diff --git a/config/config.go b/config/config.go
index 2bdab8947..c085e1f26 100644
--- a/config/config.go
+++ b/config/config.go
@@ -570,6 +570,11 @@ func (c *Config) InterpolatedVariables() map[string][]InterpolatedVariable {
 // a human-friendly source.
 func (c *Config) rawConfigs() map[string]*RawConfig {
 	result := make(map[string]*RawConfig)
+	for _, m := range c.Modules {
+		source := fmt.Sprintf("module '%s'", m.Name)
+		result[source] = m.RawConfig
+	}
+
 	for _, pc := range c.ProviderConfigs {
 		source := fmt.Sprintf("provider config '%s'", pc.Name)
 		result[source] = pc.RawConfig
diff --git a/config/module/test-fixtures/validate-bad-output-to-module/child/main.tf b/config/module/test-fixtures/validate-bad-output-to-module/child/main.tf
new file mode 100644
index 000000000..4d68c80b3
--- /dev/null
+++ b/config/module/test-fixtures/validate-bad-output-to-module/child/main.tf
@@ -0,0 +1 @@
+variable "memory" { default = "foo" }
diff --git a/config/module/test-fixtures/validate-bad-output-to-module/main.tf b/config/module/test-fixtures/validate-bad-output-to-module/main.tf
new file mode 100644
index 000000000..4b627bbe5
--- /dev/null
+++ b/config/module/test-fixtures/validate-bad-output-to-module/main.tf
@@ -0,0 +1,8 @@
+module "child" {
+    source = "./child"
+}
+
+module "child2" {
+    source = "./child"
+    memory = "${module.child.memory_max}"
+}
diff --git a/config/module/tree_test.go b/config/module/tree_test.go
index 9667c0157..74757a498 100644
--- a/config/module/tree_test.go
+++ b/config/module/tree_test.go
@@ -224,6 +224,18 @@ func TestTreeValidate_badChildOutput(t *testing.T) {
 	}
 }
 
+func TestTreeValidate_badChildOutputToModule(t *testing.T) {
+	tree := NewTree("", testConfig(t, "validate-bad-output-to-module"))
+
+	if err := tree.Load(testStorage(t), GetModeGet); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if err := tree.Validate(); err == nil {
+		t.Fatal("should error")
+	}
+}
+
 func TestTreeValidate_badChildVar(t *testing.T) {
 	tree := NewTree("", testConfig(t, "validate-bad-var"))