3 files changed, 141 insertions, 14 deletions
diff --git a/clang/test/CXX/basic/basic.link/p7.cpp b/clang/test/CXX/basic/basic.link/p7.cpp
new file mode 100644
index 00000000000..9a85eacdda4
--- /dev/null
+++ b/clang/test/CXX/basic/basic.link/p7.cpp
@@ -0,0 +1,73 @@
+// RUN: %clang_cc1 -verify -std=c++1y %s
+
+// Example from the standard.
+namespace X {
+  void p() {
+    q(); // expected-error {{undeclared}}
+    extern void q();
+  }
+  void middle() {
+    q(); // expected-error {{undeclared}}
+  }
+  void q() { /*...*/ }
+  void bottom() {
+    q();
+  }
+}
+int q();
+
+namespace Test1 {
+  void f() {
+    extern int a; // expected-note {{previous}}
+    int g(void); // expected-note {{previous}}
+  }
+  double a; // expected-error {{different type: 'double' vs 'int'}}
+  double g(); // expected-error {{differ only in their return type}}
+}
+
+namespace Test2 {
+  void f() {
+    extern int a; // expected-note {{previous}}
+    int g(void); // expected-note {{previous}}
+  }
+  void h() {
+    extern double a; // expected-error {{different type: 'double' vs 'int'}}
+    double g(void); // expected-error {{differ only in their return type}}
+  }
+}
+
+namespace Test3 {
+  constexpr void (*f())() {
+    void h();
+    return &h;
+  }
+  constexpr void (*g())() {
+    void h();
+    return &h;
+  }
+  static_assert(f() == g(), "");
+}
+
+namespace Test4 {
+  template<typename T>
+  constexpr void (*f())() {
+    void h();
+    return &h;
+  }
+  static_assert(f<int>() == f<char>(), "");
+  void h();
+  static_assert(f<int>() == &h, "");
+}
+
+namespace Test5 {
+  constexpr auto f() -> void (*)() {
+    void g();
+    struct X {
+      friend void g();
+      static constexpr auto h() -> void (*)() { return g; }
+    };
+    return X::h();
+  }
+  void g();
+  static_assert(f() == g, "");
+}
diff --git a/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p3.cpp b/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p3.cpp
index 2dbc143065e..e040d5b2642 100644
--- a/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p3.cpp
+++ b/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p3.cpp
@@ -61,6 +61,8 @@ namespace test6 {
       int x = sizeof(array); // expected-error {{invalid application of 'sizeof' to an incomplete type 'int []'}}
     }
     int y = sizeof(array);
+    extern int array[];
+    int z = sizeof(array);
   }
 }
 
@@ -71,6 +73,19 @@ namespace test7 {
     int x = sizeof(array); // expected-error {{invalid application of 'sizeof' to an incomplete type 'int []'}}
   }
   int y = sizeof(array);
+  extern int array[];
+  int z = sizeof(array);
+}
+
+namespace test8 {
+  extern int array[];
+  void test() {
+    extern int array[100];
+    int x = sizeof(array);
+  }
+  int y = sizeof(array); // expected-error {{invalid application of 'sizeof' to an incomplete type 'int []'}}
+  extern int array[];
+  int z = sizeof(array); // expected-error {{invalid application of 'sizeof' to an incomplete type 'int []'}}
 }
 
 namespace dependent {
@@ -143,10 +158,52 @@ namespace dependent {
   }
 
   template<typename T> void n() {
-    extern T n_var;
+    extern T n_var; // expected-error {{redefinition of 'n_var' with a different type: 'double' vs 'int'}} expected-note {{previous}}
+    extern T n_fn(); // expected-error {{functions that differ only in their return type cannot be overloaded}} expected-note {{previous}}
   }
   template void n<int>();
-  // FIXME: Diagnose this!
-  float n_var;
-  template void n<double>();
+  template void n<double>(); // expected-note {{in instantiation of}}
+
+  template<typename T> void o() {
+    extern T o_var; // expected-note {{previous}}
+    extern T o_fn(); // expected-note {{previous}}
+  }
+  template void o<int>();
+  float o_var; // expected-error {{redefinition of 'o_var' with a different type: 'float' vs 'int'}}
+  float o_fn(); // expected-error {{functions that differ only in their return type cannot be overloaded}}
+
+  int p_var;
+  int p_fn();
+  template<typename T> void p() {
+    extern T p_var;
+    extern T p_fn();
+  }
+}
+
+namespace use_outside_ns {
+  namespace A {
+    extern int a[3];
+    extern int b[];
+    extern int c[3];
+    void f() {
+      extern int a[];
+      extern int b[3];
+    }
+    template<typename T> void x() {
+      extern T c;
+      extern T d;
+    }
+    extern int d[3];
+    template void x<int[]>();
+  }
+  int w = sizeof(A::a);
+  int x = sizeof(A::b); // expected-error {{incomplete}}
+  int y = sizeof(A::c);
+  int z = sizeof(A::d);
+  namespace A {
+    int g() { return sizeof(a); }
+    int h() { return sizeof(b); } // expected-error {{incomplete}}
+    int i() { return sizeof(c); }
+    int j() { return sizeof(d); }
+  }
 }
diff --git a/clang/test/CXX/drs/dr0xx.cpp b/clang/test/CXX/drs/dr0xx.cpp
index f8ac57f13fd..70a9e491942 100644
--- a/clang/test/CXX/drs/dr0xx.cpp
+++ b/clang/test/CXX/drs/dr0xx.cpp
@@ -280,7 +280,7 @@ namespace dr27 { // dr27: yes
 
 // dr28: na
 
-namespace dr29 { // dr29: no
+namespace dr29 { // dr29: 3.4
   void dr29_f0(); // expected-note {{here}}
   void g0() { void dr29_f0(); }
   extern "C++" void g0_cxx() { void dr29_f0(); }
@@ -291,17 +291,14 @@ namespace dr29 { // dr29: no
   extern "C" void g1_c() { void dr29_f1(); }
   extern "C++" void g1_cxx() { void dr29_f1(); } // expected-error {{different language linkage}}
 
-  // FIXME: We should reject this.
-  void g2() { void dr29_f2(); }
-  extern "C" void dr29_f2();
+  void g2() { void dr29_f2(); } // expected-note {{here}}
+  extern "C" void dr29_f2(); // expected-error {{different language linkage}}
 
-  // FIXME: We should reject this.
-  extern "C" void g3() { void dr29_f3(); }
-  extern "C++" void dr29_f3();
+  extern "C" void g3() { void dr29_f3(); } // expected-note {{here}}
+  extern "C++" void dr29_f3(); // expected-error {{different language linkage}}
 
-  // FIXME: We should reject this.
-  extern "C++" void g4() { void dr29_f4(); }
-  extern "C" void dr29_f4();
+  extern "C++" void g4() { void dr29_f4(); } // expected-note {{here}}
+  extern "C" void dr29_f4(); // expected-error {{different language linkage}}
 
   extern "C" void g5();
   extern "C++" void dr29_f5();