diff --git a/src/format.jule b/src/format.jule
index dd93153..6a74440 100644
--- a/src/format.jule
+++ b/src/format.jule
@@ -1065,8 +1065,10 @@ impl ScopeFormatter {
             match type it.kind {
             | &ast::WhileKind:
                 let mut wk = (&ast::WhileKind)(it.kind)
-                self.fmt.pop_row_comments_by_c(wk.expr.token.row, wk.expr.token.column)
-                self.fmt.format_expr(wk.expr)
+                if wk.expr != nil {
+                    self.fmt.pop_row_comments_by_c(wk.expr.token.row, wk.expr.token.column)
+                    self.fmt.format_expr(wk.expr)
+                }
                 if wk.next != nil {
                     self.write("; ")
                     self.format_stmt(wk.next)