diff --git a/compiler/rustc_error_codes/src/error_codes/E0371.md b/compiler/rustc_error_codes/src/error_codes/E0371.md
index a44721346e20d..aacaee0c1b6e0 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0371.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0371.md
@@ -7,10 +7,18 @@ trait Foo { fn foo(&self) { } }
 trait Bar: Foo { }
 trait Baz: Bar { }
 
-impl Bar for Baz { } // error, `Baz` implements `Bar` by definition
-impl Foo for Baz { } // error, `Baz` implements `Bar` which implements `Foo`
-impl Baz for Baz { } // error, `Baz` (trivially) implements `Baz`
-impl Baz for Bar { } // Note: This is OK
+impl Bar for dyn Baz { } // error, `Baz` implements `Bar` by definition
+impl Foo for dyn Baz { } // error, `Baz` implements `Bar` which implements `Foo`
+impl Baz for dyn Baz { } // error, `Baz` (trivially) implements `Baz`
+```
+
+This is okay, because `Bar` does not implement `Baz` by definition:
+
+```
+# trait Foo { fn foo(&self) { } }
+# trait Bar: Foo { }
+# trait Baz: Bar { }
+impl Baz for dyn Bar { } // Note: This is OK
 ```
 
 When `Trait2` is a subtrait of `Trait1` (for example, when `Trait2` has a