diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index d44ec53c4..2c2950471 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -2078,7 +2078,7 @@ void ExprConcatStrings::eval(EvalState & state, Env & env, Value & v)
     else if (firstType == nFloat)
         v.mkFloat(nf);
     else if (firstType == nPath) {
-        if (!context.empty())
+        if (hasContext(context))
             state.error<EvalError>("a string that refers to a store path cannot be appended to a path").atPos(pos).withFrame(env, *this).debugThrow();
         v.mkPath(state.rootPath(CanonPath(str())));
     } else