final Type tleft = _left.typeCheck(stable);
final MethodType ptype = lookupPrimop(stable, "u-",
new MethodType(Type.Void,
tleft));
if (ptype != null) {
final Type arg1 = (Type) ptype.argsType().elementAt(0);
if (!arg1.identicalTo(tleft)) {
_left = new CastExpr(_left, arg1);
}
return _type = ptype.resultType();
}
throw new TypeCheckError(this);