diff --git a/src/librustc_errors/lib.rs b/src/librustc_errors/lib.rs
index cb45e13c4d2..7da1a652553 100644
--- a/src/librustc_errors/lib.rs
+++ b/src/librustc_errors/lib.rs
@@ -304,17 +304,17 @@ pub struct Handler {
     continue_after_error: AtomicBool,
     delayed_span_bugs: Lock<Vec<Diagnostic>>,
 
-    // This set contains the `DiagnosticId` of all emitted diagnostics to avoid
-    // emitting the same diagnostic with extended help (`--teach`) twice, which
-    // would be uneccessary repetition.
+    /// This set contains the `DiagnosticId` of all emitted diagnostics to avoid
+    /// emitting the same diagnostic with extended help (`--teach`) twice, which
+    /// would be uneccessary repetition.
     taught_diagnostics: Lock<FxHashSet<DiagnosticId>>,
 
     /// Used to suggest rustc --explain <error code>
     emitted_diagnostic_codes: Lock<FxHashSet<DiagnosticId>>,
 
-    // This set contains a hash of every diagnostic that has been emitted by
-    // this handler. These hashes is used to avoid emitting the same error
-    // twice.
+    /// This set contains a hash of every diagnostic that has been emitted by
+    /// this handler. These hashes is used to avoid emitting the same error
+    /// twice.
     emitted_diagnostics: Lock<FxHashSet<u128>>,
 }
 
diff --git a/src/librustc_macros/src/query.rs b/src/librustc_macros/src/query.rs
index e4a6dfcd4e8..8eacbfbacce 100644
--- a/src/librustc_macros/src/query.rs
+++ b/src/librustc_macros/src/query.rs
@@ -55,7 +55,7 @@ enum QueryModifier {
     /// Generate a dep node based on the dependencies of the query
     Anon,
 
-    // Always evaluate the query, ignoring its depdendencies
+    /// Always evaluate the query, ignoring its depdendencies
     EvalAlways,
 }
 
diff --git a/src/libsyntax/test.rs b/src/libsyntax/test.rs
index 6f03c585403..03d0eff266e 100644
--- a/src/libsyntax/test.rs
+++ b/src/libsyntax/test.rs
@@ -327,7 +327,7 @@ fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
     // Writing this out by hand with 'ignored_span':
     //        pub fn main() {
     //            #![main]
-    //            test::test_main_static(::std::os::args().as_slice(), &[..tests]);
+    //            test::test_main_static(&[..tests]);
     //        }
     let sp = ignored_span(cx, DUMMY_SP);
     let ecx = &cx.ext_cx;
diff --git a/src/libsyntax_ext/test.rs b/src/libsyntax_ext/test.rs
index 0dbcb7ce0b7..0fa5cd64360 100644
--- a/src/libsyntax_ext/test.rs
+++ b/src/libsyntax_ext/test.rs
@@ -86,7 +86,7 @@ pub fn expand_test_or_bench(
         cx.path(sp, vec![test_id, cx.ident_of(name)])
     };
 
-    // creates test::$name
+    // creates test::ShouldPanic::$name
     let should_panic_path = |name| {
         cx.path(sp, vec![test_id, cx.ident_of("ShouldPanic"), cx.ident_of(name)])
     };