Handel empty intializer in system module emit

Author: mhegazy

src/compiler/transformers/module/system.ts

@@ -1287,6 +1287,10 @@ namespace ts {
          * @param node The node to visit.
          */
         function visitForInitializer(node: ForInitializer): ForInitializer {
+            if (!node) {
+                return node;
+            }
+
             if (shouldHoistForInitializer(node)) {
                 let expressions: Expression[];
                 for (const variable of node.declarations) {

tests/baselines/reference/SystemModuleForStatementNoInitializer.js

@@ -0,0 +1,42 @@
+//// [SystemModuleForStatementNoInitializer.ts]
+
+export { };
+
+let i = 0;
+let limit = 10;
+
+for (; i < limit; ++i) {
+    break;
+}
+
+for (; ; ++i) {
+    break;
+}
+
+for (; ;) {
+    break;
+}
+
+
+//// [SystemModuleForStatementNoInitializer.js]
+System.register([], function (exports_1, context_1) {
+    "use strict";
+    var __moduleName = context_1 && context_1.id;
+    var i, limit;
+    return {
+        setters: [],
+        execute: function () {
+            i = 0;
+            limit = 10;
+            for (; i < limit; ++i) {
+                break;
+            }
+            for (;; ++i) {
+                break;
+            }
+            for (;;) {
+                break;
+            }
+        }
+    };
+});

tests/baselines/reference/SystemModuleForStatementNoInitializer.symbols

@@ -0,0 +1,28 @@
+=== tests/cases/compiler/SystemModuleForStatementNoInitializer.ts ===
+
+export { };
+
+let i = 0;
+>i : Symbol(i, Decl(SystemModuleForStatementNoInitializer.ts, 3, 3))
+
+let limit = 10;
+>limit : Symbol(limit, Decl(SystemModuleForStatementNoInitializer.ts, 4, 3))
+
+for (; i < limit; ++i) {
+>i : Symbol(i, Decl(SystemModuleForStatementNoInitializer.ts, 3, 3))
+>limit : Symbol(limit, Decl(SystemModuleForStatementNoInitializer.ts, 4, 3))
+>i : Symbol(i, Decl(SystemModuleForStatementNoInitializer.ts, 3, 3))
+
+    break;
+}
+
+for (; ; ++i) {
+>i : Symbol(i, Decl(SystemModuleForStatementNoInitializer.ts, 3, 3))
+
+    break;
+}
+
+for (; ;) {
+    break;
+}
+

tests/baselines/reference/SystemModuleForStatementNoInitializer.types

@@ -0,0 +1,33 @@
+=== tests/cases/compiler/SystemModuleForStatementNoInitializer.ts ===
+
+export { };
+
+let i = 0;
+>i : number
+>0 : 0
+
+let limit = 10;
+>limit : number
+>10 : 10
+
+for (; i < limit; ++i) {
+>i < limit : boolean
+>i : number
+>limit : number
+>++i : number
+>i : number
+
+    break;
+}
+
+for (; ; ++i) {
+>++i : number
+>i : number
+
+    break;
+}
+
+for (; ;) {
+    break;
+}
+

tests/cases/compiler/SystemModuleForStatementNoInitializer.ts

@@ -0,0 +1,18 @@
+//@module: system
+
+export { };
+
+let i = 0;
+let limit = 10;
+
+for (; i < limit; ++i) {
+    break;
+}
+
+for (; ; ++i) {
+    break;
+}
+
+for (; ;) {
+    break;
+}