[clang-tools-extra] [NFC] Fix potential underflow constant. (PR #118528)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-tidy

Author: Zahira Ammarguellat (zahiraam)

<details>
<summary>Changes</summary>

If the range for `llvm::any_of` is empty, `Idx` will be `0` and an underflow might occur when computing `Idx-1`.

---
Full diff: https://github.com/llvm/llvm-project/pull/118528.diff


1 Files Affected:

- (modified) clang-tools-extra/clang-tidy/bugprone/CrtpConstructorAccessibilityCheck.cpp (+4-4) 


``````````diff
diff --git a/clang-tools-extra/clang-tidy/bugprone/CrtpConstructorAccessibilityCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/CrtpConstructorAccessibilityCheck.cpp
index 8eaf54fe0088a4..ce307a2384aef7 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CrtpConstructorAccessibilityCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/CrtpConstructorAccessibilityCheck.cpp
@@ -58,10 +58,10 @@ getDerivedParameter(const ClassTemplateSpecializationDecl *CRTP,
                Arg.getAsType()->getAsCXXRecordDecl() == Derived;
       });
 
-  return AnyOf ? CRTP->getSpecializedTemplate()
-                     ->getTemplateParameters()
-                     ->getParam(Idx - 1)
-               : nullptr;
+  return AnyOf && Idx > 0 ? CRTP->getSpecializedTemplate()
+                                ->getTemplateParameters()
+                                ->getParam(Idx - 1)
+                          : nullptr;
 }
 
 static std::vector<FixItHint>

``````````

</details>


https://github.com/llvm/llvm-project/pull/118528