[clang] [clang] Add invalid check in NormalizedConstraint::fromConstraintExpr. (PR #86943)

[via cfe-commits]

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@@ -1356,6 +1356,8 @@ NormalizedConstraint::fromConstraintExpr(Sema &S, NamedDecl *D, const Expr *E) {
           S, CSE->getExprLoc(),
           Sema::InstantiatingTemplate::ConstraintNormalization{}, D,
           CSE->getSourceRange());
+      if (Inst.isInvalid())
+        return std::nullptr;
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Sirraide wrote:

```suggestion
        return std::nullopt;
```
Typo.

https://github.com/llvm/llvm-project/pull/86943