[clang] Add Clang attribute to ensure that fields are initialized explicitly (PR #102040)

[Aaron Ballman via cfe-commits]

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@@ -6919,6 +6923,9 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
   case ParsedAttr::AT_NoMerge:
     handleNoMergeAttr(S, D, AL);
     break;
+  case ParsedAttr::AT_ExplicitInit:
+    handleExplicitInitAttr(S, D, AL);
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AaronBallman wrote:

Also not needed.

https://github.com/llvm/llvm-project/pull/102040