Support 'this.super'

src/verilog.y

@@ -5342,7 +5342,14 @@ exprScope<nodeExprp>:               // scope and variable for use to inside an e
         |       packageClassScope idArrayed             { $$ = AstDot::newIfPkg($2->fileline(), $1, $2); }
         |       ~l~expr '.' idArrayed                   { $$ = new AstDot{$<fl>2, false, $1, $3}; }
         //                      // expr below must be a "yTHIS"
-        |       ~l~expr '.' ySUPER                      { $$ = $1; BBUNSUP($3, "Unsupported: super"); }
+        |       ~l~expr '.' ySUPER
+                        { AstParseRef* const anodep = VN_CAST($1, ParseRef);
+                          if (anodep && anodep->name() == "this") {
+                              $$ = new AstParseRef{$<fl>1, VParseRefExp::PX_ROOT, "super"};
+                          } else {
+                              $$ = $1;  $$->v3error("Syntax error: 'super' must be first name component, or after 'this.'");
+                          }
+                        }
         //                      // Part of implicit_class_handle
         |       ySUPER                                  { $$ = new AstParseRef{$<fl>1, VParseRefExp::PX_ROOT, "super"}; }
         ;
@@ -6093,7 +6100,8 @@ idClass<nodeExprp>:             // Misc Ref to dotted, and/or arrayed, and/or bi
                         { $$ = new AstDot{$2, false, new AstParseRef{$<fl>1, VParseRefExp::PX_ROOT, "this"}, $3}; }
         |       ySUPER '.' idDotted
                         { $$ = new AstDot{$2, false, new AstParseRef{$<fl>1, VParseRefExp::PX_ROOT, "super"}, $3}; }
-        |       yTHIS '.' ySUPER '.' idDotted           { $$ = $5; BBUNSUP($1, "Unsupported: this.super"); }
+        |       yTHIS '.' ySUPER '.' idDotted
+                        { $$ = new AstDot{$4, false, new AstParseRef{$<fl>3, VParseRefExp::PX_ROOT, "super"}, $5}; }
         //                      // Expanded: package_scope idDottedSel
         |       packageClassScope idDotted              { $$ = new AstDot{$<fl>2, true, $1, $2}; }
         ;
@@ -6105,7 +6113,8 @@ idClassSel<nodeExprp>:          // Misc Ref to dotted, and/or arrayed, and/or bi
                         { $$ = new AstDot{$2, false, new AstParseRef{$<fl>1, VParseRefExp::PX_ROOT, "this"}, $3}; }
         |       ySUPER '.' idDottedSel
                         { $$ = new AstDot{$2, false, new AstParseRef{$<fl>1, VParseRefExp::PX_ROOT, "super"}, $3}; }
-        |       yTHIS '.' ySUPER '.' idDottedSel        { $$ = $5; BBUNSUP($1, "Unsupported: this.super"); }
+        |       yTHIS '.' ySUPER '.' idDottedSel
+                        { $$ = new AstDot{$4, false, new AstParseRef{$<fl>3, VParseRefExp::PX_ROOT, "super"}, $5}; }
         //                      // Expanded: package_scope idDottedSel
         |       packageClassScope idDottedSel           { $$ = new AstDot{$<fl>2, true, $1, $2}; }
         ;
@@ -6117,7 +6126,8 @@ idClassSelForeach<nodeExprp>:
                         { $$ = new AstDot{$2, false, new AstParseRef{$<fl>1, VParseRefExp::PX_ROOT, "this"}, $3}; }
         |       ySUPER '.' idDottedForeach
                         { $$ = new AstDot{$2, false, new AstParseRef{$<fl>1, VParseRefExp::PX_ROOT, "super"}, $3}; }
-        |       yTHIS '.' ySUPER '.' idDottedForeach    { $$ = $5; BBUNSUP($1, "Unsupported: this.super"); }
+        |       yTHIS '.' ySUPER '.' idDottedForeach
+                        { $$ = new AstDot{$4, false, new AstParseRef{$<fl>3, VParseRefExp::PX_ROOT, "super"}, $5}; }
         //                      // Expanded: package_scope idForeach
         |       packageClassScope idDottedForeach       { $$ = new AstDot{$<fl>2, true, $1, $2}; }
         ;

test_regress/t/t_class_super_bad3.out

@@ -0,0 +1,5 @@
+%Error: t/t_class_super_bad3.v:10:5: Syntax error: 'super' must be first name component, or after 'this.'
+   10 |     i.super.i = 1;   
+      |     ^
+        ... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.
+%Error: Exiting due to

test_regress/t/t_class_super_bad3.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2024 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('linter')
+
+test.lint(fails=True, expect_filename=test.golden_filename)
+
+test.passes()

test_regress/t/t_class_super_bad3.v

@@ -0,0 +1,12 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2025 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+//
+
+class Cls;
+  task t;
+    i.super.i = 1;  // <--- BAD: cannot dot a reference to get super
+  endtask
+endclass

test_regress/t/t_class_this_super.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()
+
+test.execute()
+
+test.passes()

test_regress/t/t_class_this_super.v

@@ -0,0 +1,52 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2025 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+// verilog_format: off
+`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);
+// verilog_format: on
+
+// Based on icarus/ivtest/ivltests/sv_class_super6.v
+
+class B;
+  int m_x, m_y;
+
+  task set_y;
+    m_y = 2000;
+  endtask
+
+  function void check_x;
+    `checkd(m_x, 1000);
+  endfunction
+endclass
+
+class C extends B;
+  byte m_x, m_y;
+  task set_x;
+    m_x = 6;
+    this.m_y = 7;
+    this.super.m_x = 1000;
+  endtask
+
+  function void check_y;
+    `checkd(m_x, 6);
+    `checkd(this.m_y, 7);
+    `checkd(this.super.m_y, 2000);
+  endfunction
+endclass
+
+module test;
+  C c;
+
+  initial begin
+    c = new;
+    c.set_x();
+    c.set_y();
+    c.check_x();
+    c.check_y();
+    $finish;
+  end
+endmodule