syntax_data: {"ast_node_type":"other","tokens":[{"end":82,"kind":"keyword","start":0,"text":"SelectionError::SignatureMismatch(Box::new(SignatureMismatchData"}]}
source_snippet:                 SelectionError::SignatureMismatch(Box::new(SignatureMismatchData {
context_before:             .map_err(|terr| {
context_after:                     expected_trait_ref: obligation_trait_ref,