Rollup merge of #141377 - nnethercote:rm-unnecessary-is_empty-checks, r=GuillaumeGomez

Remove unnecessary `is_empty` checks
Part of #137978.
r? `@GuillaumeGomez`

Author: matthiaskrgr

compiler/rustc_span/src/symbol.rs

@@ -2823,7 +2823,7 @@ impl Ident {
 /// Whether this would be the identifier for a tuple field like `self.0`, as
 /// opposed to a named field like `self.thing`.
 pubfnis_numeric(self) -> bool{
-!self.name.is_empty() && self.as_str().bytes().all(|b| b.is_ascii_digit())
+self.as_str().bytes().all(|b| b.is_ascii_digit())
 }
 }
 

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -59,12 +59,7 @@ fn filter_assoc_items_by_name_and_namespace(
 ident:Ident,
 ns:Namespace,
 ) -> implIterator<Item = &ty::AssocItem>{
-let iter:Box<dynIterator<Item = &ty::AssocItem>> = if !ident.name.is_empty(){
-Box::new(tcx.associated_items(assoc_items_of).filter_by_name_unhygienic(ident.name))
-}else{
-Box::new([].iter())
-};
- iter.filter(move |item| {
+ tcx.associated_items(assoc_items_of).filter_by_name_unhygienic(ident.name).filter(move |item| {
  item.namespace() == ns && tcx.hygienic_eq(ident, item.ident(tcx), assoc_items_of)
 })
 }