syntax_data: {"ast_node_type":"other","tokens":[{"end":59,"kind":"keyword","start":0,"text":"subpattern:"}]}
source_snippet:                 subpattern: self.lower_pattern(subpattern),
context_before:             hir::PatKind::Box(subpattern) => PatKind::DerefPattern {
context_after:                 borrow: hir::ByRef::No,