diff --git a/CMakeLists.txt b/CMakeLists.txt
index c3f8ed8..c32cae7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -76,6 +76,7 @@ target_compile_definitions(cppjit PRIVATE
     CPPINTEROP_INCLUDE_DIR="${CPPJIT_INTEROP_RUNTIME_INCLUDES}"
     CPPJIT_CLANG_MAJOR="${CPPJIT_INTEROP_CLANG_MAJOR}"
     CPPJIT_CLANG_INCLUDE_DIR="${CPPJIT_INTEROP_CLANG_DIR}"
+    $<$<BOOL:${CPPJIT_USE_CLING}>:CPPJIT_USE_CLING>
 )
 
 target_include_directories(cppjit PRIVATE
diff --git a/src/cpyrt/CPPInstance.cxx b/src/cpyrt/CPPInstance.cxx
index 425c654..0456669 100644
--- a/src/cpyrt/CPPInstance.cxx
+++ b/src/cpyrt/CPPInstance.cxx
@@ -5,6 +5,7 @@ using namespace cppjit;
 #include "CPPInstance.h"
 #include "CPPOverload.h"
 #include "CPPScope.h"
+#include "Compatibility.h"
 #include "MemoryRegulator.h"
 #include "ProxyWrappers.h"
 #include "PyStrings.h"
@@ -841,7 +842,7 @@ static PyObject* op_str(CPPInstance* self) {
         // otherwise not found
         // TODO: ToString() still leaks ...
         const std::string& pretty =
-            interop::ToString(self->ObjectIsA(), self->GetObject());
+            compat::ObjToString(self->ObjectIsA(), self->GetObject());
         if (!pretty.empty())
           return cpyrt_PyText_FromString(pretty.c_str());
         continue;
@@ -870,22 +871,7 @@ static PyObject* op_str(CPPInstance* self) {
   // 2. Cling's pretty printing (not done through backend for performance
   // reasons)
   if (!ScopeFlagCheck(self, CPPScope::kNoPrettyPrint)) {
-    static PyObject* printValue = nullptr;
-    if (!printValue) {
-      PyObject* gbl =
-          PyDict_GetItemString(PySys_GetObject((char*)"modules"), "cppjit.gbl");
-      PyObject* cl = PyObject_GetAttrString(gbl, (char*)"cling");
-      printValue = PyObject_GetAttrString(cl, (char*)"printValue");
-      Py_DECREF(cl);
-      // gbl is borrowed
-      if (printValue) {
-        Py_DECREF(printValue); // make borrowed
-        if (!PyCallable_Check(printValue))
-          printValue = nullptr; // unusable ...
-      }
-      if (!printValue) // unlikely
-        ScopeFlagSet(self, CPPScope::kNoPrettyPrint);
-    }
+    PyObject* printValue = compat::GetClingPrintValue();
 
     if (printValue) {
       // as printValue only works well for templates taking pointer arguments,
diff --git a/src/cpyrt/Compatibility.h b/src/cpyrt/Compatibility.h
new file mode 100644
index 0000000..e9771d7
--- /dev/null
+++ b/src/cpyrt/Compatibility.h
@@ -0,0 +1,48 @@
+#ifndef CPYRT_COMPATIBILITY_H
+#define CPYRT_COMPATIBILITY_H
+
+#include "Python.h"
+
+#include "cppjit_interop.h"
+
+#include <string>
+
+namespace cppjit::cpyrt::compat {
+
+inline PyObject* GetClingPrintValue() {
+#ifdef CPPJIT_USE_CLING
+  static PyObject* printValue = nullptr;
+  if (printValue)
+    return printValue;
+
+  PyObject* gbl =
+      PyDict_GetItemString(PySys_GetObject((char*)"modules"), "cppjit.gbl");
+  PyObject* cling = gbl ? PyObject_GetAttrString(gbl, (char*)"cling") : nullptr;
+  printValue =
+      cling ? PyObject_GetAttrString(cling, (char*)"printValue") : nullptr;
+  Py_XDECREF(cling);
+
+  if (printValue) {
+    Py_DECREF(printValue); // make borrowed
+    if (!PyCallable_Check(printValue))
+      printValue = nullptr;
+  }
+
+  if (!printValue)
+    PyErr_Clear();
+
+  return printValue;
+#else
+  return nullptr;
+#endif
+}
+
+// Interpreter::toString is an assert(0) stub (CppInterOp#1100); skip it.
+inline std::string ObjToString(interop::TCppScope_t /*klass*/,
+                               interop::TCppObject_t /*obj*/) {
+  return "";
+}
+
+} // namespace cppjit::cpyrt::compat
+
+#endif // CPYRT_COMPATIBILITY_H
diff --git a/test/test_crossinheritance.py b/test/test_crossinheritance.py
index 0e405de..2e537df 100644
--- a/test/test_crossinheritance.py
+++ b/test/test_crossinheritance.py
@@ -3,7 +3,6 @@
 import py
 from pytest import mark, raises, skip
 from support import (
-    IS_CLANG_DEBUG,
     IS_CLING,
     IS_LINUX_ARM,
     IS_MAC,
@@ -27,10 +26,6 @@ def setup_class(cls):
 
         cls.example01 = cppjit.load_reflection_info(cls.test_dct)
 
-    @mark.xfail(
-        run=not (IS_CLANG_DEBUG or IS_CLING),
-        reason="Crashes with ClangRepl with 'toString not implemented' and on Cling",
-    )
     def test01_override_function(self):
         """Test ability to override a simple function"""
 
diff --git a/test/test_doc_features.py b/test/test_doc_features.py
index fd15cdc..52bb067 100644
--- a/test/test_doc_features.py
+++ b/test/test_doc_features.py
@@ -3,7 +3,6 @@
 import py
 from pytest import mark, raises, skip
 from support import (
-    IS_CLANG_REPL,
     IS_CLING,
     IS_LINUX_ARM,
     IS_MAC,
@@ -1040,11 +1039,6 @@ def test08_voidptr_array(self):
         assert n.p[2] == 0x3
         assert len(n.p) == 3
 
-    @mark.xfail(
-        condition=IS_CLANG_REPL and IS_MAC,
-        run=False,
-        reason="Crashes with ClangRepl with 'toString not implemented'",
-    )
     def test09_custom_str(self):
         """Example of customized str"""
 
diff --git a/test/test_regression.py b/test/test_regression.py
index 1add840..c82d808 100644
--- a/test/test_regression.py
+++ b/test/test_regression.py
@@ -1040,10 +1040,6 @@ class ReferenceWavefunction {};
             cppjit.gbl.std.get[0](cppjit.gbl.property_types.run_as[pt_type]()) == 20.0
         )
 
-    @mark.xfail(
-        run=False,
-        reason="Crashes on ClangRepl with 'toString not implemented', and on Cling",
-    )
     def test34_print_empty_collection(self):
         """Print empty collection through Cling"""
 
@@ -1648,3 +1644,17 @@ def test52_no_cpp_name_for_template_arg(self):
 
         with raises(TypeError):
             cppjit.gbl.std.vector[object()]
+
+    def test53_str_fallback_without_ostream_insertion(self):
+        """str() of an instance with no operator<< used to crash"""
+
+        import cppjit
+
+        cppjit.cppdef("namespace StrFallback { struct Bare { int x; }; }")
+
+        bare = cppjit.gbl.StrFallback.Bare()
+
+        # no ostream inserter and no usable pretty printer, so op_str must
+        # degrade to the generic repr
+        assert str(bare) == repr(bare)
+        assert "Bare object at" in str(bare)