diff --git a/clippy_utils/src/ast_utils.rs b/clippy_utils/src/ast_utils.rs
index 0467a8a6570..81a26a12009 100644
--- a/clippy_utils/src/ast_utils.rs
+++ b/clippy_utils/src/ast_utils.rs
@@ -144,6 +144,7 @@ pub fn eq_expr(l: &Expr, r: &Expr) -> bool {
         (Paren(l), _) => eq_expr(l, r),
         (_, Paren(r)) => eq_expr(l, r),
         (Err, Err) => true,
+        (Dummy, _) | (_, Dummy) => unreachable!("comparing `ExprKind::Dummy`"),
         (Try(l), Try(r)) | (Await(l, _), Await(r, _)) => eq_expr(l, r),
         (Array(l), Array(r)) => over(l, r, |l, r| eq_expr(l, r)),
         (Tup(l), Tup(r)) => over(l, r, |l, r| eq_expr(l, r)),
diff --git a/clippy_utils/src/sugg.rs b/clippy_utils/src/sugg.rs
index b355e66b7b1..7b1b0388b29 100644
--- a/clippy_utils/src/sugg.rs
+++ b/clippy_utils/src/sugg.rs
@@ -222,7 +222,8 @@ pub fn ast(
             | ast::ExprKind::Array(..)
             | ast::ExprKind::While(..)
             | ast::ExprKind::Await(..)
-            | ast::ExprKind::Err => Sugg::NonParen(snippet_with_context(cx, expr.span, ctxt, default, app).0),
+            | ast::ExprKind::Err
+            | ast::ExprKind::Dummy => Sugg::NonParen(snippet_with_context(cx, expr.span, ctxt, default, app).0),
             ast::ExprKind::Range(ref lhs, ref rhs, RangeLimits::HalfOpen) => Sugg::BinOp(
                 AssocOp::DotDot,
                 lhs.as_ref().map_or("".into(), |lhs| {