Added temporary compat flag to control emit output to fix tests

Jakefile.js

@@ -223,6 +223,7 @@ function concatenateFiles(destinationFile, sourceFiles) {
 
 var useDebugMode = true;
 var useTransforms = process.env.USE_TRANSFORMS || false;
+var useTransformCompat = false;
 var host = (process.env.host || process.env.TYPESCRIPT_HOST || "node");
 var compilerFilename = "tsc.js";
 var LKGCompiler = path.join(LKGDirectory, compilerFilename);
@@ -285,6 +286,9 @@ function compileFile(outFile, sources, prereqs, prefixes, useBuiltCompiler, noOu
         if (useBuiltCompiler && useTransforms) {
             options += " --experimentalTransforms"
         }
+        else if (useBuiltCompiler && useTransformCompat) {
+            options += " --transformCompatibleEmit"
+        }
 
         var cmd = host + " " + compilerPath + " " + options + " ";
         cmd = cmd + sources.join(" ");
@@ -413,6 +417,10 @@ task("setTransforms", function() {
     useTransforms = true;
 });
 
+task("setTransformCompat", function() {
+    useTransformCompat = true;
+});
+
 task("configure-nightly", [configureNightlyJs], function() {
     var cmd = host + " " + configureNightlyJs + " " + packageJson + " " + programTs;
     console.log(cmd);

src/compiler/commandLineParser.ts

@@ -322,9 +322,18 @@ namespace ts {
             description: Diagnostics.Allow_default_imports_from_modules_with_no_default_export_This_does_not_affect_code_emit_just_typechecking
         },
         {
+            // this option will be removed when this is merged with master and exists solely
+            // to enable the tree transforming emitter side-by-side with the existing emitter.
             name: "experimentalTransforms",
             type: "boolean",
             experimental: true
+        },
+        {
+            // this option will be removed when this is merged with master and exists solely
+            // to enable the tree transforming emitter side-by-side with the existing emitter.
+            name: "transformCompatibleEmit",
+            type: "boolean",
+            experimental: true
         }
     ];
 

src/compiler/emitter.ts

@@ -1915,6 +1915,9 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
 
                 if (multiLine) {
                     decreaseIndent();
+                    if (!compilerOptions.transformCompatibleEmit) {
+                        writeLine();
+                    }
                 }
 
                 write(")");
@@ -4331,7 +4334,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
                     writeLine();
                     emitStart(restParam);
                     emitNodeWithCommentsAndWithoutSourcemap(restParam.name);
-                    write(restIndex > 0
+                    write(restIndex > 0 || !compilerOptions.transformCompatibleEmit
                         ? `[${tempName} - ${restIndex}] = arguments[${tempName}];`
                         : `[${tempName}] = arguments[${tempName}];`);
                     emitEnd(restParam);
@@ -5353,7 +5356,7 @@ const _super = (function (geti, seti) {
                 const isClassExpressionWithStaticProperties = staticProperties.length > 0 && node.kind === SyntaxKind.ClassExpression;
                 let tempVariable: Identifier;
 
-                if (isClassExpressionWithStaticProperties) {
+                if (isClassExpressionWithStaticProperties && compilerOptions.transformCompatibleEmit) {
                     tempVariable = createAndRecordTempVariable(TempFlags.Auto);
                     write("(");
                     increaseIndent();
@@ -5390,6 +5393,11 @@ const _super = (function (geti, seti) {
                 writeLine();
                 emitConstructor(node, baseTypeNode);
                 emitMemberFunctionsForES5AndLower(node);
+                if (!compilerOptions.transformCompatibleEmit) {
+                    emitPropertyDeclarations(node, staticProperties);
+                    writeLine();
+                    emitDecoratorsOfClass(node, /*decoratedClassAlias*/ undefined);
+                }
                 writeLine();
                 emitToken(SyntaxKind.CloseBraceToken, node.members.end, () => {
                     write("return ");
@@ -5416,11 +5424,13 @@ const _super = (function (geti, seti) {
                 write("))");
                 if (node.kind === SyntaxKind.ClassDeclaration) {
                     write(";");
-                    emitPropertyDeclarations(node, staticProperties);
-                    writeLine();
-                    emitDecoratorsOfClass(node, /*decoratedClassAlias*/ undefined);
+                    if (compilerOptions.transformCompatibleEmit) {
+                        emitPropertyDeclarations(node, staticProperties);
+                        writeLine();
+                        emitDecoratorsOfClass(node, /*decoratedClassAlias*/ undefined);
+                    }
                 }
-                else if (isClassExpressionWithStaticProperties) {
+                else if (isClassExpressionWithStaticProperties && compilerOptions.transformCompatibleEmit) {
                     for (const property of staticProperties) {
                         write(",");
                         writeLine();

src/compiler/program.ts

@@ -1,6 +1,7 @@
 /// <reference path="sys.ts" />
 /// <reference path="emitter.ts" />
 /// <reference path="core.ts" />
+/// <reference path="printer.ts" />
 
 namespace ts {
     /* @internal */ export let programTime = 0;

src/compiler/types.ts

@@ -2470,6 +2470,7 @@ namespace ts {
         allowJs?: boolean;
         /* @internal */ stripInternal?: boolean;
         /* @internal */ experimentalTransforms?: boolean;
+        /* @internal */ transformCompatibleEmit?: boolean;
 
         // Skip checking lib.d.ts to help speed up tests.
         /* @internal */ skipDefaultLibCheck?: boolean;