Ignore syn::Type::Group in is_python

[scalexm]

Macro expansion can add invisible delimiters around types, modelled by syn::Type::Group in syn. This causes the following code to fail to compile:

#[pyclass]
struct Foo {}

macro_rules! foo {
    (
        #[pymethods]
        impl $ty: ty {
            fn $fn:ident (&self, $arg:ident : $arg_ty:ty) {}
        }
    ) => {
        #[pymethods]
        impl $ty {
            fn $fn(&self, $arg: $arg_ty) {}
        }
    };
}

foo!(
    #[pymethods]
    impl Foo {
        fn foo(&self, py: Python<'_>) {}
    }
);

error[E0277]: the trait bound pyo3::Python<'_>: PyClass is not satisfied

because pyo3 does not "see" the special py argument.

[davidhewitt]

Thanks! I would say this needs a CHANGELOG entry, though I find it hard to express what the end-user benefit is.

Maybe "Fix use of Python argument for #[pymethods] inside macro expansions" ?

[davidhewitt]

I'm going to push a CHANGELOG entry and test this morning quickly.