diff --git a/src/core/sv_parser.rs b/src/core/sv_parser.rs
index 87ba0f4..54fe03b 100644
--- a/src/core/sv_parser.rs
+++ b/src/core/sv_parser.rs
@@ -351,10 +351,17 @@ fn get_first_last_locate(x: &sv_parser::NeedGetLocate) -> Option<(Locate, Locate
                         }
                     }
                     Some(RefNode::OutputTerminal(x)) => {
-                        let id = unwrap_node!(x, Identifier).unwrap();
-                        let locate = get_identifier(id).unwrap();
-                        if locate != last_locate { last_locate = locate; }
-                        if first_locate.offset == 0 { first_locate = locate; };
+                        if let Some(id) = unwrap_node!(x, Identifier) {
+                            let locate = get_identifier(id).unwrap();
+                            if locate != last_locate { last_locate = locate; }
+                            if first_locate.offset == 0 { first_locate = locate; };
+                        } else if let Some(RefNode::Expression(x)) = unwrap_node!(x, Expression) {
+                            let exp = sv_parser::NeedParseExpression::Expression(x.clone());
+                            if let Some(locate) = parse_expression_only_locate(&exp) {
+                                if locate != last_locate { last_locate = locate; }
+                                if first_locate.offset == 0 { first_locate = locate; };
+                            }
+                        }
                     }
                     _ => ()
                 }