Reinstate error recovery for range expressions.

If an error is found whilst elaborating a range expression in a signal
declaration, create a dummy range and continue elaboration. This stops
the compiler reporting an error every time that signal is referenced.

elab_sig.cc

@@ -996,10 +996,6 @@ NetNet* PWire::elaborate_sig(Design*des, NetScope*scope) const
 		       << ". Now check for consistency." << endl;
 	    }
 
-	    /* If we find errors here, then give up on this signal. */
-	    if (bad_range)
-		  return 0;
-
 	    /* We have a port size error */
             if (port_set_ && net_set_ && !test_ranges_eeq(plist, nlist)) {
 

netmisc.cc

@@ -972,6 +972,10 @@ bool evaluate_ranges(Design*des, NetScope*scope,
 
 	    delete texpr;
 
+	      /* Error recovery */
+	    if (bad_lsb) use_lsb = 0;
+	    if (bad_msb) use_msb = use_lsb;
+
 	    llist.push_back(netrange_t(use_msb, use_lsb));
       }