syntax_data: {"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":"&'b"}]}
source_snippet:         &'b mut [&'c mut Candidate<'tcx>],
context_before:     ) -> (
context_after:         FxIndexMap<TestBranch<'tcx>, Vec<&'b mut Candidate<'tcx>>>,