Auto merge of #55382 - kennytm:rollup, r=kennytm

Rollup of 21 pull requests

Successful merges:

 - #54816 (Don't try to promote already promoted out temporaries)
 - #54824 (Cleanup rustdoc tests with `@!has` and `@!matches`)
 - #54921 (Add line numbers option to rustdoc)
 - #55167 (Add a "cheap" mode for `compute_missing_ctors`.)
 - #55258 (Fix Rustdoc ICE when checking blanket impls)
 - #55264 (Compile the libstd we distribute with -Ccodegen-unit=1)
 - #55271 (Unimplement ExactSizeIterator for MIR traversing iterators)
 - #55292 (Macro diagnostics tweaks)
 - #55298 (Point at macro definition when no rules expect token)
 - #55301 (List allowed tokens after macro fragments)
 - #55302 (Extend the impl_stable_hash_for! macro for miri.)
 - #55325 (Fix link to macros chapter)
 - #55343 (rustbuild: fix remap-debuginfo when building a release)
 - #55346 (Shrink `Statement`.)
 - #55358 (Remove redundant clone (2))
 - #55370 (Update mailmap for estebank)
 - #55375 (Typo fixes in configure_cmake comments)
 - #55378 (rustbuild: use configured linker to build boostrap)
 - #55379 (validity: assert that unions are non-empty)
 - #55383 (Use `SmallVec` for the queue in `coerce_unsized`.)
 - #55391 (bootstrap: clean up a few clippy findings)

1 files changed, 4 insertions, 4 deletions

diff --git a/src/bootstrap/tool.rs b/src/bootstrap/tool.rs
index 15d27c61342..978e3602e7d 100644
--- a/src/bootstrap/tool.rs
+++ b/src/bootstrap/tool.rs
@@ -148,7 +148,7 @@ impl Step for ToolBuild {
             }
         });
 
-        if is_expected && duplicates.len() != 0 {
+        if is_expected && !duplicates.is_empty() {
             println!("duplicate artfacts found when compiling a tool, this \
                       typically means that something was recompiled because \
                       a transitive dependency has different features activated \
@@ -170,7 +170,7 @@ impl Step for ToolBuild {
                 println!("    `{}` additionally enabled features {:?} at {:?}",
                          prev.0, &prev_features - &cur_features, prev.1);
             }
-            println!("");
+            println!();
             println!("to fix this you will probably want to edit the local \
                       src/tools/rustc-workspace-hack/Cargo.toml crate, as \
                       that will update the dependency graph to ensure that \
@@ -188,7 +188,7 @@ impl Step for ToolBuild {
             if !is_optional_tool {
                 exit(1);
             } else {
-                return None;
+                None
             }
         } else {
             let cargo_out = builder.cargo_out(compiler, self.mode, target)
@@ -251,7 +251,7 @@ pub fn prepare_tool_cargo(
     if let Some(date) = info.commit_date() {
         cargo.env("CFG_COMMIT_DATE", date);
     }
-    if features.len() > 0 {
+    if !features.is_empty() {
         cargo.arg("--features").arg(&features.join(", "));
     }
     cargo