{"ast_node_type":"function","tokens":[{"end":93,"kind":"keyword","start":0,"text":"pub(crate)"}]}
    pub(crate) fn insert(&mut self, placeholder: ty::PlaceholderRegion) -> PlaceholderIndex {
    /// Returns the `PlaceholderIndex` for the inserted `PlaceholderRegion`
        let (index, _) = self.indices.insert_full(placeholder);