[clang-tools-extra] [clang-tidy] Enhance modernize-use-starts-ends-with to handle substr patterns (PR #116033)

[via cfe-commits]

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@@ -173,7 +240,101 @@ void UseStartsEndsWithCheck::registerMatchers(MatchFinder *Finder) {
       this);
 }
 
+void UseStartsEndsWithCheck::handleSubstrMatch(const MatchFinder::MatchResult &Result) {
+  const auto *SubstrCall = Result.Nodes.getNodeAs<CXXMemberCallExpr>("substr_fun");
+  const auto *PositiveComparison = Result.Nodes.getNodeAs<Expr>("positiveComparison");
+  const auto *NegativeComparison = Result.Nodes.getNodeAs<Expr>("negativeComparison");
+  
+  if (!SubstrCall || (!PositiveComparison && !NegativeComparison))
+    return;
+
+  const bool Negated = NegativeComparison != nullptr;
+  const auto *Comparison = Negated ? NegativeComparison : PositiveComparison;
+  
+  if (SubstrCall->getBeginLoc().isMacroID())
+    return;
+
+  const auto *Str = Result.Nodes.getNodeAs<Expr>("str");
+  const auto *Literal = Result.Nodes.getNodeAs<StringLiteral>("literal");
+  const auto *Length = Result.Nodes.getNodeAs<Expr>("length");
+
+  if (!Str || !Literal || !Length)
+    return;
+
+  // Special handling for strlen and size/length member calls
+  const bool IsValidLength = [&]() {
+    if (const auto *LengthInt = dyn_cast<IntegerLiteral>(Length)) {
+      return LengthInt->getValue().getZExtValue() == Literal->getLength();
+    }
+    
+    if (const auto *Call = dyn_cast<CallExpr>(Length)) {
+      if (const auto *FD = Call->getDirectCallee()) {
+        if (FD->getName() == "strlen" && Call->getNumArgs() == 1) {
+          if (const auto *StrArg = dyn_cast<StringLiteral>(
+                  Call->getArg(0)->IgnoreParenImpCasts())) {
+            return StrArg->getLength() == Literal->getLength();
+          }
+        }
+      }
+    }
+    
+    if (const auto *MemberCall = dyn_cast<CXXMemberCallExpr>(Length)) {
+      if (const auto *Method = MemberCall->getMethodDecl()) {
+        StringRef Name = Method->getName();
----------------
EugeneZelenko wrote:

```suggestion
        const StringRef Name = Method->getName();
```

https://github.com/llvm/llvm-project/pull/116033