From ce5106eb19a08ca9721641e8560969e73b7dd60e Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Thu, 7 Sep 2023 12:55:10 +0200
Subject: [PATCH] Avoid "clang -Wimplicit-fallthrough" warnings also in C mode.

* src/output.cc (Output::output_hash_function): Enhance the fallthrough
marker, to include clang >= 10 in C mode.
* tests/*.exp: Update.
---
 ChangeLog           |   7 +++
 src/output.cc       |   4 +-
 tests/c-parse.exp   |   4 +-
 tests/charsets.exp  |  44 ++++++++---------
 tests/chill.exp     | 116 ++++++++++++++++++++++----------------------
 tests/cplusplus.exp |   8 +--
 tests/java.exp      |   4 +-
 tests/languages.exp |  12 ++---
 tests/modula2.exp   |  28 +++++------
 tests/objc.exp      |   4 +-
 10 files changed, 119 insertions(+), 112 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index eb6ba23..413f471 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2023-09-07  Bruno Haible  <bruno@clisp.org>
+
+	Avoid "clang -Wimplicit-fallthrough" warnings also in C mode.
+	* src/output.cc (Output::output_hash_function): Enhance the fallthrough
+	marker, to include clang >= 10 in C mode.
+	* tests/*.exp: Update.
+
 2023-09-05  Bruno Haible  <bruno@clisp.org>
 
 	Avoid "gcc -Wmissing-field-initializers" warnings on the generated code.
diff --git a/src/output.cc b/src/output.cc
index 9672bf3..e103c74 100644
--- a/src/output.cc
+++ b/src/output.cc
@@ -953,9 +953,9 @@ Output::output_hash_function () const
           /* Pseudo-statement or comment that avoids a compiler warning or
              lint warning.  */
           const char * const fallthrough_marker =
-            "#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))\n"
+            "#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))\n"
             "      [[fallthrough]];\n"
-            "#elif defined __GNUC__ && __GNUC__ >= 7\n"
+            "#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)\n"
             "      __attribute__ ((__fallthrough__));\n"
             "#endif\n"
             "      /*FALLTHROUGH*/\n";
diff --git a/tests/c-parse.exp b/tests/c-parse.exp
index 5c1a70c..f577abd 100644
--- a/tests/c-parse.exp
+++ b/tests/c-parse.exp
@@ -86,9 +86,9 @@ hash (str, len)
     {
       default:
         hval += asso_values[(unsigned char)str[2]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
diff --git a/tests/charsets.exp b/tests/charsets.exp
index e22b7bf..6bd759e 100644
--- a/tests/charsets.exp
+++ b/tests/charsets.exp
@@ -93,9 +93,9 @@ hash (register const char *str, register size_t len)
     {
       default:
         hval += asso_values[(unsigned char)str[21]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
@@ -111,81 +111,81 @@ hash (register const char *str, register size_t len)
       case 12:
       case 11:
         hval += asso_values[(unsigned char)str[10]+1];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 10:
         hval += asso_values[(unsigned char)str[9]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 9:
         hval += asso_values[(unsigned char)str[8]+1];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 8:
         hval += asso_values[(unsigned char)str[7]+3];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 7:
         hval += asso_values[(unsigned char)str[6]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 6:
         hval += asso_values[(unsigned char)str[5]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 5:
         hval += asso_values[(unsigned char)str[4]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 4:
         hval += asso_values[(unsigned char)str[3]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 3:
         hval += asso_values[(unsigned char)str[2]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 2:
         hval += asso_values[(unsigned char)str[1]+1];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
diff --git a/tests/chill.exp b/tests/chill.exp
index 326e01d..80b1abb 100644
--- a/tests/chill.exp
+++ b/tests/chill.exp
@@ -84,233 +84,233 @@ hash (str, len)
     {
       default:
         hval += asso_values[(unsigned char)str[29]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 29:
         hval += asso_values[(unsigned char)str[28]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 28:
         hval += asso_values[(unsigned char)str[27]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 27:
         hval += asso_values[(unsigned char)str[26]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 26:
         hval += asso_values[(unsigned char)str[25]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 25:
         hval += asso_values[(unsigned char)str[24]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 24:
         hval += asso_values[(unsigned char)str[23]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 23:
         hval += asso_values[(unsigned char)str[22]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 22:
         hval += asso_values[(unsigned char)str[21]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 21:
         hval += asso_values[(unsigned char)str[20]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 20:
         hval += asso_values[(unsigned char)str[19]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 19:
         hval += asso_values[(unsigned char)str[18]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 18:
         hval += asso_values[(unsigned char)str[17]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 17:
         hval += asso_values[(unsigned char)str[16]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 16:
         hval += asso_values[(unsigned char)str[15]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 15:
         hval += asso_values[(unsigned char)str[14]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 14:
         hval += asso_values[(unsigned char)str[13]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 13:
         hval += asso_values[(unsigned char)str[12]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 12:
         hval += asso_values[(unsigned char)str[11]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 11:
         hval += asso_values[(unsigned char)str[10]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 10:
         hval += asso_values[(unsigned char)str[9]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 9:
         hval += asso_values[(unsigned char)str[8]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 8:
         hval += asso_values[(unsigned char)str[7]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 7:
         hval += asso_values[(unsigned char)str[6]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 6:
         hval += asso_values[(unsigned char)str[5]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 5:
         hval += asso_values[(unsigned char)str[4]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 4:
         hval += asso_values[(unsigned char)str[3]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 3:
         hval += asso_values[(unsigned char)str[2]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 2:
         hval += asso_values[(unsigned char)str[1]+1];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
diff --git a/tests/cplusplus.exp b/tests/cplusplus.exp
index 7dcebaa..157c869 100644
--- a/tests/cplusplus.exp
+++ b/tests/cplusplus.exp
@@ -86,9 +86,9 @@ hash (str, len)
     {
       default:
         hval += asso_values[(unsigned char)str[6]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
@@ -96,9 +96,9 @@ hash (str, len)
       case 5:
       case 4:
         hval += asso_values[(unsigned char)str[3]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
diff --git a/tests/java.exp b/tests/java.exp
index e56955a..141b755 100644
--- a/tests/java.exp
+++ b/tests/java.exp
@@ -110,9 +110,9 @@ hash (str, len)
     {
       default:
         hval += asso_values[(unsigned char)str[2]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
diff --git a/tests/languages.exp b/tests/languages.exp
index ee78705..0a80525 100644
--- a/tests/languages.exp
+++ b/tests/languages.exp
@@ -97,26 +97,26 @@ hash (register const char *str, register size_t len)
     {
       default:
         hval += asso_values[(unsigned char)str[4]+1];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 4:
       case 3:
         hval += asso_values[(unsigned char)str[2]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 2:
         hval += asso_values[(unsigned char)str[1]+9];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
diff --git a/tests/modula2.exp b/tests/modula2.exp
index 983991a..703f188 100644
--- a/tests/modula2.exp
+++ b/tests/modula2.exp
@@ -81,57 +81,57 @@ hash (register const char *str, register size_t len)
     {
       default:
         hval += asso_values[(unsigned char)str[7]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 7:
         hval += asso_values[(unsigned char)str[6]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 6:
         hval += asso_values[(unsigned char)str[5]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 5:
         hval += asso_values[(unsigned char)str[4]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 4:
         hval += asso_values[(unsigned char)str[3]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 3:
         hval += asso_values[(unsigned char)str[2]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
       case 2:
         hval += asso_values[(unsigned char)str[1]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/
diff --git a/tests/objc.exp b/tests/objc.exp
index 649eac2..cad4783 100644
--- a/tests/objc.exp
+++ b/tests/objc.exp
@@ -84,9 +84,9 @@ hash (register const char *str, register size_t len)
     {
       default:
         hval += asso_values[(unsigned char)str[2]];
-#if defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang_major__ && defined __clang_minor__ && __clang_major__ + (__clang_minor__ >= 9) > 3))
+#if (defined __cplusplus && (__cplusplus >= 201703L || (__cplusplus >= 201103L && defined __clang__ && __clang_major__ + (__clang_minor__ >= 9) > 3))) || (__STDC_VERSION__ >= 202000L && ((defined __GNUC__ && __GNUC__ >= 10) || (defined __clang__ && __clang_major__ >= 9)))
       [[fallthrough]];
-#elif defined __GNUC__ && __GNUC__ >= 7
+#elif (defined __GNUC__ && __GNUC__ >= 7) || (defined __clang__ && __clang_major__ >= 10)
       __attribute__ ((__fallthrough__));
 #endif
       /*FALLTHROUGH*/