diff --git a/include/pybind11/pytypes.h b/include/pybind11/pytypes.h
index 5152f6804..536835f7d 100644
--- a/include/pybind11/pytypes.h
+++ b/include/pybind11/pytypes.h
@@ -370,7 +370,7 @@ bool isinstance(handle obj) { return T::check_(obj); }
 template <typename T, detail::enable_if_t<!std::is_base_of<object, T>::value, int> = 0>
 bool isinstance(handle obj) { return detail::isinstance_generic(obj, typeid(T)); }
 
-template <> inline bool isinstance<handle>(handle obj) = delete;
+template <> inline bool isinstance<handle>(handle) = delete;
 template <> inline bool isinstance<object>(handle obj) { return obj.ptr() != nullptr; }
 
 /// \ingroup python_builtins
diff --git a/tests/test_call_policies.cpp b/tests/test_call_policies.cpp
index fd2455783..26c83f81b 100644
--- a/tests/test_call_policies.cpp
+++ b/tests/test_call_policies.cpp
@@ -46,6 +46,7 @@ TEST_SUBMODULE(call_policies, m) {
     class Parent {
     public:
         Parent() { py::print("Allocating parent."); }
+        Parent(const Parent& parent) = default;
         ~Parent() { py::print("Releasing parent."); }
         void addChild(Child *) { }
         Child *returnChild() { return new Child(); }
diff --git a/tests/test_class.cpp b/tests/test_class.cpp
index 128bc39e9..7edcdce36 100644
--- a/tests/test_class.cpp
+++ b/tests/test_class.cpp
@@ -227,6 +227,8 @@ TEST_SUBMODULE(class_, m) {
         static void *operator new(size_t s, void *ptr) { py::print("C placement-new", s); return ptr; }
         static void operator delete(void *p, size_t s) { py::print("C delete", s); return ::operator delete(p); }
         virtual ~AliasedHasOpNewDelSize() = default;
+        AliasedHasOpNewDelSize() = default;
+        AliasedHasOpNewDelSize(const AliasedHasOpNewDelSize&) = delete;
     };
     struct PyAliasedHasOpNewDelSize : AliasedHasOpNewDelSize {
         PyAliasedHasOpNewDelSize() = default;
@@ -277,6 +279,8 @@ TEST_SUBMODULE(class_, m) {
     class ProtectedB {
     public:
         virtual ~ProtectedB() = default;
+        ProtectedB() = default;
+        ProtectedB(const ProtectedB &) = delete;
 
     protected:
         virtual int foo() const { return value; }
@@ -377,7 +381,11 @@ TEST_SUBMODULE(class_, m) {
     py::class_<IsNonFinalFinal>(m, "IsNonFinalFinal", py::is_final());
 }
 
-template <int N> class BreaksBase { public: virtual ~BreaksBase() = default; };
+template <int N> class BreaksBase { public:
+    virtual ~BreaksBase() = default;
+    BreaksBase() = default;
+    BreaksBase(const BreaksBase&) = delete;
+};
 template <int N> class BreaksTramp : public BreaksBase<N> {};
 // These should all compile just fine:
 typedef py::class_<BreaksBase<1>, std::unique_ptr<BreaksBase<1>>, BreaksTramp<1>> DoesntBreak1;
diff --git a/tests/test_gil_scoped.cpp b/tests/test_gil_scoped.cpp
index 76c17fdc7..dc9b7ed22 100644
--- a/tests/test_gil_scoped.cpp
+++ b/tests/test_gil_scoped.cpp
@@ -13,7 +13,9 @@
 
 class VirtClass  {
 public:
-    virtual ~VirtClass() {}
+    virtual ~VirtClass() = default;
+    VirtClass() = default;
+    VirtClass(const VirtClass&) = delete;
     virtual void virtual_func() {}
     virtual void pure_virtual_func() = 0;
 };
diff --git a/tests/test_methods_and_attributes.cpp b/tests/test_methods_and_attributes.cpp
index 901f2046c..11d4e7b35 100644
--- a/tests/test_methods_and_attributes.cpp
+++ b/tests/test_methods_and_attributes.cpp
@@ -289,6 +289,7 @@ TEST_SUBMODULE(methods_and_attributes, m) {
     class DynamicClass {
     public:
         DynamicClass() { print_default_created(this); }
+        DynamicClass(const DynamicClass&) = delete;
         ~DynamicClass() { print_destroyed(this); }
     };
     py::class_<DynamicClass>(m, "DynamicClass", py::dynamic_attr())
diff --git a/tests/test_smart_ptr.cpp b/tests/test_smart_ptr.cpp
index 6f8f3821a..bea90691d 100644
--- a/tests/test_smart_ptr.cpp
+++ b/tests/test_smart_ptr.cpp
@@ -339,6 +339,8 @@ TEST_SUBMODULE(smart_ptr, m) {
     // #187: issue involving std::shared_ptr<> return value policy & garbage collection
     struct ElementBase {
         virtual ~ElementBase() { } /* Force creation of virtual table */
+        ElementBase() = default;
+        ElementBase(const ElementBase&) = delete;
     };
     py::class_<ElementBase, std::shared_ptr<ElementBase>>(m, "ElementBase");
 
diff --git a/tests/test_virtual_functions.cpp b/tests/test_virtual_functions.cpp
index ccf018d99..583c1e647 100644
--- a/tests/test_virtual_functions.cpp
+++ b/tests/test_virtual_functions.cpp
@@ -130,6 +130,8 @@ private:
 class NCVirt {
 public:
     virtual ~NCVirt() { }
+    NCVirt() = default;
+    NCVirt(const NCVirt&) = delete;
     virtual NonCopyable get_noncopyable(int a, int b) { return NonCopyable(a, b); }
     virtual Movable get_movable(int a, int b) = 0;
 
@@ -151,6 +153,8 @@ struct Base {
     /* for some reason MSVC2015 can't compile this if the function is pure virtual */
     virtual std::string dispatch() const { return {}; };
     virtual ~Base() = default;
+    Base() = default;
+    Base(const Base&) = delete;
 };
 
 struct DispatchIssue : Base {
@@ -221,12 +225,15 @@ TEST_SUBMODULE(virtual_functions, m) {
     // don't invoke Python dispatch classes by default when instantiating C++ classes
     // that were not extended on the Python side
     struct A {
+        A() = default;
+        A(const A&) = delete;
         virtual ~A() {}
         virtual void f() { py::print("A.f()"); }
     };
 
     struct PyA : A {
         PyA() { py::print("PyA.PyA()"); }
+        PyA(const PyA&) = delete;
         ~PyA() { py::print("PyA.~PyA()"); }
 
         void f() override {
@@ -246,12 +253,15 @@ TEST_SUBMODULE(virtual_functions, m) {
     // test_alias_delay_initialization2
     // ... unless we explicitly request it, as in this example:
     struct A2 {
+        A2() = default;
+        A2(const A2&) = delete;
         virtual ~A2() {}
         virtual void f() { py::print("A2.f()"); }
     };
 
     struct PyA2 : A2 {
         PyA2() { py::print("PyA2.PyA2()"); }
+        PyA2(const PyA2&) = delete;
         ~PyA2() { py::print("PyA2.~PyA2()"); }
         void f() override {
             py::print("PyA2.f()");
@@ -282,6 +292,8 @@ TEST_SUBMODULE(virtual_functions, m) {
         std::string v;
         A a;
         explicit OverrideTest(const std::string &v) : v{v} {}
+        OverrideTest() = default;
+        OverrideTest(const OverrideTest&) = delete;
         virtual std::string str_value() { return v; }
         virtual std::string &str_ref() { return v; }
         virtual A A_value() { return a; }
@@ -339,6 +351,8 @@ public: \
         return say_something(1) + " " + std::to_string(unlucky_number()); \
     }
 A_METHODS
+    A_Repeat() = default;
+    A_Repeat(const A_Repeat&) = delete;
     virtual ~A_Repeat() = default;
 };
 class B_Repeat : public A_Repeat {
@@ -364,7 +378,12 @@ D_METHODS
 };
 
 // Base classes for templated inheritance trampolines.  Identical to the repeat-everything version:
-class A_Tpl { A_METHODS; virtual ~A_Tpl() = default; };
+class A_Tpl {
+    A_METHODS;
+    A_Tpl() = default;
+    A_Tpl(const A_Tpl&) = delete;
+    virtual ~A_Tpl() = default;
+};
 class B_Tpl : public A_Tpl { B_METHODS };
 class C_Tpl : public B_Tpl { C_METHODS };
 class D_Tpl : public C_Tpl { D_METHODS };