fn local_symbol(&self, name: SharedSymbol) -> Option<UniqueSymbol> {
        for local in self.borrow_local_scope().locals.items().iter() {
            let local_name = self.symbol_table.name(local);
            if local_name == name {
                return Some(*local);
            }
        }

        return None;
    }
Looks to see whether a name is defined as a local in
the current scope.
passerine/src/compiler/hoist.rs