[clangd] Crash when `char[]` is initialized with both `#embed` and literal values

[398utubzyt]

char message[] = {
#embed "message.txt"
, 0
};

The code above will crash when hovering over message. It functions as normal without the , 0 bit.

LLVM ERROR: Not implemented
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Signalled during AST worker action: Hover
  Filename: main.cpp
  Directory: d:\source\cpp\hover_crash\src\main
  Command Line: D:\Tools\Clang\20.1.0\bin\clang -resource-dir=D:\Tools\Clang\20.1.0\lib\clang\20 -- d:\source\cpp\hover_crash\src\main\main.cpp
  Version: 84

The logs don't seem to give a backtrace.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: 398utubzyt (398utubzyt)

```c char message[] = { #embed "message.txt" , 0 }; ```

The code above will crash when hovering over message. It functions as normal without the , 0 bit.

LLVM ERROR: Not implemented
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Signalled during AST worker action: Hover
  Filename: main.cpp
  Directory: d:\source\cpp\hover_crash\src\main
  Command Line: D:\Tools\Clang\20.1.0\bin\clang -resource-dir=D:\Tools\Clang\20.1.0\lib\clang\20 -- d:\source\cpp\hover_crash\src\main\main.cpp
  Version: 84

The logs don't seem to give a backtrace.

[cor3ntin]

@398utubzyt hovering? Is that a clangd bug?

[tbaederr]

This is probably fixed by #135957

[398utubzyt]

@398utubzyt hovering? Is that a clangd bug?

Indeed it's a clangd bug. It's in the title.

This is probably fixed by #135957

The crash still occurs on 20.1.4 (latest official release as of writing), and it seems like #135957 was merged prior to its release? I can confirm that #embed on its own behaves correctly, but the crash is caused by the inclusion of the following extra data: , 0.

[tbaederr]

@Fznamznon Did you ever backport that fix to the 20 branch?

[Fznamznon]

@Fznamznon Did you ever backport that fix to the 20 branch?

No, I did not. Should I?

[tbaederr]

It affects people so I think backporting it makes sense

[Fznamznon]

Sorry for the delay, one of the tests is crashing when the patch is applied to clang 20.x for a reason that I don't know. Is that still worth pursuing?

[cor3ntin]

@Fznamznon Probably not https://discourse.llvm.org/t/llvm-20-x-release-schedule-update/86688 @AaronBallman