Re: Issue 951 in include-what-you-use: Bug: parsing /usr/lib/llvm-12/include/llvm/Support/Casting.h fails?

[notifi...@include-what-you-use.org]

Comment #16 on issue 951 by bccox: Bug: parsing /usr/lib/llvm-12/include/llvm/Support/Casting.h fails?
https://github.com/include-what-you-use/include-what-you-use/issues/951

I'm seeing the same problem, except that IWYU is compiled against llvm-13 on my Debian system. Is there any hope of fixing this? I'd rather not have to choose between using include-what-you-use and fmt.

[notifi...@include-what-you-use.org]

Comment #16 on issue 951 by kimgr: Bug: parsing /usr/lib/llvm-12/include/llvm/Support/Casting.h fails?
https://github.com/include-what-you-use/include-what-you-use/issues/951

@bccox I've worked on this off and on, but haven't come to any conclusive root cause or fix. I'm pretty sure it's a bug in Clang. I'll try to finish up my repro case and open a proper Clang bug today.

[notifi...@include-what-you-use.org]

Comment #18 on issue 951 by gabyx: Bug: parsing /usr/lib/llvm-12/include/llvm/Support/Casting.h fails?
https://github.com/include-what-you-use/include-what-you-use/issues/951

@kimgr Thanks for your effort.

[notifi...@include-what-you-use.org]

Comment #18 on issue 951 by kimgr: Bug: parsing /usr/lib/llvm-12/include/llvm/Support/Casting.h fails?
https://github.com/include-what-you-use/include-what-you-use/issues/951

It's now confirmed to be a Clang bug, and I managed to reduce the repro case to this:
```
// consteval.cpp
struct X {
consteval X(const char*) {
}
};

void t() {
X x = "foobar";
}
```
The `consteval` is what triggers it:
```
$ include-what-you-use -std=c++20 consteval.cpp
include-what-you-use: /usr/lib/llvm-14/include/llvm/Support/Casting.h:269: typename llvm::cast_retty<X, Y*>::ret_type llvm::cast(Y*) [with X = clang::FunctionDecl; Y = const clang::NamedDecl; typename llvm::cast_retty<X, Y*>::ret_type = const clang::FunctionDecl*]: Assertion `isa<X>(Val) && "cast<Ty>() argument of incompatible type!"' failed.
Aborted (core dumped)
```

Hopefully I can get

[notifi...@include-what-you-use.org]

Comment #19 on issue 951 by kimgr: Bug: parsing /usr/lib/llvm-12/include/llvm/Support/Casting.h fails?

[notifi...@include-what-you-use.org]

Comment #20 on issue 951 by kimgr: Bug: parsing /usr/lib/llvm-12/include/llvm/Support/Casting.h fails?
https://github.com/include-what-you-use/include-what-you-use/issues/951

Update! I have a Clang patch open for this now: https://reviews.llvm.org/D117391. :crossed_fingers: