1 files changed, 90 insertions, 7 deletions
diff --git a/clang/test/SemaTemplate/instantiate-template-argument.cpp b/clang/test/SemaTemplate/instantiate-template-argument.cpp
index 43d5d00..7606619 100644
--- a/clang/test/SemaTemplate/instantiate-template-argument.cpp
+++ b/clang/test/SemaTemplate/instantiate-template-argument.cpp
@@ -1,4 +1,6 @@
-// RUN: %clang_cc1 -std=c++2a -x c++ %s -verify
+// RUN: %clang_cc1 -std=c++2a -x c++ %s -verify=expected,cxx20
+// RUN: %clang_cc1 -std=c++2c -x c++ %s -verify
+
 
 template<auto T, decltype(T) U>
 concept C1 = sizeof(U) >= 4;
@@ -9,20 +11,101 @@ concept C2 = C1<Y{}, V>;
 // sizeof(U) >= 4 [U = V (decltype(Y{}))]
 
 template<char W>
-constexpr int foo() requires C2<int, W> { return 1; }
+constexpr int foo() requires C2<int, W> { return 1; } // #cand1
 // 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; }
+constexpr int foo() requires C1<1, X> && true { return 2; } // #cand2
 // 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; }
+constexpr int foo() requires C2<long long, Z> && true { return 3; } // #cand3
 // 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
+// expected-error@-1{{call to 'foo' is ambiguous}}
+// expected-note@#cand2 {{candidate function}}
+// expected-note@#cand3 {{candidate function}}
+
+
+namespace case1 {
+
+template<auto T, decltype(T) U>
+concept C1 = sizeof(T) >= 4; // #case1_C1
+
+template<typename Y, char V>
+concept C2 = C1<Y{}, V>; // #case1_C2
+
+template<class T, char W>
+constexpr int foo() requires C2<T, W> { return 1; } // #case1_foo1
+
+template<class T, char X>
+constexpr int foo() requires C1<T{}, X> && true { return 2; } // #case1_foo2
+
+static_assert(foo<char, 'a'>() == 2);
+// expected-error@-1{{no matching function for call to 'foo'}}
+// expected-note@#case1_foo1{{candidate template ignored: constraints not satisfied [with T = char, W = 'a']}}
+// expected-note@#case1_foo1{{because 'C2<char, 'a'>' evaluated to false}}
+// expected-note@#case1_C2{{because 'C1<char{}, 'a'>' evaluated to false}}
+// expected-note@#case1_C1{{because 'sizeof ('\x00') >= 4' (1 >= 4) evaluated to false}}
+// expected-note@#case1_foo2{{candidate template ignored: constraints not satisfied [with T = char, X = 'a']}}
+// expected-note@#case1_foo2{{because 'C1<char{}, 'a'>' evaluated to false}}
+// expected-note@#case1_C1{{because 'sizeof ('\x00') >= 4' (1 >= 4) evaluated to false}}
+
+static_assert(foo<int, 'a'>() == 2);
+
+}
+
+namespace packs {
+
+template<auto T, decltype(T) U>
+concept C1 = sizeof(U) >= 4;
+
+template<typename Y, char V>
+concept C2 = C1<Y{}, V>;
+
+template<char... W>
+constexpr int foo() requires (C2<int, W> && ...) { return 1; } // #packs-cand1
+
+template<char... X>
+constexpr int foo() requires (C1<1, X> && ...) && true { return 2; } // #packs-cand2
+
+static_assert(foo<'a'>() == 2);
+// cxx20-error@-1{{call to 'foo' is ambiguous}}
+// cxx20-note@#packs-cand1 {{candidate function}}
+// cxx20-note@#packs-cand2 {{candidate function}}
+
+}
+
+namespace case2 {
+template<auto T> concept C1 = sizeof(decltype(T)) >= 0;
+template<typename Y> concept C2 = C1<Y{}>;
+
+template<char W>
+constexpr int foo() requires C2<int> { return 1; }
+
+template<char X>
+constexpr int foo() requires C1<0> && true { return 2; }
+
+static_assert(foo<0>() == 2);
+}
+
+namespace case3 {
+template<auto T> concept C1 = sizeof(decltype(T)) >= 0;
+
+template<typename Y> concept C2 = C1<Y{}>;
+
+template<char W>
+constexpr int foo() requires C2<int> { return 1; } // #case3_foo1
+
+template<char X>
+constexpr int foo() requires C1<1> && true { return 2; } // #case3_foo2
+
+static_assert(foo<0>() == 2);
+// expected-error@-1{{call to 'foo' is ambiguous}}
+// expected-note@#case3_foo1 {{candidate function}}
+// expected-note@#case3_foo2 {{candidate function}}
+}