src: Change C casts to C++ casts

[StephanTLavavej]

We've cleaned up the inc headers to always use C++ casts. We need to do the same for the src source files.

[ranolfi]

I would like to take on this. I don't see in the repo history a commit or series of commits for this refactoring you mentioned - can you point me to it?

[StephanTLavavej]

Thank you! Unfortunately, we aren’t able to make our pre-GitHub commit history public, but the header changes were simply performed by grepping for C cast syntax, and replacing each occurrence with static_cast, const_cast, and/or reinterpret_cast as described by https://eel.is/c++draft/expr.cast#4 . (Careful attention is occasionally required, e.g. to avoid using reinterpret_cast when static_cast suffices.) In some cases, we changed the code to avoid the need for any casting.

(Standardese citations as of WG21-N4835.)

[ranolfi]

Oh, I figured. Thanks for clarifying.

the header changes were simply performed by grepping for C cast syntax

Pretty much what I've been doing. If only we could run g++ -Wold-style-cast on it. :)

Ok, will report later. For this issue, a single commit with all of the changes should be alright, correct?

[StephanTLavavej]

Yes, with commit notes explaining (with line numbers) any unusual replacements. If you want, you could arrange a series of commits (e.g. all const_casts, then all static_casts, etc.), although that’s not necessary. Thanks! 😸

[CaseyCarter]

If only we could run g++ -Wold-style-cast on it. :)

Clang has -Wold-style-cast, and it's a supported front-end.

[StephanTLavavej]

Clang is supported for inc, but not for src. (It can't be in general due to the /clr support machinery, which is not yet built by our CMake build system.) However, attempting to build src with Clang -Wold-style-cast is a good idea.

[StephanTLavavej]

There are at least 2 remaining C casts:

STL/stl/src/filesys.cpp

Line 37 in c12089e

FindClose((HANDLE) _Handle);

STL/stl/src/filesys.cpp

Line 65 in c12089e

if (FindNextFileW((HANDLE) _Handle, &_Dentry) == 0) { // fail

[StephanTLavavej]

I believe that all C casts have been changed or removed now.