syntax_data: {"ast_node_type":"other","tokens":[{"end":45,"kind":"keyword","start":0,"text":"for"}]}
source_snippet:             for param in &inner_thir.params {
context_before:             // params in THIR may be unsafe, e.g. a union pattern.
context_after:                 if let Some(param_pat) = param.pat.as_deref() {