diff --git a/.mailmap b/.mailmap
index 3e512377d0377..8b5e9f96b3d8d 100644
--- a/.mailmap
+++ b/.mailmap
@@ -263,6 +263,7 @@ Xuefeng Wu <benewu@gmail.com> Xuefeng Wu <xfwu@thoughtworks.com>
 Xuefeng Wu <benewu@gmail.com> XuefengWu <benewu@gmail.com>
 York Xiang <bombless@126.com>
 Youngsoo Son <ysson83@gmail.com> <ysoo.son@samsung.com>
+Yuki Okushi <huyuumi.dev@gmail.com>
 Zach Pomerantz <zmp@umich.edu>
 Zack Corr <zack@z0w0.me> <zackcorr95@gmail.com>
 Zack Slayton <zack.slayton@gmail.com>
diff --git a/src/librustc_mir/borrow_check/universal_regions.rs b/src/librustc_mir/borrow_check/universal_regions.rs
index 141289bd2b2d3..4e3aa4c65b6a8 100644
--- a/src/librustc_mir/borrow_check/universal_regions.rs
+++ b/src/librustc_mir/borrow_check/universal_regions.rs
@@ -5,7 +5,7 @@
 //! fn foo<'a, 'b, 'c: 'b>() { }
 //! ```
 //!
-//! here we would be returning a map assigning each of `{'a, 'b, 'c}`
+//! here we would return a map assigning each of `{'a, 'b, 'c}`
 //! to an index, as well as the `FreeRegionMap` which can compute
 //! relationships between them.
 //!
diff --git a/src/libstd/env.rs b/src/libstd/env.rs
index 60facd9f8d468..13fe3bda525ae 100644
--- a/src/libstd/env.rs
+++ b/src/libstd/env.rs
@@ -6,7 +6,7 @@
 //!
 //! There are several functions and structs in this module that have a
 //! counterpart ending in `os`. Those ending in `os` will return an [`OsString`]
-//! and those without will be returning a [`String`].
+//! and those without will return a [`String`].
 //!
 //! [`OsString`]: ../../std/ffi/struct.OsString.html
 //! [`String`]: ../string/struct.String.html
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index 454f197220c54..7d7b73ebb4247 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 d5c8bada1451f..ca4d4fbc5bd1d 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;
         }
     };