[clang-tidy] Add alias cppcoreguidelines-use-default-member-init

[carlosgalvezp]

Summary

And remove identical functionality from
cppcoreguidelines-prefer-member-initializer, which had too many
responsibilities and a tight coupling to the
modernize-use-default-member-init check.

Fixes https://github.com/llvm/llvm-project/issues/62164.

[carlosgalvezp]

Revert code removal, document deprecation notice instead.

[carlosgalvezp]

Rebase and fix conflicts.

[carlosgalvezp]

Add check to list of aliases.

[carlosgalvezp]

Remove check from list of checks, since we do not add
aliases there.

[PiotrZSL]

LGTM

[Eugene.Zelenko]

Please create issue for deprecation after commit.

clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp

 //===-- CppCoreGuidelinesTidyModule.cpp - clang-tidy ----------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "../ClangTidy.h"
 #include "../ClangTidyModule.h"
 #include "../ClangTidyModuleRegistry.h"
 #include "../misc/NonPrivateMemberVariablesInClassesCheck.h"
 #include "../misc/UnconventionalAssignOperatorCheck.h"
 #include "../modernize/AvoidCArraysCheck.h"
+#include "../modernize/UseDefaultMemberInitCheck.h"
 #include "../modernize/UseOverrideCheck.h"
 #include "../readability/MagicNumbersCheck.h"
 #include "AvoidCapturingLambdaCoroutinesCheck.h"
 #include "AvoidConstOrRefDataMembersCheck.h"
 #include "AvoidDoWhileCheck.h"
 #include "AvoidGotoCheck.h"
 #include "AvoidNonConstGlobalVariablesCheck.h"
 #include "AvoidReferenceCoroutineParametersCheck.h"
CheckFactories.registerCheck<ProTypeUnionAccessCheck>(
         "cppcoreguidelines-pro-type-union-access");
     CheckFactories.registerCheck<ProTypeVarargCheck>(
         "cppcoreguidelines-pro-type-vararg");
     CheckFactories.registerCheck<RvalueReferenceParamNotMovedCheck>(
         "cppcoreguidelines-rvalue-reference-param-not-moved");
     CheckFactories.registerCheck<SpecialMemberFunctionsCheck>(
         "cppcoreguidelines-special-member-functions");
     CheckFactories.registerCheck<SlicingCheck>("cppcoreguidelines-slicing");
+    CheckFactories.registerCheck<modernize::UseDefaultMemberInitCheck>(
+        "cppcoreguidelines-use-default-member-init");
     CheckFactories.registerCheck<misc::UnconventionalAssignOperatorCheck>(
         "cppcoreguidelines-c-copy-assignment-signature");
     CheckFactories.registerCheck<VirtualClassDestructorCheck>(
         "cppcoreguidelines-virtual-class-destructor");
   }
 
   ClangTidyOptions getModuleOptions() override {
     ClangTidyOptions Options;

clang-tools-extra/docs/ReleaseNotes.rst

 - New alias :doc:`cert-msc24-c
   <clang-tidy/checks/cert/msc24-c>` to :doc:`bugprone-unsafe-functions
   <clang-tidy/checks/bugprone/unsafe-functions>` was added.
 
 - New alias :doc:`cert-msc33-c
   <clang-tidy/checks/cert/msc33-c>` to :doc:`bugprone-unsafe-functions
   <clang-tidy/checks/bugprone/unsafe-functions>` was added.
 
+- New alias :doc:`cppcoreguidelines-use-default-member-init
+  <clang-tidy/checks/cppcoreguidelines/use-default-member-init>` to
+  :doc:`modernize-use-default-member-init
+  <clang-tidy/checks/modernize/use-default-member-init>` was added.
+
 Changes in existing checks
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 - Improved :doc:`readability-redundant-string-cstr
   <clang-tidy/checks/readability/redundant-string-cstr>` check to recognise
   unnecessary ``std::string::c_str()`` and ``std::string::data()`` calls in
   arguments to ``std::print``, ``std::format`` or other functions listed in
   the ``StringParameterFunction`` check option.
 

 
 - Improved :doc:`bugprone-use-after-move
   <clang-tidy/checks/bugprone/use-after-move>` check to also cover constructor
   initializers.
 
 - Deprecated :doc:`cert-dcl21-cpp
   <clang-tidy/checks/cert/dcl21-cpp>` check.
 
+- Deprecated C.48 enforcement from :doc:`cppcoreguidelines-prefer-member-initializer
+  <clang-tidy/checks/cppcoreguidelines/prefer-member-initializer>`. Please use
+  :doc:`cppcoreguidelines-use-default-member-init
+  <clang-tidy/checks/cppcoreguidelines/use-default-member-init>` instead.
+
 - Deprecated check-local options `HeaderFileExtensions`
   in :doc:`google-build-namespaces
   <clang-tidy/checks/google/build-namespaces>` check.
   Global options of the same name should be used instead.
 
 - Deprecated check-local options `HeaderFileExtensions`
   in :doc:`google-global-names-in-headers
   <clang-tidy/checks/google/global-names-in-headers>` check.

clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/prefer-member-initializer.rst

 initialization is at the class member declaration.
 
 This latter rule is `C.48 <https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c48-prefer-in-class-initializers-to-member-initializers-in-constructors-for-constant-initializers>`_ from CppCoreGuidelines.
 
 Please note, that this check does not enforce this latter rule for
 initializations already implemented as member initializers. For that purpose
 see check `modernize-use-default-member-init <../modernize/use-default-member-init.html>`_.
 
+.. note::
+
+  Enforcement of rule C.48 in this check is deprecated, to be removed in
+  :program:`clang-tidy` version 19 (only C.49 will be enforced by this check then).
+  Please use `cppcoreguidelines-use-default-member-init <../cppcoreguidelines/use-default-member-init.html>`_
+  to enfoce rule C.48.
+
 Example 1
 ---------
 
 .. code-block:: c++
 
   class C {
     int n;
     int m;
.. code-block:: c++
   C(int nn, int mm) : n(nn) {
     if (dice())
       return;
     m = mm;
   }
 
 .. option:: UseAssignment
 
+   Note: this option is deprecated, to be removed in :program:`clang-tidy`
+   version 19. Please use the `UseAssignment` option from
+   `cppcoreguidelines-use-default-member-init <../cppcoreguidelines/use-default-member-init.html>`_
+   instead.
+
    If this option is set to `true` (default is `false`), the check will initialize
    members with an assignment. In this case the fix of the first example looks
    like this:
 
 .. code-block:: c++
 
   class C {
     int n = 1;
     int m;
   public:
     C() {
       if (dice())
         return;
       m = 1;
     }
   };

clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines/use-default-member-init.rst

+.. title:: clang-tidy - cppcoreguidelines-use-default-member-init
+.. meta::
+   :http-equiv=refresh: 5;URL=../modernize/use-default-member-init.html
+
+cppcoreguidelines-use-default-member-init
+=========================================
+
+This check implements `C.48 <https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c48-prefer-in-class-initializers-to-member-initializers-in-constructors-for-constant-initializers>`_ from the CppCoreGuidelines.
+
+The cppcoreguidelines-use-default-member-init check is an alias, please see
+`modernize-use-default-member-init <../modernize/use-default-member-init.html>`_
+for more information.

clang-tools-extra/docs/clang-tidy/checks/list.rst

.. csv-table::
    `cppcoreguidelines-pro-type-member-init <cppcoreguidelines/pro-type-member-init.html>`_, "Yes"
    `cppcoreguidelines-pro-type-reinterpret-cast <cppcoreguidelines/pro-type-reinterpret-cast.html>`_,
    `cppcoreguidelines-pro-type-static-cast-downcast <cppcoreguidelines/pro-type-static-cast-downcast.html>`_, "Yes"
    `cppcoreguidelines-pro-type-union-access <cppcoreguidelines/pro-type-union-access.html>`_,
    `cppcoreguidelines-pro-type-vararg <cppcoreguidelines/pro-type-vararg.html>`_,
    `cppcoreguidelines-rvalue-reference-param-not-moved <cppcoreguidelines/rvalue-reference-param-not-moved.html>`_,
    `cppcoreguidelines-slicing <cppcoreguidelines/slicing.html>`_,
    `cppcoreguidelines-special-member-functions <cppcoreguidelines/special-member-functions.html>`_,
+   `cppcoreguidelines-use-default-member-init <cppcoreguidelines/use-default-member-init.html>`_, "Yes"
    `cppcoreguidelines-virtual-class-destructor <cppcoreguidelines/virtual-class-destructor.html>`_, "Yes"
    `darwin-avoid-spinlock <darwin/avoid-spinlock.html>`_,
    `darwin-dispatch-once-nonstatic <darwin/dispatch-once-nonstatic.html>`_, "Yes"
    `fuchsia-default-arguments-calls <fuchsia/default-arguments-calls.html>`_,
    `fuchsia-default-arguments-declarations <fuchsia/default-arguments-declarations.html>`_, "Yes"
    `fuchsia-multiple-inheritance <fuchsia/multiple-inheritance.html>`_,
    `fuchsia-overloaded-operator <fuchsia/overloaded-operator.html>`_,
    `fuchsia-statically-constructed-objects <fuchsia/statically-constructed-objects.html>`_,