diff --git a/Makefile b/Makefile
index 18c6687..6bf5fad 100644
--- a/Makefile
+++ b/Makefile
@@ -26,7 +26,8 @@ generate: root build
 		.root/src/$(PKG)/tests/named_type.go \
 		.root/src/$(PKG)/tests/custom_map_key_type.go \
 		.root/src/$(PKG)/tests/embedded_type.go \
-		.root/src/$(PKG)/tests/reference_to_pointer.go
+		.root/src/$(PKG)/tests/reference_to_pointer.go \
+		.root/src/$(PKG)/tests/type_declaration.go
 
 	.root/bin/easyjson -all .root/src/$(PKG)/tests/data.go
 	.root/bin/easyjson -all .root/src/$(PKG)/tests/nothing.go
@@ -40,6 +41,7 @@ generate: root build
 	.root/bin/easyjson .root/src/$(PKG)/tests/embedded_type.go
 	.root/bin/easyjson .root/src/$(PKG)/tests/reference_to_pointer.go
 	.root/bin/easyjson -disallow_unknown_fields .root/src/$(PKG)/tests/disallow_unknown.go
+	.root/bin/easyjson .root/src/$(PKG)/tests/type_declaration.go
 
 test: generate root
 	go test \
diff --git a/tests/basic_test.go b/tests/basic_test.go
index 3b1cc65..958c0a8 100644
--- a/tests/basic_test.go
+++ b/tests/basic_test.go
@@ -52,6 +52,9 @@ var testCases = []struct {
 	{&intArrayStructValue, intArrayStructValueString},
 	{&myUInt8SliceValue, myUInt8SliceString},
 	{&myUInt8ArrayValue, myUInt8ArrayString},
+	{&myGenDeclaredValue, myGenDeclaredString},
+	{&myGenDeclaredWithCommentValue, myGenDeclaredWithCommentString},
+	{&myTypeDeclaredValue, myTypeDeclaredString},
 }
 
 func TestMarshal(t *testing.T) {
@@ -242,3 +245,22 @@ func TestDisallowUnknown(t *testing.T) {
 		t.Error("want error, got nil")
 	}
 }
+
+var testNotGeneratedTypeCases = []interface{}{
+	TypeNotDeclared{},
+}
+
+func TestMethodsNoGenerated(t *testing.T) {
+	var ok bool
+	for i, instance := range testNotGeneratedTypeCases {
+		_, ok = instance.(json.Marshaler)
+		if ok {
+			t.Errorf("[%d, %T] Unexpected MarshalJSON()", i, instance)
+		}
+
+		_, ok = instance.(json.Unmarshaler)
+		if ok {
+			t.Errorf("[%d, %T] Unexpected Unmarshaler()", i, instance)
+		}
+	}
+}
diff --git a/tests/type_declaration.go b/tests/type_declaration.go
new file mode 100644
index 0000000..e638455
--- /dev/null
+++ b/tests/type_declaration.go
@@ -0,0 +1,33 @@
+package tests
+
+//easyjson:json
+type (
+	GenDeclared1 struct {
+		Value string
+	}
+
+	// A gen declared easyjson struct with a comment
+	GenDeclaredWithComment struct {
+		Value string
+	}
+)
+
+type (
+	//easyjson:json
+	TypeDeclared struct {
+		Value string
+	}
+
+	TypeNotDeclared struct {
+		Value string
+	}
+)
+
+var (
+	myGenDeclaredValue             = TypeDeclared{Value: "GenDeclared"}
+	myGenDeclaredString            = `{"Value":"GenDeclared"}`
+	myGenDeclaredWithCommentValue  = TypeDeclared{Value: "GenDeclaredWithComment"}
+	myGenDeclaredWithCommentString = `{"Value":"GenDeclaredWithComment"}`
+	myTypeDeclaredValue            = TypeDeclared{Value: "TypeDeclared"}
+	myTypeDeclaredString           = `{"Value":"TypeDeclared"}`
+)