Thanks for the fix and the detailed explanation!

Hum, the nonmovable range always seems problematic to me (although format_parse_context is necessary for its existence).

#include <ranges>

struct ImmovableRange {
  using value_type = int;
  ImmovableRange();
  ImmovableRange(ImmovableRange&&) = delete;

  int* begin();
  int* end();
  void push_back(value_type);
};

using R = int[1];

void test() {
  (void)std::ranges::to<ImmovableRange>(R{}); // hard error
}

Hum, the nonmovable range always seems problematic to me (although format_parse_context is necessary for its existence).

I don't understand what this comment is saying about the change in this PR.

I don't understand what this comment is saying about the change in this PR.

Not sure why I made this comment in the first place.
Here are the exact comments about the PR:
Why don't we follow the wording and use more nested if conditions, for example:

if constexpr (_Ref_converts<_Rng, _Container>) {
    if constexpr (/* */) {
        // ...
    } else if constexpr (/* */) {
        // ...
    } else if constexpr (/* */) {
        // ...
    } else if constexpr (/* */) {
        // ...
    } else {
        static_assert(_Always_false<_Container>, "the program is ill-formed per N4950 [range.utility.conv.to]/2.3");
    }
    // ...
} else if constexpr (input_range<range_reference_t<_Rng>>) {
    // ...
} else {
    static_assert(_Always_false<_Container>, "the program is ill-formed per N4950 [range.utility.conv.to]/2.3");
}

instead use a less-nested but repeatedly-checked structure?

if constexpr (_Ref_converts<_Rng, _Container> && /* */) {
    // ...
} else if constexpr (_Ref_converts<_Rng, _Container> && /* */) {
    // ...
} else if constexpr (_Ref_converts<_Rng, _Container> && /* */) {
    // ...
} else if constexpr (_Ref_converts<_Rng, _Container> && /* */) {
    // ...
} else if constexpr (!_Ref_converts<_Rng, _Container> && input_range<range_reference_t<_Rng>>) {
    // ...
} else {
    static_assert(_Always_false<_Container>, "the program is ill-formed per N4950 [range.utility.conv.to]/2.3");
}

I think it is more appropriate to strictly adhere to the first structure especially after the editorial enhancements #6568 (Although both forms are currently equivalent).

I'm speculatively mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

Here are the exact comments about the PR: Why don't we follow the wording and use more nested if conditions, for example:
[snip]

I don't recall now why I used this structure, maybe it was simply to avoid repeating the static_assert? In any case, I agree it would be clearer if we more closely followed the structure of the Standard wording. I'd be happy to approve a PR making that change.

Thanks for fixing this bug where for your PR I commented, Thanks for fixing this bug where for your PR I commented, Thanks for fixing this bug where for your PR I commented, 😹 🎉 🤪