diff --git a/android/apex.go b/android/apex.go
index 5118a0a..44387cd 100644
--- a/android/apex.go
+++ b/android/apex.go
@@ -17,8 +17,6 @@
 import (
 	"sort"
 	"sync"
-
-	"github.com/google/blueprint"
 )
 
 // ApexModule is the interface that a module type is expected to implement if
@@ -69,7 +67,7 @@
 
 	// Mutate this module into one or more variants each of which is built
 	// for an APEX marked via BuildForApex().
-	CreateApexVariations(mctx BottomUpMutatorContext) []blueprint.Module
+	CreateApexVariations(mctx BottomUpMutatorContext) []Module
 
 	// Sets the name of the apex variant of this module. Called inside
 	// CreateApexVariations.
@@ -176,7 +174,7 @@
 	}
 }
 
-func (m *ApexModuleBase) CreateApexVariations(mctx BottomUpMutatorContext) []blueprint.Module {
+func (m *ApexModuleBase) CreateApexVariations(mctx BottomUpMutatorContext) []Module {
 	if len(m.apexVariations) > 0 {
 		m.checkApexAvailableProperty(mctx)
 		sort.Strings(m.apexVariations)
diff --git a/android/mutator.go b/android/mutator.go
index df68726..0d253eb 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -143,8 +143,8 @@
 
 	AddDependency(module blueprint.Module, tag blueprint.DependencyTag, name ...string)
 	AddReverseDependency(module blueprint.Module, tag blueprint.DependencyTag, name string)
-	CreateVariations(...string) []blueprint.Module
-	CreateLocalVariations(...string) []blueprint.Module
+	CreateVariations(...string) []Module
+	CreateLocalVariations(...string) []Module
 	SetDependencyVariation(string)
 	SetDefaultDependencyVariation(*string)
 	AddVariationDependencies([]blueprint.Variation, blueprint.DependencyTag, ...string)
@@ -285,28 +285,32 @@
 	b.bp.AddReverseDependency(module, tag, name)
 }
 
-func (b *bottomUpMutatorContext) CreateVariations(variations ...string) []blueprint.Module {
+func (b *bottomUpMutatorContext) CreateVariations(variations ...string) []Module {
 	modules := b.bp.CreateVariations(variations...)
 
+	aModules := make([]Module, len(modules))
 	for i := range variations {
-		base := modules[i].(Module).base()
+		aModules[i] = modules[i].(Module)
+		base := aModules[i].base()
 		base.commonProperties.DebugMutators = append(base.commonProperties.DebugMutators, b.MutatorName())
 		base.commonProperties.DebugVariations = append(base.commonProperties.DebugVariations, variations[i])
 	}
 
-	return modules
+	return aModules
 }
 
-func (b *bottomUpMutatorContext) CreateLocalVariations(variations ...string) []blueprint.Module {
+func (b *bottomUpMutatorContext) CreateLocalVariations(variations ...string) []Module {
 	modules := b.bp.CreateLocalVariations(variations...)
 
+	aModules := make([]Module, len(modules))
 	for i := range variations {
-		base := modules[i].(Module).base()
+		aModules[i] = modules[i].(Module)
+		base := aModules[i].base()
 		base.commonProperties.DebugMutators = append(base.commonProperties.DebugMutators, b.MutatorName())
 		base.commonProperties.DebugVariations = append(base.commonProperties.DebugVariations, variations[i])
 	}
 
-	return modules
+	return aModules
 }
 
 func (b *bottomUpMutatorContext) SetDependencyVariation(variation string) {