Fix: crash if <tbody> was omitted

Author: mysticatea

lib/transform-html.js

@@ -629,6 +629,26 @@ class HTMLTransformer {
      * @returns {ASTNode|ASTNode[]} The transformed node.
      */
     visitElementNode(parent, node) {
+        // if __location does not exists, this is auto-inserted element for some reason.
+        // E.g. if a <tr> exists as a direct child of <table>, <tbody> element is inserted implicitly.
+        if (node.__location == null) {
+            const results = []
+            for (const childNode of node.childNodes) {
+                const child = this.visit(parent, childNode)
+
+                // Flatten.
+                if (Array.isArray(child)) {
+                    for (const child1 of child) {
+                        results.push(child1)
+                    }
+                }
+                else if (child != null) {
+                    results.push(child)
+                }
+            }
+            return results
+        }
+
         const start = node.__location.startOffset
         const end = node.__location.endOffset
         const childNodes = (node.tagName === "template")