[docs] Many clang::Type sub-classes are missing on https://clang.llvm.org/doxygen/

[michael-jabbour-sonarsource]

The doxygen diagram for clang::Type is currently missing many classes, including:

• https://clang.llvm.org/doxygen/classclang_1_1TagType.html
• https://clang.llvm.org/doxygen/classclang_1_1AutoType.html
• https://clang.llvm.org/doxygen/classclang_1_1DecltypeType.html
• https://clang.llvm.org/doxygen/classclang_1_1DeducedTemplateSpecializationType.html

Additionally, all the links above currently yield 404.

The mentioned missing classes can be seen on the last snapshot on the wayback machine here.

Note that I wasn't able to reproduce the issue when generating the docs locally (by building doxygen-clang). The diagrams generated locally seem to include all these classes as expected.

[vbvictor]

Having same issue working on #165472.
Trying to make dump_ast_matchers.py generate links to files based on C++ class name, but it appears that documentation of some classes are not published in https://clang.llvm.org/doxygen/classes.html.

Though they are perfectly fine generated locally

[vbvictor]

I downloaded doxygen build from https://github.com/llvm/llvm-project/releases/tag/llvmorg-21.1.4 and It seem to work perferctly fine

[vbvictor]

FYI asked in discord about it

[vbvictor]

I found the rootcause of the problem: doxygen version.

When building https://clang.llvm.org/doxygen/ doxygen 1.14 is used and the build-log goes like this:

Generating docs for compound clang::AttributeScopeInfo...
Generating docs for compound clang::AttrVisitor< ImplClass, RetTy, ParamTys >...
Generating docs for compound clang::AutoTypeLoc...
Generating docs for compound clang::AutoTypeLocInfo...

No AutoType as you can see.

But if switched to doxygen 1.9.8 which is common in ubuntu, we get

Generating docs for compound clang::AttributeScopeInfo...
Generating docs for compound clang::AttrVisitor...
Generating docs for compound clang::AutoType...
Generating docs for compound clang::AutoTypeLoc...

Now it has AutoType!

[vbvictor]

@gkistanova, Could you please downgrade the version of doxygen to 1.9.8 on publish-doxygen-docs buildbot to resolve this issue and match the version of doxygen we use to publish release builds (e.g. https://github.com/llvm/llvm-project/releases/tag/llvmorg-21.1.4)?