Strange monomorphism for generic with array in type parameter

struct Foo<T> {
  inner: T
}

#[no_mangle]
pub extern "C" fn foo_array -> Foo<[u8;32]> {
  todo!()
}

will generate types like:

typedef struct Foo__________u8__________32 {
  uint8_t[32]
} Foo__________u8__________32;

Why so many underscores? I'm tempted to use rename_item and rename all these to have a single underscore. but leads me to wonder if this is intentional and needed for some reason?

Start by reproducing the issue with the Rust Foo and foo_array example, then inspect the generated C type name and compare it with the expected naming behavior. Determine whether the repeated underscores are intentional or a naming defect; done means the behavior is explained and, if needed, covered by a focused regression test.