[Concepts] Class template associated constraints

Summary:
This adds associated constraints as a property of class templates.
An error is produced if redeclarations are not similarly constrained.

Reviewers: rsmith, faisalv, aaron.ballman

Reviewed By: rsmith

Subscribers: cfe-commits, nwilson

Differential Revision: https://reviews.llvm.org/D25674

llvm-svn: 294697

1 files changed, 65 insertions, 0 deletions

diff --git a/clang/test/CXX/concepts-ts/temp/temp.constr/temp.constr.decl/class-template-decl.cpp b/clang/test/CXX/concepts-ts/temp/temp.constr/temp.constr.decl/class-template-decl.cpp
new file mode 100644
index 00000000000..d1ad0404ef4
--- /dev/null
+++ b/clang/test/CXX/concepts-ts/temp/temp.constr/temp.constr.decl/class-template-decl.cpp
@@ -0,0 +1,65 @@
+// RUN: %clang_cc1 -std=c++14 -fconcepts-ts -x c++ -verify %s
+
+namespace nodiag {
+
+template <typename T> requires bool(T())
+struct A;
+template <typename U> requires bool(U())
+struct A;
+
+} // end namespace nodiag
+
+namespace diag {
+
+template <typename T> requires true // expected-note{{previous template declaration is here}}
+struct A;
+template <typename T> struct A; // expected-error{{associated constraints differ in template redeclaration}}
+
+template <typename T> struct B; // expected-note{{previous template declaration is here}}
+template <typename T> requires true // expected-error{{associated constraints differ in template redeclaration}}
+struct B;
+
+template <typename T> requires true // expected-note{{previous template declaration is here}}
+struct C;
+template <typename T> requires !0 // expected-error{{associated constraints differ in template redeclaration}}
+struct C;
+
+} // end namespace diag
+
+namespace nodiag {
+
+struct AA {
+  template <typename T> requires someFunc(T())
+  struct A;
+};
+
+template <typename T> requires someFunc(T())
+struct AA::A { };
+
+struct AAF {
+  template <typename T> requires someFunc(T())
+  friend struct AA::A;
+};
+
+} // end namespace nodiag
+
+namespace diag {
+
+template <unsigned N>
+struct TA {
+  template <template <unsigned> class TT> requires TT<N>::happy // expected-note 2{{previous template declaration is here}}
+  struct A;
+
+  struct AF;
+};
+
+template <unsigned N>
+template <template <unsigned> class TT> struct TA<N>::A { }; // expected-error{{associated constraints differ in template redeclaration}}
+
+template <unsigned N>
+struct TA<N>::AF {
+  template <template <unsigned> class TT> requires TT<N + 0>::happy // expected-error{{associated constraints differ in template redeclaration}}
+  friend struct TA::A;
+};
+
+} // end namespace diag