Issue #100222 added a struct to Include/cpython/code.h (which is included by default by Python.h) that is not compliant C++:

typedef union {
    uint16_t cache;
    struct {
        uint8_t opcode;
        uint8_t oparg;
    };
} _Py_CODEUNIT;

The struct member requires a name, as only anonymous structs are currently permitted in standard C++.

(And since the original issue invokes PEP 7, I'll do the same and point out that "The public C API should be compatible with C++". The intention of this clause is that standard C++ can #include <Python.h>, which is currently broken.)

Linked PRs

• gh-101907: Removes use of non-standard C++ extension from Include/cpython/code.h #101909
• gh-101907: Stop using _Py_OPCODE and _Py_OPARG macros #101912