p4lang · kfcripps · Aug 26, 2025 · Aug 15, 2025
diff --git a/backends/tofino/bf-p4c/test/gtest/error_reporter.cpp b/backends/tofino/bf-p4c/test/gtest/error_reporter.cpp
@@ -91,13 +91,13 @@ TEST_F(ErrorReporterTest, WarningsConformToExpectedFormat) {
 )";
 
     const std::string EXPECTED_WARN_1 =
-        R"(TestCode(46): [--Wwarn=uninitialized_use] warning: tmp may be uninitialized
+        R"(TestCode(46): [--Wwarn=uninitialized-use] warning: tmp may be uninitialized
         tmp = tmp * (make_zero ? 16w0 : 16w1);
               ^^^
 )";
 
     const std::string EXPECTED_WARN_2 =
-        R"(TestCode(44): [--Wwarn=uninitialized_out_param] warning: out parameter 'val_undefined' may be uninitialized when 'do_global_action' terminates
+        R"(TestCode(44): [--Wwarn=uninitialized-out-param] warning: out parameter 'val_undefined' may be uninitialized when 'do_global_action' terminates
     action do_global_action(in bool make_zero, out bool val_undefined) {
                                                         ^^^^^^^^^^^^^
 TestCode(44)
@@ -106,8 +106,8 @@ TestCode(44)
 )";
 
     const std::string EXPECTED_WARN_3 =
-        R"([--Wwarn=uninitialized_use] warning: val_undefined may be uninitialized
-TestCode(44): [--Wwarn=uninitialized_use] warning: val_undefined may be uninitialized
+        R"([--Wwarn=uninitialized-use] warning: val_undefined may be uninitialized
+TestCode(44): [--Wwarn=uninitialized-use] warning: val_undefined may be uninitialized
     action do_global_action(in bool make_zero, out bool val_undefined) {
                                                         ^^^^^^^^^^^^^
 )";

diff --git a/frontends/common/parser_options.cpp b/frontends/common/parser_options.cpp
@@ -529,7 +529,7 @@ const P4CConfiguration &P4CContext::getConfig() {
 
 bool P4CContext::isRecognizedDiagnostic(cstring diagnostic) {
     static const std::unordered_set<cstring> recognizedDiagnostics = {
-        "uninitialized_out_param"_cs, "uninitialized_use"_cs, "unknown_diagnostic"_cs};
+        "uninitialized-out-param"_cs, "uninitialized-use"_cs, "unknown_diagnostic"_cs};
 
     return recognizedDiagnostics.count(diagnostic);
 }

diff --git a/lib/error_catalog.cpp b/lib/error_catalog.cpp
@@ -122,13 +122,13 @@ std::map<int, cstring> ErrorCatalog::errorCatalog = {
     {ErrorType::WARN_PARSER_TRANSITION, "parser-transition"_cs},
     {ErrorType::WARN_UNREACHABLE, "unreachable"_cs},
     {ErrorType::WARN_SHADOWING, "shadow"_cs},
-    {ErrorType::WARN_UNINITIALIZED_USE, "uninitialized_use"_cs},
-    {ErrorType::WARN_UNINITIALIZED_OUT_PARAM, "uninitialized_out_param"_cs},
+    {ErrorType::WARN_UNINITIALIZED_USE, "uninitialized-use"_cs},
+    {ErrorType::WARN_UNINITIALIZED_OUT_PARAM, "uninitialized-out-param"_cs},
     {ErrorType::WARN_IGNORE, "ignore"_cs},
-    {ErrorType::WARN_INVALID_HEADER, "invalid_header"_cs},
-    {ErrorType::WARN_DUPLICATE_PRIORITIES, "duplicate_priorities"_cs},
-    {ErrorType::WARN_ENTRIES_OUT_OF_ORDER, "entries_out_of_priority_order"_cs},
-    {ErrorType::WARN_MULTI_HDR_EXTRACT, "multi_header_extract"_cs},
+    {ErrorType::WARN_INVALID_HEADER, "invalid-header"_cs},
+    {ErrorType::WARN_DUPLICATE_PRIORITIES, "duplicate-priorities"_cs},
+    {ErrorType::WARN_ENTRIES_OUT_OF_ORDER, "entries-out-of-priority-order"_cs},
+    {ErrorType::WARN_MULTI_HDR_EXTRACT, "multi-header-extract"_cs},
     {ErrorType::WARN_EXPRESSION, "expr"_cs},
     {ErrorType::WARN_DUPLICATE, "duplicate"_cs},
     {ErrorType::WARN_BRANCH_HINT, "branch"_cs},

diff --git a/test/gtest/diagnostics.cpp b/test/gtest/diagnostics.cpp
@@ -66,7 +66,7 @@ class Diagnostics : public P4CTest {};
 
 TEST_F(Diagnostics, P4_16_Disable) {
     auto test = createP4_16DiagnosticsTestCase(P4_SOURCE(R"(
-        @diagnostic("uninitialized_out_param", "disable")
+        @diagnostic("uninitialized-out-param", "disable")
     )"));
     EXPECT_TRUE(test);
     EXPECT_EQ(0u, diagnosticCount());
@@ -77,7 +77,7 @@ TEST_F(Diagnostics, P4_16_Disable) {
 
 TEST_F(Diagnostics, P4_16_Warn) {
     auto test = createP4_16DiagnosticsTestCase(P4_SOURCE(R"(
-        @diagnostic("uninitialized_out_param", "warn")
+        @diagnostic("uninitialized-out-param", "warn")
     )"));
     EXPECT_TRUE(test);
     EXPECT_EQ(1u, diagnosticCount());
@@ -87,7 +87,7 @@ TEST_F(Diagnostics, P4_16_Warn) {
 
 TEST_F(Diagnostics, P4_16_Error) {
     auto test = createP4_16DiagnosticsTestCase(P4_SOURCE(R"(
-        @diagnostic("uninitialized_out_param", "error")
+        @diagnostic("uninitialized-out-param", "error")
     )"));
     EXPECT_FALSE(test);
     EXPECT_EQ(1u, diagnosticCount());
@@ -97,15 +97,15 @@ TEST_F(Diagnostics, P4_16_Error) {
 
 TEST_F(Diagnostics, DISABLED_P4_14_Disable) {
     auto test = createP4_14DiagnosticsTestCase(P4_SOURCE(R"(
-        @pragma diagnostic uninitialized_use disable
+        @pragma diagnostic uninitialized-use disable
     )"));
     EXPECT_TRUE(test);
     EXPECT_EQ(0u, diagnosticCount());
 }
 
 TEST_F(Diagnostics, DISABLED_P4_14_Warn) {
     auto test = createP4_14DiagnosticsTestCase(P4_SOURCE(R"(
-        @pragma diagnostic uninitialized_use warn
+        @pragma diagnostic uninitialized-use warn
     )"));
     EXPECT_TRUE(test);
     EXPECT_EQ(1u, diagnosticCount());
@@ -115,7 +115,7 @@ TEST_F(Diagnostics, DISABLED_P4_14_Warn) {
 
 TEST_F(Diagnostics, DISABLED_P4_14_Error) {
     auto test = createP4_14DiagnosticsTestCase(P4_SOURCE(R"(
-        @pragma diagnostic uninitialized_use error
+        @pragma diagnostic uninitialized-use error
     )"));
     EXPECT_FALSE(test);
     EXPECT_EQ(1u, diagnosticCount());
@@ -133,26 +133,26 @@ TEST_F(Diagnostics, NestedCompileContexts) {
         {
             AutoCompileContext autoErrorContext(new GTestContext);
 
-            // Run a test with `uninitialized_out_param` set to trigger an error.
+            // Run a test with `uninitialized-out-param` set to trigger an error.
             auto test = createP4_16DiagnosticsTestCase(P4_SOURCE(R"(
-                @diagnostic("uninitialized_out_param", "error")
+                @diagnostic("uninitialized-out-param", "error")
             )"));
             EXPECT_FALSE(test);
             EXPECT_EQ(1u, diagnosticCount());
             EXPECT_EQ(0u, warningCount());
             EXPECT_EQ(1u, errorCount());
         }
 
-        // Run a test with `uninitialized_out_param` disabled. The error from
+        // Run a test with `uninitialized-out-param` disabled. The error from
         // the previous test should be gone, and no new error should appear.
         auto test = createP4_16DiagnosticsTestCase(P4_SOURCE(R"(
-            @diagnostic("uninitialized_out_param", "disable")
+            @diagnostic("uninitialized-out-param", "disable")
         )"));
         EXPECT_TRUE(test);
         EXPECT_EQ(0u, diagnosticCount());
     }
 
-    // Run a test with no diagnostic pragma for `uninitialized_out_param`. It
+    // Run a test with no diagnostic pragma for `uninitialized-out-param`. It
     // should default to triggering a warning; the diagnostic actions configured
     // by the previous tests should be gone.
     auto test = createP4_16DiagnosticsTestCase(P4_SOURCE(R"()"));
@@ -205,7 +205,7 @@ TEST_F(Diagnostics, CompilerOptions) {
 
     {
         AutoCompileContext autoContext(new GTestContext);
-        auto test = parseWithCompilerOptions({"(test)", "--Wdisable=uninitialized_out_param"});
+        auto test = parseWithCompilerOptions({"(test)", "--Wdisable=uninitialized-out-param"});
         EXPECT_TRUE(test);
         EXPECT_EQ(0u, diagnosticCount());
     }
@@ -221,7 +221,7 @@ TEST_F(Diagnostics, CompilerOptions) {
 
     {
         AutoCompileContext autoContext(new GTestContext);
-        auto test = parseWithCompilerOptions({"(test)", "--Wwarn=uninitialized_out_param"});
+        auto test = parseWithCompilerOptions({"(test)", "--Wwarn=uninitialized-out-param"});
         EXPECT_TRUE(test);
         EXPECT_EQ(1u, diagnosticCount());
         EXPECT_EQ(1u, warningCount());
@@ -230,7 +230,7 @@ TEST_F(Diagnostics, CompilerOptions) {
 
     {
         AutoCompileContext autoContext(new GTestContext);
-        auto test = parseWithCompilerOptions({"(test)", "--Werror=uninitialized_out_param"});
+        auto test = parseWithCompilerOptions({"(test)", "--Werror=uninitialized-out-param"});
         EXPECT_FALSE(test);
         EXPECT_EQ(1u, diagnosticCount());
         EXPECT_EQ(0u, warningCount());
@@ -256,7 +256,7 @@ TEST_F(Diagnostics, CompilerOptions) {
 
         // We expect all warnings to be disabled. If `unknown_diagnostic` was
         // treated as an argument to `--Wdisable`, then
-        // `uninitialized_out_param` would still be enabled and a warning would
+        // `uninitialized-out-param` would still be enabled and a warning would
         // fire.
         EXPECT_EQ(0u, diagnosticCount());
     }

diff --git a/testdata/p4_16_dpdk_errors_outputs/psa-dpdk-struct-field.p4-error b/testdata/p4_16_dpdk_errors_outputs/psa-dpdk-struct-field.p4-error
@@ -1,4 +1,4 @@
-psa-dpdk-struct-field.p4(51): [--Wwarn=uninitialized_use] warning: flg may be uninitialized
+psa-dpdk-struct-field.p4(51): [--Wwarn=uninitialized-use] warning: flg may be uninitialized
   if (flg == 0x2) {
       ^^^
 psa-dpdk-struct-field.p4(51): [--Werror=target-error] error: Unsupported bitwidth 80 in flg

diff --git a/testdata/p4_16_errors_outputs/issue-2123_e.p4-stderr b/testdata/p4_16_errors_outputs/issue-2123_e.p4-stderr
@@ -1,13 +1,13 @@
-issue-2123_e.p4(63): [--Wwarn=uninitialized_use] warning: hdr.ipv4.totalLen may be uninitialized
+issue-2123_e.p4(63): [--Wwarn=uninitialized-use] warning: hdr.ipv4.totalLen may be uninitialized
             hdr.ipv4.totalLen .. 0x0800 : parse_ipv4;
             ^^^^^^^^^^^^^^^^^
-issue-2123_e.p4(64): [--Wwarn=uninitialized_use] warning: hdr.ipv4.totalLen may be uninitialized
+issue-2123_e.p4(64): [--Wwarn=uninitialized-use] warning: hdr.ipv4.totalLen may be uninitialized
             0x0800 .. hdr.ipv4.totalLen : parse_ipv4;
                       ^^^^^^^^^^^^^^^^^
-issue-2123_e.p4(63): [--Wwarn=invalid_header] warning: accessing a field of an invalid header hdr.ipv4
+issue-2123_e.p4(63): [--Wwarn=invalid-header] warning: accessing a field of an invalid header hdr.ipv4
             hdr.ipv4.totalLen .. 0x0800 : parse_ipv4;
             ^^^^^^^^
-issue-2123_e.p4(64): [--Wwarn=invalid_header] warning: accessing a field of an invalid header hdr.ipv4
+issue-2123_e.p4(64): [--Wwarn=invalid-header] warning: accessing a field of an invalid header hdr.ipv4
             0x0800 .. hdr.ipv4.totalLen : parse_ipv4;
                       ^^^^^^^^
 issue-2123_e.p4(61): [--Wwarn=invalid] warning: 16w0x806-16w0x800: Range with end less than start is treated as an empty range

diff --git a/testdata/p4_16_errors_outputs/no_warn_const_switch_expr.p4-stderr b/testdata/p4_16_errors_outputs/no_warn_const_switch_expr.p4-stderr
@@ -1,10 +1,10 @@
-no_warn_const_switch_expr.p4(1): [--Wwarn=uninitialized_out_param] warning: out parameter 'y' may be uninitialized when 'bar' terminates
+no_warn_const_switch_expr.p4(1): [--Wwarn=uninitialized-out-param] warning: out parameter 'y' may be uninitialized when 'bar' terminates
 void bar(in bit<2> x, out bit<8> y) {
                                  ^
 no_warn_const_switch_expr.p4(1)
 void bar(in bit<2> x, out bit<8> y) {
      ^^^
-[--Wwarn=uninitialized_use] warning: y_0 may be uninitialized
+[--Wwarn=uninitialized-use] warning: y_0 may be uninitialized
 no_warn_const_switch_expr.p4(2): error: SwitchStatement: switch statements not supported in actions on this target
     switch (x) {
     ^^^^^^
diff --git a/testdata/p4_16_pna_errors_outputs/pna-example-tcp-connection-tracking-err-1.p4-error b/testdata/p4_16_pna_errors_outputs/pna-example-tcp-connection-tracking-err-1.p4-error
@@ -13,13 +13,13 @@ const ExpireTimeProfileId_t EXPIRE_TIME_PROFILE_TCP_NEVER = (ExpireTimeProfileId
 pna-example-tcp-connection-tracking-err-1.p4(141): [--Wwarn=unused] warning: 'drop' is unused
     action drop () {
            ^^^^
-pna-example-tcp-connection-tracking-err-1.p4(206): [--Wwarn=uninitialized_use] warning: update_aging_info may be uninitialized
+pna-example-tcp-connection-tracking-err-1.p4(206): [--Wwarn=uninitialized-use] warning: update_aging_info may be uninitialized
         if (update_aging_info) {
             ^^^^^^^^^^^^^^^^^
-pna-example-tcp-connection-tracking-err-1.p4(208): [--Wwarn=uninitialized_use] warning: new_expire_time_profile_id may not be completely initialized
+pna-example-tcp-connection-tracking-err-1.p4(208): [--Wwarn=uninitialized-use] warning: new_expire_time_profile_id may not be completely initialized
                 set_entry_expire_time(new_expire_time_profile_id);
                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^
-pna-example-tcp-connection-tracking-err-1.p4(240): [--Wwarn=uninitialized_use] warning: new_expire_time_profile_id may not be completely initialized
+pna-example-tcp-connection-tracking-err-1.p4(240): [--Wwarn=uninitialized-use] warning: new_expire_time_profile_id may not be completely initialized
                           expire_time_profile_id = new_expire_time_profile_id);
                                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^
 pna-example-tcp-connection-tracking-err-1.p4(208): [--Werror=unexpected] error: set_entry_expire_time(new_expire_time_profile_id) must only be called from within an action with ' ct_tcp_table_hit' property equal to true

diff --git a/testdata/p4_16_pna_errors_outputs/pna-example-tcp-connection-tracking-err.p4-error b/testdata/p4_16_pna_errors_outputs/pna-example-tcp-connection-tracking-err.p4-error
@@ -13,13 +13,13 @@ const ExpireTimeProfileId_t EXPIRE_TIME_PROFILE_TCP_NEVER = (ExpireTimeProfileId
 pna-example-tcp-connection-tracking-err.p4(141): [--Wwarn=unused] warning: 'drop' is unused
     action drop () {
            ^^^^
-pna-example-tcp-connection-tracking-err.p4(206): [--Wwarn=uninitialized_use] warning: update_aging_info may be uninitialized
+pna-example-tcp-connection-tracking-err.p4(206): [--Wwarn=uninitialized-use] warning: update_aging_info may be uninitialized
         if (update_aging_info) {
             ^^^^^^^^^^^^^^^^^
-pna-example-tcp-connection-tracking-err.p4(208): [--Wwarn=uninitialized_use] warning: new_expire_time_profile_id may not be completely initialized
+pna-example-tcp-connection-tracking-err.p4(208): [--Wwarn=uninitialized-use] warning: new_expire_time_profile_id may not be completely initialized
                 set_entry_expire_time(new_expire_time_profile_id);
                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^
-pna-example-tcp-connection-tracking-err.p4(240): [--Wwarn=uninitialized_use] warning: new_expire_time_profile_id may not be completely initialized
+pna-example-tcp-connection-tracking-err.p4(240): [--Wwarn=uninitialized-use] warning: new_expire_time_profile_id may not be completely initialized
                           expire_time_profile_id = new_expire_time_profile_id);
                                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^
 pna-example-tcp-connection-tracking-err.p4(208): [--Werror=unexpected] error: set_entry_expire_time(new_expire_time_profile_id) must only be called from within an action with 'idle_timeout_with_auto_delete ct_tcp_table_hit' property equal to true

diff --git a/testdata/p4_16_samples/entries-prio.p4 b/testdata/p4_16_samples/entries-prio.p4
@@ -29,7 +29,7 @@ control c(in Headers h) {
         largest_priority_wins = false;
         priority_delta = 10;
 
- 	@noWarn("duplicate_priorities")
+ 	@noWarn("duplicate-priorities")
         entries = {
             const priority=10: (0x01, 0x1111 &&& 0xF   ) : a_params(1);
                                (0x02, 0x1181           ) : a_params(2); // priority=20

diff --git a/testdata/p4_16_samples/init-entries-bmv2.p4 b/testdata/p4_16_samples/init-entries-bmv2.p4
@@ -91,11 +91,11 @@ control ingressImpl(
         actions = { a; a_params; }
         default_action = a;
         // t1b is same as t1, but because it has
-        // @noWarn("duplicate_priorities") annotation, no warning
+        // @noWarn("duplicate-priorities") annotation, no warning
         // should be created for it about duplicate priorities.
         largest_priority_wins = false;
         priority_delta = 10;
- 	@noWarn("duplicate_priorities")
+ 	@noWarn("duplicate-priorities")
         entries = {
             const priority=10: (0x01, 0x1111 &&& 0xF   ) : a_params(1);
                                (0x02, 0x1181           ) : a_params(2); // priority=20
@@ -136,10 +136,10 @@ control ingressImpl(
         largest_priority_wins = false;
         priority_delta = 10;
         // t2b is same as t2, but because it has
-        // @noWarn("entries_out_of_priority_order") annotation, no
+        // @noWarn("entries-out-of-priority-order") annotation, no
         // warning should be created for it about entries out of
         // priority order.
-        @noWarn("entries_out_of_priority_order")
+        @noWarn("entries-out-of-priority-order")
         entries = {
             const priority=11: (0x01, 0x1111 &&& 0xF   ) : a_params(1);
                                (0x02, 0x1181           ) : a_params(2); // priority=21
@@ -181,8 +181,8 @@ control ingressImpl(
         // t3b is same as t3, but because it has both noWarn
         // annotations, there should be no warnings issues for it
         // about entry priorities.
- 	@noWarn("duplicate_priorities")
-        @noWarn("entries_out_of_priority_order")
+ 	@noWarn("duplicate-priorities")
+        @noWarn("entries-out-of-priority-order")
         entries = {
             const priority=11: (0x01, 0x1111 &&& 0xF   ) : a_params(1);
                                (0x02, 0x1181           ) : a_params(2); // priority=12
@@ -221,9 +221,9 @@ control ingressImpl(
         default_action = a;
         largest_priority_wins = false;
         // t4b is same as t4, but because it has
-        // @noWarn("duplicate_priorities") annotation, no warning
+        // @noWarn("duplicate-priorities") annotation, no warning
         // should be created for it about duplicate priorities.
- 	@noWarn("duplicate_priorities")
+ 	@noWarn("duplicate-priorities")
         entries = {
             const priority=2001: (0x01, 0x1111 &&& 0xF   ) : a_params(1);
                   priority=2001: (0x02, 0x1181           ) : a_params(2);

diff --git a/testdata/p4_16_samples/invalid-hdr-warnings7.p4 b/testdata/p4_16_samples/invalid-hdr-warnings7.p4
@@ -57,7 +57,7 @@ control c(inout bit<32> x) {
                  ^ us1[0].h2.a ^ us1[1].h1.a ^ us1[1].h2.a;
     }
 
-    apply @noWarn("uninitialized_use") {
+    apply @noWarn("uninitialized-use") {
         u.h1.setValid();
         hs[0].setValid();
         us[0].h1.setValid();

diff --git a/testdata/p4_16_samples/invalid-hdr-warnings8.p4 b/testdata/p4_16_samples/invalid-hdr-warnings8.p4
@@ -69,7 +69,7 @@ control c(inout bit<32> x) {
                  ^ us1[0].h2.a ^ us1[1].h1.a ^ us1[1].h2.a;
     }
 
-    apply @noWarn("uninitialized_use") {
+    apply @noWarn("uninitialized-use") {
         u.h1.setValid();
         hs[0].setValid();
         us[0].h1.setValid();

diff --git a/testdata/p4_16_samples/issue4365_wdisable_precedence_over_werror.p4 b/testdata/p4_16_samples/issue4365_wdisable_precedence_over_werror.p4
@@ -1,5 +1,5 @@
 // Expect no errors, as --Wdisable should take precedence over --Werror for warnings.
-@command_line("--Werror", "--Wdisable=uninitialized_use", "--Wdisable=invalid_header")
+@command_line("--Werror", "--Wdisable=uninitialized-use", "--Wdisable=invalid-header")
 header h_t {
     bit<28> f1;
     bit<4> f2;

diff --git a/testdata/p4_16_samples/issue4365_wdisable_precedence_over_werror_control.p4 b/testdata/p4_16_samples/issue4365_wdisable_precedence_over_werror_control.p4
@@ -1,5 +1,5 @@
 // Control testcase to ensure that this program actually emits warnings
-// that can be disabled with --Wdisable=uninitialized_use and --Wdisable=invalid_header.
+// that can be disabled with --Wdisable=uninitialized-use and --Wdisable=invalid-header.
 header h_t {
     bit<28> f1;
     bit<4> f2;

diff --git a/testdata/p4_16_samples/uninit-nowarnings.p4 b/testdata/p4_16_samples/uninit-nowarnings.p4
@@ -25,14 +25,14 @@ header Header {
 extern void func(in Header h);
 extern bit<32> g(inout bit<32> v, in bit<32> w);
 
-@noWarn("uninitialized_use")
+@noWarn("uninitialized-use")
 parser p1(packet_in p, out Header h) {
     Header[2] stack;
     bool b;
     bool c;
     bool d;
 
-    @noWarn("invalid_header")
+    @noWarn("invalid-header")
     @noWarn("ordering")
     state start {
         h.data1 = 0;
@@ -41,7 +41,7 @@ parser p1(packet_in p, out Header h) {
         transition next;
     }
 
-    @noWarn("invalid_header")
+    @noWarn("invalid-header")
     state next {
         h.data2 = h.data3 + 1;  // uninitialized
         stack[0] = stack[1];  // uninitialized
@@ -83,7 +83,7 @@ control c(out bit<32> v) {  // uninitialized
         default_action = a1();
     }
 
-    apply @noWarn("uninitialized_use")
+    apply @noWarn("uninitialized-use")
     {
         b = b + 1;  // uninitialized
         d = d + 1;

diff --git a/testdata/p4_16_samples_outputs/annotation-bug.p4-stderr b/testdata/p4_16_samples_outputs/annotation-bug.p4-stderr
@@ -1,3 +1,3 @@
-annotation-bug.p4(24): [--Wwarn=uninitialized_use] warning: hdr.ipv4_option_timestamp.len may be uninitialized
+annotation-bug.p4(24): [--Wwarn=uninitialized-use] warning: hdr.ipv4_option_timestamp.len may be uninitialized
         get<headers>({ hdr.ipv4_option_timestamp });
                        ^^^^^^^^^^^^^^^^^^^^^^^^^