diff --git a/internal/common/lexer.go b/internal/common/lexer.go
index ec348745b56..42b0bcd520b 100644
--- a/internal/common/lexer.go
+++ b/internal/common/lexer.go
@@ -15,11 +15,6 @@ type Lexer struct {
 	descComment string
 }
 
-type BasicLit struct {
-	Type rune
-	Text string
-}
-
 type Ident struct {
 	Name string
 	Loc  errors.Location
diff --git a/internal/common/literals.go b/internal/common/literals.go
new file mode 100644
index 00000000000..5440b2452bc
--- /dev/null
+++ b/internal/common/literals.go
@@ -0,0 +1,46 @@
+package common
+
+import (
+	"strconv"
+	"text/scanner"
+)
+
+type Literal interface {
+	Value() interface{}
+}
+
+type BasicLit struct {
+	Type rune
+	Text string
+}
+
+func (lit *BasicLit) Value() interface{} {
+	switch lit.Type {
+	case scanner.Int, scanner.Float:
+		value, err := strconv.ParseFloat(lit.Text, 64)
+		if err != nil {
+			panic(err)
+		}
+		return value
+
+	case scanner.String:
+		value, err := strconv.Unquote(lit.Text)
+		if err != nil {
+			panic(err)
+		}
+		return value
+
+	case scanner.Ident:
+		switch lit.Text {
+		case "true":
+			return true
+		case "false":
+			return false
+		default:
+			return lit.Text
+		}
+
+	default:
+		panic("invalid literal")
+	}
+}
diff --git a/internal/common/values.go b/internal/common/values.go
index e3a0ad542a0..ef587cf8f7b 100644
--- a/internal/common/values.go
+++ b/internal/common/values.go
@@ -1,7 +1,6 @@
 package common
 
 import (
-	"strconv"
 	"text/scanner"
 
 	"github.com/neelance/graphql-go/errors"
@@ -125,34 +124,3 @@ func parseValue(l *Lexer, constOnly bool) interface{} {
 		panic("unreachable")
 	}
 }
-
-func UnmarshalLiteral(lit *BasicLit) interface{} {
-	switch lit.Type {
-	case scanner.Int, scanner.Float:
-		value, err := strconv.ParseFloat(lit.Text, 64)
-		if err != nil {
-			panic(err)
-		}
-		return value
-
-	case scanner.String:
-		value, err := strconv.Unquote(lit.Text)
-		if err != nil {
-			panic(err)
-		}
-		return value
-
-	case scanner.Ident:
-		switch lit.Text {
-		case "true":
-			return true
-		case "false":
-			return false
-		default:
-			return lit.Text
-		}
-
-	default:
-		panic("invalid literal")
-	}
-}
diff --git a/internal/exec/resolvable/packer.go b/internal/exec/resolvable/packer.go
index d1c3d516674..ffd92dc0681 100644
--- a/internal/exec/resolvable/packer.go
+++ b/internal/exec/resolvable/packer.go
@@ -261,8 +261,8 @@ func (p *ValuePacker) Pack(r *Request, value interface{}) (reflect.Value, error)
 		return reflect.Value{}, errors.Errorf("got null for non-null")
 	}
 
-	if lit, ok := value.(*common.BasicLit); ok {
-		value = common.UnmarshalLiteral(lit)
+	if lit, ok := value.(common.Literal); ok {
+		value = lit.Value()
 	}
 
 	coerced, err := unmarshalInput(p.ValueType, value)
@@ -281,8 +281,8 @@ func (p *unmarshalerPacker) Pack(r *Request, value interface{}) (reflect.Value,
 		return reflect.Value{}, errors.Errorf("got null for non-null")
 	}
 
-	if lit, ok := value.(*common.BasicLit); ok {
-		value = common.UnmarshalLiteral(lit)
+	if lit, ok := value.(common.Literal); ok {
+		value = lit.Value()
 	}
 
 	v := reflect.New(p.ValueType)
diff --git a/internal/validation/validation.go b/internal/validation/validation.go
index 3d970d30503..2046090190c 100644
--- a/internal/validation/validation.go
+++ b/internal/validation/validation.go
@@ -410,35 +410,31 @@ func validateValue(v interface{}, t common.Type) (bool, string) {
 		return true, ""
 	}
 
-	if l, ok := t.(*common.List); ok {
-		if _, ok := v.([]interface{}); !ok {
-			return validateValue(v, l.OfType)
-		}
-	}
-
 	if _, ok := v.(common.Variable); ok {
 		// TODO
 		return true, ""
 	}
 
-	if v, ok := v.(*common.BasicLit); ok {
-		if validateLiteral(v, t) {
-			return true, ""
+	switch t := t.(type) {
+	case *schema.Scalar, *schema.Enum:
+		if lit, ok := v.(*common.BasicLit); ok {
+			if validateBasicLit(lit, t) {
+				return true, ""
+			}
 		}
-	}
 
-	switch t := t.(type) {
 	case *common.List:
-		v, ok := v.([]interface{})
+		list, ok := v.([]interface{})
 		if !ok {
-			return false, fmt.Sprintf("Expected %q, found not a list.", t)
+			return validateValue(v, t.OfType) // single value instead of list
 		}
-		for i, entry := range v {
+		for i, entry := range list {
 			if ok, reason := validateValue(entry, t.OfType); !ok {
 				return false, fmt.Sprintf("In element #%d: %s", i, reason)
 			}
 		}
 		return true, ""
+
 	case *schema.InputObject:
 		v, ok := v.(map[string]interface{})
 		if !ok {
@@ -466,7 +462,7 @@ func validateValue(v interface{}, t common.Type) (bool, string) {
 	return false, fmt.Sprintf("Expected type %q, found %s.", t, common.Stringify(v))
 }
 
-func validateLiteral(v *common.BasicLit, t common.Type) bool {
+func validateBasicLit(v *common.BasicLit, t common.Type) bool {
 	switch t := t.(type) {
 	case *schema.Scalar:
 		switch t.Name {
diff --git a/introspection/introspection.go b/introspection/introspection.go
index fabcd9a2dc9..87327b18536 100644
--- a/introspection/introspection.go
+++ b/introspection/introspection.go
@@ -226,7 +226,7 @@ func (r *Field) DeprecationReason() *string {
 	if d == nil {
 		return nil
 	}
-	reason := common.UnmarshalLiteral(d.Args.MustGet("reason").Value.(*common.BasicLit)).(string)
+	reason := d.Args.MustGet("reason").Value.(*common.BasicLit).Value().(string)
 	return &reason
 }
 
@@ -281,7 +281,7 @@ func (r *EnumValue) DeprecationReason() *string {
 	if d == nil {
 		return nil
 	}
-	reason := common.UnmarshalLiteral(d.Args.MustGet("reason").Value.(*common.BasicLit)).(string)
+	reason := d.Args.MustGet("reason").Value.(*common.BasicLit).Value().(string)
 	return &reason
 }