clang-tidy fixes related to PR #3250

.codespell-ignorelines

@@ -1,8 +1,8 @@
     assert m.atyp_valu().get_mtxt() == "Valu"
 atyp_valu        rtrn_valu() { atyp_valu obj{"Valu"}; return obj; }
-    indestructible_int(int v) : valu{v} {}
+    explicit indestructible_int(int v) : valu{v} {}
+    explicit movable_int(int v) : valu{v} {}
     int valu;
-    movable_int(int v) : valu{v} {}
         (m.pass_valu, "Valu", "pass_valu:Valu(_MvCtor)*_CpCtor"),
         other.valu = 91;
     REQUIRE(hld.as_raw_ptr_unowned<zombie>()->valu == 19);

include/pybind11/detail/smart_holder_type_casters.h

@@ -43,7 +43,7 @@ inline bool deregister_instance(instance *self, void *valptr, const type_info *t
 // clang-format off
 class modified_type_caster_generic_load_impl {
 public:
-    PYBIND11_NOINLINE modified_type_caster_generic_load_impl(const std::type_info &type_info)
+    PYBIND11_NOINLINE explicit modified_type_caster_generic_load_impl(const std::type_info &type_info)
         : typeinfo(get_type_info(type_info)), cpptype(&type_info) { }
 
     explicit modified_type_caster_generic_load_impl(const type_info *typeinfo = nullptr)
@@ -598,13 +598,17 @@ struct smart_holder_type_caster : smart_holder_type_caster_load<T>,
     // The const operators here prove that the existing type_caster mechanism already supports
     // const-correctness. However, fully implementing const-correctness inside this type_caster
     // is still a major project.
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator T const &() const {
         return const_cast<smart_holder_type_caster *>(this)->loaded_as_lvalue_ref();
     }
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator T const *() const {
         return const_cast<smart_holder_type_caster *>(this)->loaded_as_raw_ptr_unowned();
     }
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator T &() { return this->loaded_as_lvalue_ref(); }
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator T *() { return this->loaded_as_raw_ptr_unowned(); }
 
     // Originally type_caster_generic::cast.
@@ -749,6 +753,7 @@ struct smart_holder_type_caster<std::shared_ptr<T>> : smart_holder_type_caster_l
     template <typename>
     using cast_op_type = std::shared_ptr<T>;
 
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator std::shared_ptr<T>() { return this->loaded_as_shared_ptr(); }
 };
 
@@ -768,6 +773,7 @@ struct smart_holder_type_caster<std::shared_ptr<T const>> : smart_holder_type_ca
     template <typename>
     using cast_op_type = std::shared_ptr<T const>;
 
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator std::shared_ptr<T const>() { return this->loaded_as_shared_ptr(); } // Mutbl2Const
 };
 
@@ -844,6 +850,7 @@ struct smart_holder_type_caster<std::unique_ptr<T, D>> : smart_holder_type_caste
     template <typename>
     using cast_op_type = std::unique_ptr<T, D>;
 
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator std::unique_ptr<T, D>() { return this->template loaded_as_unique_ptr<D>(); }
 };
 
@@ -863,6 +870,7 @@ struct smart_holder_type_caster<std::unique_ptr<T const, D>>
     template <typename>
     using cast_op_type = std::unique_ptr<T const, D>;
 
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator std::unique_ptr<T const, D>() { return this->template loaded_as_unique_ptr<D>(); }
 };
 

tests/pure_cpp/smart_holder_poc_test.cpp

@@ -9,7 +9,7 @@ namespace helpers {
 
 struct movable_int {
     int valu;
-    movable_int(int v) : valu{v} {}
+    explicit movable_int(int v) : valu{v} {}
     movable_int(movable_int &&other) noexcept {
         valu = other.valu;
         other.valu = 91;
@@ -26,7 +26,7 @@ struct functor_other_delete : functor_builtin_delete<T> {};
 
 struct indestructible_int {
     int valu;
-    indestructible_int(int v) : valu{v} {}
+    explicit indestructible_int(int v) : valu{v} {}
 
 private:
     ~indestructible_int() = default;

tests/test_class_sh_basic.cpp

@@ -12,7 +12,7 @@ namespace class_sh_basic {
 struct atyp { // Short for "any type".
     std::string mtxt;
     atyp() : mtxt("DefaultConstructor") {}
-    atyp(const std::string &mtxt_) : mtxt(mtxt_) {}
+    explicit atyp(const std::string &mtxt_) : mtxt(mtxt_) {}
     atyp(const atyp &other) { mtxt = other.mtxt + "_CpCtor"; }
     atyp(atyp &&other) noexcept { mtxt = other.mtxt + "_MvCtor"; }
 };

tests/test_class_sh_disowning.cpp

@@ -10,7 +10,7 @@ namespace class_sh_disowning {
 template <int SerNo> // Using int as a trick to easily generate a series of types.
 struct Atype {
     int val = 0;
-    Atype(int val_) : val{val_} {}
+    explicit Atype(int val_) : val{val_} {}
     int get() const { return val * 10 + SerNo; }
 };
 

tests/test_class_sh_disowning_mi.cpp

@@ -31,13 +31,13 @@ void disown_b(std::unique_ptr<B>) {}
 
 // test_multiple_inheritance_python
 struct Base1 {
-    Base1(int i) : i(i) {}
+    explicit Base1(int i) : i(i) {}
     int foo() const { return i; }
     int i;
 };
 
 struct Base2 {
-    Base2(int j) : j(j) {}
+    explicit Base2(int j) : j(j) {}
     int bar() const { return j; }
     int j;
 };

tests/test_class_sh_shared_ptr_copy_move.cpp

@@ -14,7 +14,7 @@ const std::string fooNames[] = {"ShPtr_", "SmHld_"};
 template <int SerNo>
 struct Foo {
     std::string history;
-    Foo(const std::string &history_) : history(history_) {}
+    explicit Foo(const std::string &history_) : history(history_) {}
     Foo(const Foo &other) : history(other.history + "_CpCtor") {}
     Foo(Foo &&other) noexcept : history(other.history + "_MvCtor") {}
     Foo &operator=(const Foo &other) {

tests/test_class_sh_trampoline_basic.cpp

@@ -11,7 +11,7 @@ template <int SerNo> // Using int as a trick to easily generate a series of type
 struct Abase {
     int val = 0;
     virtual ~Abase() = default;
-    Abase(int val_) : val{val_} {}
+    explicit Abase(int val_) : val{val_} {}
     int Get() const { return val * 10 + 3; }
     virtual int Add(int other_val) const = 0;