test passing in implicitly used provider

terraform/test-fixtures/transform-provider-implicit-module/main.tf

@@ -0,0 +1,10 @@
+provider "aws" {
+  alias = "foo"
+}
+
+module "mod" {
+  source = "./mod"
+  providers = {
+    "aws" = "aws.foo"
+  }
+}

terraform/test-fixtures/transform-provider-implicit-module/mod/main.tf

@@ -0,0 +1,2 @@
+resource "aws_instance" "bar" {
+}

terraform/transform_provider_test.go

@@ -511,6 +511,40 @@ func TestProviderConfigTransformer_grandparentProviders(t *testing.T) {
 	}
 }
 
+// pass a specific provider into a module using it implicitly
+func TestProviderConfigTransformer_implicitModule(t *testing.T) {
+	mod := testModule(t, "transform-provider-implicit-module")
+	concrete := func(a *NodeAbstractProvider) dag.Vertex { return a }
+
+	g := Graph{Path: RootModulePath}
+	{
+		tf := &ConfigTransformer{Module: mod}
+		if err := tf.Transform(&g); err != nil {
+			t.Fatalf("err: %s", err)
+		}
+	}
+	{
+		tf := &AttachResourceConfigTransformer{Module: mod}
+		if err := tf.Transform(&g); err != nil {
+			t.Fatalf("err: %s", err)
+		}
+	}
+	{
+		tf := TransformProviders([]string{"aws"}, concrete, mod)
+		if err := tf.Transform(&g); err != nil {
+			t.Fatalf("err: %s", err)
+		}
+	}
+
+	actual := strings.TrimSpace(g.String())
+	expected := strings.TrimSpace(`module.mod.aws_instance.bar
+  provider.aws.foo
+provider.aws.foo`)
+	if actual != expected {
+		t.Fatalf("expected:\n%s\n\ngot:\n%s", expected, actual)
+	}
+}
+
 const testTransformProviderBasicStr = `
 aws_instance.web
   provider.aws