4 files changed, 103 insertions, 13 deletions
diff --git a/clang/test/Modules/Inputs/module.map b/clang/test/Modules/Inputs/module.map
index d6effcf0ad0..061abbd24d5 100644
--- a/clang/test/Modules/Inputs/module.map
+++ b/clang/test/Modules/Inputs/module.map
@@ -69,6 +69,8 @@ module redeclarations_left { header "redeclarations_left.h" }
 module redeclarations_right { header "redeclarations_right.h" }
 module redecl_namespaces_left { header "redecl_namespaces_left.h" }
 module redecl_namespaces_right { header "redecl_namespaces_right.h" }
+module redecl_add_after_load_top { header "redecl-add-after-load-top.h" }
+module redecl_add_after_load { header "redecl-add-after-load.h" }
 module load_failure { header "load_failure.h" }
 
 module decldef {
diff --git a/clang/test/Modules/Inputs/redecl-add-after-load.h b/clang/test/Modules/Inputs/redecl-add-after-load.h
new file mode 100644
index 00000000000..6951a76289f
--- /dev/null
+++ b/clang/test/Modules/Inputs/redecl-add-after-load.h
@@ -0,0 +1,23 @@
+struct A {};
+extern const int variable = 0;
+extern constexpr int function() { return 0; }
+
+namespace N {
+  struct A {};
+  extern const int variable = 0;
+  extern constexpr int function() { return 0; }
+}
+
+@import redecl_add_after_load_top;
+struct C::A {};
+const int C::variable = 0;
+constexpr int C::function() { return 0; }
+
+struct D {
+  struct A;
+  static const int variable;
+  static constexpr int function();
+};
+struct D::A {};
+const int D::variable = 0;
+constexpr int D::function() { return 0; }
diff --git a/clang/test/Modules/decldef.mm b/clang/test/Modules/decldef.mm
index 35694935dfb..2e2bd8a75e2 100644
--- a/clang/test/Modules/decldef.mm
+++ b/clang/test/Modules/decldef.mm
@@ -1,14 +1,18 @@
 // RUN: rm -rf %t
-// RUN: %clang_cc1 -fmodules -fobjc-arc -I %S/Inputs -fmodules-cache-path=%t %s -verify -DUSE_EARLY
-// RUN: %clang_cc1 -fmodules -fobjc-arc -I %S/Inputs -fmodules-cache-path=%t %s -verify
+// RUN: %clang_cc1 -fmodules -fobjc-arc -I %S/Inputs -fmodules-cache-path=%t %s -verify -DUSE_1 -DUSE_2 -DUSE_3 -DUSE_4
+// RUN: %clang_cc1 -fmodules -fobjc-arc -I %S/Inputs -fmodules-cache-path=%t %s -verify -DUSE_2 -DUSE_3 -DUSE_4
+// RUN: %clang_cc1 -fmodules -fobjc-arc -I %S/Inputs -fmodules-cache-path=%t %s -verify -DUSE_3 -DUSE_4
+// RUN: %clang_cc1 -fmodules -fobjc-arc -I %S/Inputs -fmodules-cache-path=%t %s -verify -DUSE_4
 
-// expected-note@Inputs/def.h:5 {{previous}}
+// expected-note@Inputs/def.h:5 0-1{{previous}}
+// expected-note@Inputs/def.h:16 0-1{{previous}}
+// expected-note@Inputs/def-include.h:11 0-1{{previous}}
 
 @class Def;
 Def *def;
-class Def2; // expected-note {{forward decl}}
+class Def2; // expected-note 0-1{{forward decl}}
 Def2 *def2;
-namespace Def3NS { class Def3; } // expected-note {{forward decl}}
+namespace Def3NS { class Def3; } // expected-note 0-1{{forward decl}}
 Def3NS::Def3 *def3;
 
 @interface Unrelated
@@ -16,9 +20,10 @@ Def3NS::Def3 *def3;
 @end
 
 @import decldef;
-#ifdef USE_EARLY
+#ifdef USE_1
 A *a1; // expected-error{{declaration of 'A' must be imported from module 'decldef.Def'}}
 B *b1;
+#define USED
 #endif
 @import decldef.Decl;
 
@@ -26,14 +31,23 @@ A *a2;
 B *b;
 
 void testA(A *a) {
+#ifdef USE_2
   a->ivar = 17;
-#ifndef USE_EARLY
+  #ifndef USED
   // expected-error@-2{{definition of 'A' must be imported from module 'decldef.Def' before it is required}}
+  #define USED
+  #endif
 #endif
 }
 
 void testB() {
-  B b; // Note: redundant error silenced
+#ifdef USE_3
+  B b;
+  #ifndef USED
+  // expected-error@-2{{definition of 'B' must be imported from module 'decldef.Def' before it is required}}
+  #define USED
+  #endif
+#endif
 }
 
 void testDef() {
@@ -41,9 +55,12 @@ void testDef() {
 }
 
 void testDef2() {
-  // FIXME: These should both work, since we've (implicitly) imported
-  // decldef.Def here, but they don't, because nothing has triggered the lazy
-  // loading of the definitions of these classes.
-  def2->func(); // expected-error {{incomplete}}
-  def3->func(); // expected-error {{incomplete}}
+#ifdef USE_4
+  def2->func();
+  def3->func();
+  #ifndef USED
+  // expected-error@-3 {{definition of 'Def2' must be imported}}
+  #define USED
+  #endif
+#endif
 }
diff --git a/clang/test/Modules/redecl-add-after-load.cpp b/clang/test/Modules/redecl-add-after-load.cpp
new file mode 100644
index 00000000000..4ee63b5d815
--- /dev/null
+++ b/clang/test/Modules/redecl-add-after-load.cpp
@@ -0,0 +1,48 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -x objective-c++ -fmodules -fno-modules-error-recovery -fmodules-cache-path=%t -I %S/Inputs %s -verify -std=c++11
+
+typedef struct A B;
+extern const int variable;
+extern constexpr int function();
+constexpr int test(bool b) { return b ? variable : function(); }
+
+namespace N {
+  typedef struct A B;
+  extern const int variable;
+  extern constexpr int function();
+}
+typedef N::B NB;
+constexpr int N_test(bool b) { return b ? N::variable : N::function(); }
+
+@import redecl_add_after_load_top;
+typedef C::A CB;
+constexpr int C_test(bool b) { return b ? C::variable : C::function(); }
+
+struct D {
+  struct A; // expected-note {{forward}}
+  static const int variable;
+  static constexpr int function(); // expected-note {{here}}
+};
+typedef D::A DB;
+constexpr int D_test(bool b) { return b ? D::variable : D::function(); } // expected-note {{subexpression}} expected-note {{undefined}}
+
+@import redecl_add_after_load;
+
+B tu_struct_test;
+constexpr int tu_variable_test = test(true);
+constexpr int tu_function_test = test(false);
+
+NB ns_struct_test;
+constexpr int ns_variable_test = N_test(true);
+constexpr int ns_function_test = N_test(false);
+
+CB struct_struct_test;
+constexpr int struct_variable_test = C_test(true);
+constexpr int struct_function_test = C_test(false);
+
+// FIXME: We should accept this, but we're currently too lazy when merging class
+// definitions to determine that the definitions in redecl_add_after_load are
+// definitions of these entities.
+DB merged_struct_struct_test; // expected-error {{incomplete}}
+constexpr int merged_struct_variable_test = D_test(true); // expected-error {{constant}} expected-note {{in call to}}
+constexpr int merged_struct_function_test = D_test(false); // expected-error {{constant}} expected-note {{in call to}}