[clang-tools-extra] [clang-tidy] Support find for string-like classes in readability-container-contains (PR #157243)

[Victor Chernyakin via cfe-commits]

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@@ -458,3 +454,41 @@ void testOperandPermutations(std::map<int, int>& Map) {
   // CHECK-MESSAGES: :[[@LINE-1]]:{{[0-9]+}}: warning: use 'contains' to check for membership [readability-container-contains]
   // CHECK-FIXES: if (!Map.contains(0)) {};
 }
+
+void testStringNpos(std::string Str1, std::string Str2, std::string_view StrView) {
+  if (Str1.find(Str2) == std::string::npos) {};
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localspook wrote:

Nit: stray semicolons after all the `if`s in this function

https://github.com/llvm/llvm-project/pull/157243