Revert "Compile-time error if mixin class has a fact

runtime/vm/class_finalizer.cc

Index: runtime/vm/class_finalizer.cc
diff --git a/runtime/vm/class_finalizer.cc b/runtime/vm/class_finalizer.cc
index ebf986896e5ad1901c0a4d3a5121d1756d1b3e71..c7cf184a9976dffb72798613e0eb0d6204a6d6c5 100644
--- a/runtime/vm/class_finalizer.cc
+++ b/runtime/vm/class_finalizer.cc
@@ -2227,23 +2227,12 @@ void ClassFinalizer::ApplyMixinMembers(const Class& cls) {
   const intptr_t num_functions = functions.Length();
   for (intptr_t i = 0; i < num_functions; i++) {
     func ^= functions.At(i);
-    if (func.IsFactory() || func.IsGenerativeConstructor()) {
+    if (func.IsGenerativeConstructor()) {
       // A mixin class must not have explicit constructors.
       if (!func.IsImplicitConstructor()) {
-        const char* ctr_kind = func.IsFactory() ? "factory" : "constructor";

[Ivan Posva, 2016/02/17 07:51:26]

You need to preserve the improved error message below.

[Jacob, 2016/02/19 20:53:03]

Done.

-        const Script& script = Script::Handle(cls.script());
-        const Error& error = Error::Handle(
-            LanguageError::NewFormatted(Error::Handle(),
-                script, func.token_pos(), Report::AtLocation,
-                Report::kError, Heap::kNew,
-                "%s '%s' is illegal in mixin class %s",
-                ctr_kind,
-                String::Handle(func.PrettyName()).ToCString(),
-                String::Handle(zone, mixin_cls.Name()).ToCString()));
-
-        ReportErrors(error, cls, cls.token_pos(),
-                     "mixin class '%s' must not have constructors",
-                     String::Handle(zone, mixin_cls.Name()).ToCString());
+        ReportError(cls, cls.token_pos(),
+                    "mixin class '%s' must not have constructors\n",
+                    String::Handle(zone, mixin_cls.Name()).ToCString());
       }
       continue;  // Skip the implicit constructor.
     }