syntax_data: {"ast_node_type":"other","tokens":[{"end":46,"kind":"keyword","start":0,"text":"for"}]}
source_snippet:                 for pat in pat.iter_fields() {
context_before:             if let rustc_pattern_analysis::rustc::Constructor::Or = pat.ctor() {
context_after:                     // For top-level or-patterns (the only ones we accept right now), when the