From af13f8dd2c18cf6c7c862f225bde24fc52c0317f Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Fri, 31 Jul 2020 15:50:16 +0100
Subject: [PATCH] improve diagnostics upon AST validation failure (#4033)

---
 lib/ast.js | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/ast.js b/lib/ast.js
index 093e192c..2c27cbbe 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -123,7 +123,14 @@ var AST_Node = DEFNODE("Node", "start end", {
     validate_ast: function() {
         var marker = {};
         this.walk(new TreeWalker(function(node) {
-            if (node.validate_visited === marker) throw new Error("invalid node reuse: " + node);
+            if (node.validate_visited === marker) {
+                throw new Error(string_template("cannot reuse {type} from [{file}:{line},{col}]", {
+                    type: "AST_" + node.TYPE,
+                    file: node.start.file,
+                    line: node.start.line,
+                    col: node.start.col,
+                }));
+            }
             node.validate_visited = marker;
         }));
     },
-- 
2.34.1