<filesystem> Should path::make_preferred collapse directory_separators?

I think this deserves an L[E]WG issue. TL;DR, should it be that:

path p("a////b");
p.make_preferred();
assert(p.string() == "a\\\\\\\\b");

or

path p("a////b");
p.make_preferred();
assert(p.string() == "a\\b");

?

The standard for make_preferred says: http://eel.is/c++draft/fs.class.path#fs.path.modifiers-2

Effects: Each directory-separator of the pathname in the generic format is converted to preferred-separator.

with examples showing /s replaced with \s on Windows. Upon closer inspection, however, directory-separator is defined as any number of directory separator characters. From http://eel.is/c++draft/fs.path.generic

directory-separator:
preferred-separator directory-separator(opt)
fallback-separator fallback-separator(opt)

preferred-separator:
operating system dependent directory separator character

fallback-separator:
/ if preferred-separator is not /

The microsoft/STL implements this by replacing all /s with \s in the path:

https://github.com/microsoft/STL/blob/bd7adb4a932725f60ba096580c415616486ab64c/stl/inc/filesystem#L913

(I probably wrote this code so you know who to blame 😅)

as does Boost:

https://github.com/boostorg/filesystem/blob/87d3c1fd8ab94c188719681ee0bb8f63c2998586/src/path.cpp#L231

Start with the C++ standard clauses for path::make_preferred and the directory-separator definition, then inspect stl/inc/filesystem at the referenced line and compare Boost's implementation. Determine whether repeated separators should be preserved or collapsed and whether an LWG issue is needed; done means the expected behavior is resolved and documented.