[cas] Definitions from unimported submodules should not be visible

In 66228ed a merge conflict was incorrectly resolved leading to
modules built with caching to expose definitions that come from
unimported submodules to codegen. This would then cause linking errors
if multiple TUs imported any part of that module.

rdar://131028078

Author: benlangmuir

clang/lib/Serialization/ASTReaderDecl.cpp

@@ -3205,7 +3205,7 @@ bool ASTReader::isConsumerInterestedIn(Decl *D) {
   // emitted when we import the relevant module.
   if (isPartOfPerModuleInitializer(D)) {
     auto *M = D->getImportedOwningModule();
-    if (M && M->Kind == Module::ModuleMapModule &&
+    if (M && M->isModuleMapModule() &&
         getContext().DeclMustBeEmitted(D))
       return false;
   }

clang/test/CAS/modules-include-tree-unimported-impl.c

@@ -0,0 +1,50 @@
+// Check that a definition for a symbol in an unimported submodule is not
+// visible for codegen.
+
+// REQUIRES: ondisk_cas
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: sed "s|DIR|%/t|g" %t/cdb.json.template > %t/cdb.json
+
+// RUN: clang-scan-deps -compilation-database %t/cdb.json -j 1 \
+// RUN:   -cas-path %t/cas -module-files-dir %t/outputs \
+// RUN:   -format experimental-include-tree-full -mode preprocess-dependency-directives \
+// RUN:   > %t/deps.json
+
+// RUN: %deps-to-rsp %t/deps.json --module Mod > %t/Mod.rsp
+// RUN: %deps-to-rsp %t/deps.json --tu-index 0 > %t/tu.rsp
+// RUN: %clang @%t/Mod.rsp
+// RUN: %clang @%t/tu.rsp -o - | FileCheck %s
+
+// CHECK-NOT: @record = global
+// CHECK: @record = external global
+
+//--- cdb.json.template
+[{
+  "file": "DIR/tu.c",
+  "directory": "DIR",
+  "command": "clang -S -emit-llvm DIR/tu.c -fmodules -fimplicit-modules -fimplicit-module-maps -fmodules-cache-path=DIR/module-cache"
+}]
+
+//--- module.modulemap
+module Mod {
+  module A {
+    header "A.h"
+  }
+  explicit module B {
+    header "B.h"
+  }
+}
+
+//--- A.h
+extern int record;
+
+//--- B.h
+int record = 7;
+
+//--- tu.c
+#include "A.h"
+int tu(void) {
+  return record;
+}