{"ast_node_type":"other","tokens":[{"end":60,"kind":"keyword","start":0,"text":"for"}]}
        for (mut key, mut ty) in infcx.take_opaque_types() {
        // Check that any hidden types found during wf checking match the hidden types that `type_of` sees.
            ty.ty = infcx.resolve_vars_if_possible(ty.ty);