Inline str::repeat `str` is non-generic and `str.repeat()` doesn't get inlined, which makes it use a slower algorithm in case of 1-char repetitions. Equivalent byte slice does get inlined: https://rust.godbolt.org/z/4arvh97r4
proc_macro::ToTokens
profiler_builtins
&Option<T>
Option<&T>
compiler_builtins