syntax_data: {"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":"ClosureKind::FnMut"}]}
source_snippet:             ClosureKind::FnMut => "FnMut",
context_before:             ClosureKind::Fn => "Fn",
context_after:             ClosureKind::FnOnce => "FnOnce",