Parameters get their types (signedness) from expressions.

Parameters get their signedness from the expression that is assigned
to them unless the type is explicitly expressed where the parameter
is declared.

net_design.cc

@@ -377,10 +377,6 @@ void NetScope::evaluate_parameters(Design*des)
 			assert(nexpr);
 			delete expr;
 			(*cur).second.expr = nexpr;
-
-			  // Set the signedness flag.
-			(*cur).second.expr
-			      ->cast_signed( (*cur).second.signed_flag );
 		  }
 		  break;
 
@@ -393,7 +389,9 @@ void NetScope::evaluate_parameters(Design*des)
 	    }
 
 	      /* If the parameter has range information, then make
-		 sure the value is set right. */
+		 sure the value is set right. Note that if the
+		 parameter doesn't have an explicit range, then it
+		 will get the signedness from the expression itself. */
 	    if (range_flag) {
 		  unsigned long wid = (msb >= lsb)? msb - lsb : lsb - msb;
 		  wid += 1;