Fix an assertion crash when substitute deduced tempalte arguments into

the deduction guide f.

We tried to build a ConstantExpr on a ConstantExpr, which triggers the
assertion in the ConstantExpr::Create method.

Author: hokein

clang/lib/Sema/SemaOverload.cpp

@@ -40,6 +40,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Casting.h"
+#include "llvm/Support/Signals.h"
 #include <algorithm>
 #include <cstddef>
 #include <cstdlib>

clang/test/SemaCXX/cxx20-ctad-type-alias.cpp

@@ -71,3 +71,14 @@ template<int... C>
 using AF = Foo<1>;
 auto a = AF {};
 }
+
+namespace test6 {
+template<typename T, bool B = false>
+struct Foo {
+  Foo(T);
+};
+// non-type template argument.
+template<typename T>
+using AF = Foo<T, 1>;
+AF b{0};//
+}