diff --git a/Misc/NEWS.d/next/Build/2025-10-25-08-07-06.gh-issue-140513.6OhLTs.rst b/Misc/NEWS.d/next/Build/2025-10-25-08-07-06.gh-issue-140513.6OhLTs.rst new file mode 100644 index 00000000000000..1035ebf8d781cf --- /dev/null +++ b/Misc/NEWS.d/next/Build/2025-10-25-08-07-06.gh-issue-140513.6OhLTs.rst @@ -0,0 +1,2 @@ +Generate a clear compilation error when ``_Py_TAIL_CALL_INTERP`` is enabled but +either ``preserve_none`` or ``musttail`` is not supported. diff --git a/Python/ceval_macros.h b/Python/ceval_macros.h index 4ed03b7fb01bdf..227885797513a0 100644 --- a/Python/ceval_macros.h +++ b/Python/ceval_macros.h @@ -79,6 +79,14 @@ #endif #if _Py_TAIL_CALL_INTERP +# if defined(__clang__) || defined(__GNUC__) +# if !_Py__has_attribute(preserve_none) || !_Py__has_attribute(musttail) +# error "This compiler does not have support for efficient tail calling." +# endif +# elif defined(_MSC_VER) && (_MSC_VER < 1950) +# error "You need at least VS 2026 / PlatformToolset v145 for tail calling." +# endif + // Note: [[clang::musttail]] works for GCC 15, but not __attribute__((musttail)) at the moment. # define Py_MUSTTAIL [[clang::musttail]] # define Py_PRESERVE_NONE_CC __attribute__((preserve_none))