merge with master, fix emit for omitted expressions

src/compiler/emitter.ts

@@ -3726,6 +3726,10 @@ module ts {
             }
 
             function emitExportVariableAssignments(node: VariableDeclaration | BindingElement) {
+                if (node.kind === SyntaxKind.OmittedExpression) {
+                    return;
+                }
+
                 var name = (<VariableLikeDeclaration>node).name;
                 if (name.kind === SyntaxKind.Identifier) {
                     emitExportMemberAssignments(<Identifier>name);

tests/baselines/reference/declarationEmitDestructuringOptionalBindingParametersInOverloads.js

@@ -11,16 +11,8 @@ function foo2(...rest: any[]) {
 
 //// [declarationEmitDestructuringOptionalBindingParametersInOverloads.js]
 function foo() {
-    var rest = [];
-    for (var _i = 0; _i < arguments.length; _i++) {
-        rest[_i - 0] = arguments[_i];
-    }
 }
 function foo2() {
-    var rest = [];
-    for (var _i = 0; _i < arguments.length; _i++) {
-        rest[_i - 0] = arguments[_i];
-    }
 }