fn transcribe_metavar_expr<'a>(
dcx: DiagCtxtHandle<'a>,
expr: &MetaVarExpr,
interp: &FxHashMap<MacroRulesNormalizedIdent, NamedMatch>,
marker: &mut Marker,
repeats: &[(usize, usize)],
result: &mut Vec<TokenTree>,
sp: &DelimSpan,
symbol_gallery: &SymbolGallery,
) -> PResult<'a, ()>