[Python-Dev] Structural pattern matching and mangling private names

For this code: class C: def f(self, x): match x: case D(__something=y): return y It appears that the name "__something" isn't mangled. Under most other circumstances I'd expect this to be mangled to "_C__something". Is this: * intentional, * accidental, but how that it's done it's the defined behaviour, * or a defect? It doesn't seem like it's explicitly tested for in test_patma.py either way. Thanks David