rust-lang · erickt · Jul 30, 2026
diff --git a/.github/workflows/bindgen.yml b/.github/workflows/bindgen.yml
@@ -111,7 +111,7 @@ jobs:
             libtinfo: libtinfo5_6.3+20220423-2ubuntu0.1_amd64.deb
           - os: ubuntu-24.04-arm
             libtinfo: libtinfo5_6.3+20220423-2ubuntu0.1_arm64.deb
-        llvm_version: ["16.0", "20.1"]
+        llvm_version: ["16.0", "20.1", "21.1"]
         release_build: [0, 1]
         no_default_features: [0, 1]
         # FIXME: There are no pre-built static libclang libraries, so the
@@ -125,15 +125,15 @@ jobs:
           - platform:
               os: ubuntu-latest
               libtinfo: libtinfo5_6.3+20220423-2ubuntu0.1_amd64.deb
-            llvm_version: "20.1"
+            llvm_version: "21.1"
             release_build: 0
             no_default_features: 0
             feature_extra_asserts: 1
 
           # Ensure stuff works on macos too
           - platform:
               os: macos-latest
-            llvm_version: "20.1"
+            llvm_version: "21.1"
             release_build: 0
             no_default_features: 0
             feature_extra_asserts: 0
@@ -160,7 +160,7 @@ jobs:
           BINDGEN_FEATURE_RUNTIME: ${{matrix.feature_runtime}}
           BINDGEN_FEATURE_EXTRA_ASSERTS: ${{matrix.feature_extra_asserts}}
           BINDGEN_NO_DEFAULT_FEATURES: ${{matrix.no_default_features}}
-          BINDGEN_RUST_FOR_LINUX_TEST: ${{startsWith(matrix.platform.os, 'ubuntu') && matrix.llvm_version == '20.1' && matrix.feature_extra_asserts == 0 && 1 || 0}}
+          BINDGEN_RUST_FOR_LINUX_TEST: ${{startsWith(matrix.platform.os, 'ubuntu') && matrix.llvm_version == '21.1' && matrix.feature_extra_asserts == 0 && 1 || 0}}
         run: ./ci/test.sh
 
   test-book:

diff --git a/bindgen-tests/Cargo.toml b/bindgen-tests/Cargo.toml
@@ -26,3 +26,4 @@ runtime = ["bindgen/runtime"]
 __testing_only_extra_assertions = ["bindgen/__testing_only_extra_assertions"]
 __testing_only_libclang_16 = ["bindgen/__testing_only_libclang_16"]
 __testing_only_libclang_20 = ["bindgen/__testing_only_libclang_20"]
+__testing_only_libclang_21 = []
diff --git a/bindgen-tests/tests/expectations/tests/libclang-21/issue-544-stylo-creduce-2.rs b/bindgen-tests/tests/expectations/tests/libclang-21/issue-544-stylo-creduce-2.rs
diff --git a/bindgen-tests/tests/expectations/tests/libclang-21/nsBaseHashtable.rs b/bindgen-tests/tests/expectations/tests/libclang-21/nsBaseHashtable.rs
diff --git a/bindgen-tests/tests/expectations/tests/recursive_alias_canonicalization.rs b/bindgen-tests/tests/expectations/tests/recursive_alias_canonicalization.rs
diff --git a/bindgen-tests/tests/expectations/tests/transform-op.rs b/bindgen-tests/tests/expectations/tests/transform-op.rs
diff --git a/bindgen-tests/tests/expectations/tests/variadic_template_union.rs b/bindgen-tests/tests/expectations/tests/variadic_template_union.rs
diff --git a/bindgen-tests/tests/expectations/tests/variadic_template_union_alignment.rs b/bindgen-tests/tests/expectations/tests/variadic_template_union_alignment.rs
diff --git a/bindgen-tests/tests/headers/recursive_alias_canonicalization.hpp b/bindgen-tests/tests/headers/recursive_alias_canonicalization.hpp
@@ -0,0 +1,11 @@
+// bindgen-flags: -- -std=c++14
+
+namespace test {
+union RecursiveUnion;
+typedef RecursiveUnion AliasUnion;
+
+union RecursiveUnion {
+    int x;
+    AliasUnion* self_ptr;
+};
+}
diff --git a/bindgen-tests/tests/headers/variadic_template_union.hpp b/bindgen-tests/tests/headers/variadic_template_union.hpp
@@ -0,0 +1,9 @@
+// bindgen-flags: -- -std=c++14
+
+namespace test {
+template <class _Arg0, class... _Args>
+union __union {
+  _Arg0 __arg;
+  __union<_Args...> __u;
+};
+}