syntax_data: {"ast_node_type":"other","tokens":[{"end":39,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:                 if a.len() != b.len() {
context_before:             (&ty::PatternKind::Or(a), &ty::PatternKind::Or(b)) => {
context_after:                     return Err(TypeError::Mismatch);