Divergence between std and fmt on ranges formatting

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
63/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
cpp
Domain
tooling

Research direction

Run the provided C++ example and compare fmt::println with std::println for the repeated-character view. Read the range-formatting implementation and its existing tests to locate how {:s} handles this range. Done means a regression test confirms fmt matches the standard library's unquoted output.

Written by the indexing model from the issue text.

Description

fmt emits surrouding quotes on {:s}, while std doesn't

#include <fmt/format.h>
#include <fmt/ranges.h>
#include <fmt/std.h>
#include <print>
#include <algorithm>
#include <ranges>

int main() {
    std::println("...{:s}...", std::views::repeat('x', 4)); // prints ...xxxx...
    fmt::println("...{:s}...", std::views::repeat('x', 4)); // prints ..."xxxx"...
}

https://godbolt.org/z/3ezsWYhvE

Dominant language
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