[clang] [analyzer][NFC] Document getVarRegion shortcomings (PR #191168)

[via cfe-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 53531 tests passed
* 1082 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### Clang
<details>
<summary>Clang.Analysis/track-control-dependency-conditions.cpp</summary>

```
Exit Code: 3221225501

Command Output (stdout):
--
# RUN: at line 1
c:\_work\llvm-project\llvm-project\build\bin\clang.exe -cc1 -internal-isystem C:\_work\llvm-project\llvm-project\build\lib\clang\23\include -nostdsysteminc -analyze -setup-static-analyzer C:\_work\llvm-project\llvm-project\clang\test\Analysis\track-control-dependency-conditions.cpp -std=c++17    -verify=expected,tracking    -analyzer-config track-conditions=true    -analyzer-output=text    -analyzer-checker=core
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\clang.exe' -cc1 -internal-isystem 'C:\_work\llvm-project\llvm-project\build\lib\clang\23\include' -nostdsysteminc -analyze -setup-static-analyzer 'C:\_work\llvm-project\llvm-project\clang\test\Analysis\track-control-dependency-conditions.cpp' -std=c++17 -verify=expected,tracking -analyzer-config track-conditions=true -analyzer-output=text -analyzer-checker=core
# .---command stderr------------
# | Assertion failed: CurrentParam, file C:\_work\llvm-project\llvm-project\clang\lib\StaticAnalyzer\Core\MemRegion.cpp, line 1054
# | PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
# | Stack dump:
# | 0.	Program arguments: c:\\_work\\llvm-project\\llvm-project\\build\\bin\\clang.exe -cc1 -internal-isystem C:\\_work\\llvm-project\\llvm-project\\build\\lib\\clang\\23\\include -nostdsysteminc -analyze -setup-static-analyzer C:\\_work\\llvm-project\\llvm-project\\clang\\test\\Analysis\\track-control-dependency-conditions.cpp -std=c++17 -verify=expected,tracking -analyzer-config track-conditions=true -analyzer-output=text -analyzer-checker=core
# | 1.	<eof> parser at end of file
# | Exception Code: 0xC000001D
# |  #0 0x00007ff693537b56 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x807b56)
# |  #1 0x00007ffb30c4bb04 (C:\Windows\System32\ucrtbase.dll+0x7bb04)
# |  #2 0x00007ffb30c4cad1 (C:\Windows\System32\ucrtbase.dll+0x7cad1)
# |  #3 0x00007ffb30c4e4a1 (C:\Windows\System32\ucrtbase.dll+0x7e4a1)
# |  #4 0x00007ffb30c4e6e1 (C:\Windows\System32\ucrtbase.dll+0x7e6e1)
# |  #5 0x00007ff69a006346 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x72d6346)
# |  #6 0x00007ff699abd078 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6d8d078)
# |  #7 0x00007ff69a052fe9 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x7322fe9)
# |  #8 0x00007ff69a04fd56 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x731fd56)
# |  #9 0x00007ff69a04ec0a (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x731ec0a)
# | #10 0x00007ff69a04e5ba (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x731e5ba)
# | #11 0x00007ff69a04e467 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x731e467)
# | #12 0x00007ff699b0b829 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6ddb829)
# | #13 0x00007ff699b0735a (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6dd735a)
# | #14 0x00007ff699b0a7b2 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6dda7b2)
# | #15 0x00007ff699b052da (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6dd52da)
# | #16 0x00007ff699b04eab (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x6dd4eab)
# | #17 0x00007ff698b35cfa (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x5e05cfa)
# | #18 0x00007ff698b3351a (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x5e0351a)
# | #19 0x00007ff698995557 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x5c65557)
# | #20 0x00007ff695b40c1f (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x2e10c1f)
# | #21 0x00007ff693678434 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x948434)
# | #22 0x00007ff69372c36c (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x9fc36c)
# | #23 0x00007ff692d388a1 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x88a1)
# | #24 0x00007ff692d341a4 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x41a4)
# | #25 0x00007ff692d3294c (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x294c)
# | #26 0x00007ff692d47c6c (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x17c6c)
# | #27 0x00007ff69a11f920 (c:\_work\llvm-project\llvm-project\build\bin\clang.exe+0x73ef920)
# | #28 0x00007ffb38384cb0 (C:\Windows\System32\KERNEL32.DLL+0x14cb0)
# | #29 0x00007ffb40d3edcb (C:\Windows\SYSTEM32\ntdll.dll+0x7edcb)
# `-----------------------------
# error: command failed with exit status: 0xc000001d

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/191168