Handle ts-only declaration export aliases in system transformer (#22919)

* handle ts declarations export alises in system transformer

* Retain end of declaration marker

src/compiler/transformers/module/system.ts

@@ -913,6 +913,12 @@ namespace ts {
                 delete deferredExports[id];
                 return append(statements, node);
             }
+            else {
+                const original = getOriginalNode(node);
+                if (isModuleOrEnumDeclaration(original)) {
+                    return append(appendExportsOfDeclaration(statements, original), node);
+                }
+            }
 
             return node;
         }

tests/baselines/reference/systemNamespaceAliasEmit.js

@@ -0,0 +1,34 @@
+//// [systemNamespaceAliasEmit.ts]
+namespace ns {
+    const value = 1;
+}
+
+enum AnEnum {
+    ONE,
+    TWO
+}
+
+export {ns, AnEnum, ns as FooBar, AnEnum as BarEnum};
+
+//// [systemNamespaceAliasEmit.js]
+System.register([], function (exports_1, context_1) {
+    "use strict";
+    var __moduleName = context_1 && context_1.id;
+    var ns, AnEnum;
+    return {
+        setters: [],
+        execute: function () {
+            (function (ns) {
+                var value = 1;
+            })(ns || (ns = {}));
+            exports_1("ns", ns);
+            exports_1("FooBar", ns);
+            (function (AnEnum) {
+                AnEnum[AnEnum["ONE"] = 0] = "ONE";
+                AnEnum[AnEnum["TWO"] = 1] = "TWO";
+            })(AnEnum || (AnEnum = {}));
+            exports_1("AnEnum", AnEnum);
+            exports_1("BarEnum", AnEnum);
+        }
+    };
+});

tests/baselines/reference/systemNamespaceAliasEmit.symbols

@@ -0,0 +1,26 @@
+=== tests/cases/compiler/systemNamespaceAliasEmit.ts ===
+namespace ns {
+>ns : Symbol(ns, Decl(systemNamespaceAliasEmit.ts, 0, 0))
+
+    const value = 1;
+>value : Symbol(value, Decl(systemNamespaceAliasEmit.ts, 1, 9))
+}
+
+enum AnEnum {
+>AnEnum : Symbol(AnEnum, Decl(systemNamespaceAliasEmit.ts, 2, 1))
+
+    ONE,
+>ONE : Symbol(BarEnum.ONE, Decl(systemNamespaceAliasEmit.ts, 4, 13))
+
+    TWO
+>TWO : Symbol(BarEnum.TWO, Decl(systemNamespaceAliasEmit.ts, 5, 8))
+}
+
+export {ns, AnEnum, ns as FooBar, AnEnum as BarEnum};
+>ns : Symbol(ns, Decl(systemNamespaceAliasEmit.ts, 9, 8))
+>AnEnum : Symbol(AnEnum, Decl(systemNamespaceAliasEmit.ts, 9, 11))
+>ns : Symbol(FooBar, Decl(systemNamespaceAliasEmit.ts, 9, 19))
+>FooBar : Symbol(FooBar, Decl(systemNamespaceAliasEmit.ts, 9, 19))
+>AnEnum : Symbol(BarEnum, Decl(systemNamespaceAliasEmit.ts, 9, 33))
+>BarEnum : Symbol(BarEnum, Decl(systemNamespaceAliasEmit.ts, 9, 33))
+

tests/baselines/reference/systemNamespaceAliasEmit.types

@@ -0,0 +1,27 @@
+=== tests/cases/compiler/systemNamespaceAliasEmit.ts ===
+namespace ns {
+>ns : typeof ns
+
+    const value = 1;
+>value : 1
+>1 : 1
+}
+
+enum AnEnum {
+>AnEnum : AnEnum
+
+    ONE,
+>ONE : AnEnum.ONE
+
+    TWO
+>TWO : AnEnum.TWO
+}
+
+export {ns, AnEnum, ns as FooBar, AnEnum as BarEnum};
+>ns : typeof ns
+>AnEnum : typeof AnEnum
+>ns : typeof ns
+>FooBar : typeof ns
+>AnEnum : typeof AnEnum
+>BarEnum : typeof AnEnum
+

tests/cases/compiler/systemNamespaceAliasEmit.ts

@@ -0,0 +1,11 @@
+// @module: system
+namespace ns {
+    const value = 1;
+}
+
+enum AnEnum {
+    ONE,
+    TWO
+}
+
+export {ns, AnEnum, ns as FooBar, AnEnum as BarEnum};