syntax_data: {"ast_node_type":"other","tokens":[{"end":65,"kind":"keyword","start":0,"text":".map_err(|_|"}]}
source_snippet:                     .map_err(|_| SelectionError::Unimplemented)?;
context_before:                     .eq(DefineOpaqueTypes::Yes, target, new_struct)
context_after:                 nested.extend(obligations);