[Serialization] Use the new logic for transitive dependencies in the scanner

Author: xymus

lib/Serialization/SerializedModuleLoader.cpp

@@ -420,14 +420,18 @@ llvm::ErrorOr<ModuleDependencyInfo> SerializedModuleLoaderBase::scanModuleFile(
     if (dependency.isHeader())
       continue;
 
-    // Transitive @_implementationOnly dependencies of
-    // binary modules are not required to be imported during normal builds
-    // TODO: This is worth revisiting for debugger purposes
-    if (dependency.isImplementationOnly())
-      continue;
-
-    if (dependency.isPackageOnly() &&
-        Ctx.LangOpts.PackageName != loadedModuleFile->getModulePackageName())
+    // Some transitive dependencies of binary modules are not required to be
+    // imported during normal builds.
+    // TODO: This is worth revisiting for debugger purposes where
+    //       loading the module is optional, and implementation-only imports
+    //       from modules with testing enabled where the dependency is
+    //       optional.
+    ModuleLoadingBehavior transitiveBehavior =
+      loadedModuleFile->getTransitiveLoadingBehavior(dependency,
+                                         /*debuggerMode*/false,
+                                         /*isPartialModule*/false,
+                                         /*package*/Ctx.LangOpts.PackageName);
+    if (transitiveBehavior != ModuleLoadingBehavior::Required)
       continue;
 
     // Find the top-level module name.