diff --git a/internal/common/common.go b/internal/common/common.go
new file mode 100644
index 00000000000..3d7fc3c65b5
--- /dev/null
+++ b/internal/common/common.go
@@ -0,0 +1,43 @@
+package common
+
+import "github.com/neelance/graphql-go/internal/lexer"
+
+type Type interface {
+	IsType()
+}
+
+type List struct {
+	OfType Type
+}
+
+type NonNull struct {
+	OfType Type
+}
+
+type TypeName struct {
+	Name string
+}
+
+func (*List) IsType()     {}
+func (*NonNull) IsType()  {}
+func (*TypeName) IsType() {}
+
+func ParseType(l *lexer.Lexer) Type {
+	t := parseNullType(l)
+	if l.Peek() == '!' {
+		l.ConsumeToken('!')
+		return &NonNull{OfType: t}
+	}
+	return t
+}
+
+func parseNullType(l *lexer.Lexer) Type {
+	if l.Peek() == '[' {
+		l.ConsumeToken('[')
+		ofType := ParseType(l)
+		l.ConsumeToken(']')
+		return &List{OfType: ofType}
+	}
+
+	return &TypeName{Name: l.ConsumeIdent()}
+}
diff --git a/internal/exec/exec.go b/internal/exec/exec.go
index ff3b595445d..cc1b51b0ab6 100644
--- a/internal/exec/exec.go
+++ b/internal/exec/exec.go
@@ -10,6 +10,7 @@ import (
 	"sync"
 
 	"github.com/neelance/graphql-go/errors"
+	"github.com/neelance/graphql-go/internal/common"
 	"github.com/neelance/graphql-go/internal/query"
 	"github.com/neelance/graphql-go/internal/schema"
 )
@@ -47,7 +48,7 @@ func Make(s *schema.Schema, resolver interface{}) (*Exec, error) {
 }
 
 type typeRefMapKey struct {
-	s schema.Type
+	s common.Type
 	r reflect.Type
 }
 
@@ -56,7 +57,7 @@ type typeRef struct {
 	exec    iExec
 }
 
-func makeWithType(s *schema.Schema, t schema.Type, resolver interface{}) (iExec, error) {
+func makeWithType(s *schema.Schema, t common.Type, resolver interface{}) (iExec, error) {
 	m := make(map[typeRefMapKey]*typeRef)
 	var e iExec
 	if err := makeExec(&e, s, t, reflect.TypeOf(resolver), m); err != nil {
@@ -72,7 +73,7 @@ func makeWithType(s *schema.Schema, t schema.Type, resolver interface{}) (iExec,
 	return e, nil
 }
 
-func makeExec(target *iExec, s *schema.Schema, t schema.Type, resolverType reflect.Type, typeRefMap map[typeRefMapKey]*typeRef) error {
+func makeExec(target *iExec, s *schema.Schema, t common.Type, resolverType reflect.Type, typeRefMap map[typeRefMapKey]*typeRef) error {
 	k := typeRefMapKey{t, resolverType}
 	ref, ok := typeRefMap[k]
 	if !ok {
@@ -96,9 +97,9 @@ var scalarTypes = map[string]reflect.Type{
 	"ID":      reflect.TypeOf(""),
 }
 
-func makeExec2(s *schema.Schema, t schema.Type, resolverType reflect.Type, typeRefMap map[typeRefMapKey]*typeRef) (iExec, error) {
+func makeExec2(s *schema.Schema, t common.Type, resolverType reflect.Type, typeRefMap map[typeRefMapKey]*typeRef) (iExec, error) {
 	nonNull := false
-	if nn, ok := t.(*schema.NonNull); ok {
+	if nn, ok := t.(*common.NonNull); ok {
 		nonNull = true
 		t = nn.OfType
 	}
@@ -164,7 +165,7 @@ func makeExec2(s *schema.Schema, t schema.Type, resolverType reflect.Type, typeR
 	case *schema.Enum:
 		return &scalarExec{}, nil
 
-	case *schema.List:
+	case *common.List:
 		if !nonNull {
 			resolverType = resolverType.Elem()
 		}
@@ -506,7 +507,7 @@ type fieldExec struct {
 
 type argExec struct {
 	name       string
-	typ        schema.Type
+	typ        common.Type
 	fieldIndex []int
 	defaultVal reflect.Value
 }
@@ -575,8 +576,8 @@ func execValue(r *request, v query.Value) interface{} {
 	}
 }
 
-func checkType(st schema.Type, rt reflect.Type) bool {
-	if nn, ok := st.(*schema.NonNull); ok {
+func checkType(st common.Type, rt reflect.Type) bool {
+	if nn, ok := st.(*common.NonNull); ok {
 		st = nn.OfType
 	}
 
diff --git a/internal/exec/introspection.go b/internal/exec/introspection.go
index e13912742ff..9f620e5b248 100644
--- a/internal/exec/introspection.go
+++ b/internal/exec/introspection.go
@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"github.com/neelance/graphql-go/errors"
+	"github.com/neelance/graphql-go/internal/common"
 	"github.com/neelance/graphql-go/internal/query"
 	"github.com/neelance/graphql-go/internal/schema"
 )
@@ -249,7 +250,7 @@ func (r *schemaResolver) Directives() []*directiveResolver {
 }
 
 type typeResolver struct {
-	typ schema.Type
+	typ common.Type
 }
 
 func (r *typeResolver) Kind() string {
@@ -266,9 +267,9 @@ func (r *typeResolver) Kind() string {
 		return "ENUM"
 	case *schema.InputObject:
 		return "INPUT_OBJECT"
-	case *schema.List:
+	case *common.List:
 		return "LIST"
-	case *schema.NonNull:
+	case *common.NonNull:
 		return "NON_NULL"
 	default:
 		panic("unreachable")
@@ -378,9 +379,9 @@ func (r *typeResolver) InputFields() *[]*inputValueResolver {
 
 func (r *typeResolver) OfType() *typeResolver {
 	switch t := r.typ.(type) {
-	case *schema.List:
+	case *common.List:
 		return &typeResolver{t.OfType}
-	case *schema.NonNull:
+	case *common.NonNull:
 		return &typeResolver{t.OfType}
 	default:
 		return nil
diff --git a/internal/query/query.go b/internal/query/query.go
index af2b1836eb6..85873f33882 100644
--- a/internal/query/query.go
+++ b/internal/query/query.go
@@ -6,8 +6,8 @@ import (
 	"text/scanner"
 
 	"github.com/neelance/graphql-go/errors"
+	"github.com/neelance/graphql-go/internal/common"
 	"github.com/neelance/graphql-go/internal/lexer"
-	"github.com/neelance/graphql-go/internal/schema"
 )
 
 type Document struct {
@@ -31,7 +31,7 @@ const (
 
 type VariableDef struct {
 	Name string
-	Type schema.Type
+	Type common.Type
 }
 
 type NamedFragment struct {
@@ -170,7 +170,7 @@ func parseVariableDef(l *lexer.Lexer) *VariableDef {
 	l.ConsumeToken('$')
 	v.Name = l.ConsumeIdent()
 	l.ConsumeToken(':')
-	v.Type = schema.ParseType(l)
+	v.Type = common.ParseType(l)
 	return v
 }
 
diff --git a/internal/schema/schema.go b/internal/schema/schema.go
index 2748e02ca7d..f1851a93640 100644
--- a/internal/schema/schema.go
+++ b/internal/schema/schema.go
@@ -6,22 +6,19 @@ import (
 	"text/scanner"
 
 	"github.com/neelance/graphql-go/errors"
+	"github.com/neelance/graphql-go/internal/common"
 	"github.com/neelance/graphql-go/internal/lexer"
 )
 
 type Schema struct {
-	EntryPoints map[string]Type
-	Types       map[string]Type
+	EntryPoints map[string]common.Type
+	Types       map[string]common.Type
 
 	entryPointNames map[string]string
 	objects         []*Object
 	unions          []*Union
 }
 
-type Type interface {
-	isType()
-}
-
 type Scalar struct {
 	Name string
 }
@@ -60,38 +57,23 @@ type InputObject struct {
 	InputFieldOrder []string
 }
 
-type List struct {
-	OfType Type
-}
-
-type NonNull struct {
-	OfType Type
-}
-
-type typeRef struct {
-	name string
-}
-
-func (*Scalar) isType()      {}
-func (*Object) isType()      {}
-func (*Interface) isType()   {}
-func (*Union) isType()       {}
-func (*Enum) isType()        {}
-func (*InputObject) isType() {}
-func (*List) isType()        {}
-func (*NonNull) isType()     {}
-func (*typeRef) isType()     {}
+func (*Scalar) IsType()      {}
+func (*Object) IsType()      {}
+func (*Interface) IsType()   {}
+func (*Union) IsType()       {}
+func (*Enum) IsType()        {}
+func (*InputObject) IsType() {}
 
 type Field struct {
 	Name     string
 	Args     map[string]*InputValue
 	ArgOrder []string
-	Type     Type
+	Type     common.Type
 }
 
 type InputValue struct {
 	Name    string
-	Type    Type
+	Type    common.Type
 	Default interface{}
 }
 
@@ -115,7 +97,7 @@ func Parse(schemaString string) (s *Schema, err *errors.GraphQLError) {
 		}
 	}
 
-	s.EntryPoints = make(map[string]Type)
+	s.EntryPoints = make(map[string]common.Type)
 	for key, name := range s.entryPointNames {
 		t, ok := s.Types[name]
 		if !ok {
@@ -160,7 +142,7 @@ func Parse(schemaString string) (s *Schema, err *errors.GraphQLError) {
 	return s, nil
 }
 
-func resolveType(s *Schema, t Type) *errors.GraphQLError {
+func resolveType(s *Schema, t common.Type) *errors.GraphQLError {
 	var err *errors.GraphQLError
 	switch t := t.(type) {
 	case *Scalar:
@@ -183,18 +165,18 @@ func resolveType(s *Schema, t Type) *errors.GraphQLError {
 		// nothing
 	case *InputObject:
 		for _, f := range t.InputFields {
-			f.Type, err = resolveTypeRef(s, f.Type)
+			f.Type, err = resolveTypeName(s, f.Type)
 			if err != nil {
 				return err
 			}
 		}
-	case *List:
-		t.OfType, err = resolveTypeRef(s, t.OfType)
+	case *common.List:
+		t.OfType, err = resolveTypeName(s, t.OfType)
 		if err != nil {
 			return err
 		}
-	case *NonNull:
-		t.OfType, err = resolveTypeRef(s, t.OfType)
+	case *common.NonNull:
+		t.OfType, err = resolveTypeName(s, t.OfType)
 		if err != nil {
 			return err
 		}
@@ -206,12 +188,12 @@ func resolveType(s *Schema, t Type) *errors.GraphQLError {
 
 func resolveField(s *Schema, f *Field) *errors.GraphQLError {
 	var err *errors.GraphQLError
-	f.Type, err = resolveTypeRef(s, f.Type)
+	f.Type, err = resolveTypeName(s, f.Type)
 	if err != nil {
 		return err
 	}
 	for _, arg := range f.Args {
-		arg.Type, err = resolveTypeRef(s, arg.Type)
+		arg.Type, err = resolveTypeName(s, arg.Type)
 		if err != nil {
 			return err
 		}
@@ -219,11 +201,11 @@ func resolveField(s *Schema, f *Field) *errors.GraphQLError {
 	return nil
 }
 
-func resolveTypeRef(s *Schema, t Type) (Type, *errors.GraphQLError) {
-	if ref, ok := t.(*typeRef); ok {
-		refT, ok := s.Types[ref.name]
+func resolveTypeName(s *Schema, t common.Type) (common.Type, *errors.GraphQLError) {
+	if name, ok := t.(*common.TypeName); ok {
+		refT, ok := s.Types[name.Name]
 		if !ok {
-			return nil, errors.Errorf("type %q not found", ref.name)
+			return nil, errors.Errorf("type %q not found", name.Name)
 		}
 		return refT, nil
 	}
@@ -234,7 +216,7 @@ func resolveTypeRef(s *Schema, t Type) (Type, *errors.GraphQLError) {
 func parseSchema(l *lexer.Lexer) *Schema {
 	s := &Schema{
 		entryPointNames: make(map[string]string),
-		Types: map[string]Type{
+		Types: map[string]common.Type{
 			"Int":     &Scalar{Name: "Int"},
 			"Float":   &Scalar{Name: "Float"},
 			"String":  &Scalar{Name: "String"},
@@ -361,7 +343,7 @@ func parseFields(l *lexer.Lexer) (map[string]*Field, []string) {
 			l.ConsumeToken(')')
 		}
 		l.ConsumeToken(':')
-		f.Type = ParseType(l)
+		f.Type = common.ParseType(l)
 		fields[f.Name] = f
 		fieldOrder = append(fieldOrder, f.Name)
 	}
@@ -372,7 +354,7 @@ func parseInputValue(l *lexer.Lexer) *InputValue {
 	p := &InputValue{}
 	p.Name = l.ConsumeIdent()
 	l.ConsumeToken(':')
-	p.Type = ParseType(l)
+	p.Type = common.ParseType(l)
 	if l.Peek() == '=' {
 		l.ConsumeToken('=')
 		p.Default = parseValue(l)
@@ -380,26 +362,6 @@ func parseInputValue(l *lexer.Lexer) *InputValue {
 	return p
 }
 
-func ParseType(l *lexer.Lexer) Type {
-	t := parseNullType(l)
-	if l.Peek() == '!' {
-		l.ConsumeToken('!')
-		return &NonNull{OfType: t}
-	}
-	return t
-}
-
-func parseNullType(l *lexer.Lexer) Type {
-	if l.Peek() == '[' {
-		l.ConsumeToken('[')
-		ofType := ParseType(l)
-		l.ConsumeToken(']')
-		return &List{OfType: ofType}
-	}
-
-	return &typeRef{name: l.ConsumeIdent()}
-}
-
 func parseValue(l *lexer.Lexer) interface{} {
 	switch l.Peek() {
 	case scanner.Int: