FATAL ERROR: template with template parameter with default value:

Summary

compiler proba.ttcn 
Notify: Parsing TTCN-3 module `proba.ttcn'...
Notify: Checking modules...
Notify: Generating code...
FATAL ERROR: compiler: In line 6414 of TtcnTemplate.cc: Template::get_single_expr()

Steps and/or TTCN-3 code to reproduce

module proba {

template charstring t_ch(in template charstring cc:= pattern "w+") :=  cc 

control {
  template charstring tt := t_ch
}

}

Titan version

git head 1772b903

/cc @aknappqwt @mmagyari