[clang] [C] Warn on uninitialized const objects (PR #137166)

[Aaron Ballman via cfe-commits]

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@@ -8197,6 +8197,16 @@ def err_address_space_qualified_new : Error<
 def err_address_space_qualified_delete : Error<
   "'delete' cannot delete objects of type %0 in address space '%1'">;
 
+def note_default_init_const_member : Note<
+  "member %0 declared 'const' here">;
+def warn_default_init_const : Warning<
+  "default initialization of an object of type %0%select{| with const member}1 "
+  "is incompatible with C++">,
+  InGroup<DefaultConstInit>, DefaultIgnore;
+def warn_default_init_const_unsafe : Warning<
+  "default initialization of an object of type %0%select{| with const member}1 "
+  "leaves the object uninitialized and is incompatible with C++">,
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AaronBallman wrote:

I posted https://github.com/llvm/llvm-project/pull/138266 to try to improve this, thank you for bringing it up!

https://github.com/llvm/llvm-project/pull/137166