Bug#890294: asymptote: complex eval-using code triggers assert failure

[KAction@gnu.org]

Package: asymptote
Version: 2.41-4
Severity: normal

Hello! Following piece of code is meant to create wrapper structures
around primitive types, simplifying creation of generic code.

	var casts = quote {
		public TWrap operator cast(TInner value)
		{
			var obj = new TWrap;
			obj.value = value;
			return obj;
		}
		public TInner operator cast(TWrap obj)
		{
			return obj.value;
		}
	};

	void define_wrapper(string type)
	{
		string wrapper = 'A' + type;
		string prog = 'public struct ' + wrapper + '{ ' + type + ' value; };';
		eval(prog, true);
		eval('typedef ' + wrapper + ' TWrap', true);
		eval('typedef ' + type + ' TInner', true);
		eval(casts, true);
	}
	define_wrapper('int');
	define_wrapper('real');


Unfortunately, following error is produced instead:

	asy: exp.cc:43: virtual void absyntax::exp::transAsType(trans::coenv&, types::ty*): Assertion `t->kind==ty_error || equivalent(t,target)' failed.

Problem is present in both versions in sid and stretch.