clean up few alloc

src/librustdoc/html/format.rs

@@ -1480,7 +1480,7 @@ pub(crate) fn visibility_print_with_space<'a, 'tcx: 'a>(
                 debug!("path={:?}", path);
                 // modified from `resolved_path()` to work with `DefPathData`
                 let last_name = path.data.last().unwrap().data.get_opt_name().unwrap();
-                let anchor = anchor(vis_did, last_name, cx).to_string();
+                let anchor = anchor(vis_did, last_name, cx);
 
                 let mut s = "pub(in ".to_owned();
                 for seg in &path.data[..path.data.len() - 1] {

src/librustdoc/html/render/context.rs

@@ -352,7 +352,7 @@ impl<'tcx> Context<'tcx> {
                 },
             );
 
-            path = href.into_inner().to_string_lossy().to_string();
+            path = href.into_inner().to_string_lossy().into_owned();
 
             if let Some(c) = path.as_bytes().last() && *c != b'/' {
                 path.push('/');

src/librustdoc/html/sources.rs

@@ -85,7 +85,7 @@ impl LocalSourcesCollector<'_, '_> {
             },
         );
 
-        let mut href = href.into_inner().to_string_lossy().to_string();
+        let mut href = href.into_inner().to_string_lossy().into_owned();
         if let Some(c) = href.as_bytes().last() && *c != b'/' {
             href.push('/');
         }

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -286,7 +286,6 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
             split.next().map(|f|  Symbol::intern(f)).ok_or_else(no_res)?;
         let path = split
             .next()
-            .map(|f| f.to_owned())
             // If there's no third component, we saw `[a::b]` before and it failed to resolve.
             // So there's no partial res.
             .ok_or_else(no_res)?;
@@ -429,7 +428,6 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
         let item_name = Symbol::intern(item_str);
         let path_root = split
             .next()
-            .map(|f| f.to_owned())
             // If there's no `::`, it's not an associated item.
             // So we can be sure that `rustc_resolve` was accurate when it said it wasn't resolved.
             .ok_or_else(|| {