[clang] [Clang][UnsafeBufferUsage] Warn about two-arg string_view constructors. (PR #180471)

[Ziqing Luo via cfe-commits]

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@@ -13559,6 +13549,9 @@ def note_safe_buffer_usage_suggestions_disabled : Note<
 def warn_unsafe_buffer_usage_in_container : Warning<
   "the two-parameter std::span construction is unsafe as it can introduce mismatch between buffer size and the bound information">,
   InGroup<UnsafeBufferUsageInContainer>, DefaultIgnore;
+def warn_unsafe_buffer_usage_in_string_view : Warning<
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ziqingluo-90 wrote:

The original idea is to let `warn_unsafe_buffer_usage_in_container` to cover both unsafe constructors of `std::span` and `std::string_view`, so we used the word "container" here (even though it is not very precise).   

I suggest you use `warn_unsafe_buffer_usage_in_container` for both warnings and use `warn_unsafe_buffer_usage_in_string_view` to suppress the new warning for a smooth transition.

https://github.com/llvm/llvm-project/pull/180471