Make sure that GCC 13 also compilies with std::expected; resolves #570

[liuzicheng1987]

No description provided.

[gemini-code-assist]

Summary of Changes

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This pull request addresses and resolves compilation issues that arise when building the project with GCC 13, specifically concerning the usage of std::expected. The changes primarily focus on refining the rfl::Error class's special member functions, adjusting the std::bad_expected_access specialization, and making minor corrections to how std::expected's transform and error() methods are invoked within the parsing utilities. These modifications ensure that the Result and parsing components are fully compatible and behave correctly under the newer GCC 13 compiler environment.

Highlights

• rfl::Error Class Enhancements: Added default constructor and destructor, and applied noexcept specifiers to the move constructor and move assignment operator of the rfl::Error class for improved C++ standard compliance.
• std::bad_expected_access Specialization Update: Modified the error() method within the std::bad_expected_access<rfl::Error> specialization to remove the C++23 'deducing this' syntax, resolving potential compilation issues with GCC 13.
• std::unique_ptr Parsing Lambda Adjustment: Changed the lambda parameter from an rvalue reference (T&&) to a by-value parameter (T) in Parser_unique_ptr.hpp when using std::expected::transform to create std::unique_ptr instances, ensuring correct object handling.
• std::variant Error Handling Refinement: Removed a redundant std::move call when retrieving errors from std::expected in Parser_variant.hpp, aligning with the expected return type of std::expected::error().

Ignored Files

• Ignored by pattern: .github/workflows/** (1)
  • .github/workflows/linux.yaml

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[gemini-code-assist]

Code Review

This pull request updates the code to improve compatibility with GCC 13 and std::expected. The changes to the rfl::Error class are solid improvements, making it a more well-behaved type. However, I have a couple of suggestions regarding other changes. The modification to std::bad_expected_access<rfl::Error>::error() introduces potential performance and correctness issues, and I've proposed an alternative that is more robust. Additionally, a change in Parser_variant.hpp seems to degrade performance by replacing a move with a copy, which I've recommended reverting if it wasn't for a specific compiler workaround.