syntax_data: {"ast_node_type":"variable","tokens":[{"end":25,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let arm =
context_before:                 let Ok(pat) = this.lower_pattern(&cx, &arm.pattern) else { return true };
context_after:                     MatchArm { pat, arm_data: this.lint_level, has_guard: arm.guard.is_some() };