QualifierAlignment Right doesn't handle Pointer to member declarators correctly

[AlexanderHederstaf]

Example input:

$ cat /tmp/memberpointer.cpp
struct S;
void foo(const int S::*const ptr) {}
void bar(int const S::*const ptr) {}

Output:

$ ./clang-format  --style="{QualifierAlignment: Right}" /tmp/memberpointer.cpp
struct S;
void foo(int const S::*const ptr) {}
void bar(int S::const *const ptr) {}

Discovered by running Clang-Format on an existing codebase that had a few instances of pointer to member function. The const qualifier is moved iteratively until the code no longer compiles. Probably caused in this section

    // The case  `const Foo` -> `Foo const`
    // The case  `const ::Foo` -> `::Foo const`
    // The case  `const Foo *` -> `Foo const *`
    // The case  `const Foo &` -> `Foo const &`
    // The case  `const Foo &&` -> `Foo const &&`
    // The case  `const std::Foo &&` -> `std::Foo const &&`
    // The case  `const std::Foo<T> &&` -> `std::Foo<T> const &&`
    while (Next && Next->isOneOf(tok::identifier, tok::coloncolon))
      Next = Next->Next;

Where special treatment would be required for the following case, causing no change.

    // The case  `const Foo::*` -> `const Foo::*`

[llvmbot]

@llvm/issue-subscribers-clang-format

[rymiel]

https://reviews.llvm.org/D144537

[AlexanderHederstaf]

I tried to also solve #57154 as well by refactoring and taking a slightly different approach with testing the previous tokens. I uploaded a review here https://reviews.llvm.org/D144709. This patch succeeds in always moving qualifiers to the right but fails unit-tests related to the ordering of const/volatile. I also did not make any changes to west-const and did not yet add any new tests.

Worth noting is that the cases that fail now for int would fail on main for Foo.

[JVApen]

@rymiel Is this backported to 16?