Address PR comments

1. Remove extra line in __rest shim.
2. Improve __rest vs __assign check for destructuring assignment.

Author: sandersn

src/compiler/binder.ts

@@ -1935,10 +1935,18 @@ namespace ts {
                 case SyntaxKind.SpreadElementExpression:
                 case SyntaxKind.JsxSpreadAttribute:
                     let root = container;
-                    while (root && root.kind !== SyntaxKind.BinaryExpression) {
+                    let hasRest = false;
+                    while (root.parent) {
+                        if (root.kind === SyntaxKind.ObjectLiteralExpression &&
+                            root.parent.kind === SyntaxKind.BinaryExpression &&
+                            (root.parent as BinaryExpression).operatorToken.kind === SyntaxKind.EqualsToken &&
+                            (root.parent as BinaryExpression).left === root) {
+                            hasRest = true;
+                            break;
+                        }
                         root = root.parent;
                     }
-                    emitFlags |= root && isDestructuringAssignment(root) ? NodeFlags.HasRestAttribute : NodeFlags.HasSpreadAttribute;
+                    emitFlags |= hasRest ? NodeFlags.HasRestAttribute : NodeFlags.HasSpreadAttribute;
                     return;
 
                 case SyntaxKind.CallSignature:

src/compiler/emitter.ts

@@ -45,7 +45,6 @@ var __assign = (this && this.__assign) || Object.assign || function(t) {
         const restHelper = `
 var __rest = (this && this.__rest) || function (s, e) {
     var t = {};
-
     for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && !e.indexOf(p))
         t[p] = s[p];
     return t;