I tried to clone the latest version of webkit from github, and build it with following commands on Ubuntu 16.04 : ./Tools/Scripts/build-jsc --jsc-only --cmakeargs="-DCMAKE_C_COMPILER='/usr/bin/clang' -DCMAKE_CXX_COMPILER='/usr/bin/clang++'", crashed on here : ../../Source/WTF/wtf/PtrTag.h:431:23: error: use of undeclared identifier 'nullptr_t'; did you mean 'nullptr'? inline T* tagArrayPtr(nullptr_t, size_t size) ^~~~~~~~~ nullptr ../../Source/WTF/wtf/PtrTag.h:431:34: error: unexpected type name 'size_t': expected expression inline T* tagArrayPtr(nullptr_t, size_t size) ^ ../../Source/WTF/wtf/PtrTag.h:431:46: error: expected ';' at end of declaration inline T* tagArrayPtr(nullptr_t, size_t size) ^ ; ../../Source/WTF/wtf/PtrTag.h:432:1: error: expected unqualified-id { ^ ../../Source/WTF/wtf/PtrTag.h:438:11: error: redefinition of 'tagArrayPtr' as different kind of symbol inline T* tagArrayPtr(T* ptr, size_t) ^ ../../Source/WTF/wtf/PtrTag.h:431:11: note: previous definition is here inline T* tagArrayPtr(nullptr_t, size_t size) ^ 5 errors generated. for clang, I have tried both clang-6.0 and 8.0, none of them works Seems this patch has break the webkit : https://github.com/WebKit/webkit/commit/9bca742407c2a68c4aeeb12e7ff744f8ec653b91
Seems fixed already. *** This bug has been marked as a duplicate of bug 197911 ***