False positive `clangd(unused-includes)` with deduced return `operator<=>`

[Eisenwave]

The following code raises clang(implied_comparison_category_type_not_found):

struct awoo {
    friend auto operator<=>(awoo,awoo) = default;
};

The following code then raises: clangd(unused-includes):

#include <compare>
struct awoo {
    friend auto operator<=>(awoo,awoo) = default;
};

Not sure how to reproduce on Compiler Explorer.

To fix it, one must use std::strong_ordering instead of auto.

[llvmbot]

@llvm/issue-subscribers-clang-include-cleaner

Author: Jan Schultke (Eisenwave)

The following code raises `clang(implied_comparison_category_type_not_found)`: ```cpp struct awoo { friend auto operator<=>(awoo,awoo) = default; }; ``` The following code then raises: `clangd(unused-includes)`: ```cpp #include <compare> struct awoo { friend auto operator<=>(awoo,awoo) = default; }; ``` Not sure how to reproduce on Compiler Explorer.

To fix it, one must use std::strong_ordering instead of auto.