Update: fix false negative of no-useless-escape in template literal tags (#8238)

Author: not-an-aardvark

lib/rules/no-useless-escape.js

@@ -147,7 +147,13 @@ module.exports = {
         function check(node) {
             const isTemplateElement = node.type === "TemplateElement";
 
-            if (isTemplateElement && node.parent && node.parent.parent && node.parent.parent.type === "TaggedTemplateExpression") {
+            if (
+                isTemplateElement &&
+                node.parent &&
+                node.parent.parent &&
+                node.parent.parent.type === "TaggedTemplateExpression" &&
+                node.parent === node.parent.parent.quasi
+            ) {
 
                 // Don't report tagged template literals, because the backslash character is accessible to the tag function.
                 return;

tests/lib/rules/no-useless-escape.js

@@ -269,6 +269,11 @@ ruleTester.run("no-useless-escape", rule, {
             code: "`multiline template\nliteral with useless \\escape`",
             parserOptions: { ecmaVersion: 6 },
             errors: [{ line: 2, column: 22, message: "Unnecessary escape character: \\e.", type: "TemplateElement" }]
+        },
+        {
+            code: "`\\a```",
+            parserOptions: { ecmaVersion: 6 },
+            errors: [{ line: 1, column: 2, message: "Unnecessary escape character: \\a.", type: "TemplateElement" }]
         }
     ]
 });