Add error on illegal enum base type (#3010).

Changes

@@ -13,8 +13,9 @@ Verilator 5.031 devel
 
 **Minor:**
 
-* Add coverage point hierarchy to coverage reports (#5575) (#5576). [Andrew Nolte]
+* Add error on illegal enum base type (#3010). [Iztok Jeras]
 * Add error when improperly storing to parameter (#5147). [Gökçe Aydos]
+* Add coverage point hierarchy to coverage reports (#5575) (#5576). [Andrew Nolte]
 * Fix can't locate scope error in interface task delayed assignment (#5462) (#5568). [Zhou Shen]
 * Fix BLKANDNBLK for for VARXREFs (#5569). [Todd Strader]
 * Fix VPI error instead of fatal for vpi_get_value() on large signals (#5571). [Todd Strader]

src/V3Width.cpp

@@ -2346,6 +2346,13 @@ class WidthVisitor final : public VNVisitor {
         UINFO(5, "  ENUMDTYPE " << nodep << endl);
         nodep->refDTypep(iterateEditMoveDTypep(nodep, nodep->subDTypep()));
         nodep->dtypep(nodep);
+        AstBasicDType* basicp = nodep->dtypep()->skipRefp()->basicp();
+        if (!basicp || !basicp->keyword().isIntNumeric()) {
+            nodep->v3error(
+                "Enum type must be an integer atom or vector type (IEEE 1800-2023 6.19)");
+            basicp = nodep->findSigned32DType()->basicp();
+            nodep->refDTypep(basicp);
+        }
         nodep->widthFromSub(nodep->subDTypep());
         // Assign widths
         userIterateAndNext(nodep->itemsp(), WidthVP{nodep->dtypep(), BOTH}.p());
@@ -2376,17 +2383,11 @@ class WidthVisitor final : public VNVisitor {
                     itemp->v3error("Enum value that is unassigned cannot follow value with X/Zs "
                                    "(IEEE 1800-2023 6.19)");
                 }
-                if (!nodep->dtypep()->basicp()
-                    && !nodep->dtypep()->basicp()->keyword().isIntNumeric()) {
-                    itemp->v3error("Enum names without values only allowed on numeric types");
-                    // as can't +1 to resolve them.
-                }
                 itemp->valuep(new AstConst{itemp->fileline(), num});
             }
 
             const AstConst* const constp = VN_AS(itemp->valuep(), Const);
-            if (constp->num().isFourState() && nodep->dtypep()->basicp()
-                && !nodep->dtypep()->basicp()->isFourstate()) {
+            if (constp->num().isFourState() && basicp->basicp() && !basicp->isFourstate()) {
                 itemp->v3error("Enum value with X/Zs cannot be assigned to non-fourstate type "
                                "(IEEE 1800-2023 6.19)");
             }

test_regress/t/t_dist_warn_coverage.py

@@ -20,7 +20,6 @@ Suppressed = {}
 for s in [
         ' exited with ',  # Is hit; driver.py filters out
         'EOF in unterminated string',  # Instead get normal unterminated
-        'Enum names without values only allowed on numeric types',  # Hard to hit
         'Enum ranges must be integral, per spec',  # Hard to hit
         'Import package not found: ',  # Errors earlier, until future parser released
         'Return with return value isn\'t underneath a function',  # Hard to hit, get other bad return messages

test_regress/t/t_enum_base_bad.out

@@ -0,0 +1,5 @@
+%Error: t/t_enum_base_bad.v:13:12: Enum type must be an integer atom or vector type (IEEE 1800-2023 6.19)
+                                 : ... note: In instance 't'
+   13 |    typedef enum s_t {
+      |            ^~~~
+%Error: Exiting due to

test_regress/t/t_enum_base_bad.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_enum_base_bad.v

@@ -0,0 +1,23 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t(/*AUTOARG*/);
+
+   typedef struct {
+      int a;
+   } s_t;
+
+   typedef enum s_t {
+                     EN_ZERO } bad_t;
+
+   typedef int int_t;
+
+   typedef enum int_t { EN_ONE = 1 } ok1_t;
+
+   s_t s;
+   int_t i;
+
+endmodule