diff --git a/android/defaults.go b/android/defaults.go
index 6a908ea..81e340e 100644
--- a/android/defaults.go
+++ b/android/defaults.go
@@ -35,6 +35,9 @@
 	defaultsProperties            defaultsProperties
 	defaultableProperties         []interface{}
 	defaultableVariableProperties interface{}
+
+	// The optional hook to call after any defaults have been applied.
+	hook DefaultableHook
 }
 
 func (d *DefaultableModuleBase) defaults() *defaultsProperties {
@@ -46,6 +49,16 @@
 	d.defaultableVariableProperties = variableProperties
 }
 
+func (d *DefaultableModuleBase) SetDefaultableHook(hook DefaultableHook) {
+	d.hook = hook
+}
+
+func (d *DefaultableModuleBase) callHookIfAvailable(ctx DefaultableHookContext) {
+	if d.hook != nil {
+		d.hook(ctx)
+	}
+}
+
 // Interface that must be supported by any module to which defaults can be applied.
 type Defaultable interface {
 	// Get a pointer to the struct containing the Defaults property.
@@ -57,6 +70,15 @@
 	// Apply defaults from the supplied Defaults to the property structures supplied to
 	// setProperties(...).
 	applyDefaults(TopDownMutatorContext, []Defaults)
+
+	// Set the hook to be called after any defaults have been applied.
+	//
+	// Should be used in preference to a AddLoadHook when the behavior of the load
+	// hook is dependent on properties supplied in the Android.bp file.
+	SetDefaultableHook(hook DefaultableHook)
+
+	// Call the hook if specified.
+	callHookIfAvailable(context DefaultableHookContext)
 }
 
 type DefaultableModule interface {
@@ -75,6 +97,15 @@
 	module.AddProperties(module.defaults())
 }
 
+// A restricted subset of context methods, similar to LoadHookContext.
+type DefaultableHookContext interface {
+	EarlyModuleContext
+
+	CreateModule(ModuleFactory, ...interface{}) Module
+}
+
+type DefaultableHook func(ctx DefaultableHookContext)
+
 // The Defaults_visibility property.
 type DefaultsVisibilityProperties struct {
 
@@ -268,25 +299,29 @@
 }
 
 func defaultsMutator(ctx TopDownMutatorContext) {
-	if defaultable, ok := ctx.Module().(Defaultable); ok && len(defaultable.defaults().Defaults) > 0 {
-		var defaultsList []Defaults
-		seen := make(map[Defaults]bool)
+	if defaultable, ok := ctx.Module().(Defaultable); ok {
+		if len(defaultable.defaults().Defaults) > 0 {
+			var defaultsList []Defaults
+			seen := make(map[Defaults]bool)
 
-		ctx.WalkDeps(func(module, parent Module) bool {
-			if ctx.OtherModuleDependencyTag(module) == DefaultsDepTag {
-				if defaults, ok := module.(Defaults); ok {
-					if !seen[defaults] {
-						seen[defaults] = true
-						defaultsList = append(defaultsList, defaults)
-						return len(defaults.defaults().Defaults) > 0
+			ctx.WalkDeps(func(module, parent Module) bool {
+				if ctx.OtherModuleDependencyTag(module) == DefaultsDepTag {
+					if defaults, ok := module.(Defaults); ok {
+						if !seen[defaults] {
+							seen[defaults] = true
+							defaultsList = append(defaultsList, defaults)
+							return len(defaults.defaults().Defaults) > 0
+						}
+					} else {
+						ctx.PropertyErrorf("defaults", "module %s is not an defaults module",
+							ctx.OtherModuleName(module))
 					}
-				} else {
-					ctx.PropertyErrorf("defaults", "module %s is not an defaults module",
-						ctx.OtherModuleName(module))
 				}
-			}
-			return false
-		})
-		defaultable.applyDefaults(ctx, defaultsList)
+				return false
+			})
+			defaultable.applyDefaults(ctx, defaultsList)
+		}
+
+		defaultable.callHookIfAvailable(ctx)
 	}
 }
diff --git a/android/hooks.go b/android/hooks.go
index 47f69d1..f43a007 100644
--- a/android/hooks.go
+++ b/android/hooks.go
@@ -39,6 +39,12 @@
 	moduleFactories() map[string]blueprint.ModuleFactory
 }
 
+// Add a hook that will be called once the module has been loaded, i.e. its
+// properties have been initialized from the Android.bp file.
+//
+// Consider using SetDefaultableHook to register a hook for any module that implements
+// DefaultableModule as the hook is called after any defaults have been applied to the
+// module which could reduce duplication and make it easier to use.
 func AddLoadHook(m blueprint.Module, hook func(LoadHookContext)) {
 	blueprint.AddLoadHook(m, func(ctx blueprint.LoadHookContext) {
 		actx := &loadHookContext{
diff --git a/android/mutator.go b/android/mutator.go
index 247eb4d..77d5f43 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -82,18 +82,6 @@
 var preArch = []RegisterMutatorFunc{
 	RegisterNamespaceMutator,
 
-	// Rename package module types.
-	//
-	// The package module type does not have a name property, instead its name is determined
-	// by the location of the containing .bp file relative to the root of the file structure
-	// being built by Soong. Unfortunately, due to limitations in LoadHook the module has to
-	// be given a synthetic temporary name which is then fixed up by these mutators.
-	RegisterPackageRenamer,
-
-	// Create an association between prebuilt modules and their corresponding source
-	// modules (if any).
-	RegisterPrebuiltsPreArchMutators,
-
 	// Check the visibility rules are valid.
 	//
 	// This must run after the package renamer mutators so that any issues found during
@@ -122,8 +110,19 @@
 	RegisterVisibilityRuleChecker,
 
 	// Apply properties from defaults modules to the referencing modules.
+	//
+	// Any mutators that are added before this will not see any modules created by
+	// a DefaultableHook.
 	RegisterDefaultsPreArchMutators,
 
+	// Create an association between prebuilt modules and their corresponding source
+	// modules (if any).
+	//
+	// Must be run after defaults mutators to ensure that any modules created by
+	// a DefaultableHook can be either a prebuilt or a source module with a matching
+	// prebuilt.
+	RegisterPrebuiltsPreArchMutators,
+
 	// Gather the visibility rules for all modules for us during visibility enforcement.
 	//
 	// This must come after the defaults mutators to ensure that any visibility supplied
diff --git a/android/package.go b/android/package.go
index bb5f4e7..182b3ed 100644
--- a/android/package.go
+++ b/android/package.go
@@ -15,43 +15,20 @@
 package android
 
 import (
-	"fmt"
-	"sync/atomic"
-
 	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
 )
 
 func init() {
 	RegisterPackageBuildComponents(InitRegistrationContext)
 }
 
-// Register the package module type and supporting mutators.
-//
-// This must be called in the correct order (relative to other methods that also
-// register mutators) to match the order of mutator registration in mutator.go.
-// Failing to do so will result in an unrealistic test environment.
+// Register the package module type.
 func RegisterPackageBuildComponents(ctx RegistrationContext) {
 	ctx.RegisterModuleType("package", PackageFactory)
-
-	// Register mutators that are hard coded in to mutator.go.
-	ctx.HardCodedPreArchMutators(RegisterPackageRenamer)
-}
-
-// The information maintained about each package.
-type packageInfo struct {
-	// The module from which this information was populated. If `duplicated` = true then this is the
-	// module that has been renamed and must be used to report errors.
-	module *packageModule
-
-	// If true this indicates that there are two package statements in the same package which is not
-	// allowed and will cause the build to fail. This flag is set by packageRenamer and checked in
-	// packageErrorReporter
-	duplicated bool
 }
 
 type packageProperties struct {
-	Name string `blueprint:"mutated"`
-
 	// Specifies the default visibility for all modules defined in this package.
 	Default_visibility []string
 }
@@ -59,8 +36,7 @@
 type packageModule struct {
 	ModuleBase
 
-	properties  packageProperties
-	packageInfo *packageInfo
+	properties packageProperties
 }
 
 func (p *packageModule) GenerateAndroidBuildActions(ModuleContext) {
@@ -76,126 +52,21 @@
 	return newPackageId(ctx.ModuleDir())
 }
 
-func (p *packageModule) Name() string {
-	return p.properties.Name
-}
-
-func (p *packageModule) setName(name string) {
-	p.properties.Name = name
-}
-
-// Counter to ensure package modules are created with a unique name within whatever namespace they
-// belong.
-var packageCount uint32 = 0
-
 func PackageFactory() Module {
 	module := &packageModule{}
 
-	// Get a unique if for the package. Has to be done atomically as the creation of the modules are
-	// done in parallel.
-	id := atomic.AddUint32(&packageCount, 1)
-	name := fmt.Sprintf("soong_package_%d", id)
-
-	module.properties.Name = name
-
 	module.AddProperties(&module.properties)
 
+	// The name is the relative path from build root to the directory containing this
+	// module. Set that name at the earliest possible moment that information is available
+	// which is in a LoadHook.
+	AddLoadHook(module, func(ctx LoadHookContext) {
+		module.nameProperties.Name = proptools.StringPtr("//" + ctx.ModuleDir())
+	})
+
 	// The default_visibility property needs to be checked and parsed by the visibility module during
 	// its checking and parsing phases so make it the primary visibility property.
 	setPrimaryVisibilityProperty(module, "default_visibility", &module.properties.Default_visibility)
 
 	return module
 }
-
-// Registers the function that renames the packages.
-func RegisterPackageRenamer(ctx RegisterMutatorsContext) {
-	ctx.BottomUp("packageRenamer", packageRenamer).Parallel()
-	ctx.BottomUp("packageErrorReporter", packageErrorReporter).Parallel()
-}
-
-// Renames the package to match the package directory.
-//
-// This also creates a PackageInfo object for each package and uses that to detect and remember
-// duplicates for later error reporting.
-func packageRenamer(ctx BottomUpMutatorContext) {
-	m, ok := ctx.Module().(*packageModule)
-	if !ok {
-		return
-	}
-
-	packageName := "//" + ctx.ModuleDir()
-
-	pi := newPackageInfo(ctx, packageName, m)
-	if pi.module != m {
-		// Remember that the package was duplicated but do not rename as that will cause an error to
-		// be logged with the generated name. Similarly, reporting the error here will use the generated
-		// name as renames are only processed after this phase.
-		pi.duplicated = true
-	} else {
-		// This is the first package module in this package so rename it to match the package name.
-		m.setName(packageName)
-		ctx.Rename(packageName)
-
-		// Store a package info reference in the module.
-		m.packageInfo = pi
-	}
-}
-
-// Logs any deferred errors.
-func packageErrorReporter(ctx BottomUpMutatorContext) {
-	m, ok := ctx.Module().(*packageModule)
-	if !ok {
-		return
-	}
-
-	packageDir := ctx.ModuleDir()
-	packageName := "//" + packageDir
-
-	// Get the PackageInfo for the package. Should have been populated in the packageRenamer phase.
-	pi := findPackageInfo(ctx, packageName)
-	if pi == nil {
-		ctx.ModuleErrorf("internal error, expected package info to be present for package '%s'",
-			packageName)
-		return
-	}
-
-	if pi.module != m {
-		// The package module has been duplicated but this is not the module that has been renamed so
-		// ignore it. An error will be logged for the renamed module which will ensure that the error
-		// message uses the correct name.
-		return
-	}
-
-	// Check to see whether there are duplicate package modules in the package.
-	if pi.duplicated {
-		ctx.ModuleErrorf("package {...} specified multiple times")
-		return
-	}
-}
-
-type defaultPackageInfoKey string
-
-func newPackageInfo(
-	ctx BaseModuleContext, packageName string, module *packageModule) *packageInfo {
-	key := NewCustomOnceKey(defaultPackageInfoKey(packageName))
-
-	return ctx.Config().Once(key, func() interface{} {
-		return &packageInfo{module: module}
-	}).(*packageInfo)
-}
-
-// Get the PackageInfo for the package name (starts with //, no trailing /), is nil if no package
-// module type was specified.
-func findPackageInfo(ctx BaseModuleContext, packageName string) *packageInfo {
-	key := NewCustomOnceKey(defaultPackageInfoKey(packageName))
-
-	pi := ctx.Config().Once(key, func() interface{} {
-		return nil
-	})
-
-	if pi == nil {
-		return nil
-	} else {
-		return pi.(*packageInfo)
-	}
-}
diff --git a/android/package_test.go b/android/package_test.go
index 4710e39..04dfc08 100644
--- a/android/package_test.go
+++ b/android/package_test.go
@@ -20,7 +20,7 @@
 				}`),
 		},
 		expectedErrors: []string{
-			`top/Blueprints:3:10: mutated field name cannot be set in a Blueprint file`,
+			`top/Blueprints:3:10: unrecognized property "name"`,
 			`top/Blueprints:4:16: unrecognized property "visibility"`,
 		},
 	},
@@ -50,7 +50,7 @@
 				}`),
 		},
 		expectedErrors: []string{
-			`module "//top": package {...} specified multiple times`,
+			`module "//top" already defined`,
 		},
 	},
 }
diff --git a/android/visibility_test.go b/android/visibility_test.go
index 8dd6a8f..4cf41a6 100644
--- a/android/visibility_test.go
+++ b/android/visibility_test.go
@@ -903,6 +903,69 @@
 				}`),
 		},
 	},
+	{
+		name: "ensure visibility properties are checked for correctness",
+		fs: map[string][]byte{
+			"top/Blueprints": []byte(`
+				mock_parent {
+					name: "parent",
+					visibility: ["//top/nested"],
+					child: {
+						name: "libchild",
+						visibility: ["top/other"],
+					},
+				}`),
+		},
+		expectedErrors: []string{
+			`module "parent": child.visibility: invalid visibility pattern "top/other"`,
+		},
+	},
+	{
+		name: "invalid visibility added to child detected during gather phase",
+		fs: map[string][]byte{
+			"top/Blueprints": []byte(`
+				mock_parent {
+					name: "parent",
+					visibility: ["//top/nested"],
+					child: {
+						name: "libchild",
+						invalid_visibility: ["top/other"],
+					},
+				}`),
+		},
+		expectedErrors: []string{
+			// That this error is reported against the child not the parent shows it was
+			// not being detected in the parent which is correct as invalid_visibility is
+			// purposely not added to the list of visibility properties to check, and was
+			// in fact detected in the child in the gather phase. Contrast this error message
+			// with the preceding one.
+			`module "libchild" \(created by module "parent"\): visibility: invalid visibility pattern "top/other"`,
+		},
+	},
+	{
+		name: "automatic visibility inheritance enabled",
+		fs: map[string][]byte{
+			"top/Blueprints": []byte(`
+				mock_parent {
+					name: "parent",
+					visibility: ["//top/nested"],
+					child: {
+						name: "libchild",
+						visibility: ["//top/other"],
+					},
+				}`),
+			"top/nested/Blueprints": []byte(`
+				mock_library {
+					name: "libnested",
+					deps: ["libchild"],
+				}`),
+			"top/other/Blueprints": []byte(`
+				mock_library {
+					name: "libother",
+					deps: ["libchild"],
+				}`),
+		},
+	},
 }
 
 func TestVisibility(t *testing.T) {
@@ -936,6 +999,7 @@
 
 	ctx := NewTestArchContext()
 	ctx.RegisterModuleType("mock_library", newMockLibraryModule)
+	ctx.RegisterModuleType("mock_parent", newMockParentFactory)
 	ctx.RegisterModuleType("mock_defaults", defaultsFactory)
 
 	// Order of the following method calls is significant.
@@ -996,3 +1060,42 @@
 	InitDefaultsModule(m)
 	return m
 }
+
+type mockParentProperties struct {
+	Child struct {
+		Name *string
+
+		// Visibility to pass to the child module.
+		Visibility []string
+
+		// Purposely not validated visibility to pass to the child.
+		Invalid_visibility []string
+	}
+}
+
+type mockParent struct {
+	ModuleBase
+	DefaultableModuleBase
+	properties mockParentProperties
+}
+
+func (p *mockParent) GenerateAndroidBuildActions(ModuleContext) {
+}
+
+func newMockParentFactory() Module {
+	m := &mockParent{}
+	m.AddProperties(&m.properties)
+	InitAndroidArchModule(m, HostAndDeviceSupported, MultilibCommon)
+	InitDefaultableModule(m)
+	AddVisibilityProperty(m, "child.visibility", &m.properties.Child.Visibility)
+
+	m.SetDefaultableHook(func(ctx DefaultableHookContext) {
+		visibility := m.properties.Child.Visibility
+		visibility = append(visibility, m.properties.Child.Invalid_visibility...)
+		ctx.CreateModule(newMockLibraryModule, &struct {
+			Name       *string
+			Visibility []string
+		}{m.properties.Child.Name, visibility})
+	})
+	return m
+}
diff --git a/apex/apex.go b/apex/apex.go
index 45ba908..57fc650 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -226,7 +226,6 @@
 		"netd_aidl_interface-unstable-java",
 		"netd_event_listener_interface-java",
 		"netlink-client",
-		"networkstack-aidl-interfaces-unstable-java",
 		"networkstack-client",
 		"sap-api-java-static",
 		"services.net",
@@ -682,7 +681,6 @@
 		"netd_aidl_interface-unstable-java",
 		"netd_event_listener_interface-java",
 		"netlink-client",
-		"networkstack-aidl-interfaces-unstable-java",
 		"networkstack-client",
 		"services.net",
 		"wifi-lite-protos",
diff --git a/apex/apex_test.go b/apex/apex_test.go
index 11a8bd2..a99d2ea 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -4361,12 +4361,12 @@
 	ctx.RegisterModuleType("apex", BundleFactory)
 	ctx.RegisterModuleType("apex_key", ApexKeyFactory)
 	ctx.RegisterModuleType("filegroup", android.FileGroupFactory)
+	ctx.PreArchMutators(android.RegisterDefaultsPreArchMutators)
 	cc.RegisterRequiredBuildComponentsForTest(ctx)
 	java.RegisterJavaBuildComponents(ctx)
 	java.RegisterSystemModulesBuildComponents(ctx)
 	java.RegisterAppBuildComponents(ctx)
 	java.RegisterDexpreoptBootJarsComponents(ctx)
-	ctx.PreArchMutators(android.RegisterDefaultsPreArchMutators)
 	ctx.PostDepsMutators(android.RegisterOverridePostDepsMutators)
 	ctx.PreDepsMutators(RegisterPreDepsMutators)
 	ctx.PostDepsMutators(RegisterPostDepsMutators)
diff --git a/cc/testing.go b/cc/testing.go
index 53f0995..6119920 100644
--- a/cc/testing.go
+++ b/cc/testing.go
@@ -485,8 +485,8 @@
 	ctx.RegisterModuleType("filegroup", android.FileGroupFactory)
 	ctx.RegisterModuleType("vndk_prebuilt_shared", VndkPrebuiltSharedFactory)
 	ctx.RegisterModuleType("vndk_libraries_txt", VndkLibrariesTxtFactory)
-	RegisterRequiredBuildComponentsForTest(ctx)
 	ctx.PreArchMutators(android.RegisterDefaultsPreArchMutators)
+	RegisterRequiredBuildComponentsForTest(ctx)
 	ctx.RegisterSingletonType("vndk-snapshot", VndkSnapshotSingleton)
 	ctx.RegisterSingletonType("vendor-snapshot", VendorSnapshotSingleton)
 
diff --git a/java/sdk_library.go b/java/sdk_library.go
index d9c948f..3a6c5de 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -67,6 +67,9 @@
 	// The name of the api scope, e.g. public, system, test
 	name string
 
+	// The api scope that this scope extends.
+	extends *apiScope
+
 	// The name of the field in the dynamically created structure.
 	fieldName string
 
@@ -134,6 +137,7 @@
 	})
 	apiScopeSystem = initApiScope(&apiScope{
 		name:           "system",
+		extends:        apiScopePublic,
 		apiFilePrefix:  "system-",
 		moduleSuffix:   sdkSystemApiSuffix,
 		sdkVersion:     "system_current",
@@ -141,6 +145,7 @@
 	})
 	apiScopeTest = initApiScope(&apiScope{
 		name:           "test",
+		extends:        apiScopePublic,
 		apiFilePrefix:  "test-",
 		moduleSuffix:   sdkTestApiSuffix,
 		sdkVersion:     "test_current",
diff --git a/sdk/sdk_test.go b/sdk/sdk_test.go
index fde9230..2f125e2 100644
--- a/sdk/sdk_test.go
+++ b/sdk/sdk_test.go
@@ -242,9 +242,13 @@
 	EmbeddedPropertiesStruct
 }
 
+func (p *testPropertiesStruct) optimizableProperties() interface{} {
+	return p
+}
+
 func TestCommonValueOptimization(t *testing.T) {
 	common := &testPropertiesStruct{}
-	structs := []*testPropertiesStruct{
+	structs := []propertiesContainer{
 		&testPropertiesStruct{
 			private:     "common",
 			Public_Kept: "common",
diff --git a/sdk/update.go b/sdk/update.go
index e14347f..ae74b9d 100644
--- a/sdk/update.go
+++ b/sdk/update.go
@@ -301,18 +301,18 @@
 
 	addHostDeviceSupportedProperties(s.ModuleBase.DeviceSupported(), s.ModuleBase.HostSupported(), snapshotModule)
 
-	var dynamicMemberPropertiesList []interface{}
+	var dynamicMemberPropertiesContainers []propertiesContainer
 	osTypeToMemberProperties := make(map[android.OsType]*sdk)
 	for _, sdkVariant := range sdkVariants {
 		properties := sdkVariant.dynamicMemberTypeListProperties
 		osTypeToMemberProperties[sdkVariant.Target().Os] = sdkVariant
-		dynamicMemberPropertiesList = append(dynamicMemberPropertiesList, properties)
+		dynamicMemberPropertiesContainers = append(dynamicMemberPropertiesContainers, &dynamicMemberPropertiesContainer{properties})
 	}
 
 	// Extract the common lists of members into a separate struct.
 	commonDynamicMemberProperties := s.dynamicSdkMemberTypes.createMemberListProperties()
 	extractor := newCommonValueExtractor(commonDynamicMemberProperties)
-	extractor.extractCommonProperties(commonDynamicMemberProperties, dynamicMemberPropertiesList)
+	extractor.extractCommonProperties(commonDynamicMemberProperties, dynamicMemberPropertiesContainers)
 
 	// Add properties common to all os types.
 	s.addMemberPropertiesToPropertySet(builder, snapshotModule, commonDynamicMemberProperties)
@@ -814,6 +814,10 @@
 	Properties android.SdkMemberProperties
 }
 
+func (b *baseInfo) optimizableProperties() interface{} {
+	return b.Properties
+}
+
 type osTypeSpecificInfo struct {
 	baseInfo
 
@@ -889,17 +893,14 @@
 	}
 
 	multilib := multilibNone
-	var archPropertiesList []android.SdkMemberProperties
 	for _, archInfo := range osInfo.archInfos {
 		multilib = multilib.addArchType(archInfo.archType)
 
 		// Optimize the arch properties first.
 		archInfo.optimizeProperties(commonValueExtractor)
-
-		archPropertiesList = append(archPropertiesList, archInfo.Properties)
 	}
 
-	commonValueExtractor.extractCommonProperties(osInfo.Properties, archPropertiesList)
+	commonValueExtractor.extractCommonProperties(osInfo.Properties, osInfo.archInfos)
 
 	// Choose setting for compile_multilib that is appropriate for the arch variants supplied.
 	osInfo.Properties.Base().Compile_multilib = multilib.String()
@@ -1011,6 +1012,10 @@
 	return archInfo
 }
 
+func (archInfo *archTypeSpecificInfo) optimizableProperties() interface{} {
+	return archInfo.Properties
+}
+
 // Get the link type of the variant
 //
 // If the variant is not differentiated by link type then it returns "",
@@ -1038,12 +1043,7 @@
 		return
 	}
 
-	var propertiesList []android.SdkMemberProperties
-	for _, linkInfo := range archInfo.linkInfos {
-		propertiesList = append(propertiesList, linkInfo.Properties)
-	}
-
-	commonValueExtractor.extractCommonProperties(archInfo.Properties, propertiesList)
+	commonValueExtractor.extractCommonProperties(archInfo.Properties, archInfo.linkInfos)
 }
 
 // Add the properties for an arch type to a property set.
@@ -1133,21 +1133,21 @@
 
 	// The list of property structures which are os type specific but common across
 	// architectures within that os type.
-	var osSpecificPropertiesList []android.SdkMemberProperties
+	var osSpecificPropertiesContainers []*osTypeSpecificInfo
 
 	for osType, osTypeVariants := range variantsByOsType {
 		osInfo := newOsTypeSpecificInfo(ctx, osType, variantPropertiesFactory, osTypeVariants)
 		osTypeToInfo[osType] = osInfo
 		// Add the os specific properties to a list of os type specific yet architecture
 		// independent properties structs.
-		osSpecificPropertiesList = append(osSpecificPropertiesList, osInfo.Properties)
+		osSpecificPropertiesContainers = append(osSpecificPropertiesContainers, osInfo)
 
 		// Optimize the properties across all the variants for a specific os type.
 		osInfo.optimizeProperties(commonValueExtractor)
 	}
 
 	// Extract properties which are common across all architectures and os types.
-	commonValueExtractor.extractCommonProperties(commonProperties, osSpecificPropertiesList)
+	commonValueExtractor.extractCommonProperties(commonProperties, osSpecificPropertiesContainers)
 
 	// Add the common properties to the module.
 	commonProperties.AddToPropertySet(ctx, bpModule)
@@ -1186,15 +1186,24 @@
 	return osTypes
 }
 
-// Given a struct value, access a field within that struct (or one of its embedded
-// structs).
+// Given a set of properties (struct value), return the value of the field within that
+// struct (or one of its embedded structs).
 type fieldAccessorFunc func(structValue reflect.Value) reflect.Value
 
+// A property that can be optimized by the commonValueExtractor.
+type extractorProperty struct {
+	// Retrieves the value on which common value optimization will be performed.
+	getter fieldAccessorFunc
+
+	// The empty value for the field.
+	emptyValue reflect.Value
+}
+
 // Supports extracting common values from a number of instances of a properties
 // structure into a separate common set of properties.
 type commonValueExtractor struct {
-	// The getters for every field from which common values can be extracted.
-	fieldGetters []fieldAccessorFunc
+	// The properties that the extractor can optimize.
+	properties []extractorProperty
 }
 
 // Create a new common value extractor for the structure type for the supplied
@@ -1249,7 +1258,11 @@
 			// Gather fields from the embedded structure.
 			e.gatherFields(field.Type, fieldGetter)
 		} else {
-			e.fieldGetters = append(e.fieldGetters, fieldGetter)
+			property := extractorProperty{
+				fieldGetter,
+				reflect.Zero(field.Type),
+			}
+			e.properties = append(e.properties, property)
 		}
 	}
 }
@@ -1270,11 +1283,29 @@
 	return value
 }
 
+// A container of properties to be optimized.
+//
+// Allows additional information to be associated with the properties, e.g. for
+// filtering.
+type propertiesContainer interface {
+	// Get the properties that need optimizing.
+	optimizableProperties() interface{}
+}
+
+// A wrapper for dynamic member properties to allow them to be optimized.
+type dynamicMemberPropertiesContainer struct {
+	dynamicMemberProperties interface{}
+}
+
+func (c dynamicMemberPropertiesContainer) optimizableProperties() interface{} {
+	return c.dynamicMemberProperties
+}
+
 // Extract common properties from a slice of property structures of the same type.
 //
 // All the property structures must be of the same type.
 // commonProperties - must be a pointer to the structure into which common properties will be added.
-// inputPropertiesSlice - must be a slice of input properties structures.
+// inputPropertiesSlice - must be a slice of propertiesContainer interfaces.
 //
 // Iterates over each exported field (capitalized name) and checks to see whether they
 // have the same value (using DeepEquals) across all the input properties. If it does not then no
@@ -1284,15 +1315,19 @@
 	commonPropertiesValue := reflect.ValueOf(commonProperties)
 	commonStructValue := commonPropertiesValue.Elem()
 
-	for _, fieldGetter := range e.fieldGetters {
+	sliceValue := reflect.ValueOf(inputPropertiesSlice)
+
+	for _, property := range e.properties {
+		fieldGetter := property.getter
+
 		// Check to see if all the structures have the same value for the field. The commonValue
 		// is nil on entry to the loop and if it is nil on exit then there is no common value,
 		// otherwise it points to the common value.
 		var commonValue *reflect.Value
-		sliceValue := reflect.ValueOf(inputPropertiesSlice)
 
 		for i := 0; i < sliceValue.Len(); i++ {
-			itemValue := sliceValue.Index(i)
+			container := sliceValue.Index(i).Interface().(propertiesContainer)
+			itemValue := reflect.ValueOf(container.optimizableProperties())
 			fieldValue := fieldGetter(itemValue)
 
 			if commonValue == nil {
@@ -1311,10 +1346,11 @@
 		// If the fields all have a common value then store it in the common struct field
 		// and set the input struct's field to the empty value.
 		if commonValue != nil {
-			emptyValue := reflect.Zero(commonValue.Type())
+			emptyValue := property.emptyValue
 			fieldGetter(commonStructValue).Set(*commonValue)
 			for i := 0; i < sliceValue.Len(); i++ {
-				itemValue := sliceValue.Index(i)
+				container := sliceValue.Index(i).Interface().(propertiesContainer)
+				itemValue := reflect.ValueOf(container.optimizableProperties())
 				fieldValue := fieldGetter(itemValue)
 				fieldValue.Set(emptyValue)
 			}