[Bug libstdc++/119121] [14/15 Regression] subrange conversion to tuple-like does not work

[tkaminsk at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119121

--- Comment #1 from Tomasz Kamiński <tkaminsk at gcc dot gnu.org> ---
Introduced in g:65b4cba9d6a9ffe9b4d4bdff90727a7064cc0e3b

The `is_reference_v<_Vp>` should use `_Tp` instead.
```
     template<typename _Tp, typename _Up, typename _Vp>
       concept __pair_like_convertible_from
-       = !range<_Tp> && __pair_like<_Tp>
+       = !range<_Tp> && !is_reference_v<_Vp> && __pair_like<_Tp>
        && constructible_from<_Tp, _Up, _Vp>
        && __convertible_to_non_slicing<_Up, tuple_element_t<0, _Tp>>
        && convertible_to<_Vp, tuple_element_t<1, _Tp>>;
```
This check was previously part of `__pair_like` concept.