From 2762874a7097ff60879a1761b57e64be0d741a75 Mon Sep 17 00:00:00 2001
From: Evan Nemerson <evan@nemerson.com>
Date: Sun, 15 Sep 2024 21:08:16 -0400
Subject: [PATCH] fix: icc < 22.0.1 advertises but doesn't support the
 fallthrough attribute

---
 .github/workflows/ci.yml | 34 +++++++++++++++++-----------------
 hedley.h                 | 17 ++++++++++++++---
 2 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fc71734..605528e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -56,20 +56,20 @@ jobs:
       fail-fast: false
       matrix:
         version:
-        - "2021.1.1"
-        - "2021.1.2"
-        - "2021.2.0"
-        - "2021.3.0"
-        - "2021.4.0"
-        - "2022.0.1"
-        - "2022.0.2"
-        - "2022.1.0"
-        - "2022.2.0"
-        - "2022.2.1"
-        - "2023.0.0"
-        - "2023.1.0"
-        - "2023.2.0"
-        - "2023.2.1"
+        # - "2021.1.1"
+        # - "2021.1.2"
+        - "2021.2.0" # bad
+        # - "2021.3.0"
+        # - "2021.4.0"
+        # - "2022.0.1" # ok
+        # - "2022.0.2"
+        # - "2022.1.0"
+        # - "2022.2.0"
+        # - "2022.2.1"
+        # - "2023.0.0"
+        # - "2023.1.0"
+        # - "2023.2.0"
+        # - "2023.2.1"
     steps:
       - uses: actions/checkout@v4
       - name: Free some disk space
@@ -86,8 +86,8 @@ jobs:
           . /opt/intel/oneapi/setvars.sh
           icc --version
           icc -dM -E - </dev/null
-      # - name: tmate session
-      #   uses: mxschmitt/action-tmate@v3
+      - name: tmate session
+        uses: mxschmitt/action-tmate@v3
       - name: Compile
         env:
           CC: icc
@@ -95,7 +95,7 @@ jobs:
         working-directory: test
         run: |
           . /opt/intel/oneapi/setvars.sh
-          make likely
+          make
 
   # nvhpc:
   #   runs-on: ubuntu-latest
diff --git a/hedley.h b/hedley.h
index 8876ae9..19e42a0 100644
--- a/hedley.h
+++ b/hedley.h
@@ -1727,13 +1727,24 @@ HEDLEY_DIAGNOSTIC_POP
 # undef HEDLEY_FALL_THROUGH
 #endif
 #if \
-  HEDLEY_HAS_ATTRIBUTE(fallthrough) || \
+  ( \
+    HEDLEY_HAS_ATTRIBUTE(fallthrough) && \
+    (!defined(HEDLEY_INTEL_VERSION) || HEDLEY_INTEL_VERSION_CHECK(20,21,5)) \
+  ) || \
   HEDLEY_GCC_VERSION_CHECK(7,0,0) || \
   HEDLEY_MCST_LCC_VERSION_CHECK(1,25,10)
 #  define HEDLEY_FALL_THROUGH __attribute__((__fallthrough__))
-#elif HEDLEY_HAS_CPP_ATTRIBUTE_NS(clang,fallthrough)
+#elif \
+  ( \
+    HEDLEY_HAS_CPP_ATTRIBUTE_NS(clang,fallthrough) && \
+    (!defined(HEDLEY_INTEL_VERSION) || HEDLEY_INTEL_VERSION_CHECK(20,21,5) || 1) \
+  )
 #  define HEDLEY_FALL_THROUGH HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[clang::fallthrough]])
-#elif HEDLEY_HAS_CPP_ATTRIBUTE(fallthrough)
+#elif \
+  ( \
+    HEDLEY_HAS_CPP_ATTRIBUTE(fallthrough) && \
+    (!defined(HEDLEY_INTEL_VERSION) || HEDLEY_INTEL_VERSION_CHECK(20,21,5) || 1) \
+  )
 #  define HEDLEY_FALL_THROUGH HEDLEY_DIAGNOSTIC_DISABLE_CPP98_COMPAT_WRAP_([[fallthrough]])
 #elif defined(__fallthrough) /* SAL */
 #  define HEDLEY_FALL_THROUGH __fallthrough