diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 1c8a2ea575f..6b8c82fde71 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -899,6 +899,7 @@ impl Session {
         ret
     }
 
+    /// Is this edition 2015?
     pub fn rust_2015(&self) -> bool {
         self.edition().rust_2015()
     }
diff --git a/compiler/rustc_span/src/edition.rs b/compiler/rustc_span/src/edition.rs
index b43183916bc..db1cde985d3 100644
--- a/compiler/rustc_span/src/edition.rs
+++ b/compiler/rustc_span/src/edition.rs
@@ -76,6 +76,7 @@ impl Edition {
         }
     }
 
+    /// Is this edition 2015?
     pub fn rust_2015(&self) -> bool {
         *self == Edition::Edition2015
     }