rustdoc: few small cleanups

src/librustdoc/formats/cache.rs

@@ -242,7 +242,7 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
         }
 
         // Index this method for searching later on.
-        if let Some(ref s) = item.name.or_else(|| {
+        if let Some(s) = item.name.or_else(|| {
             if item.is_stripped() {
                 None
             } else if let clean::ImportItem(ref i) = *item.kind &&
@@ -317,14 +317,15 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
                             short_markdown_summary(x.as_str(), &item.link_names(self.cache))
                         });
                         let ty = item.type_();
-                        let name = s.to_string();
-                        if ty != ItemType::StructField || u16::from_str_radix(&name, 10).is_err() {
+                        if ty != ItemType::StructField
+                            || u16::from_str_radix(s.as_str(), 10).is_err()
+                        {
                             // In case this is a field from a tuple struct, we don't add it into
                             // the search index because its name is something like "0", which is
                             // not useful for rustdoc search.
                             self.cache.search_index.push(IndexItem {
                                 ty,
-                                name,
+                                name: s,
                                 path: join_with_double_colon(path),
                                 desc,
                                 parent,

src/librustdoc/html/format.rs

@@ -569,7 +569,7 @@ fn generate_macro_def_id_path(
     root_path: Option<&str>,
 ) -> Result<(String, ItemType, Vec<Symbol>), HrefError> {
     let tcx = cx.shared.tcx;
-    let crate_name = tcx.crate_name(def_id.krate).to_string();
+    let crate_name = tcx.crate_name(def_id.krate);
     let cache = cx.cache();
 
     let fqp: Vec<Symbol> = tcx
@@ -584,7 +584,7 @@ fn generate_macro_def_id_path(
             }
         })
         .collect();
-    let mut relative = fqp.iter().map(|elem| elem.to_string());
+    let mut relative = fqp.iter().copied();
     let cstore = CStore::from_tcx(tcx);
     // We need this to prevent a `panic` when this function is used from intra doc links...
     if !cstore.has_crate_data(def_id.krate) {
@@ -602,9 +602,9 @@ fn generate_macro_def_id_path(
     };
 
     let mut path = if is_macro_2 {
-        once(crate_name.clone()).chain(relative).collect()
+        once(crate_name).chain(relative).collect()
     } else {
-        vec![crate_name.clone(), relative.next_back().unwrap()]
+        vec![crate_name, relative.next_back().unwrap()]
     };
     if path.len() < 2 {
         // The minimum we can have is the crate name followed by the macro name. If shorter, then
@@ -614,17 +614,22 @@ fn generate_macro_def_id_path(
     }
 
     if let Some(last) = path.last_mut() {
-        *last = format!("macro.{}.html", last);
+        *last = Symbol::intern(&format!("macro.{}.html", last.as_str()));
     }
 
     let url = match cache.extern_locations[&def_id.krate] {
         ExternalLocation::Remote(ref s) => {
             // `ExternalLocation::Remote` always end with a `/`.
-            format!("{}{}", s, path.join("/"))
+            format!("{}{}", s, path.iter().map(|p| p.as_str()).join("/"))
         }
         ExternalLocation::Local => {
             // `root_path` always end with a `/`.
-            format!("{}{}/{}", root_path.unwrap_or(""), crate_name, path.join("/"))
+            format!(
+                "{}{}/{}",
+                root_path.unwrap_or(""),
+                crate_name,
+                path.iter().map(|p| p.as_str()).join("/")
+            )
         }
         ExternalLocation::Unknown => {
             debug!("crate {} not in cache when linkifying macros", crate_name);
@@ -1050,7 +1055,7 @@ fn fmt_type<'cx>(
                 _ => String::new(),
             };
             let m = mutability.print_with_space();
-            let amp = if f.alternate() { "&".to_string() } else { "&amp;".to_string() };
+            let amp = if f.alternate() { "&" } else { "&amp;" };
             match **ty {
                 clean::DynTrait(ref bounds, ref trait_lt)
                     if bounds.len() > 1 || trait_lt.is_some() =>

src/librustdoc/html/markdown.rs

@@ -30,7 +30,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::HirId;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::edition::Edition;
-use rustc_span::Span;
+use rustc_span::{Span, Symbol};
 
 use once_cell::sync::Lazy;
 use std::borrow::Cow;
@@ -198,7 +198,7 @@ fn slugify(c: char) -> Option<char> {
 
 #[derive(Clone, Debug)]
 pub struct Playground {
-    pub crate_name: Option<String>,
+    pub crate_name: Option<Symbol>,
     pub url: String,
 }
 
@@ -290,7 +290,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                 .map(|l| map_line(l).for_code())
                 .intersperse("\n".into())
                 .collect::<String>();
-            let krate = krate.as_ref().map(|s| &**s);
+            let krate = krate.as_ref().map(|s| s.as_str());
             let (test, _, _) =
                 doctest::make_test(&test, krate, false, &Default::default(), edition, None);
             let channel = if test.contains("#![feature(") { "&amp;version=nightly" } else { "" };

src/librustdoc/html/render/context.rs

@@ -464,8 +464,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
         // If user passed in `--playground-url` arg, we fill in crate name here
         let mut playground = None;
         if let Some(url) = playground_url {
-            playground =
-                Some(markdown::Playground { crate_name: Some(krate.name(tcx).to_string()), url });
+            playground = Some(markdown::Playground { crate_name: Some(krate.name(tcx)), url });
         }
         let mut layout = layout::Layout {
             logo: String::new(),
@@ -491,7 +490,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
                 }
                 (sym::html_playground_url, Some(s)) => {
                     playground = Some(markdown::Playground {
-                        crate_name: Some(krate.name(tcx).to_string()),
+                        crate_name: Some(krate.name(tcx)),
                         url: s.to_string(),
                     });
                 }

src/librustdoc/html/render/mod.rs

@@ -100,7 +100,7 @@ pub(crate) fn ensure_trailing_slash(v: &str) -> impl fmt::Display + '_ {
 #[derive(Debug)]
 pub(crate) struct IndexItem {
     pub(crate) ty: ItemType,
-    pub(crate) name: String,
+    pub(crate) name: Symbol,
     pub(crate) path: String,
     pub(crate) desc: String,
     pub(crate) parent: Option<DefId>,
@@ -2769,8 +2769,8 @@ fn collect_paths_for_type(first_ty: clean::Type, cache: &Cache) -> Vec<String> {
     let mut work = VecDeque::new();
 
     let mut process_path = |did: DefId| {
-        let get_extern = || cache.external_paths.get(&did).map(|s| s.0.clone());
-        let fqp = cache.exact_paths.get(&did).cloned().or_else(get_extern);
+        let get_extern = || cache.external_paths.get(&did).map(|s| &s.0);
+        let fqp = cache.exact_paths.get(&did).or_else(get_extern);
 
         if let Some(path) = fqp {
             out.push(join_with_double_colon(&path));

src/librustdoc/html/render/print_item.rs

@@ -1027,8 +1027,8 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
         .chain(std::iter::once("implementors"))
         .collect();
     if let Some(did) = it.item_id.as_def_id() &&
-        let get_extern = { || cache.external_paths.get(&did).map(|s| s.0.clone()) } &&
-        let Some(fqp) = cache.exact_paths.get(&did).cloned().or_else(get_extern) {
+        let get_extern = { || cache.external_paths.get(&did).map(|s| &s.0) } &&
+        let Some(fqp) = cache.exact_paths.get(&did).or_else(get_extern) {
         js_src_path.extend(fqp[..fqp.len() - 1].iter().copied());
         js_src_path.push_fmt(format_args!("{}.{}.js", it.type_(), fqp.last().unwrap()));
     } else {

src/librustdoc/html/render/search_index.rs

@@ -35,7 +35,7 @@ pub(crate) fn build_index<'tcx>(
                 .map_or_else(String::new, |s| short_markdown_summary(&s, &item.link_names(cache)));
             cache.search_index.push(IndexItem {
                 ty: item.type_(),
-                name: item.name.unwrap().to_string(),
+                name: item.name.unwrap(),
                 path: join_with_double_colon(&fqp[..fqp.len() - 1]),
                 desc,
                 parent: Some(parent),
@@ -58,8 +58,8 @@ pub(crate) fn build_index<'tcx>(
     // Sort search index items. This improves the compressibility of the search index.
     cache.search_index.sort_unstable_by(|k1, k2| {
         // `sort_unstable_by_key` produces lifetime errors
-        let k1 = (&k1.path, &k1.name, &k1.ty, &k1.parent);
-        let k2 = (&k2.path, &k2.name, &k2.ty, &k2.parent);
+        let k1 = (&k1.path, k1.name.as_str(), &k1.ty, &k1.parent);
+        let k2 = (&k2.path, k2.name.as_str(), &k2.ty, &k2.parent);
         std::cmp::Ord::cmp(&k1, &k2)
     });
 
@@ -240,7 +240,7 @@ pub(crate) fn build_index<'tcx>(
             )?;
             crate_data.serialize_field(
                 "n",
-                &self.items.iter().map(|item| &item.name).collect::<Vec<_>>(),
+                &self.items.iter().map(|item| item.name.as_str()).collect::<Vec<_>>(),
             )?;
             crate_data.serialize_field(
                 "q",
@@ -299,7 +299,7 @@ pub(crate) fn build_index<'tcx>(
             )?;
             crate_data.serialize_field(
                 "p",
-                &self.paths.iter().map(|(it, s)| (it, s.to_string())).collect::<Vec<_>>(),
+                &self.paths.iter().map(|(it, s)| (it, s.as_str())).collect::<Vec<_>>(),
             )?;
             if has_aliases {
                 crate_data.serialize_field("a", &self.aliases)?;