1 files changed, 4 insertions, 4 deletions

diff --git a/src/nix/show-derivation.cc b/src/nix/show-derivation.cc
index d13960280..f07fedaf0 100644
--- a/src/nix/show-derivation.cc
+++ b/src/nix/show-derivation.cc
@@ -65,19 +65,19 @@ struct CmdShowDerivation : InstallablesCommand
                     auto & outputName = _outputName; // work around clang bug
                     auto outputObj { outputsObj.object(outputName) };
                     std::visit(overloaded {
-                        [&](DerivationOutputInputAddressed doi) {
+                        [&](const DerivationOutputInputAddressed & doi) {
                             outputObj.attr("path", store->printStorePath(doi.path));
                         },
-                        [&](DerivationOutputCAFixed dof) {
+                        [&](const DerivationOutputCAFixed & dof) {
                             outputObj.attr("path", store->printStorePath(dof.path(*store, drv.name, outputName)));
                             outputObj.attr("hashAlgo", printMethodAlgo(dof.ca));
                             outputObj.attr("hash", getContentAddressHash(dof.ca).to_string(Base16, false));
                             // FIXME print refs?
                         },
-                        [&](DerivationOutputCAFloating dof) {
+                        [&](const DerivationOutputCAFloating & dof) {
                             outputObj.attr("hashAlgo", makeContentAddressingPrefix(dof.method) + printHashType(dof.hashType));
                         },
-                        [&](DerivationOutputDeferred) {},
+                        [&](const DerivationOutputDeferred &) {},
                     }, output.output);
                 }
             }