syntax_data: {"ast_node_type":"variable","tokens":[{"end":42,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let lhs = &self.thir[lhs];
context_before:             ExprKind::Assign { lhs, rhs } | ExprKind::AssignOp { lhs, rhs, .. } => {
context_after:                 // First, check whether we are mutating a layout constrained field