Fix VM crash when parsing a non-existing redirecting constructor

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
diff --git a/runtime/vm/parser.cc b/runtime/vm/parser.cc
index bc6740cd67e8c6f34b7b1142f08060463ce24a6e..112a37c6e2cf5b3a45383c46d570f5c1b69cc05f 100644
--- a/runtime/vm/parser.cc
+++ b/runtime/vm/parser.cc
@@ -3121,12 +3121,11 @@ void Parser::ParseConstructorRedirection(const Class& cls,
       Function::ZoneHandle(Z, cls.LookupConstructor(ctor_name));
   if (redirect_ctor.IsNull()) {
     if (cls.LookupFactory(ctor_name) != Function::null()) {
-      ReportError(
-          call_pos, "redirection constructor '%s' must not be a factory",
-          String::Handle(Z, redirect_ctor.UserVisibleName()).ToCString());
+      ReportError(call_pos,
+                  "redirection constructor '%s' must not be a factory",
+                  ctor_name.ToCString());

[hausner, 2017/02/26 18:30:27]

I think you want to use a user-visible name here, not a decorated one. For
example, the unnamed constructor for class C should be reported as "C", not
"C.". See String::ScrubName().

[Florian Schneider, 2017/02/27 18:14:50]

Good point. I'll change it to use ScrubName instead.

     }
-    ReportError(call_pos, "constructor '%s' not found",
-                String::Handle(Z, redirect_ctor.UserVisibleName()).ToCString());
+    ReportError(call_pos, "constructor '%s' not found", ctor_name.ToCString());
   }
   if (current_function().is_const() && !redirect_ctor.is_const()) {
     ReportError(call_pos, "redirection constructor '%s' must be const",