syntax_data: {"ast_node_type":"variable","tokens":[{"end":56,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:         if let Err(conflict) = self.is_knowable(stack) {
context_before:     ) -> SelectionResult<'tcx, SelectionCandidate<'tcx>> {
context_after:             debug!("coherence stage: not knowable");