[analyzer] Add documentation for std::variant checker

[spaits]

Add a short documentation for StdVariantChecker.

[llvmbot]

@llvm/pr-subscribers-clang-static-analyzer-1

@llvm/pr-subscribers-clang

Author: Gábor Spaits (spaits)

Changes

Add a short documentation for StdVariantChecker.

---

Full diff: https://github.com/llvm/llvm-project/pull/76501.diff

1 Files Affected:

• (modified) clang/docs/analyzer/checkers.rst (+12)

diff --git a/clang/docs/analyzer/checkers.rst b/clang/docs/analyzer/checkers.rst
index 81d40395067c9a..1e5ba013f85d67 100644
--- a/clang/docs/analyzer/checkers.rst
+++ b/clang/docs/analyzer/checkers.rst
@@ -2097,6 +2097,18 @@ This checker is a part of ``core.StackAddressEscape``, but is temporarily disabl
 
 .. _alpha-core-TestAfterDivZero:
 
+alpha.core.StdVariant (C++)
+"""""""""""""""""""""""
+Check if the active value accessed in an ``std::variant`` instance.
+.. code-block:: cpp
+
+ void test() {
+   std::variant <int, char> v = 25;
+   char c = stg::get<char>(v); // warn
+ }
+
+.. _alpha-core-StdVariant:
+
 alpha.core.TestAfterDivZero (C)
 """""""""""""""""""""""""""""""
 Check for division by variable that is later compared against 0.

[NagyDonat]

Note: the docs build check failed with

/home/runner/work/llvm-project/llvm-project/clang-build/tools/clang/docs/analyzer/checkers.rst:2108:Definition list ends without a blank line; unexpected unindent.

[NagyDonat]

There is a trivial typo, otherwise LGTM.

Thanks for the update!

[spaits]

Added some more explanation. I will continue using "Check if" since the other descriptions that I saw stared like that (or "Check for").

[steakhal]

Please also update the release notes with a link as documentation. Follow the existing patterns there.

[NagyDonat]

Added some more explanation. I will continue using "Check if" since the other descriptions that I saw stared like that (or "Check for").

That's a good point for using "Check if".

[steakhal]

let me check it again

[steakhal]

LGTM now. Thanks.

[spaits]

I will merge the PR when the CI builds have finished. Thank you for reviewing.