Added duplicate import checking to no-reassign.

I would expect no-redeclare to catch this more generally, but it seems not to with ESLint 0.17.1.

lib/rules/no-reassign.js

@@ -17,14 +17,17 @@ module.exports = function (context) {
 
   return {
     "ImportSpecifier": function (node) {
+      checkIdentifier(node.local);
       locals.add(node.local.name);
     },
 
     "ImportDefaultSpecifier": function (node) {
+      checkIdentifier(node.local);
       locals.add(node.local.name);
     },
 
     "ImportNamespaceSpecifier": function (node) {
+      checkIdentifier(node.local);
       locals.add(node.local.name);
       namespaces.add(node.local.name);
     },

tests/lib/rules/no-reassign.js

@@ -42,9 +42,20 @@ eslintTester.addRuleTest("lib/rules/no-reassign", {
       code: "import { foo } from './bar';\nvar bar = 32, foo = function() { return false; }",
       errors: [{ message: "Reassignment of local imported name 'foo'." }]}),
 
+    test({
+      code: "import { foo } from './bar';\nimport { foo } from './common';",
+      errors: [{ message: "Reassignment of local imported name 'foo'." }]}),
+
+    test({
+      code: "import { foo } from './bar';\nimport foo from './common';",
+      errors: [{ message: "Reassignment of local imported name 'foo'." }]}),
+
+    test({
+      code: "import { foo } from './bar';\nimport * as foo from './common';",
+      errors: [{ message: "Reassignment of local imported name 'foo'." }]}),
+
     test({
       code: "import * as foo from './bar'; foo.x = 'y';",
-      errors: [{ message: "Assignment to member of namespace 'foo'."}]
-    })
+      errors: [{ message: "Assignment to member of namespace 'foo'."}]})
   ]
 });