Fix: wrong location with babel-eslint (refs vuejs/eslint-plugin-vue#208)

Author: mysticatea

src/script/index.ts

@@ -35,14 +35,20 @@ interface ESLintCustomParser {
 function postprocess(ast: ESLintProgram, locationCalculator: LocationCalculator): void {
     // There are cases which the same node instance appears twice in the tree.
     // E.g. `let {a} = {}` // This `a` appears twice at `Property#key` and `Property#value`.
-    const traversed = new Set<Node>()
+    const traversed = new Set<Node|number[]>()
 
     traverseNodes(ast, {
         enterNode(node, parent) {
             if (!traversed.has(node)) {
                 traversed.add(node)
                 node.parent = parent
-                locationCalculator.fixLocation(node)
+
+                // `babel-eslint@8` has shared `Node#range` with multiple nodes.
+                // See also: https://github.com/vuejs/eslint-plugin-vue/issues/208
+                if (!traversed.has(node.range)) {
+                    traversed.add(node.range)
+                    locationCalculator.fixLocation(node)
+                }
             }
         },
         leaveNode() {

test/fixtures/location-issue-with-babel-eslint.vue

@@ -0,0 +1,24 @@
+<style>
+</style>
+
+<template>
+  <div id="app">
+    <img src="./assets/logo.png">
+    <hello></hello>
+  </div>
+</template>
+
+<script>
+import { a, b } from './deps';
+import Hello from './components/Hello';
+
+export default {
+  name: 'app',
+  calc (x) {
+    return x + a + b;
+  },
+  components: {
+    Hello
+  }
+}
+</script>

test/index.js

@@ -345,6 +345,29 @@ describe("Basic tests", () => {
         })
     })
 
+    describe("About fixtures/location-issue-with-babel-eslint.vue", () => {
+        it("Identifiers in import declarations should has correct location.", () => {
+            const cli = new CLIEngine({
+                cwd: FIXTURE_DIR,
+                envs: ["browser", "node"],
+                parser: PARSER_PATH,
+                parserOptions: {
+                    parser: "babel-eslint",
+                    sourceType: "module",
+                    ecmaVersion: 2017,
+                },
+                rules: {
+                    "no-use-before-define": "error",
+                },
+                useEslintrc: false,
+            })
+            const report = cli.executeOnFiles(["location-issue-with-babel-eslint.vue"])
+            const messages = report.results[0].messages
+
+            assert(messages.length === 0)
+        })
+    })
+
     describe("About unexpected-null-character errors", () => {
         it("should keep NULL in DATA state.", () => {
             const ast = parse("<template>\u0000</template>")