syntax_data: {"ast_node_type":"variable","tokens":[{"end":76,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // Optimize the case of `let x = ...` to write directly into `x`
context_before:         match irrefutable_pat.kind {
context_after:             PatKind::Binding { mode: BindingMode(ByRef::No, _), var, subpattern: None, .. } => {