diff --git a/clang/include/clang/Frontend/CompilerInstance.h b/clang/include/clang/Frontend/CompilerInstance.h
--- a/clang/include/clang/Frontend/CompilerInstance.h
+++ b/clang/include/clang/Frontend/CompilerInstance.h
@@ -786,10 +786,11 @@
   /// ModuleMap.  First attempt to load it from the given path on disk.  If that
   /// fails, defer to compileModuleAndReadAST, which will first build and then
   /// load it.
-  ModuleLoadResult findOrCompileModuleAndReadAST(StringRef ModuleName,
-                                                 SourceLocation ImportLoc,
-                                                 SourceLocation ModuleNameLoc,
-                                                 bool IsInclusionDirective);
+  ModuleLoadResult
+  findOrCompileModuleAndReadAST(StringRef ModuleName, SourceLocation ImportLoc,
+                                SourceLocation ModuleNameLoc, ModuleIdPath Path,
+                                Module::NameVisibilityKind Visibility,
+                                bool IsInclusionDirective);
 
   // Get the submodule corresponding to the module path.
   Module *getSubmoduleCorrespondingToPath(
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -1772,9 +1772,24 @@
   return MS_ModuleNotFound;
 }
 
+static ModuleLoadResult handleMissingSubmodule(DiagnosticsEngine &Diags,
+                                               Module *SubM,
+                                               SourceLocation ImportLoc,
+                                               ModuleIdPath Path) {
+  // We have an umbrella header or directory that doesn't actually include all
+  // the headers within the directory it covers. Complain about this missing
+  // submodule and recover by forgetting that we ever saw this submodule.
+  Diags.Report(ImportLoc, diag::warn_missing_submodule)
+      << SubM->getFullModuleName()
+      << SourceRange(Path.front().second, Path.back().second);
+
+  return ModuleLoadResult::MissingExpected;
+}
+
 ModuleLoadResult CompilerInstance::findOrCompileModuleAndReadAST(
     StringRef ModuleName, SourceLocation ImportLoc,
-    SourceLocation ModuleNameLoc, bool IsInclusionDirective) {
+    SourceLocation ModuleNameLoc, ModuleIdPath Path,
+    Module::NameVisibilityKind Visibility, bool IsInclusionDirective) {
   // Search for a module with the given name.
   HeaderSearch &HS = PP->getHeaderSearchInfo();
   Module *M =
@@ -1797,6 +1812,16 @@
       return ModuleLoadResult::ConfigMismatch;
     }
 
+    bool MapPrivateSubModToTopLevel = false;
+    // FIXME: Should we detect this at module load time? It seems fairly
+    // expensive (and rare).
+    Module *SubM = getSubmoduleCorrespondingToPath(
+        MapPrivateSubModToTopLevel, M, ImportLoc, Path, Visibility,
+        IsInclusionDirective);
+
+    if (SubM != M && !SubM->IsFromModuleFile && !MapPrivateSubModToTopLevel)
+      return handleMissingSubmodule(getDiagnostics(), SubM, ImportLoc, Path);
+
     getDiagnostics().Report(ModuleNameLoc, diag::err_module_build_disabled)
         << ModuleName;
     return nullptr;
@@ -2061,8 +2086,9 @@
     //}
     MM.cacheModuleLoad(*Path[0].first, Module);
   } else {
-    ModuleLoadResult Result = findOrCompileModuleAndReadAST(
-        ModuleName, ImportLoc, ModuleNameLoc, IsInclusionDirective);
+    ModuleLoadResult Result =
+        findOrCompileModuleAndReadAST(ModuleName, ImportLoc, ModuleNameLoc,
+                                      Path, Visibility, IsInclusionDirective);
     if (!Result.isNormal())
       return Result;
     if (!Result)
@@ -2077,6 +2103,9 @@
     return ModuleLoadResult();
 
   bool MapPrivateSubModToTopLevel = false;
+  class Module *TopLevelModule = Module;
+  // FIXME: Should we detect this at module load time? It seems fairly
+  // expensive (and rare).
   Module = getSubmoduleCorrespondingToPath(MapPrivateSubModToTopLevel, Module,
                                            ImportLoc, Path, Visibility,
                                            IsInclusionDirective);
@@ -2084,19 +2113,9 @@
   // Make the named module visible, if it's not already part of the module
   // we are parsing.
   if (ModuleName != getLangOpts().CurrentModule) {
-    if (!Module->IsFromModuleFile && !MapPrivateSubModToTopLevel) {
-      // We have an umbrella header or directory that doesn't actually include
-      // all of the headers within the directory it covers. Complain about
-      // this missing submodule and recover by forgetting that we ever saw
-      // this submodule.
-      // FIXME: Should we detect this at module load time? It seems fairly
-      // expensive (and rare).
-      getDiagnostics().Report(ImportLoc, diag::warn_missing_submodule)
-        << Module->getFullModuleName()
-        << SourceRange(Path.front().second, Path.back().second);
-
-      return ModuleLoadResult::MissingExpected;
-    }
+    if (Module != TopLevelModule && !Module->IsFromModuleFile &&
+        !MapPrivateSubModToTopLevel)
+      return handleMissingSubmodule(getDiagnostics(), Module, ImportLoc, Path);
 
     // Check whether this module is available.
     if (Preprocessor::checkModuleIsAvailable(getLangOpts(), getTarget(),
diff --git a/clang/test/Modules/missing-submodule.m b/clang/test/Modules/missing-submodule.m
--- a/clang/test/Modules/missing-submodule.m
+++ b/clang/test/Modules/missing-submodule.m
@@ -1,5 +1,6 @@
 // RUN: rm -rf %t
 // RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -F %S/Inputs %s -verify
+// RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fno-implicit-modules   -F %S/Inputs %s -verify
 #include <Module/NotInModule.h> // expected-warning{{missing submodule 'Module.NotInModule'}}
 
 int getNotInModule() {