[clang] [clang][dataflow] Correctly treat empty initializer lists for unions. (PR #82986)

[Gábor Horváth via cfe-commits]

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@@ -685,9 +685,22 @@ class TransferVisitor : public ConstStmtVisitor<TransferVisitor> {
 
     // `S->inits()` contains all the initializer expressions, including the
     // ones for direct base classes.
-    auto Inits = S->inits();
+    ArrayRef<Expr *> Inits = S->inits();
     size_t InitIdx = 0;
 
+    // Unions initialized with an empty initializer list need special treatment.
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Xazax-hun wrote:

I am wondering how does CodeGen deal with this? If it happens to have similar extra logic, we could simplify both by changing the AST. 

https://github.com/llvm/llvm-project/pull/82986