307581 2026-02-11 12:08:08 -0800 REGRESSION(307222@main): Cannot build with Clang 18 2026-02-11 17:29:12 -0800 1 1 1 Unclassified WebKit JavaScriptCore WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED https://bugs.webkit.org/show_bug.cgi?id=307389 InRadar P2 Normal --- 1 aperez aperez csaavedra webkit-bug-importer oldest_to_newest 2180400 0 aperez 2026-02-11 12:08:08 -0800 Full build log: https://build.webkit.org/#/builders/629/builds/22638 ---- FAILED: Tools/TestWebKitAPI/CMakeFiles/TestWTF.dir/Tests/WTF/GenerationalSet.cpp.o /usr/bin/ccache /usr/local/bin/clang++ -DBUILDING_GTK__=1 -DBUILDING_TestWTF -DBUILDING_WEBKIT=1 -DBUILDING_WITH_CMAKE=1 -DBWRAP_EXECUTABLE=\"/usr/bin/bwrap\" -DDBUS_PROXY_EXECUTABLE=\"/usr/bin/xdg-dbus-proxy\" -DGETTEXT_PACKAGE=\"WebKitGTK-6.0\" -DGTEST_CREATE_SHARED_LIBRARY=1 -DGTEST_HAS_PTHREAD=1 -DGTEST_HAS_RTTI=0 -DHAVE_CONFIG_H=1 -DJSC_GLIB_API_ENABLED -DPAS_BMALLOC=1 -DSTATICALLY_LINKED_WITH_WTF -DSTATICALLY_LINKED_WITH_bmalloc -D_GLIBCXX_ASSERTIONS=1 -I/sdk/webkit/WebKitBuild/GTK/Release -I/sdk/webkit/Tools/TestWebKitAPI -I/sdk/webkit/Source/ThirdParty/gtest/include -I/sdk/webkit/WebKitBuild/GTK/Release/WTF/Headers -I/sdk/webkit/WebKitBuild/GTK/Release/bmalloc/Headers -isystem /usr/include/glib-2.0 -isystem /usr/lib/x86_64-linux-gnu/glib-2.0/include -isystem /usr/include/libmount -isystem /usr/include/blkid -isystem /jhbuild/install/include/sysprof-6 -fdiagnostics-color=always -fcolor-diagnostics -Wextra -Wall -Werror=undefined-internal -Werror=undefined-inline -pipe -Wno-noexcept-type -Wno-nullability-completeness -Wno-psabi -Wno-misleading-indentation -Wno-parentheses-equality -Qunused-arguments -Wundef -Wpointer-arith -Wmissing-format-attribute -Wformat-security -Wcast-align -Wno-tautological-compare -fasynchronous-unwind-tables -fdebug-types-section -fno-omit-frame-pointer -fno-strict-aliasing -fno-exceptions -fno-rtti -fcoroutines -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++23 -fPIE -fvisibility=hidden -Wno-dangling-else -Wno-sign-compare -Wno-undef -Wno-unused-parameter -I/usr/include -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -pthread -I/usr/include/libmount -I/usr/include/blkid -MD -MT Tools/TestWebKitAPI/CMakeFiles/TestWTF.dir/Tests/WTF/GenerationalSet.cpp.o -MF Tools/TestWebKitAPI/CMakeFiles/TestWTF.dir/Tests/WTF/GenerationalSet.cpp.o.d -o Tools/TestWebKitAPI/CMakeFiles/TestWTF.dir/Tests/WTF/GenerationalSet.cpp.o -c /sdk/webkit/Tools/TestWebKitAPI/Tests/WTF/GenerationalSet.cpp In file included from ../../../Tools/TestWebKitAPI/Tests/WTF/GenerationalSet.cpp:27: WTF/Headers/wtf/GenerationalSet.h:36:76: error: template template argument has different template parameters than its corresponding template template parameter 36 | template<typename GenerationType, template<typename> typename VectorType = Vector> | ^ ../../../Tools/TestWebKitAPI/Tests/WTF/GenerationalSet.cpp:35:28: note: while checking a default template argument used here 35 | GenerationalSet<uint8_t> set(100); | ~~~~~~~~~~~~~~~~~~~~~~~^ WTF/Headers/wtf/Vector.h:574:1: note: too many template parameters in template template argument 574 | template<typename T, size_t inlineCapacity, typename OverflowHandler, size_t minCapacity, typename Malloc> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ WTF/Headers/wtf/GenerationalSet.h:36:35: note: previous template template parameter is here 36 | template<typename GenerationType, template<typename> typename VectorType = Vector> | ^~~~~~~~~~~~~~~~~~ WTF/Headers/wtf/GenerationalSet.h:36:76: error: template template argument has different template parameters than its corresponding template template parameter 36 | template<typename GenerationType, template<typename> typename VectorType = Vector> | ^ ../../../Tools/TestWebKitAPI/Tests/WTF/GenerationalSet.cpp:60:28: note: while checking a default template argument used here 60 | GenerationalSet<uint8_t> set(10); | ~~~~~~~~~~~~~~~~~~~~~~~^ WTF/Headers/wtf/Vector.h:574:1: note: too many template parameters in template template argument 574 | template<typename T, size_t inlineCapacity, typename OverflowHandler, size_t minCapacity, typename Malloc> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ WTF/Headers/wtf/GenerationalSet.h:36:35: note: previous template template parameter is here 36 | template<typename GenerationType, template<typename> typename VectorType = Vector> | ^~~~~~~~~~~~~~~~~~ WTF/Headers/wtf/GenerationalSet.h:36:76: error: template template argument has different template parameters than its corresponding template template parameter 36 | template<typename GenerationType, template<typename> typename VectorType = Vector> | ^ ../../../Tools/TestWebKitAPI/Tests/WTF/GenerationalSet.cpp:83:28: note: while checking a default template argument used here 83 | GenerationalSet<uint8_t> set(10); | ~~~~~~~~~~~~~~~~~~~~~~~^ WTF/Headers/wtf/Vector.h:574:1: note: too many template parameters in template template argument 574 | template<typename T, size_t inlineCapacity, typename OverflowHandler, size_t minCapacity, typename Malloc> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ WTF/Headers/wtf/GenerationalSet.h:36:35: note: previous template template parameter is here 36 | template<typename GenerationType, template<typename> typename VectorType = Vector> | ^~~~~~~~~~~~~~~~~~ WTF/Headers/wtf/GenerationalSet.h:36:76: error: template template argument has different template parameters than its corresponding template template parameter 36 | template<typename GenerationType, template<typename> typename VectorType = Vector> | ^ ../../../Tools/TestWebKitAPI/Tests/WTF/GenerationalSet.cpp:126:29: note: while checking a default template argument used here 126 | GenerationalSet<uint16_t> set16(50); | ~~~~~~~~~~~~~~~~~~~~~~~~^ WTF/Headers/wtf/Vector.h:574:1: note: too many template parameters in template template argument 574 | template<typename T, size_t inlineCapacity, typename OverflowHandler, size_t minCapacity, typename Malloc> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ WTF/Headers/wtf/GenerationalSet.h:36:35: note: previous template template parameter is here 36 | template<typename GenerationType, template<typename> typename VectorType = Vector> | ^~~~~~~~~~~~~~~~~~ WTF/Headers/wtf/GenerationalSet.h:36:76: error: template template argument has different template parameters than its corresponding template template parameter 36 | template<typename GenerationType, template<typename> typename VectorType = Vector> | ^ ../../../Tools/TestWebKitAPI/Tests/WTF/GenerationalSet.cpp:132:29: note: while checking a default template argument used here 132 | GenerationalSet<uint64_t> set64(50); | ~~~~~~~~~~~~~~~~~~~~~~~~^ WTF/Headers/wtf/Vector.h:574:1: note: too many template parameters in template template argument 574 | template<typename T, size_t inlineCapacity, typename OverflowHandler, size_t minCapacity, typename Malloc> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ WTF/Headers/wtf/GenerationalSet.h:36:35: note: previous template template parameter is here 36 | template<typename GenerationType, template<typename> typename VectorType = Vector> | ^~~~~~~~~~~~~~~~~~ 5 errors generated. 2180402 1 aperez 2026-02-11 12:09:00 -0800 The GTK/WPE/JSCOnly EWS builders use GCC and that's why this went unnoticed until it hit the post-commit bots. 2180404 2 aperez 2026-02-11 12:11:56 -0800 For the record, Clang 21 is able to build this source file, so it could be that this may need some workaround for Clang 18, while we still need to support it for the GTK and WPE ports. 2180422 3 aperez 2026-02-11 12:43:19 -0800 Digging a bit further, the discussion in https://github.com/llvm/llvm-project/issues/56373 points to -frelaxed-template-template-args, which indeed has been turned on by default for C++17 (and up) starting with Clang 19: https://releases.llvm.org/19.1.0/tools/clang/docs/ReleaseNotes.html#c-specific-potentially-breaking-changes I am testing a build with the flag added, and if that works I think we can have CMake add it for Clang <19. 2180492 4 aperez 2026-02-11 15:52:22 -0800 Pull request: https://github.com/WebKit/WebKit/pull/58445 2180546 5 ews-feeder 2026-02-11 17:28:31 -0800 Committed 307325@main (ffcf808e34af): <https://commits.webkit.org/307325@main> Reviewed commits have been landed. Closing PR #58445 and removing active labels. 2180547 6 webkit-bug-importer 2026-02-11 17:29:12 -0800 <rdar://problem/170189356>