diff --git a/terraform/module_dependencies.go b/terraform/module_dependencies.go
index cf9a4228f..bc8e7dca7 100644
--- a/terraform/module_dependencies.go
+++ b/terraform/module_dependencies.go
@@ -34,7 +34,8 @@ func configTreeConfigDependencies(root *configs.Config, inheritProviders map[str
 		// This isn't necessarily correct if we're called with a nil that
 		// *isn't* at the root, but in practice that can never happen.
 		return &moduledeps.Module{
-			Name: "root",
+			Name:      "root",
+			Providers: make(moduledeps.Providers),
 		}
 	}
 
@@ -109,7 +110,7 @@ func configTreeConfigDependencies(root *configs.Config, inheritProviders map[str
 			}
 
 			reason := moduledeps.ProviderDependencyImplicit
-			if _, inherited := inheritProviders[addr.String()]; inherited {
+			if _, inherited := inheritProviders[addr.StringCompact()]; inherited {
 				reason = moduledeps.ProviderDependencyInherited
 			}
 
diff --git a/terraform/module_dependencies_test.go b/terraform/module_dependencies_test.go
index 4c87a4c9a..8a1af1417 100644
--- a/terraform/module_dependencies_test.go
+++ b/terraform/module_dependencies_test.go
@@ -3,7 +3,7 @@ package terraform
 import (
 	"testing"
 
-	"github.com/davecgh/go-spew/spew"
+	"github.com/go-test/deep"
 	"github.com/hashicorp/terraform/configs"
 	"github.com/hashicorp/terraform/moduledeps"
 	"github.com/hashicorp/terraform/plugin/discovery"
@@ -249,12 +249,8 @@ func TestModuleTreeDependencies(t *testing.T) {
 			}
 
 			got := ConfigTreeDependencies(root, test.State)
-			if !got.Equal(test.Want) {
-				t.Errorf(
-					"wrong dependency tree\ngot:  %s\nwant: %s",
-					spew.Sdump(got),
-					spew.Sdump(test.Want),
-				)
+			for _, problem := range deep.Equal(got, test.Want) {
+				t.Error(problem)
 			}
 		})
 	}