[clang-tools-extra] [clang-tidy] introduce a must use check (PR #76101)

[Piotr Zegar via cfe-commits]

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@@ -0,0 +1,28 @@
+.. title:: clang-tidy - misc-must-use
+
+misc-must-use
+=============
+
+Allow strictly enforcing that variables are used for specific classes,
+even with they would not be normally warned using `-Wunused-variable` due 
+templates or custom destructors.
+
+In the following example, `future2` normally would not trigger any unused variable checks,
+but using `{key: "misc-must-use.Types", value: "std::future"}` would cause `future2` to have
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PiotrZSL wrote:

this configuration is in deprecated style, use new one misc-must-use.Types: 'std::future'

https://github.com/llvm/llvm-project/pull/76101