diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index 01e234c9be9..cbeaa6018d1 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -914,6 +914,7 @@ impl<'a> State<'a> {
 
     pub fn print_assoc_constraint(&mut self, constraint: &ast::AssocTyConstraint) {
         self.print_ident(constraint.ident);
+        constraint.gen_args.as_ref().map(|args| self.print_generic_args(args, false));
         self.s.space();
         match &constraint.kind {
             ast::AssocTyConstraintKind::Equality { ty } => {
diff --git a/src/test/pretty/gat-bounds.rs b/src/test/pretty/gat-bounds.rs
index 789e4bc80ac..8877c6cc992 100644
--- a/src/test/pretty/gat-bounds.rs
+++ b/src/test/pretty/gat-bounds.rs
@@ -13,4 +13,6 @@ impl X for () {
     type Y<T> where Self: Sized = u32;
 }
 
+fn f<T: X<Y<()> = i32>>() {}
+
 fn main() { }