diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index 454f197220c5..7d7b73ebb424 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -412,7 +412,8 @@ impl<'a> TraitDef<'a> {
                     _ => {
                         // Non-ADT derive is an error, but it should have been
                         // set earlier; see
-                        // libsyntax/ext/expand.rs:MacroExpander::expand()
+                        // libsyntax_expand/expand.rs:MacroExpander::fully_expand_fragment()
+                        // libsyntax_expand/base.rs:Annotatable::derive_allowed()
                         return;
                     }
                 };
@@ -486,7 +487,8 @@ impl<'a> TraitDef<'a> {
             _ => {
                 // Non-Item derive is an error, but it should have been
                 // set earlier; see
-                // libsyntax/ext/expand.rs:MacroExpander::expand()
+                // libsyntax_expand/expand.rs:MacroExpander::fully_expand_fragment()
+                // libsyntax_expand/base.rs:Annotatable::derive_allowed()
                 return;
             }
         }
diff --git a/src/libsyntax_ext/deriving/mod.rs b/src/libsyntax_ext/deriving/mod.rs
index d5c8bada1451..ca4d4fbc5bd1 100644
--- a/src/libsyntax_ext/deriving/mod.rs
+++ b/src/libsyntax_ext/deriving/mod.rs
@@ -92,7 +92,8 @@ fn inject_impl_of_structural_trait(
         _ => {
             // Non-Item derive is an error, but it should have been
             // set earlier; see
-            // libsyntax/ext/expand.rs:MacroExpander::expand()
+            // libsyntax_expand/expand.rs:MacroExpander::fully_expand_fragment()
+            // libsyntax_expand/base.rs:Annotatable::derive_allowed()
             return;
         }
     };