Merge pull request babel/babel-eslint#140 from hzoo/i-138

create scope for each comprehension - fixes babel/babel-eslint#138

eslint/babel-eslint-parser/index.js

@@ -300,22 +300,41 @@ function monkeypatch() {
     }
   };
 
-  referencer.prototype.ComprehensionBlock = function(node) {
+  referencer.prototype.ComprehensionExpression = function(node) {
-    var left = node.left;
+    for (var i = 0; i < node.blocks.length; i++) {
-    if (left) {
+      var block = node.blocks[i];
+      if (block.left) {
+        var scope = new escope.Scope(this.scopeManager, "comprehensions", this.currentScope(), node, false);
+        this.scopeManager.__nestScope(scope);
+
+        var left = block.left;
         if (left.type === "Identifier") {
-        createScopeVariable.call(this, node, left);
+          scope.__define(left, new Definition("ComprehensionElement", left, left));
         } else if (left.type === "ArrayPattern") {
           for (var i = 0; i < left.elements.length; i++) {
-          if (left.elements[i]) {
+            var name = left.elements[i];
-            createScopeVariable.call(this, left.elements, left.elements[i]);
+            if (name) {
+              scope.__define(name, new Definition("ComprehensionElement", name, name));
+            }
+          }
+        } else if (left.type === "ObjectPattern") {
+          for (var i = 0; i < left.properties.length; i++) {
+            var name = left.properties[i];
+            if (name && name.key && name.key.type === 'Identifier') {
+              scope.__define(name.key, new Definition("ComprehensionElement", name.key, name.key));
             }
           }
         }
       }
-    if (node.right) {
+      if (block.right) {
-      this.visit(node.right);
+        this.visit(block.right);
       }
+    }
+    if (node.filter) {
+      this.visit(block.filter);
+    }
+    this.visit(node.body);
+    this.close(node);
   };
 
   referencer.prototype.DeclareModule =

eslint/babel-eslint-parser/test/non-regression.js

@@ -1017,7 +1017,7 @@ describe("verify", function () {
       );
     });
 
-    it("expression, if statement, multiple blocks", function () {
+    it("generator, if statement, multiple blocks", function () {
       verifyAndAssertMessages([
           "let arr = [1, 2, 3];",
           "let arr2 = [1, 2, 3];",
@@ -1031,13 +1031,37 @@ describe("verify", function () {
     it("ArrayPattern", function () {
       verifyAndAssertMessages([
           "let arr = [1, 2, 3];",
-          "let arr2 = [1, 2, 3];",
+          "[for ([,x] of arr) x]"
-          "[for ([,x] of arr) for ({[start.x]: x, [start.y]: y} of arr2) x]"
         ].join("\n"),
         { "no-unused-vars": 1, "no-undef": 1 },
         []
       );
     });
+
+    it("ObjectPattern", function () {
+      verifyAndAssertMessages([
+          "let arr = [{x: 1, y: 2}, {x: 2, y: 3}];",
+          "[for ({x, y} of arr) x + y]"
+        ].join("\n"),
+        { "no-unused-vars": 1, "no-undef": 1 },
+        []
+      );
+    });
+
+    it("multiple comprehensions #138", function () {
+      verifyAndAssertMessages([
+          "function test() {",
+            "let items;",
+            "return {",
+              "a: [for (i of items) i],",
+              "b: [for (i of items) i]",
+            "};",
+          "} test;"
+        ].join("\n"),
+        { "no-unused-vars": 1, "no-undef": 1, "no-redeclare": 1 },
+        []
+      );
+    });
   });
 
   describe("decorators #72", function () {