syntax_data: {"ast_node_type":"other","tokens":[{"end":100,"kind":"keyword","start":0,"text":"subpatterns:"}]}
source_snippet:                 subpatterns: self.field_pats(cv.unwrap_branch().iter().copied().zip(fields.iter())),
context_before:             ty::Tuple(fields) => PatKind::Leaf {
context_after:             },