diff --git a/src/librustc/middle/region.rs b/src/librustc/middle/region.rs
index 6455d7ecf85..39cb5d1b8c8 100644
--- a/src/librustc/middle/region.rs
+++ b/src/librustc/middle/region.rs
@@ -458,10 +458,10 @@ impl<'tcx> RegionMaps {
                                    -> CodeExtent {
         if scope_a == scope_b { return scope_a; }
 
-        /// [1] The initial values for `a_buf` and `b_buf` are not used.
-        /// The `ancestors_of` function will return some prefix that
-        /// is re-initialized with new values (or else fallback to a
-        /// heap-allocated vector).
+        // [1] The initial values for `a_buf` and `b_buf` are not used.
+        // The `ancestors_of` function will return some prefix that
+        // is re-initialized with new values (or else fallback to a
+        // heap-allocated vector).
         let mut a_buf: [CodeExtent; 32] = [scope_a /* [1] */; 32];
         let mut a_vec: Vec<CodeExtent> = vec![];
         let mut b_buf: [CodeExtent; 32] = [scope_b /* [1] */; 32];
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index 69cd1414628..cf5882bb9bd 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -89,23 +89,23 @@ impl<'a, 'gcx> CheckTypeWellFormedVisitor<'a, 'gcx> {
                tcx.item_path_str(tcx.hir.local_def_id(item.id)));
 
         match item.node {
-            /// Right now we check that every default trait implementation
-            /// has an implementation of itself. Basically, a case like:
-            ///
-            /// `impl Trait for T {}`
-            ///
-            /// has a requirement of `T: Trait` which was required for default
-            /// method implementations. Although this could be improved now that
-            /// there's a better infrastructure in place for this, it's being left
-            /// for a follow-up work.
-            ///
-            /// Since there's such a requirement, we need to check *just* positive
-            /// implementations, otherwise things like:
-            ///
-            /// impl !Send for T {}
-            ///
-            /// won't be allowed unless there's an *explicit* implementation of `Send`
-            /// for `T`
+            // Right now we check that every default trait implementation
+            // has an implementation of itself. Basically, a case like:
+            //
+            // `impl Trait for T {}`
+            //
+            // has a requirement of `T: Trait` which was required for default
+            // method implementations. Although this could be improved now that
+            // there's a better infrastructure in place for this, it's being left
+            // for a follow-up work.
+            //
+            // Since there's such a requirement, we need to check *just* positive
+            // implementations, otherwise things like:
+            //
+            // impl !Send for T {}
+            //
+            // won't be allowed unless there's an *explicit* implementation of `Send`
+            // for `T`
             hir::ItemImpl(_, hir::ImplPolarity::Positive, _, _,
                           ref trait_ref, ref self_ty, _) => {
                 self.check_impl(item, self_ty, trait_ref);