v1.4.0

MPark.Variant is an implementation of C++17 std::variant for C++11/14/17.

The implementation is based on my implementation of std::variant for libc++ and is continuously tested against libc++'s std::variant test suite.

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New Features

• #56: Replaced the visitation mechanism to be switch-based.
  • Blog post: Variant Visitation V2
  • Thank you @quicknir for the contribution and collaboration on this effort!
• Improved visitor same return type error message:

error: static_assert failed due to requirement 'expected<int>::template but_got<double>()'
    "`visit` requires the visitor to have a single return type"

• Improved visitor exhaustiveness error message:

error: static_assert failed due to requirement
    'visitor<add_ints>::template does not handle<const int &, const int &>()'
    "`visit` requires the visitor to be exhaustive"

Bug Fixes

• Relational operators must return a type implicitly convertible to bool.
• #34: Support for pointers to incomplete types
• #41: Crash under MSVC (VS 2015 update 3)
• Visual Studio 2017 related issues:
  • #48: Fails to compile with MSVC 19.15
  • #49: Disable MPARK_CPP14_CONSTEXPR for MSVC <= 19.15
  • #55: Compilation failed in Visual Studio 2017
  • #57: Use constexpr compiler bug workaround for VS2017 version 15.9

v1.3.0

MPark.Variant is an implementation of C++17 std::variant for C++11/14/17.

The implementation is based on my implementation of std::variant for libc++ and is continuously tested against libc++'s std::variant test suite.

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New Features

• Added support for GCC 4.8
• Lowered the minimum MSVC version from 190024215 to 190024210
• #36: Significant reduction in binary size

Bug Fixes

• #34: "Support for pointers to incomplete types"
• #35, #38: Fixed regression in MSVC 19.12.

v1.2.2

MPark.Variant is an implementation of C++17 std::variant for C++11/14/17.

The implementation is based on my implementation of std::variant for libc++ and is continuously tested against libc++'s std::variant test suite.

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Bug Fixes

• Fix exception support detection on MSVC.

v1.2.1

MPark.Variant is an implementation of C++17 std::variant for C++11/14/17.

The implementation is based on my implementation of std::variant for libc++ and is continuously tested against libc++'s std::variant test suite.

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Bug Fixes

• Add missing SFINAE condition for the converting constructor
• Fix an incorrect use of __has_include
• Fix a big compile-time performance issue on GCC 4.9 and 5

v1.2.0

MPark.Variant is an implementation of C++17 std::variant for C++11/14/17.

The implementation is based on my implementation of std::variant for libc++ and is continuously tested against libc++'s std::variant test suite.

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New Features

• Support for GCC 4.9 (no constexpr support for visit and relational operators)
• Support for -fno-exceptions
• Support for #include of mpark/variant.hpp without the -I flag
• Single header versions of mpark/variant.hpp hosted on the single-header branch
• Support for try it | on godbolt
• Increase warning levels

Bug Fixes

• LWG2904: "Make variant move-assignment more exception safe."

v1.1.0

MPark.Variant is an implementation of C++17 std::variant for C++11/14/17.

The implementation is based on my implementation of std::variant for libc++ and is continuously tested against libc++'s std::variant test suite.

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New Features

• Support for C++11
• Support for MSVC 2015 / 2017

Bug Fixes

• LWG2857: "{variant,optional,any}::emplace should return the constructed value"
• Implement P0513: "Poisoning the Hash"
• Implement P0599: "noexcept for Hash functions"
• llvm.org/PR31916: "std::visit does not accept visitors which require non-const lvalue references"
• llvm.org/PR33000: "std::visit with zero variants is broken"

v1.0.1

MPark.Variant is an implementation of C++17 std::variant as a C++14 library.

The implementation is based on my implementation of std::variant for libc++ and is continuously tested against libc++ std::variant test suite.

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Bug Fixes

• LWG2857: "{variant,optional,any}::emplace should return the constructed value"
• Implement P0513: "Poisoning the Hash"
• Implement P0599: "noexcept for Hash functions"
• llvm.org/PR31916: "std::visit does not accept visitors which require non-const lvalue references"
• llvm.org/PR33000: "std::visit with zero variants is broken"

v1.0.0

MPark.Variant is an implementation of C++17 std::variant as of N4618 as a standalone C++14 library.

The implementation is based on my implementation of std::variant for libc++ and is continuously tested against libc++ std::variant test suite.