From d34aa10fafef343d03ae940e20448b83d955b95b Mon Sep 17 00:00:00 2001
From: Ryszard Rozak <rrozak@antmicro.com>
Date: Fri, 10 Feb 2023 13:44:14 +0100
Subject: [PATCH] Fix class field linking when a super classes is a param
 (#3949)

---
 src/V3LinkDot.cpp                      | 19 +++++++++++++++++--
 test_regress/t/t_class_extends_param.v | 24 ++++++++++++++++++------
 2 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/src/V3LinkDot.cpp b/src/V3LinkDot.cpp
index e0926534a..311809d68 100644
--- a/src/V3LinkDot.cpp
+++ b/src/V3LinkDot.cpp
@@ -1999,10 +1999,13 @@ private:
     // Cleared on global
     //  *::user1p()             -> See LinkDotState
     //  *::user2p()             -> See LinkDotState
-    //  *::user3()              // bool.          Processed
+    //  *::user3()              // bool. Processed
     //  *::user4()              -> See LinkDotState
     // Cleared on Cell
-    //  AstVar::user5()         // bool.          True if pin used in this cell
+    //  AstVar::user5()         // bool. True if pin used in this cell
+    //  AstClass::user5()       // bool. True if class has a parameter
+    //                                   as a (possibly indirect) base class.
+    //                                   Used only in LDS_PRIMARY pass
     const VNUser3InUse m_inuser3;
     const VNUser5InUse m_inuser5;
 
@@ -3230,6 +3233,7 @@ private:
         iterateChildren(nodep);
     }
     void visit(AstClass* nodep) override {
+        nodep->user3SetOnce();
         UINFO(5, "   " << nodep << endl);
         checkNoDot(nodep);
         VL_RESTORER(m_curSymp);
@@ -3261,6 +3265,16 @@ private:
                             AstClassRefDType* classRefDtypep = nullptr;
                             AstClass* classp = VN_CAST(foundp->nodep(), Class);
                             if (classp) {
+                                if (classp != nodep) {
+                                    // Case with recursive inheritance is handled later in this
+                                    // function
+                                    iterate(classp);
+                                }
+                                if (classp->user5()) {
+                                    // Has a parameter as its base class
+                                    nodep->user5(true);
+                                    return;
+                                }
                                 AstPin* paramsp = cpackagerefp->paramsp();
                                 if (paramsp) paramsp = paramsp->cloneTree(true);
                                 classRefDtypep
@@ -3271,6 +3285,7 @@ private:
                                     // Extending has to be handled after V3Param.cpp, but the type
                                     // reference has to be visited
                                     iterate(paramp);
+                                    nodep->user5(true);
                                     return;
                                 } else {
                                     AstNodeDType* const paramTypep = paramp->getChildDTypep();
diff --git a/test_regress/t/t_class_extends_param.v b/test_regress/t/t_class_extends_param.v
index 056985bc5..0d5e8cf36 100644
--- a/test_regress/t/t_class_extends_param.v
+++ b/test_regress/t/t_class_extends_param.v
@@ -7,7 +7,7 @@
 module t (/*AUTOARG*/
    );
 
-   class foo;
+   class Foo;
       int x = 1;
       function int get_x;
          return x;
@@ -17,10 +17,10 @@ module t (/*AUTOARG*/
       endfunction
    endclass
 
-   class bar #(type T=foo) extends T;
+   class Bar #(type T=Foo) extends T;
    endclass
 
-   class baz;
+   class Baz;
       int x = 2;
       function int get_x;
          return x;
@@ -30,14 +30,26 @@ module t (/*AUTOARG*/
       endfunction
    endclass
 
-   bar bar_foo_i;
-   bar #(baz) bar_baz_i;
+   class ExtendBar extends Bar;
+     function int get_x;
+        return super.get_x();
+     endfunction
+     function int get_6;
+        return 2 * get_3();
+     endfunction
+   endclass
+
+   Bar bar_foo_i;
+   Bar #(Baz) bar_baz_i;
+   ExtendBar extend_bar_i;
 
    initial begin
       bar_foo_i = new;
       bar_baz_i = new;
+      extend_bar_i = new;
       if (bar_foo_i.get_x() == 1 && bar_foo_i.get_3() == 3 &&
-          bar_baz_i.get_x() == 2 && bar_baz_i.get_4() == 4) begin
+          bar_baz_i.get_x() == 2 && bar_baz_i.get_4() == 4 &&
+          extend_bar_i.get_x() == 1 && extend_bar_i.get_6() == 6) begin
          $write("*-* All Finished *-*\n");
          $finish;
       end