diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 9091f6341bd9b..bd92818f0c09d 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -810,6 +810,7 @@ Bug Fixes to C++ Support
 - Clang now diagnoses unexpanded parameter packs in attributes. (Fixes #GH93269).
 - Clang now allows ``@$``` in raw string literals. Fixes (#GH93130).
 - Fix an assertion failure when checking invalid ``this`` usage in the wrong context. (Fixes #GH91536).
+- Clang no longer models dependent NTTP arguments as ``TemplateParamObjectDecl`` s. Fixes (#GH84052).
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/AST/TemplateBase.cpp b/clang/lib/AST/TemplateBase.cpp
index a7ee973b7f7d0..b50daf5fbed6a 100644
--- a/clang/lib/AST/TemplateBase.cpp
+++ b/clang/lib/AST/TemplateBase.cpp
@@ -221,8 +221,13 @@ static const ValueDecl *getAsSimpleValueDeclRef(const ASTContext &Ctx,
 
   // We model class non-type template parameters as their template parameter
   // object declaration.
-  if (V.isStruct() || V.isUnion())
+  if (V.isStruct() || V.isUnion()) {
+    // Dependent types are not supposed to be described as
+    // TemplateParamObjectDecls.
+    if (T->isDependentType() || T->isInstantiationDependentType())
+      return nullptr;
     return Ctx.getTemplateParamObjectDecl(T, V);
+  }
 
   // Pointers and references with an empty path use the special 'Declaration'
   // representation.
diff --git a/clang/test/SemaTemplate/temp_arg_nontype_cxx2c.cpp b/clang/test/SemaTemplate/temp_arg_nontype_cxx2c.cpp
index 9fb6b440b6b2a..e74c031eba4c1 100644
--- a/clang/test/SemaTemplate/temp_arg_nontype_cxx2c.cpp
+++ b/clang/test/SemaTemplate/temp_arg_nontype_cxx2c.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -std=c++20 -Wconversion -verify %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++2c -Wconversion -verify %s
 
 struct Test {
     int a = 0;
@@ -102,3 +102,24 @@ void bar() {
 }
 
 }
+
+namespace GH84052 {
+
+template <class... T>
+concept C = sizeof(T...[1]) == 1; // #C
+
+struct A {};
+
+template <class T, C<T> auto = A{}> struct Set {}; // #Set
+
+template <class T> void foo() {
+  Set<T> unrelated;
+}
+
+Set<bool> sb;
+Set<float> sf;
+// expected-error@-1 {{constraints not satisfied for class template 'Set'}}
+// expected-note@#Set {{because 'C<decltype(GH84052::A{}), float>' evaluated to false}}
+// expected-note@#C {{evaluated to false}}
+
+} // namespace GH84052