Generate all runtime files from dart.

lib/src/js/template.dart

Index: lib/src/js/template.dart
diff --git a/lib/src/js/template.dart b/lib/src/js/template.dart
index 88e7321bae747d335bf9840dc36746b66c37e9cd..0dea734d868b1611203d44eaae9f4041bafb21c8 100644
--- a/lib/src/js/template.dart
+++ b/lib/src/js/template.dart
@@ -102,7 +102,7 @@ class Template {
     if (arguments is List) {
       if (arguments.length != positionalArgumentCount) {
         throw 'Wrong number of template arguments, given ${arguments.length}, '
-            'expected $positionalArgumentCount';
+            'expected $positionalArgumentCount:\n$source';
       }
       return instantiator(arguments);
     }