syntax_data: {"ast_node_type":"other","tokens":[{"end":97,"kind":"keyword","start":0,"text":"CanonicalUserTypeAnnotation"}]}
source_snippet:             CanonicalUserTypeAnnotation { user_ty: Box::new(annotation), span, inferred_ty: ty };
context_before:         let annotation =
context_after:         PatKind::AscribeUserType {