.cpp:2:
./catch.hpp:380:63: error: expected ';' at end of declaration list
SourceLineInfo( char const* _file, std::size_t _line ) noexcept
^
./catch.hpp:390:27: error: expected ';' at end of declaration list
bool empty() const noexcept;
^
./catch.hpp:391:63: error: expected ';' at end of declaration list
bool operator == ( SourceLineInfo const& other ) const noexcept;
^
./catch.hpp:392:62: error: expected ';' at end of declaration list
bool operator < ( SourceLineInfo const& other ) const noexcept;
^
./catch.hpp:496:16: error: unknown type name 'constexpr'
static constexpr char const* const s_empty = "";
^
./catch.hpp:496:26: error: expected member name or ';' after declaration
specifiers
static constexpr char const* const s_empty = "";
~~~~~~~~~~~~~~~~ ^
./catch.hpp:499:20: error: expected ';' at end of declaration list
StringRef() noexcept
^
./catch.hpp:518:58: error: expected ';' at end of declaration list
StringRef( char const* rawChars, size_type size ) noexcept
^
./catch.hpp:542:38: error: expected ';' at end of declaration list
void swap( StringRef& other ) noexcept;
^
./catch.hpp:545:9: error: 'auto' not allowed in function return type
auto operator == ( StringRef const& other ) const noexcept -> bool;
^~~~
./catch.hpp:545:58: error: expected ';' at end of declaration list
auto operator == ( StringRef const& other ) const noexcept -> bool;
^
./catch.hpp:546:9: error: 'auto' not allowed in function return type
auto operator != ( StringRef const& other ) const noexcept -> bool;
^~~~
./catch.hpp:546:58: error: expected ';' at end of declaration list
auto operator != ( StringRef const& other ) const noexcept -> bool;
^
./catch.hpp:548:9: error: 'auto' not allowed in function return type
auto operator[] ( size_type index ) const noexcept -> char;
^~~~
./catch.hpp:548:50: error: expected ';' at end of declaration list
auto operator[] ( size_type index ) const noexcept -> char;
^
./catch.hpp:551:9: error: 'auto' not allowed in function return type
auto empty() const noexcept -> bool {
^~~~
./catch.hpp:551:27: error: expected ';' at end of declaration list
auto empty() const noexcept -> bool {
^
./catch.hpp:559:9: error: 'auto' not allowed in function return type
auto c_str() const -> char const*;
^~~~
./catch.hpp:559:27: error: expected ';' at end of declaration list
auto c_str() const -> char const*;
^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.

简而言之，Catch2 源代码本身正在生成几个相同的语法错误。我怀疑这可能与 Catch 编写C++版本的"版本"与我的编译器期望的版本不同有关，但我无法快速确定这是否是 Google 搜索此错误的问题。

以下是我的g++编译器的详细信息：

$ g++ -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 10.0.0 (clang-1000.11.45.2)
Target: x86_64-apple-darwin17.7.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

知道是什么导致了此错误，以及如何让 Catch2 单元测试工作吗？