1 files changed, 28 insertions, 0 deletions
diff --git a/clang/test/SemaTemplate/instantiate-template-argument.cpp b/clang/test/SemaTemplate/instantiate-template-argument.cpp
new file mode 100644
index 00000000000..43d5d00c8cb
--- /dev/null
+++ b/clang/test/SemaTemplate/instantiate-template-argument.cpp
@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -std=c++2a -x c++ %s -verify
+
+template<auto T, decltype(T) U>
+concept C1 = sizeof(U) >= 4;
+// sizeof(U) >= 4 [U = U (decltype(T))]
+
+template<typename Y, char V>
+concept C2 = C1<Y{}, V>;
+// sizeof(U) >= 4 [U = V (decltype(Y{}))]
+
+template<char W>
+constexpr int foo() requires C2<int, W> { return 1; }
+// sizeof(U) >= 4 [U = W (decltype(int{}))]
+
+template<char X>
+// expected-note@+1{{candidate function}}
+constexpr int foo() requires C1<1, X> && true { return 2; }
+// sizeof(U) >= 4 [U = X (decltype(1))]
+
+static_assert(foo<'a'>() == 2);
+
+template<char Z>
+// expected-note@+1{{candidate function}}
+constexpr int foo() requires C2<long long, Z> && true { return 3; }
+// sizeof(U) >= 4 [U = Z (decltype(long long{}))]
+
+static_assert(foo<'a'>() == 3);
+// expected-error@-1{{call to 'foo' is ambiguous}}
+\ No newline at end of file