Filter out lookup_can_derive_copy for template type

[ileixe]

Template type in tagged union should not be copiable field as it requires ManuallyDrop. Filter out copy derive when the variable is resolved to template type.

Fix: #2157

Now the input.hpp in the issue will generate non rust union or correct ManuallyDrop for generic type.

rust-bindgen$ target/debug/bindgen input.hpp
/* automatically generated by rust-bindgen 0.69.4 */

#[repr(C)]
pub struct __BindgenUnionField<T>(::std::marker::PhantomData<T>);
impl<T> __BindgenUnionField<T> {
    #[inline]
    pub const fn new() -> Self {
        __BindgenUnionField(::std::marker::PhantomData)
    }
    #[inline]
    pub unsafe fn as_ref(&self) -> &T {
        ::std::mem::transmute(self)
    }
    #[inline]
    pub unsafe fn as_mut(&mut self) -> &mut T {
        ::std::mem::transmute(self)
    }
}
impl<T> ::std::default::Default for __BindgenUnionField<T> {
    #[inline]
    fn default() -> Self {
        Self::new()
    }
}
impl<T> ::std::clone::Clone for __BindgenUnionField<T> {
    #[inline]
    fn clone(&self) -> Self {
        *self
    }
}
impl<T> ::std::marker::Copy for __BindgenUnionField<T> {}
impl<T> ::std::fmt::Debug for __BindgenUnionField<T> {
    fn fmt(&self, fmt: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
        fmt.write_str("__BindgenUnionField")
    }
}
impl<T> ::std::hash::Hash for __BindgenUnionField<T> {
    fn hash<H: ::std::hash::Hasher>(&self, _state: &mut H) {}
}
impl<T> ::std::cmp::PartialEq for __BindgenUnionField<T> {
    fn eq(&self, _other: &__BindgenUnionField<T>) -> bool {
        true
    }
}
impl<T> ::std::cmp::Eq for __BindgenUnionField<T> {}
#[repr(C)]
#[derive(Debug, Copy, Clone)]
pub struct _Vector_base {
    pub _address: u8,
}
#[repr(C)]
pub struct _Vector_base__Storage<_Tp> {
    pub _M_byte: __BindgenUnionField<::std::os::raw::c_uchar>,
    pub _M_val: __BindgenUnionField<_Tp>,
    pub bindgen_union_field: u8,
    pub _phantom_0: ::std::marker::PhantomData<::std::cell::UnsafeCell<_Tp>>,
}

rust-bindgen$ target/debug/bindgen input.hpp --default-non-copy-union-style manually_drop
/* automatically generated by rust-bindgen 0.69.4 */

#[repr(C)]
#[derive(Debug, Copy, Clone)]
pub struct _Vector_base {
    pub _address: u8,
}
#[repr(C)]
pub union _Vector_base__Storage<_Tp> {
    pub _M_byte: ::std::mem::ManuallyDrop<::std::os::raw::c_uchar>,
    pub _M_val: ::std::mem::ManuallyDrop<_Tp>,
    pub _phantom_0: ::std::marker::PhantomData<::std::cell::UnsafeCell<_Tp>>,
}

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