Function patch_seq_variant_first 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn patch_seq_variant_first(
    stack: Stack,
) -> Stack

Get the first field from a variant

Stack effect: ( Variant – Value )

Returns a clone of the first field. Panics if the variant has no fields. Mirrors variant_last so callers reaching for either head- or tail-of-fields find the same shape.

Safety

Stack must have a Variant on top