Function parse_detached_item 

pub(crate) fn parse_detached_item(
    cx: &mut ParseCtxt<'_>,
) -> ParseResult<DetachedItem>

 ⟨specs⟩ ::= ⟨fn-spec⟩
           | ⟨struct-spec⟩
           | ⟨enum-spec⟩
           | ⟨mod⟩
           | ⟨impl⟩