--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/SemaTemplate/concepts-PR54629.cpp	Wed Nov 09 17:45:10 2022 +0900
@@ -0,0 +1,58 @@
+// RUN: %clang_cc1 -std=c++20 -verify %s
+
+template <class T>
+struct A {
+  void primary();
+};
+
+template <class T>
+  requires requires(T &t) { requires sizeof(t) > 4; }
+struct A<T> {
+  void specialization1();
+};
+
+template <class T>
+  requires requires(T &t) { requires sizeof(t) > 8; }
+struct A<T> {
+  void specialization2();
+};
+
+int main() {
+  A<char>().primary();
+  A<char[5]>().specialization1();
+  A<char[16]>(); // expected-error {{ambiguous partial specialization}}
+                 // expected-note@10 {{partial specialization matches [with T = char[16]}}
+                 // expected-note@16 {{partial specialization matches [with T = char[16]}}
+}
+
+// Check error messages when no overload with constraints matches.
+template <class T>
+void foo()
+  requires requires(T &t) { requires sizeof(t) < 4; }
+{}
+
+template <class T>
+void foo()
+  requires requires(T &t) { requires sizeof(t) > 4; }
+{}
+
+template <class T>
+void foo()
+  requires requires(T &t) { requires sizeof(t) > 8; }
+{}
+
+void test() {
+  foo<char[4]>();
+  // expected-error@-1 {{no matching function for call to 'foo'}}
+  // expected-note@30 {{candidate template ignored: constraints not satisfied}}
+  // expected-note@31 {{because 'sizeof (t) < 4' (4 < 4) evaluated to false}}
+  // expected-note@35 {{candidate template ignored: constraints not satisfied}}
+  // expected-note@36 {{because 'sizeof (t) > 4' (4 > 4) evaluated to false}}
+  // expected-note@40 {{candidate template ignored: constraints not satisfied}}
+  // expected-note@41 {{because 'sizeof (t) > 8' (4 > 8) evaluated to false}}
+
+  foo<char[16]>();
+  // expected-error@-1 {{call to 'foo' is ambiguous}}
+  // expected-note@35 {{candidate function}}
+  // expected-note@40 {{candidate function}}
+}