diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index 1ca071560618..c85d6f454321 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -1415,6 +1415,9 @@ fn print_formal_generic_params(&mut self, generic_params: &[ast::GenericParam])
     }
 
     fn print_poly_trait_ref(&mut self, t: &ast::PolyTraitRef) {
+        if let ast::Parens::Yes = t.parens {
+            self.popen();
+        }
         self.print_formal_generic_params(&t.bound_generic_params);
 
         let ast::TraitBoundModifiers { constness, asyncness, polarity } = t.modifiers;
@@ -1437,7 +1440,10 @@ fn print_poly_trait_ref(&mut self, t: &ast::PolyTraitRef) {
             }
         }
 
-        self.print_trait_ref(&t.trait_ref)
+        self.print_trait_ref(&t.trait_ref);
+        if let ast::Parens::Yes = t.parens {
+            self.pclose();
+        }
     }
 
     fn print_stmt(&mut self, st: &ast::Stmt) {
diff --git a/tests/pretty/paren-trait-bound.rs b/tests/pretty/paren-trait-bound.rs
new file mode 100644
index 000000000000..98e75308abfe
--- /dev/null
+++ b/tests/pretty/paren-trait-bound.rs
@@ -0,0 +1,11 @@
+//@ pp-exact
+
+trait Dummy {}
+
+// Without parens, `+ Send` would bind to `dyn Dummy` instead of the outer `dyn`.
+fn f1(_: Box<dyn (Fn() -> Box<dyn Dummy>) + Send>) {}
+
+// Without parens, `+ Send + Sync` would bind to `dyn Dummy` instead of the outer `impl`.
+fn f2(_: impl (FnMut(&mut u8) -> &mut dyn Dummy) + Send + Sync) {}
+
+fn main() {}