syntax_data: {"ast_node_type":"variable","tokens":[{"end":96,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:     if let Some(&impl_item_id) = tcx.impl_item_implementor_ids(impl_def_id).get(&assoc_def_id) {
context_before:     // cycle error if the specialization graph is currently being built.
context_after:         // Ensure that the impl is constrained, otherwise projection may give us