syntax_data: {"ast_node_type":"variable","tokens":[{"end":51,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let field_ty = field.ty(tcx, args);
context_before:             for (field, field_valtree) in iter::zip(fields, branches) {
context_after:                 let field_const = ty::Const::new_value(tcx, *field_valtree, field_ty);