parse error in concrete fragment breaks compiler

[jurgenvinju]

syntax C = "c";

rascal>(C) `b`
Error: Unexpected compiler exception EXCEPTION in translateFunctionDeclaration, compiling main: ParseError(|test-modules:///ConsoleInput.rsc|(124,7,<7,15>,<7,16>)) IN 'module ConsoleInput
syntax Cs = {C ","}+;
syntax C = "c";
syntax C = "c";
layout W = " "*;
layout W = " "*;

value main() = (C) `b`;'

Time: 126ms