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    pub(crate) use self::inner::{do_alloc, Allocator, Global};

    #[cfg(feature = "nightly")]
    mod inner {
        use crate::alloc::alloc::Layout;
        pub use crate::alloc::alloc::{Allocator, Global};
        use core::ptr::NonNull;

        #[allow(clippy::map_err_ignore)]
        pub fn do_alloc<A: Allocator>(alloc: &A, layout: Layout) -> Result<NonNull<u8>, ()> {
            match alloc.allocate(layout) {
                Ok(ptr) => Ok(ptr.as_non_null_ptr()),
                Err(_) => Err(()),
            }
        }

        #[cfg(feature = "bumpalo")]
        unsafe impl Allocator for crate::BumpWrapper<'_> {
            #[inline]
            fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, core::alloc::AllocError> {
                match self.0.try_alloc_layout(layout) {
                    Ok(ptr) => Ok(NonNull::slice_from_raw_parts(ptr, layout.size())),
                    Err(_) => Err(core::alloc::AllocError),
                }
            }
            #[inline]
            unsafe fn deallocate(&self, _ptr: NonNull<u8>, _layout: Layout) {}
        }
    }

    #[cfg(not(feature = "nightly"))]
    mod inner {
        use crate::alloc::alloc::{alloc, dealloc, Layout};
        use core::ptr::NonNull;

        #[allow(clippy::missing_safety_doc)] // not exposed outside of this crate
        pub unsafe trait Allocator {
            fn allocate(&self, layout: Layout) -> Result<NonNull<u8>, ()>;
            unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout);
        }

        #[derive(Copy, Clone)]
        pub struct Global;
        unsafe impl Allocator for Global {
            #[inline]
            fn allocate(&self, layout: Layout) -> Result<NonNull<u8>, ()> {
                unsafe { NonNull::new(alloc(layout)).ok_or(()) }
            }
            #[inline]
            unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
                dealloc(ptr.as_ptr(), layout);
            }
        }
        impl Default for Global {
            #[inline]
            fn default() -> Self {
                Global
            }
        }

        pub fn do_alloc<A: Allocator>(alloc: &A, layout: Layout) -> Result<NonNull<u8>, ()> {
            alloc.allocate(layout)
        }

        #[cfg(feature = "bumpalo")]
        unsafe impl Allocator for crate::BumpWrapper<'_> {
            #[allow(clippy::map_err_ignore)]
            fn allocate(&self, layout: Layout) -> Result<NonNull<u8>, ()> {
                self.0.try_alloc_layout(layout).map_err(|_| ())
            }
            unsafe fn deallocate(&self, _ptr: NonNull<u8>, _layout: Layout) {}
        }
    }