[clang] [Clang][Diagnostics] Update select uses in DiagnosticXKinds.td to use enum_select (PR #130868)

[via cfe-commits]

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@@ -131,17 +131,21 @@ def note_constexpr_past_end : Note<
   "dereferenced pointer past the end of %select{|subobject of }0"
   "%select{temporary|%2}1 is not a constant expression">;
 def note_constexpr_past_end_subobject : Note<
-  "cannot %select{access base class of|access derived class of|access field of|"
-  "access array element of|ERROR|"
-  "access real component of|access imaginary component of}0 "
-  "pointer past the end of object">;
+  "cannot %enum_select<AccessType>{"
+    "%BaseClassAccess{access base class of}|%DerivedClassAccess{access derived class of}|"
+    "%FieldAccess{access field of}|%ArrayElementAccess{access array element of}|"
+    "%ErrorAccess{ERROR}|"
+    "%RealComponentAccess{access real component of}|%ImaginaryComponentAccess{access imaginary component of}"
+  "}0 pointer past the end of object">;
 def note_non_null_attribute_failed : Note<
   "null passed to a callee that requires a non-null argument">;
 def note_constexpr_null_subobject : Note<
-  "cannot %select{access base class of|access derived class of|access field of|"
-  "access array element of|perform pointer arithmetic on|"
-  "access real component of|"
-  "access imaginary component of}0 null pointer">;
+  "cannot %enum_select<NullSubobjectAccess>{"
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Sirraide wrote:

Hmm, so `NullSubobjectAccess` has basically the same enumerators as `AccessType` above—except that the latter has an additional `ERROR` case, which I’m candidly not sure what that one is even for, but I also haven’t checked the call site(s) for that diagnostic.

Somewhat relatedly, below we have `AccessKind` twice two different diagnostics, which currently isn’t supported.

@erichkeane We recently discussed allowing ‘redeclaring’ an `%enum_select` iff the enumerators and text are the same across all uses of `%enum_select` with the same enumeration. I think it might additionally make sense to allow just e.g. `%enum_select<T>`, that is e.g. `cannot %enum_select<AccessType>0 null pointer`, to reference an existing `%enum_select`. That *should* be fairly simple to implement; I finally have some more time on my hands, so I could come up w/ a patch for that later today.

https://github.com/llvm/llvm-project/pull/130868