syntax_data: {"ast_node_type":"variable","tokens":[{"end":73,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let const_ = Const::Ty(self.tcx.types.usize, *len_const);
context_before:                 self.cfg.push_fake_read(block, source_info, FakeReadCause::ForIndex, place);
context_after:                 Operand::Constant(Box::new(ConstOperand { span, user_ty: None, const_ }))