Derive abstract cells in top module during hierarchy

passes/hierarchy/hierarchy.cc

@@ -1066,6 +1066,17 @@ struct HierarchyPass : public Pass {
 					mod->attributes[ID::initial_top] = RTLIL::Const(1);
 				else
 					mod->attributes.erase(ID::initial_top);
+
+			std::vector<IdString> abstract_ids;
+			for (auto cell : top_mod->cells()) {
+				IdString abstract_id = "$abstract" + cell->type.str();
+				if (design->module(cell->type) == nullptr && design->module(abstract_id))
+					abstract_ids.push_back(abstract_id);
+			}
+			for (auto abstract_id : abstract_ids)
+				design->module(abstract_id)->derive(design, {});
+			for (auto abstract_id : abstract_ids)
+				design->remove(design->module(abstract_id));
 		}
 
 		bool did_something = true;

tests/various/hierarchy_reassign_localparam.ys

@@ -0,0 +1,18 @@
+read_verilog -defer <<EOT
+
+module bb (...);
+localparam A = "abc";
+input a;
+output b;
+endmodule
+
+module top (...);
+input a;
+output b;
+bb #(.A("def")) my_bb (a, b);
+endmodule
+
+EOT
+
+logger -expect error "does not have a parameter named 'A'" 1
+hierarchy -check -top top