diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 71e956e10..ce410162e 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -1692,7 +1692,11 @@ void EvalState::callFunction(Value & fun, size_t nrArgs, Value * * args, Value &
         }
 
         else
-            error("attempt to call something which is not a function but %1%", showType(vCur)).atPos(pos).debugThrow<TypeError>();
+            error("attempt to call something which is not a function but %1%: %2%",
+                    showType(vCur),
+                    ValuePrinter(*this, vCur, errorPrintOptions))
+                .atPos(pos)
+                .debugThrow<TypeError>();
     }
 
     vRes = vCur;
diff --git a/tests/unit/libexpr/error_traces.cc b/tests/unit/libexpr/error_traces.cc
index f0cad58bb..f99aafd74 100644
--- a/tests/unit/libexpr/error_traces.cc
+++ b/tests/unit/libexpr/error_traces.cc
@@ -750,7 +750,7 @@ namespace nix {
 
         ASSERT_TRACE1("foldl' (_: 1) \"foo\" [ true ]",
                       TypeError,
-                      hintfmt("attempt to call something which is not a function but %s", "an integer"));
+                      hintfmt("attempt to call something which is not a function but %s: %s", "an integer", ANSI_CYAN "1" ANSI_NORMAL));
 
         ASSERT_TRACE2("foldl' (a: b: a && b) \"foo\" [ true ]",
                       TypeError,
@@ -835,7 +835,7 @@ namespace nix {
 
         ASSERT_TRACE1("sort (_: 1) [ \"foo\" \"bar\" ]",
                       TypeError,
-                      hintfmt("attempt to call something which is not a function but %s", "an integer"));
+                      hintfmt("attempt to call something which is not a function but %s: %s", "an integer", ANSI_CYAN "1" ANSI_NORMAL));
 
         ASSERT_TRACE2("sort (_: _: 1) [ \"foo\" \"bar\" ]",
                       TypeError,