syntax_data: {"ast_node_type":"other","tokens":[{"end":30,"kind":"keyword","start":0,"text":"mut"}]}
source_snippet:         mut self_ty: Ty<'tcx>,
context_before:         &mut self,
context_after:         mut for_each: impl FnMut(&mut Self, ty::Clause<'tcx>, usize) -> ControlFlow<T, ()>,