Addition inside a polymorphic function

[Anastassija]

The following example crashes:

import Exception;
import List;

list[&T] f(list[&T] l) {
    return head(l) + l;
}

value main(list[value] args) {
    return f([1,2,3]);
}

This is due to the addition expression head(l) + l. The add Rascal primitive is called and leads to an exception (see the improved exception message below):

|rascal://experiments::Compiler::RVM::Run|(217,618,<12,0>,<22,28>): Java("RuntimeException","PANIC: (instruction execution): instruction: CALLPRIM add, 2; message: null",Java("RuntimeException","Illegal type combination: INT and LIST"))
    at org.rascalmpl.library.experiments.Compiler.RVM.Interpreter.RVM.executeProgram(|file:///RVM.java|(0,0,<1495,0>,<1495,0>))