clang-tidy module: add check for string concatenation

Co-Authored-by: Kyle Edwards <kyle.edwards@kitware.com>

Utilities/ClangTidyModule/StringConcatenationUseCmstrcatCheck.h

@@ -0,0 +1,34 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#pragma once
+
+#include <clang-tidy/ClangTidyCheck.h>
+#include <clang/ASTMatchers/ASTMatchFinder.h>
+
+namespace clang {
+namespace tidy {
+namespace cmake {
+class StringConcatenationUseCmstrcatCheck : public ClangTidyCheck
+{
+public:
+  StringConcatenationUseCmstrcatCheck(StringRef Name,
+                                      ClangTidyContext* Context);
+  void registerMatchers(ast_matchers::MatchFinder* Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult& Result) override;
+
+private:
+  enum class OperatorType
+  {
+    Plus,
+    PlusEquals
+  };
+  typedef std::pair<OperatorType, std::vector<const CXXOperatorCallExpr*>>
+    ExprChain;
+  std::map<const CXXOperatorCallExpr*, ExprChain> InProgressExprChains;
+
+  void issueCorrection(const ExprChain& ExprChain,
+                       const ast_matchers::MatchFinder::MatchResult& Result);
+};
+}
+}
+}