[clang] [clang][Sema] Fix initialization of `NonTypeTemplateParmDecl`... (PR #121768)

[Alejandro Álvarez Ayllón via cfe-commits]

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@@ -0,0 +1,54 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: cd %t
+
+// RUN: %clang_cc1 -std=c++20 mod.cppm -emit-module-interface -o mod.pcm -fallow-pcm-with-compiler-errors -verify
+// RUN: %clang_cc1 -std=c++20 main.cpp -fmodule-file=mod=mod.pcm -verify -fallow-pcm-with-compiler-errors -fsyntax-only -ast-dump-all | FileCheck %s
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alejandro-alvarez-sonarsource wrote:

We don't even need serialization. IIRC it can be triggered with an ast dump, but only if the uninitialized value happens not  to be a 0, which is the tricky part to trigger (not using sanitizers, that is).

https://github.com/llvm/llvm-project/pull/121768