Improve comments.

Author: ywxt

compiler/rustc_middle/src/mir/mono.rs

@@ -525,14 +525,14 @@ impl<'tcx> CodegenUnit<'tcx> {
         tcx: TyCtxt<'tcx>,
     ) -> Vec<(MonoItem<'tcx>, MonoItemData)> {
         // The codegen tests rely on items being process in the same order as
-        // they appear in the file, so for local items, we sort by node_id first
+        // they appear in the file, so for local items, we sort by span and
+        // def_path first
         #[derive(PartialEq, Eq, PartialOrd, Ord)]
         struct ItemSortKey<'tcx>(Option<Span>, Option<String>, SymbolName<'tcx>);
 
-        // We only want to take HirIds of user-defined
-        // instances into account. The others don't matter for
-        // the codegen tests and can even make item order
-        // unstable.
+        // We only want to take HirIds of user-defines instances into account.
+        // The others don't matter for the codegen tests and can even make item
+        // order unstable.
         fn local_item_query<'tcx, T>(
             item: MonoItem<'tcx>,
             op: impl FnOnce(DefId) -> T,

src/tools/compiletest/src/runtest.rs

@@ -1695,7 +1695,7 @@ impl<'test> TestCx<'test> {
             TestMode::Assembly | TestMode::Codegen => {
                 rustc.arg("-Cdebug-assertions=no");
                 // For assembly and codegen tests, we want to use the same order
-                // of the items of a codegen unit as the source order，so that
+                // of the items of a codegen unit as the source order, so that
                 // we can compare the output with the source code through filecheck.
                 rustc.arg("-Zcodegen-source-order");
             }