Fix type deduction for variable parameterized classes (#6281) (#6813)

src/V3AstNodes.cpp

@@ -1775,7 +1775,7 @@ void AstCellInlineScope::dumpJson(std::ostream& str) const {
     dumpJsonGen(str);
 }
 bool AstClass::isCacheableChild(const AstNode* nodep) {
-    return VN_IS(nodep, Var)
+    return VN_IS(nodep, Var) || VN_IS(nodep, Typedef)
            || (VN_IS(nodep, Constraint) && !VN_AS(nodep, Constraint)->isExternProto())
            || VN_IS(nodep, EnumItemRef)
            || (VN_IS(nodep, NodeFTask) && !VN_AS(nodep, NodeFTask)->isExternProto())

src/V3Param.cpp

@@ -54,6 +54,7 @@
 #include "V3EmitV.h"
 #include "V3Hasher.h"
 #include "V3LinkDotIfaceCapture.h"
+#include "V3MemberMap.h"
 #include "V3Os.h"
 #include "V3Parse.h"
 #include "V3Simulate.h"
@@ -291,6 +292,9 @@ class ParamProcessor final {
     std::vector<std::pair<AstParamTypeDType*, int>> m_classParams;
     std::unordered_map<AstParamTypeDType*, int> m_paramIndex;
 
+    // member names cached for fast lookup
+    VMemberMap m_memberMap;
+
     // METHODS
 
     static void makeSmallNames(AstNodeModule* modp) {
@@ -846,7 +850,10 @@ class ParamProcessor final {
                     pinExprp->replaceWith(new AstConst{pinp->fileline(), AstConst::WidthedValue{},
                                                        modvarp->width(), 0});
                     VL_DO_DANGLING(pinExprp->deleteTree(), pinExprp);
-                } else if (origp && exprp->sameTree(origp)) {
+                } else if (origp
+                           && (exprp->sameTree(origp)
+                               || (exprp->num().width() == origp->num().width()
+                                   && ParameterizedHierBlocks::areSame(exprp, origp)))) {
                     // Setting parameter to its default value.  Just ignore it.
                     // This prevents making additional modules, and makes coverage more
                     // obvious as it won't show up under a unique module page name.
@@ -1246,17 +1253,13 @@ class ParamProcessor final {
         AstRefDType* const refDTypep = VN_CAST(nodep->backp(), RefDType);
         AstClass* const newClassp = refDTypep ? VN_CAST(newModp, Class) : nullptr;
         if (newClassp && !refDTypep->typedefp() && !refDTypep->subDTypep()) {
-            for (AstNode* itemp = newClassp->membersp(); itemp; itemp = itemp->nextp()) {
+            if (AstTypedef* const typedefp
-                if (AstTypedef* const typedefp = VN_CAST(itemp, Typedef)) {
+                = VN_CAST(m_memberMap.findMember(newClassp, refDTypep->name()), Typedef)) {
-                    if (typedefp->name() == refDTypep->name()) {
                 refDTypep->typedefp(typedefp);
                 refDTypep->classOrPackagep(newClassp);
-                        UINFO(9, "Resolved parameterized class typedef: "
+                UINFO(9, "Resolved parameterized class typedef: " << refDTypep->name() << " -> "
-                                     << refDTypep->name() << " -> " << typedefp << " in "
+                                                                  << typedefp << " in "
                                                                   << newClassp->name());
-                        break;
-                    }
-                }
             }
         }
         return newModp;

test_regress/t/t_class_param_typedef5.v

@@ -16,8 +16,8 @@ class func_c #(parameter p_width=4);
 endclass
 
 module modA #(parameter p_width = 7)(
-  input func_c#(p_width)::my_type_t sig_a
+  input func_c#(p_width)::my_type_t sig_a,
-  ,output func_c#(p_width)::my_type_t sig_b
+  output func_c#(p_width)::my_type_t sig_b
 );
   assign sig_b.data = func_c#(p_width)::func(sig_a);
 endmodule
@@ -28,8 +28,8 @@ module the_top();
   func_c#(Size)::my_type_t sig_a, sig_b, sig_c;
 
   modA #(.p_width(Size)) modA(
-    .sig_a(sig_a)
+    .sig_a(sig_a),
-    ,.sig_b(sig_b)
+    .sig_b(sig_b)
   );
 
   initial begin

test_regress/t/t_class_param_typedef6.v

@@ -35,7 +35,8 @@ endmodule
 module the_top #() ();
 
   typedef logic [7:0] my_t;
-  typedef pipeline_class #(my_t)::if_id_t if_id_t;
+  typedef pipeline_class #(my_t)::if_id_t if_id2_t;
+  typedef if_id2_t if_id_t;
   pipe_reg #(if_id_t) if_id_reg();
 
   initial begin

test_regress/t/t_param_pattern3.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2025 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+test.compile(verilator_flags2=["--binary"])
+
+test.execute()
+
+test.passes()

test_regress/t/t_param_pattern3.v

@@ -0,0 +1,34 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty.
+// SPDX-License-Identifier: CC0-1.0
+
+`define stop $stop
+`define checkd(gotv,expv) \
+  do if ((gotv) !== (expv)) begin \
+    $write("%%Error: %s:%0d:  got=%0d exp=%0d\n", \
+            `__FILE__,`__LINE__, (gotv), (expv)); \
+    `stop; \
+  end while(0);
+
+class Class_A #(parameter int myparam = 32);
+endclass
+
+module tb_top;
+  localparam int WIDTH_A=32;
+  localparam int WIDTH_B=2*16;
+
+  Class_A#(32) a;
+  Class_A#(WIDTH_A) b;
+  Class_A#(WIDTH_B) c;
+
+  initial begin
+    #1;
+
+    a = b;
+
+    $write("*-* All Finished *-*\n");
+    $finish;
+  end
+endmodule