Fix CASEINCOMPLETE to not warn on `unique0 case` (#7647).

Fixes #7647.

Changes

@@ -83,6 +83,7 @@ Verilator 5.049 devel
 * Fix force determinism (#7620) (#7637). [Artur Bieniek, Antmicro Ltd.]
 * Fix reference counting for modport task references (#7628). [Nick Brereton]
 * Fix implicit conversions of VlWide (#7642). [Geza Lore, Testorrent USA, Inc.]
+* Fix CASEINCOMPLETE to not warn on `unique0 case` (#7647).
 
 
 Verilator 5.048 2026-04-26

docs/guide/warnings.rst

@@ -382,6 +382,9 @@ List Of Warnings
    non-enumerated values (IEEE 1800-2023 12.5.3). Verilator checks that
    illegal values are not hit, unless :vlopt:`--no-assert-case` was used.
 
+   Unique0 case statements will never cause this warning. (Although unique0
+   should be avoided in synthesizable code as may result in latch behavior.)
+
    Ignoring this warning will only suppress the lint check; it will
    simulate correctly.
 

src/V3Case.cpp

@@ -178,8 +178,10 @@ class CaseVisitor final : public VNVisitor {
             for (uint32_t i = 0; i < numCases; ++i) {
                 if ((i & mask) == val) {
                     if (!m_valueItem[i]) {
-                        nodep->v3warn(CASEINCOMPLETE, "Enum item " << itemp->prettyNameQ()
-                                                                   << " not covered by case\n");
+                        if (!nodep->unique0Pragma())
+                            nodep->v3warn(CASEINCOMPLETE, "Enum item "
+                                                              << itemp->prettyNameQ()
+                                                              << " not covered by case\n");
                         m_caseIncomplete = true;
                         return false;  // enum has uncovered value by case items
                     }
@@ -310,9 +312,10 @@ class CaseVisitor final : public VNVisitor {
             } else {
                 for (uint32_t i = 0; i < numCases; ++i) {
                     if (!m_valueItem[i]) {  // has uncovered case
-                        nodep->v3warn(CASEINCOMPLETE, "Case values incompletely covered "
-                                                      "(example pattern 0x"
-                                                          << std::hex << i << ")");
+                        if (!nodep->unique0Pragma())
+                            nodep->v3warn(CASEINCOMPLETE, "Case values incompletely covered "
+                                                          "(example pattern 0x"
+                                                              << std::hex << i << ")");
                         m_caseIncomplete = true;
                         m_caseNoOverlapsAllCovered = false;
                         return false;

test_regress/t/t_lint_caseincomplete_bad.v

@@ -14,5 +14,10 @@ module t (
       2'b10: ;
       2'b11: ;
     endcase
+
+    unique0 case (i)  // No warning
+      2'b00: ;
+    endcase
   end
+
 endmodule