diff --git a/Jakefile.js b/Jakefile.js
index dc0585d3b1..dca1d4ad09 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -282,7 +282,7 @@ var builtLocalCompiler = path.join(builtLocalDirectory, compilerFilename);
 function compileFile(outFile, sources, prereqs, prefixes, useBuiltCompiler, opts, callback) {
     file(outFile, prereqs, function() {
         var compilerPath = useBuiltCompiler ? builtLocalCompiler : LKGCompiler;
-        var options = "--noImplicitAny --noEmitOnError --pretty";
+        var options = "--noImplicitAny --noEmitOnError --types --pretty";
         opts = opts || {};
         // Keep comments when specifically requested
         // or when in debug mode.