[clang] [clang][AST] Invalidate DecompositionDecl if it has invalid initializer. (PR #72428)

[Haojian Wu via cfe-commits]

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@@ -13540,6 +13540,15 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) {
           CreateRecoveryExpr(Init->getBeginLoc(), Init->getEndLoc(), Args);
       if (RecoveryExpr.get())
         VDecl->setInit(RecoveryExpr.get());
+      // In general, for error recovery purposes, the initalizer doesn't play
+      // part in the valid bit of the declaration. There are a few exceptions:
+      //  1) if the var decl has a deduced auto type, and the type cannot be
+      //     deduced by an invalid initializer;
+      //  2) if the var decl is decompsition decl with a concrete type (e.g.
+      //    `int [a, b] = 1;`), and the initializer is invalid;
+      // Case 1) is already handled earlier in this function.
+      if (llvm::isa<DecompositionDecl>(VDecl)) // Case 2)
+        VDecl->setInvalidDecl();
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hokein wrote:

I think this comment is helpful (especially the context is not obvious here). I'd like to keep it.

The code handling the case `1)` is https://github.com/llvm/llvm-project/blob/1c05fe350064aa3a1784bb09829a07d501842d97/clang/lib/Sema/SemaDecl.cpp#L13363C3-L13384, and it is easier to understand the purpose by reading the code. I'd avoid having two similar comments in the codebase.


https://github.com/llvm/llvm-project/pull/72428