Fix false ENUMVALUE errors in unstable branch (#3761)

src/V3Width.cpp

@@ -1841,9 +1841,12 @@ private:
         }
     }
     void visit(AstCast* nodep) override {
+        if (nodep->didWidth()) return;
+        UINFO(9, "CAST " << nodep << endl);
         nodep->dtypep(iterateEditMoveDTypep(nodep, nodep->subDTypep()));
         if (m_vup->prelim()) {
             // if (debug()) nodep->dumpTree(cout, "  CastPre: ");
+            // if (debug()) nodep->backp()->dumpTree(cout, "  CastPreUpUp: ");
             userIterateAndNext(nodep->fromp(), WidthVP(SELF, PRELIM).p());
             AstNodeDType* const toDtp = nodep->dtypep()->skipRefToEnump();
             AstNodeDType* const fromDtp = nodep->fromp()->dtypep()->skipRefToEnump();
@@ -1878,8 +1881,10 @@ private:
             if (bad) {
             } else if (const AstBasicDType* const basicp = toDtp->basicp()) {
                 if (!basicp->isDouble() && !fromDtp->isDouble()) {
+                    AstNodeDType* const origDTypep = nodep->dtypep();
                     const int width = toDtp->width();
                     castSized(nodep, nodep->fromp(), width);
+                    nodep->dtypeFrom(origDTypep);  // If was enum, need dtype to preserve as enum
                     // Note castSized might modify nodep->fromp()
                 } else {
                     iterateCheck(nodep, "value", nodep->fromp(), SELF, FINAL, fromDtp, EXTEND_EXP,
@@ -1924,8 +1929,10 @@ private:
                          EXTEND_EXP, false);
             AstNode* const underp = nodep->fromp()->unlinkFrBack();
             // if (debug()) underp->dumpTree(cout, "  CastRep: ");
+            underp->dtypeFrom(nodep);
             nodep->replaceWith(underp);
             VL_DO_DANGLING(pushDeletep(nodep), nodep);
+            underp->didWidth(true);
         }
     }
     void visit(AstCastSize* nodep) override {
@@ -2217,6 +2224,9 @@ private:
             // and if we keep minwidth we'll consider it unsized which is incorrect
             iterateCheck(nodep, "Enum value", nodep->valuep(), CONTEXT_DET, FINAL, nodep->dtypep(),
                          EXTEND_EXP);
+            // Always create a cast, to avoid later ENUMVALUE warnings
+            nodep->valuep(new AstCast{nodep->valuep()->fileline(), nodep->valuep()->unlinkFrBack(),
+                                      nodep->dtypep()});
         }
     }
     void visit(AstEnumItemRef* nodep) override {
@@ -6139,12 +6149,13 @@ private:
                     if (castable != COMPATIBLE && castable != ENUM_IMPLICIT && !VN_IS(underp, Cast)
                         && !VN_IS(underp, CastDynamic) && !m_enumItemp && warnOn) {
                         nodep->v3warn(ENUMVALUE,
-                                      "Illegal implicit conversion to enum "
+                                      "Implicit conversion to enum "
                                           << expDTypep->prettyDTypeNameQ() << " from "
                                           << underp->dtypep()->prettyDTypeNameQ()
                                           << " (IEEE 1800-2017 6.19.3)\n"
                                           << nodep->warnMore()
                                           << "... Suggest use enum's mnemonic, or static cast");
+                        if (debug()) nodep->backp()->dumpTree(cout, "- back: ");
                     }
                 }
                 AstNodeDType* subDTypep = expDTypep;

src/V3WidthCommit.h

@@ -85,6 +85,7 @@ public:
             num.isSigned(nodep->isSigned());
             AstConst* const newp = new AstConst{nodep->fileline(), num};
             newp->dtypeFrom(nodep);
+            newp->user1(true);
             return newp;
         } else {
             return nullptr;
@@ -163,6 +164,7 @@ private:
         }
     }
     void visit(AstConst* nodep) override {
+        if (nodep->user1SetOnce()) return;  // Process once
         UASSERT_OBJ(nodep->dtypep(), nodep, "No dtype");
         iterate(nodep->dtypep());  // Do datatype first
         if (AstConst* const newp = newIfConstCommitSize(nodep)) {

test_regress/t/t_enum_type_bad.out

@@ -1,15 +1,15 @@
-%Error-ENUMVALUE: t/t_enum_type_bad.v:28:9: Illegal implicit conversion to enum 't.e_t' from 'logic[31:0]' (IEEE 1800-2017 6.19.3)
+%Error-ENUMVALUE: t/t_enum_type_bad.v:28:9: Implicit conversion to enum 't.e_t' from 'logic[31:0]' (IEEE 1800-2017 6.19.3)
                                           : ... In instance t
                                           : ... Suggest use enum's mnemonic, or static cast
    28 |       e = 1;   
       |         ^
                   ... For error description see https://verilator.org/warn/ENUMVALUE?v=latest
-%Error-ENUMVALUE: t/t_enum_type_bad.v:29:9: Illegal implicit conversion to enum 't.o_t' from 't.e_t' (IEEE 1800-2017 6.19.3)
+%Error-ENUMVALUE: t/t_enum_type_bad.v:29:9: Implicit conversion to enum 't.o_t' from 't.e_t' (IEEE 1800-2017 6.19.3)
                                           : ... In instance t
                                           : ... Suggest use enum's mnemonic, or static cast
    29 |       o = e;   
       |         ^
-%Error-ENUMVALUE: t/t_enum_type_bad.v:35:9: Illegal implicit conversion to enum 't.o_t' from 'ENUMDTYPE 't.e_t'' (IEEE 1800-2017 6.19.3)
+%Error-ENUMVALUE: t/t_enum_type_bad.v:35:9: Implicit conversion to enum 't.o_t' from 'ENUMDTYPE 't.e_t'' (IEEE 1800-2017 6.19.3)
                                           : ... In instance t
                                           : ... Suggest use enum's mnemonic, or static cast
    35 |       o = str.m_e;   

test_regress/t/t_enum_value_assign.pl

@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2022 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
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;

test_regress/t/t_enum_value_assign.v

@@ -0,0 +1,34 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t(/*AUTOARG*/);
+
+   localparam logic [9:0] V2 = (1 << 2);
+   localparam logic [9:0] V1 = (1 << 1);
+   localparam logic [9:0] V0 = (1 << 0);
+   typedef enum logic [9:0] {
+                             ZERO = '0,
+                             VAL0 = V0,
+                             VAL1 = V1,
+                             VAL01 = V0 | V1
+                             } enum_t;
+
+   localparam enum_t PARAMVAL1 = VAL1;
+   localparam enum_t PARAMVAL1CONST = enum_t'(2);
+
+   initial begin
+      enum_t e;
+      e = VAL01;
+      if (e != VAL01) $stop;
+
+      if (PARAMVAL1 != VAL1) $stop;
+      if (PARAMVAL1CONST != VAL1) $stop;
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+endmodule