Fix randomize() with shadowing a user variable named 'item' (#7993) (#7994)

Fixes #7993.

docs/CONTRIBUTORS

@@ -39,6 +39,7 @@ Aylon Chaim Porat
 Bartłomiej Chmiel
 Bartosz Skorowski
 Benjamin Collier
+BRDR LIFE
 Brian Li
 Cameron Kirk
 Cameron Waite

src/V3LinkDot.cpp

@@ -2195,7 +2195,7 @@ class LinkDotFindVisitor final : public VNVisitor {
         if (const AstDot* const dotp = VN_CAST(nodep->funcrefp(), Dot))
             funcrefp = VN_CAST(dotp->rhsp(), NodeFTaskRef);
         UASSERT_OBJ(funcrefp, nodep, "'with' only can operate on a function/task");
-        string name = "item";
+        string name = funcrefp->name() == "randomize" ? "__Vrandwith_obj" : "item";
         FileLine* argFl = nodep->fileline();
         AstArg* const argsp = funcrefp->argsp();
         if (argsp) {
@@ -4298,7 +4298,7 @@ class LinkDotResolveVisitor final : public VNVisitor {
                     }
                     UINFO(9, indent() << "randomize-with fromSym " << foundp->nodep());
                     AstLambdaArgRef* const lambdaRefp
-                        = new AstLambdaArgRef{nodep->fileline(), "item", false};
+                        = new AstLambdaArgRef{nodep->fileline(), "__Vrandwith_obj", false};
                     AstMemberSel* newp = new AstMemberSel{nodep->fileline(), lambdaRefp,
                                                           VFlagChildDType{}, nodep->name()};
                     nodep->replaceWith(newp);
@@ -5259,7 +5259,8 @@ class LinkDotResolveVisitor final : public VNVisitor {
                     }
                     if (m_ds.m_dotPos != DP_NONE) m_ds.m_dotPos = DP_MEMBER;
                     AstNode* const newp = new AstMethodCall{
-                        nodep->fileline(), new AstLambdaArgRef{nodep->fileline(), "item", false},
+                        nodep->fileline(),
+                        new AstLambdaArgRef{nodep->fileline(), "__Vrandwith_obj", false},
                         VFlagChildDType{}, nodep->name(), argsp};
                     nodep->replaceWith(newp);
                     VL_DO_DANGLING(pushDeletep(nodep), nodep);

test_regress/t/t_debug_emitv.out

@@ -1287,7 +1287,7 @@ package Vt_debug_emitv___024unit;
         begin : label8
             rand_restricted = randomize() with (
                 ???? // CONSTRAINTEXPR
-                (item.rmember1 < member)) ;
+                (__Vrandwith_obj.rmember1 < member)) ;
             disable label8;
         end
     endfunction

test_regress/t/t_randomize_with_item_name.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# 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-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+if not test.have_solver:
+    test.skip("No constraint solver installed")
+
+test.compile()
+
+test.execute()
+
+test.passes()

test_regress/t/t_randomize_with_item_name.v

@@ -0,0 +1,124 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
+// SPDX-License-Identifier: CC0-1.0
+
+// verilog_format: off
+`define stop $stop
+`define checkh(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got=%0x exp=%0x\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0);
+`define checkd(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got=%0d exp=%0d\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0);
+// verilog_format: on
+
+// IEEE 1800-2023 7.12.1 gives array-method 'with' clauses a default iterator
+// named 'item'. randomize() with (18.7) has no such iterator, so a user
+// variable named 'item' must resolve normally inside the constraint.
+
+class Payload;
+  rand bit [31:0] addr;
+endclass
+
+// The randomized class's own member is spelled 'item'. An undotted name in a
+// randomize() with resolves in the object's scope first (18.7), so this must
+// reach the member being randomized and not any outer 'item'.
+class Tagged;
+  rand bit [31:0] item;
+  rand bit [31:0] other;
+endclass
+
+// A queue to fold with an array-method 'with', from inside a randomize 'with'.
+class Summed;
+  rand bit [31:0] other;
+  int q[$] = '{1, 4, 2, 7};
+endclass
+
+class Seq;
+  Payload item;  // class member deliberately named 'item'
+
+  function new();
+    item = new();
+    item.addr = 32'h8000_0084;
+  endfunction
+
+  // Member handle named 'item', dereferenced in the constraint.
+  function void check_member_handle();
+    Payload r = new();
+    int ok;
+    ok = r.randomize() with {addr == item.addr;};
+    `checkd(ok, 1)
+    `checkh(r.addr, 32'h8000_0084)
+  endfunction
+
+  // Same, but not a tautology even when misbound. Before the fix this became
+  // 'addr == addr + 1' and randomize() returned 0.
+  function void check_not_tautology();
+    Payload r = new();
+    int ok;
+    ok = r.randomize() with {addr == item.addr + 1;};
+    `checkd(ok, 1)
+    `checkh(r.addr, 32'h8000_0085)
+  endfunction
+
+
+  // A local, rather than a member, also named 'item'.
+  function void check_local_handle();
+    Payload r = new();
+    Payload item = new();
+    int ok;
+    item.addr = 32'hdead_beef;
+    ok = r.randomize() with {addr == item.addr;};
+    `checkd(ok, 1)
+    `checkh(r.addr, 32'hdead_beef)
+  endfunction
+
+
+  // The array-method iterator must keep working, in a class that also has a
+  // variable named 'item'. This is what the name exists for.
+  function void check_array_method_iterator();
+    int q[$] = '{1, 4, 2, 7};
+    int found[$];
+    found = q.find with (item > 3);
+    `checkd(found.size(), 2)
+    `checkd(found[0], 4)
+    `checkd(found[1], 7)
+  endfunction
+
+  // A rand member of the randomized class named 'item', referenced undotted.
+  // The member wins over the caller's own 'item'.
+  function void check_target_member();
+    Tagged t = new();
+    int ok;
+    ok = t.randomize() with {
+      item == 32'd42;
+      other == item + 1;
+    };
+    `checkd(ok, 1)
+    `checkh(t.item, 32'd42)
+    `checkh(t.other, 32'd43)
+  endfunction
+
+  // An array-method 'with' nested inside a randomize() 'with'. The two now use
+  // different implicit names, so both must bind: the inner 'item' to the queue
+  // element, the constraint to the object being randomized.
+  function void check_nested_iterator();
+    Summed t = new();
+    int ok;
+    ok = t.randomize() with {other == q.sum() with (item);};
+    `checkd(ok, 1)
+    `checkh(t.other, 32'd14)
+  endfunction
+endclass
+
+module t (  /*AUTOARG*/);
+  initial begin
+    automatic Seq s = new();
+    s.check_member_handle();
+    s.check_not_tautology();
+    s.check_local_handle();
+    s.check_array_method_iterator();
+    s.check_target_member();
+    s.check_nested_iterator();
+    $write("*-* All Finished *-*\n");
+    $finish;
+  end
+endmodule

test_regress/t/t_randomize_with_item_name_types.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# 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-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+if not test.have_solver:
+    test.skip("No constraint solver installed")
+
+test.compile()
+
+test.execute()
+
+test.passes()

test_regress/t/t_randomize_with_item_name_types.v

@@ -0,0 +1,87 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain.
+// SPDX-FileCopyrightText: 2026 Wilson Snyder
+// SPDX-License-Identifier: CC0-1.0
+
+// verilog_format: off
+`define stop $stop
+`define checkh(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got=%0x exp=%0x\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0);
+`define checkd(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got=%0d exp=%0d\n", `__FILE__,`__LINE__, (gotv), (expv)); `stop; end while(0);
+// verilog_format: on
+
+// IEEE 1800-2023 7.12.1 gives array-method 'with' clauses a default iterator
+// named 'item'. randomize() with (18.7) has no such iterator, so a user
+// variable named 'item' must resolve normally inside the constraint.
+
+class Payload;
+  rand bit [31:0] addr;
+endclass
+
+class Other;
+  bit [31:0] tag;
+endclass
+
+class Seq;
+  Other item;  // class member named 'item', of a type with no 'addr'
+
+  function new();
+    item = new();
+    item.tag = 32'h5a5a_5a5a;
+  endfunction
+
+  // Before the fix 'item' bound to the randomize target, so this failed
+  // elaboration with "Member 'tag' not found in class 'Payload'".
+  function void check_other_type();
+    Payload r = new();
+    int ok;
+    ok = r.randomize() with {addr == item.tag;};
+    `checkd(ok, 1)
+    `checkh(r.addr, 32'h5a5a_5a5a)
+  endfunction
+
+  // Undotted scalar named 'item'. Before the fix this produced C++ that did
+  // not compile: "'item' was not declared in this scope".
+  function void check_bare_scalar();
+    Payload r = new();
+    bit [31:0] item = 32'hcafe_f00d;
+    int ok;
+    ok = r.randomize() with {addr == item;};
+    `checkd(ok, 1)
+    `checkh(r.addr, 32'hcafe_f00d)
+  endfunction
+
+  // A queue member named 'item'. The randomize target has no such member, so
+  // this must resolve to the caller's queue and index it normally.
+  function void check_queue_element();
+    Payload r = new();
+    bit [31:0] item[$] = '{32'h1111_1111, 32'h2222_2222};
+    int ok;
+    ok = r.randomize() with {addr == item[1];};
+    `checkd(ok, 1)
+    `checkh(r.addr, 32'h2222_2222)
+  endfunction
+endclass
+
+module t (  /*AUTOARG*/);
+  // std::randomize() with reaches the 'with' clause through a different call
+  // site than a class randomize(), and must not shadow 'item' either.
+  function automatic void check_std_randomize();
+    bit [31:0] item = 32'h5eed_5eed;
+    bit [31:0] v;
+    int ok;
+    ok = std::randomize(v) with {v == item;};
+    `checkd(ok, 1)
+    `checkh(v, 32'h5eed_5eed)
+  endfunction
+
+  initial begin
+    automatic Seq s = new();
+    s.check_other_type();
+    s.check_bare_scalar();
+    s.check_queue_element();
+    check_std_randomize();
+    $write("*-* All Finished *-*\n");
+    $finish;
+  end
+endmodule