[clang] [Sema] Fix parameter index checks on explicit object member functions (PR #165586)

[via cfe-commits]

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@@ -11,6 +11,11 @@ struct S {
 
   void h(const char*) __attribute__((nonnull(1))); // \
       expected-error{{invalid for the implicit this argument}}
+
+  void i(this S* self, const char*) __attribute__((nonnull(1)));
+
+  void j(this S* self, const char*) __attribute__((nonnull(3))); // \
+      expected-error{{'nonnull' attribute parameter 1 is out of bounds}}
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Sirraide wrote:

Also add a test to make sure that parameter index `2` works.

https://github.com/llvm/llvm-project/pull/165586