Function parameters can be opaque and have no size information. For example, __va_list in AArch64 ABI. header-abi-diff considers opaque types compatible if their mangled names are the same. The mangled name of __va_list can be _ZTI9__va_list or _ZTISt9__va_list. They are also compatible. Test: ./test.py Bug: 248418092 Change-Id: I812abcabb620301eb575c54c7e3d2ff63dade488