8 files changed, 40 insertions, 15 deletions
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 47ac4076757..efb7793ef61 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -3436,20 +3436,6 @@ Decl *ASTReader::ReadDeclRecord(DeclID ID) {
 }
 
 void ASTReader::loadDeclUpdateRecords(serialization::DeclID ID, Decl *D) {
-  // Load the pending visible updates for this decl context, if it has any.
-  auto I = PendingVisibleUpdates.find(ID);
-  if (I != PendingVisibleUpdates.end()) {
-    auto VisibleUpdates = std::move(I->second);
-    PendingVisibleUpdates.erase(I);
-
-    auto *DC = cast<DeclContext>(D)->getPrimaryContext();
-    for (const PendingVisibleUpdate &Update : VisibleUpdates)
-      Lookups[DC].Table.add(
-          Update.Mod, Update.Data,
-          reader::ASTDeclContextNameLookupTrait(*this, *Update.Mod));
-    DC->setHasExternalVisibleStorage(true);
-  }
-
   // The declaration may have been modified by files later in the chain.
   // If this is the case, read the record containing the updates from each file
   // and pass it to ASTDeclReader to make the modifications.
@@ -3485,6 +3471,20 @@ void ASTReader::loadDeclUpdateRecords(serialization::DeclID ID, Decl *D) {
       }
     }
   }
+
+  // Load the pending visible updates for this decl context, if it has any.
+  auto I = PendingVisibleUpdates.find(ID);
+  if (I != PendingVisibleUpdates.end()) {
+    auto VisibleUpdates = std::move(I->second);
+    PendingVisibleUpdates.erase(I);
+
+    auto *DC = cast<DeclContext>(D)->getPrimaryContext();
+    for (const PendingVisibleUpdate &Update : VisibleUpdates)
+      Lookups[DC].Table.add(
+          Update.Mod, Update.Data,
+          reader::ASTDeclContextNameLookupTrait(*this, *Update.Mod));
+    DC->setHasExternalVisibleStorage(true);
+  }
 }
 
 void ASTReader::loadPendingDeclChain(Decl *FirstLocal, uint64_t LocalOffset) {
@@ -3757,7 +3757,7 @@ void ASTDeclReader::UpdateDecl(Decl *D, ModuleFile &ModuleFile,
 
     case UPD_CXX_INSTANTIATED_CLASS_DEFINITION: {
       auto *RD = cast<CXXRecordDecl>(D);
-      auto *OldDD = RD->DefinitionData.getNotUpdated();
+      auto *OldDD = RD->getCanonicalDecl()->DefinitionData.getNotUpdated();
       bool HadRealDefinition =
           OldDD && (OldDD->Definition != RD ||
                     !Reader.PendingFakeDefinitionData.count(OldDD));
diff --git a/clang/test/Modules/Inputs/PR25501/Vector.h b/clang/test/Modules/Inputs/PR25501/Vector.h
new file mode 100644
index 00000000000..9da48303a3a
--- /dev/null
+++ b/clang/test/Modules/Inputs/PR25501/Vector.h
@@ -0,0 +1,5 @@
+template <typename> struct _Vector_base {};
+struct vector {
+  vector() {}
+  vector(_Vector_base<int>);
+};
diff --git a/clang/test/Modules/Inputs/PR25501/a0.h b/clang/test/Modules/Inputs/PR25501/a0.h
new file mode 100644
index 00000000000..1a0d306ca7c
--- /dev/null
+++ b/clang/test/Modules/Inputs/PR25501/a0.h
@@ -0,0 +1 @@
+#include "Vector.h"
diff --git a/clang/test/Modules/Inputs/PR25501/a1.h b/clang/test/Modules/Inputs/PR25501/a1.h
new file mode 100644
index 00000000000..1a0d306ca7c
--- /dev/null
+++ b/clang/test/Modules/Inputs/PR25501/a1.h
@@ -0,0 +1 @@
+#include "Vector.h"
diff --git a/clang/test/Modules/Inputs/PR25501/a2.h b/clang/test/Modules/Inputs/PR25501/a2.h
new file mode 100644
index 00000000000..7876f310e85
--- /dev/null
+++ b/clang/test/Modules/Inputs/PR25501/a2.h
@@ -0,0 +1,3 @@
+#include "a0.h"
+vector aaa = vector();
+#include "a1.h"
diff --git a/clang/test/Modules/Inputs/PR25501/b.h b/clang/test/Modules/Inputs/PR25501/b.h
new file mode 100644
index 00000000000..7b519836953
--- /dev/null
+++ b/clang/test/Modules/Inputs/PR25501/b.h
@@ -0,0 +1,2 @@
+#include "Vector.h"
+vector aaa = vector();
diff --git a/clang/test/Modules/Inputs/PR25501/module.modulemap b/clang/test/Modules/Inputs/PR25501/module.modulemap
new file mode 100644
index 00000000000..c6c8d5ca40f
--- /dev/null
+++ b/clang/test/Modules/Inputs/PR25501/module.modulemap
@@ -0,0 +1,4 @@
+module "a0" { header "a0.h" export * }
+module "a1" { header "a1.h" export * }
+module "a2" { header "a2.h" export * }
+module "b" { header "b.h" export * }
diff --git a/clang/test/Modules/pr25501.cpp b/clang/test/Modules/pr25501.cpp
new file mode 100644
index 00000000000..18002d6dff3
--- /dev/null
+++ b/clang/test/Modules/pr25501.cpp
@@ -0,0 +1,9 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -std=c++11 -fmodules -fmodule-map-file=%S/Inputs/PR25501/module.modulemap -fmodules-cache-path=%t -I%S/Inputs/PR25501 -verify %s
+
+#include "a2.h"
+#include "b.h"
+
+auto use = aaa;
+
+// expected-no-diagnostics