Report an error when trying to take the select of a real value.

This patch adds checks in various places to prevent the user from
taking a select of a real value (bit, part and indexed selects).
(cherry picked from commit 5852f1eb7a)

elab_expr.cc

@@ -2354,6 +2354,14 @@ NetExpr* PEIdent::elaborate_expr_param_(Design*des,
       if (!name_tail.index.empty())
 	    use_sel = name_tail.index.back().sel;
 
+      if (par->expr_type() == IVL_VT_REAL && 
+          use_sel != index_component_t::SEL_NONE) {
+	    cerr << get_fileline() << ": error: "
+	         << "Can not select part of a real parameter value." << endl;
+	    des->errors += 1;
+	    return 0;
+      }
+
 	// NOTE TO SELF: This is the way I want to see this code
 	// structured. This closely follows the structure of the
 	// elaborate_expr_net_ code, which splits all the various
@@ -2626,6 +2634,14 @@ NetExpr* PEIdent::elaborate_expr_net_word_(Design*des, NetScope*scope,
       if (name_tail.index.size() > 1)
 	    word_sel = name_tail.index.back().sel;
 
+      if (res->expr_type() == IVL_VT_REAL && 
+          word_sel != index_component_t::SEL_NONE) {
+	    cerr << get_fileline() << ": error: "
+	         << "Can not select part of a real array word." << endl;
+	    des->errors += 1;
+	    return 0;
+      }
+
       if (word_sel == index_component_t::SEL_PART)
 	    return elaborate_expr_net_part_(des, scope, res, found_in);
 
@@ -2920,6 +2936,14 @@ NetExpr* PEIdent::elaborate_expr_net(Design*des, NetScope*scope,
       if (! path_.back().index.empty())
 	    use_sel = path_.back().index.back().sel;
 
+      if (node->expr_type() == IVL_VT_REAL && 
+          use_sel != index_component_t::SEL_NONE) {
+	    cerr << get_fileline() << ": error: "
+	         << "Can not select part of a real value." << endl;
+	    des->errors += 1;
+	    return 0;
+      }
+
 	// If this is a part select of a signal, then make a new
 	// temporary signal that is connected to just the
 	// selected bits. The lsb_ and msb_ expressions are from

elab_lval.cc

@@ -195,6 +195,15 @@ NetAssign_* PEIdent::elaborate_lval(Design*des,
       if (reg->array_dimensions() > 0)
 	    return elaborate_lval_net_word_(des, scope, reg);
 
+     	// This must be after the array word elaboration above!
+      if (reg->data_type() == IVL_VT_REAL &&
+          use_sel != index_component_t::SEL_NONE) {
+	    cerr << get_fileline() << ": error: "
+	         << "Can not select part of a real value." << endl;
+	    des->errors += 1;
+	    return 0;
+      }
+
       if (use_sel == index_component_t::SEL_PART) {
 	    NetAssign_*lv = new NetAssign_(reg);
 	    elaborate_lval_net_part_(des, scope, lv);
@@ -289,6 +298,14 @@ NetAssign_* PEIdent::elaborate_lval_net_word_(Design*des,
       if (name_tail.index.size() > 1)
 	    use_sel = name_tail.index.back().sel;
 
+      if (reg->data_type() == IVL_VT_REAL &&
+          use_sel != index_component_t::SEL_NONE) {
+	    cerr << get_fileline() << ": error: "
+	         << "Can not select part of a real array word." << endl;
+	    des->errors += 1;
+	    return 0;
+      }
+
       if (use_sel == index_component_t::SEL_BIT)
 	    elaborate_lval_net_bit_(des, scope, lv);
 

elab_net.cc

@@ -460,6 +460,14 @@ NetNet* PEIdent::elaborate_lnet_common_(Design*des, NetScope*scope,
 
 	      /* The array has a part/bit select at the end. */
 	    if (name_tail.index.size() > sig->array_dimensions()) {
+		  if (sig->data_type() == IVL_VT_REAL) {
+		        cerr << get_fileline() << ": error: " 
+		             << "Can not select part of a real array word."
+		             << endl;
+		        des->errors += 1;
+		        return 0;
+		  }
+
 		  long midx_tmp, lidx_tmp;
 		  if (! eval_part_select_(des, scope, sig, midx_tmp, lidx_tmp))
 		        return 0;
@@ -475,6 +483,13 @@ NetNet* PEIdent::elaborate_lnet_common_(Design*des, NetScope*scope,
 		  lidx = lidx_tmp;
 	    }
       } else if (!name_tail.index.empty()) {
+	    if (sig->data_type() == IVL_VT_REAL) {
+		  cerr << get_fileline() << ": error: " 
+		       << "Can not select part of a real value." << endl;
+		  des->errors += 1;
+		  return 0;
+	    }
+
 	    long midx_tmp, lidx_tmp;
 	    if (! eval_part_select_(des, scope, sig, midx_tmp, lidx_tmp))
 		  return 0;

elaborate.cc

@@ -625,7 +625,9 @@ void PGBuiltin::elaborate(Design*des, NetScope*scope) const
 		  return;
 	    }
 	    lval_sigs[idx] = pin(idx)->elaborate_lnet(des, scope);
-	    ivl_assert(*this, lval_sigs[idx]);
+	      // The only way this should return zero is if an error
+	      // happened, so for that case just return.
+	    if (lval_sigs[idx] == 0) return;
 
 	      // For now, assume all the outputs are the same width.
 	    ivl_assert(*this, idx == 0 || lval_sigs[idx]->vector_width() == lval_sigs[0]->vector_width());