[clang-tools-extra] [clang-tidy] Unsafe CRTP check (PR #82403)

[via cfe-commits]

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@@ -0,0 +1,232 @@
+// RUN: %check_clang_tidy %s bugprone-unsafe-crtp %t
+
+namespace class_implicit_ctor {
+template <typename T>
+class CRTP {};
+// CHECK-MESSAGES: :[[@LINE-1]]:7: warning: the implicit default constructor of the CRTP is publicly accessible [bugprone-unsafe-crtp]
+// CHECK-MESSAGES: :[[@LINE-2]]:7: note: consider making it private
----------------
isuckatcs wrote:

In this case the other warning is triggered. I didn't want to concatenate multiple warnings and fixes, because I don't think I've seen it happen with other clang-tidy checks either, but that might just be me not paying enough attention.

```
warning: the CRTP cannot be constructed from the derived class [bugprone-unsafe-crtp]
    1 | template <typename T> class CRTP {
      |                             ^
    2 | private:
    3 |   CRTP() = default;
    4 | };
note: consider declaring the derived class as friend
```

https://github.com/llvm/llvm-project/pull/82403