[clang] [clang] Warn [[clang::lifetimebound]] misusages on types (PR #118281)

[Maksim Ivanov via cfe-commits]

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@@ -9,11 +9,20 @@ namespace usage_invalid {
     ~A() [[clang::lifetimebound]]; // expected-error {{cannot be applied to a destructor}}
     static int *static_class_member() [[clang::lifetimebound]]; // expected-error {{static member function has no implicit object parameter}}
     int *explicit_object(this A&) [[clang::lifetimebound]]; // expected-error {{explicit object member function has no implicit object parameter}}
-    int not_function [[clang::lifetimebound]]; // expected-error {{only applies to parameters and implicit object parameters}}
-    int [[clang::lifetimebound]] also_not_function; // expected-error {{cannot be applied to types}}
+    int attr_on_var [[clang::lifetimebound]]; // expected-error {{only applies to parameters and implicit object parameters}}
+    int [[clang::lifetimebound]] attr_on_int; // expected-error {{cannot be applied to types}}
+    int * [[clang::lifetimebound]] attr_on_int_ptr; // expected-error {{cannot be applied to types}}
+    int * [[clang::lifetimebound]] * attr_on_int_ptr_ptr; // expected-error {{cannot be applied to types}}
+    int (* [[clang::lifetimebound]] attr_on_func_ptr)(); // expected-error {{cannot be applied to types}}
     void void_return_member() [[clang::lifetimebound]]; // expected-error {{'lifetimebound' attribute cannot be applied to an implicit object parameter of a function that returns void; did you mean 'lifetime_capture_by(X)'}}
   };
   int *attr_with_param(int &param [[clang::lifetimebound(42)]]); // expected-error {{takes no arguments}}
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emaxx-google wrote:

Thanks. I think I'll prefer to track them via separate Issues as opposed to TODOs, because it's not totally clear to me how many "fundamental" issues we have remaining, and how we're going to tackle those.

https://github.com/llvm/llvm-project/pull/118281