diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 3ba4c11e2c1fa..ed5a282ec0635 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -2668,7 +2668,7 @@ pub struct Trait {
 /// are concatenated together.
 ///
 /// Take this example:
-/// ```rust, ignore
+/// ```ignore (only-for-syntax-highlight)
 /// trait Foo {
 ///   type Assoc<'a, 'b> where Self: 'a, Self: 'b;
 /// }
@@ -2677,9 +2677,9 @@ pub struct Trait {
 ///   //                 ^^^^^^^^^^^^^^ first where clause
 ///   //                                     ^^^^^^^^^^^^^^ second where clause
 /// }
+/// ```
 ///
 /// If there is no where clause, then this is `false` with `DUMMY_SP`.
-/// ```
 #[derive(Copy, Clone, Encodable, Decodable, Debug, Default)]
 pub struct TyAliasWhereClause(pub bool, pub Span);