fix: switch to std::nullptr_t, add release-mode defined behavior

[dascandy]

Description

Add workaround for LLVM bug llvm/llvm-project#154577 . Add return statement in function that otherwise in release mode has a path that does not return.

Related Issues

Motivation and Context

Fixing the main builds

Testing

Running the main builds on Clang/LLVM.

Meta

• If all approvals are obtained and the PR is green, any Beman member can merge the PR.

[github-actions]

[pre-commit] _{reported by reviewdog 🐶}

cstring_view/include/beman/cstring_view/cstring_view.hpp

Lines 87 to 150 in 9e0139f

	template<class charT, class traits /* = char_traits<charT> */>
	class basic_cstring_view {
	public:
	// types
	using traits_type = traits;
	using value_type = charT;
	using pointer = value_type*;
	using const_pointer = const value_type*;
	using reference = value_type&;
	using const_reference = const value_type&;
	using const_iterator = const charT*; // see [cstring.view.iterators]
	using iterator = const_iterator;
	using const_reverse_iterator = std::reverse_iterator<const_iterator>;
	using reverse_iterator = const_reverse_iterator;
	using size_type = size_t;
	using difference_type = ptrdiff_t;
	static constexpr size_type npos = size_type(-1);
	// [cstring.view.cons], construction and assignment
	constexpr basic_cstring_view() noexcept : size_() {
	static const charT empty_string[1]{};
	data_ = std::data(empty_string);
	}
	constexpr basic_cstring_view(const basic_cstring_view&) noexcept = default;
	constexpr basic_cstring_view& operator=(const basic_cstring_view&) noexcept = default;
	constexpr basic_cstring_view(const charT* str) : basic_cstring_view(str, traits::length(str)) {}
	constexpr basic_cstring_view(const charT* str, size_type len) : data_(str), size_(len) {
	assert(str[len] == charT());
	}
	// https://github.com/llvm/llvm-project/issues/154577
	// constexpr basic_cstring_view(nullptr_t) = delete;
	constexpr basic_cstring_view(decltype(nullptr)) = delete;
	// NOTE: Not part of proposal, just to make examples work since I can't add the conversion operator to
	// basic_string.
	template<typename Traits, typename Allocator>
	constexpr basic_cstring_view(const std::basic_string<charT, Traits, Allocator>& str)
	: basic_cstring_view(str.c_str(), str.size()) {}
	// [cstring.view.iterators], iterator support
	constexpr const_iterator begin() const noexcept {
	return data_;
	}
	constexpr const_iterator end() const noexcept {
	return data_ + size_;
	}
	constexpr const_iterator cbegin() const noexcept {
	return begin();
	}
	constexpr const_iterator cend() const noexcept {
	return end();
	}
	constexpr const_reverse_iterator rbegin() const noexcept {
	return data_ + size_;
	}
	constexpr const_reverse_iterator rend() const noexcept {
	return data_;
	}
	constexpr const_reverse_iterator crbegin() const noexcept {
	return rbegin();
	}
	constexpr const_reverse_iterator crend() const noexcept {
	return rend();
	}

[dascandy]

... what?

[github-actions]

[pre-commit] _{reported by reviewdog 🐶}

cstring_view/include/beman/cstring_view/cstring_view.hpp

Lines 14 to 85 in f2c03db

	// [cstring.view.template], class template basic_cstring_view
	template<class charT, class traits = std::char_traits<charT>>
	class basic_cstring_view; // partially freestanding
	/*
	#if __cpp_lib_ranges >= 201911L
	namespace ranges {
	template<class charT, class traits>
	constexpr bool enable_view<basic_cstring_view<charT, traits>> = true;
	template<class charT, class traits>
	constexpr bool enable_borrowed_range<basic_cstring_view<charT, traits>> = true;
	}
	#endif
	*/
	// [cstring.view.comparison], non-member comparison functions
	template<class charT, class traits>
	constexpr bool operator==(
	basic_cstring_view<charT, traits> x,
	std::type_identity_t<basic_cstring_view<charT, traits>> y
	) noexcept;
	template<class charT, class traits>
	constexpr auto operator<=>(
	basic_cstring_view<charT, traits> x,
	std::type_identity_t<basic_cstring_view<charT, traits>> y
	) noexcept;
	// [cstring.view.io], inserters and extractors
	template<class charT, class traits>
	std::basic_ostream<charT, traits>& operator<<(std::basic_ostream<charT, traits>& os, basic_cstring_view<charT, traits> str);
	// basic_cstring_view typedef-names
	using cstring_view = basic_cstring_view<char>;
	using u8cstring_view = basic_cstring_view<char8_t>;
	using u16cstring_view = basic_cstring_view<char16_t>;
	using u32cstring_view = basic_cstring_view<char32_t>;
	using wcstring_view = basic_cstring_view<wchar_t>;
	// [cstring.view.hash], hash support
	template<class T> struct hash;
	template<> struct hash<cstring_view>;
	template<> struct hash<u8cstring_view>;
	template<> struct hash<u16cstring_view>;
	template<> struct hash<u32cstring_view>;
	template<> struct hash<wcstring_view>;
	inline namespace literals {
	inline namespace cstring_view_literals {
	#ifndef _MSC_VER
	#pragma GCC diagnostic push
	#ifdef __clang__
	#pragma GCC diagnostic ignored "-Wuser-defined-literals"
	#else
	#pragma GCC diagnostic ignored "-Wliteral-suffix"
	#endif
	#else
	#pragma warning(push)
	#pragma warning(disable: 4455)
	#endif
	// [cstring.view.literals], suffix for basic_cstring_view literals
	constexpr cstring_view operator"" csv(const char* str, size_t len) noexcept;
	constexpr u8cstring_view operator"" csv(const char8_t* str, size_t len) noexcept;
	constexpr u16cstring_view operator"" csv(const char16_t* str, size_t len) noexcept;
	constexpr u32cstring_view operator"" csv(const char32_t* str, size_t len) noexcept;
	constexpr wcstring_view operator"" csv(const wchar_t* str, size_t len) noexcept;
	#ifndef _MSC_VER
	#pragma GCC diagnostic pop
	#else
	#pragma warning(pop)
	#endif
	}
	}
	}

[github-actions]

[pre-commit] _{reported by reviewdog 🐶}

cstring_view/include/beman/cstring_view/cstring_view.hpp

Lines 87 to 117 in f2c03db

	namespace beman {
	template<class charT, class traits /* = char_traits<charT> */>
	class basic_cstring_view {
	public:
	// types
	using traits_type = traits;
	using value_type = charT;
	using pointer = value_type*;
	using const_pointer = const value_type*;
	using reference = value_type&;
	using const_reference = const value_type&;
	using const_iterator = const charT*; // see [cstring.view.iterators]
	using iterator = const_iterator;
	using const_reverse_iterator = std::reverse_iterator<const_iterator>;
	using reverse_iterator = const_reverse_iterator;
	using size_type = size_t;
	using difference_type = ptrdiff_t;
	static constexpr size_type npos = size_type(-1);
	// [cstring.view.cons], construction and assignment
	constexpr basic_cstring_view() noexcept : size_() {
	static const charT empty_string[1]{};
	data_ = std::data(empty_string);
	}
	constexpr basic_cstring_view(const basic_cstring_view&) noexcept = default;
	constexpr basic_cstring_view& operator=(const basic_cstring_view&) noexcept = default;
	constexpr basic_cstring_view(const charT* str) : basic_cstring_view(str, traits::length(str)) {}
	constexpr basic_cstring_view(const charT* str, size_type len) : data_(str), size_(len) {
	assert(str[len] == charT());
	}
	constexpr basic_cstring_view(std::nullptr_t) = delete;

[github-actions]

[pre-commit] _{reported by reviewdog 🐶}

cstring_view/include/beman/cstring_view/cstring_view.hpp

Lines 119 to 123 in f2c03db

	// NOTE: Not part of proposal, just to make examples work since I can't add the conversion operator to
	// basic_string.
	template<typename Traits, typename Allocator>
	constexpr basic_cstring_view(const std::basic_string<charT, Traits, Allocator>& str)
	: basic_cstring_view(str.c_str(), str.size()) {}

[dascandy]

turns out that it is a bug in Clang/LLVM. llvm/llvm-project#154577