diff --git a/internal/common/types.go b/internal/common/types.go
index f0b699b77f3..f69509ee5f2 100644
--- a/internal/common/types.go
+++ b/internal/common/types.go
@@ -1,7 +1,8 @@
 package common
 
 import (
-	"github.com/neelance/graphql-go/errors"
+	"fmt"
+
 	"github.com/neelance/graphql-go/internal/lexer"
 )
 
@@ -47,7 +48,7 @@ func parseNullType(l *lexer.Lexer) Type {
 
 type Resolver func(name string) Type
 
-func ResolveType(t Type, resolver Resolver) (Type, *errors.QueryError) {
+func ResolveType(t Type, resolver Resolver) (Type, error) {
 	switch t := t.(type) {
 	case *List:
 		ofType, err := ResolveType(t.OfType, resolver)
@@ -64,7 +65,7 @@ func ResolveType(t Type, resolver Resolver) (Type, *errors.QueryError) {
 	case *TypeName:
 		refT := resolver(t.Name)
 		if refT == nil {
-			return nil, errors.Errorf("type %q not found", t.Name)
+			return nil, fmt.Errorf("type %q not found", t.Name)
 		}
 		return refT, nil
 	default:
diff --git a/internal/exec/exec.go b/internal/exec/exec.go
index 0fa5219115a..06c8b7d7e65 100644
--- a/internal/exec/exec.go
+++ b/internal/exec/exec.go
@@ -384,12 +384,12 @@ func (r *request) handlePanic() {
 func ExecuteRequest(ctx context.Context, e *Exec, document *query.Document, operationName string, variables map[string]interface{}) (interface{}, []*errors.QueryError) {
 	op, err := getOperation(document, operationName)
 	if err != nil {
-		return nil, []*errors.QueryError{err}
+		return nil, []*errors.QueryError{errors.Errorf("%s", err)}
 	}
 
 	coercedVariables, err := coerceInputObject(&op.Vars, variables)
 	if err != nil {
-		return nil, []*errors.QueryError{err}
+		return nil, []*errors.QueryError{errors.Errorf("%s", err)}
 	}
 
 	r := &request{
@@ -417,14 +417,14 @@ func ExecuteRequest(ctx context.Context, e *Exec, document *query.Document, oper
 	return data, r.errs
 }
 
-func getOperation(document *query.Document, operationName string) (*query.Operation, *errors.QueryError) {
+func getOperation(document *query.Document, operationName string) (*query.Operation, error) {
 	if len(document.Operations) == 0 {
-		return nil, errors.Errorf("no operations in query document")
+		return nil, fmt.Errorf("no operations in query document")
 	}
 
 	if operationName == "" {
 		if len(document.Operations) > 1 {
-			return nil, errors.Errorf("more than one operation in query document and no operation name given")
+			return nil, fmt.Errorf("more than one operation in query document and no operation name given")
 		}
 		for _, op := range document.Operations {
 			return op, nil // return the one and only operation
@@ -433,12 +433,12 @@ func getOperation(document *query.Document, operationName string) (*query.Operat
 
 	op, ok := document.Operations[operationName]
 	if !ok {
-		return nil, errors.Errorf("no operation with name %q", operationName)
+		return nil, fmt.Errorf("no operation with name %q", operationName)
 	}
 	return op, nil
 }
 
-func coerceInputObject(io *common.InputMap, variables map[string]interface{}) (map[string]interface{}, *errors.QueryError) {
+func coerceInputObject(io *common.InputMap, variables map[string]interface{}) (map[string]interface{}, error) {
 	coerced := make(map[string]interface{})
 	for _, iv := range io.Fields {
 		value, ok := variables[iv.Name]
@@ -458,7 +458,7 @@ func coerceInputObject(io *common.InputMap, variables map[string]interface{}) (m
 	return coerced, nil
 }
 
-func coerceInputValue(iv *common.InputValue, value interface{}) (interface{}, *errors.QueryError) {
+func coerceInputValue(iv *common.InputValue, value interface{}) (interface{}, error) {
 	t, _ := unwrapNonNull(iv.Type)
 	switch t := t.(type) {
 	case *scalar:
diff --git a/internal/exec/scalar.go b/internal/exec/scalar.go
index dbb6cb680e2..8d54c5458d0 100644
--- a/internal/exec/scalar.go
+++ b/internal/exec/scalar.go
@@ -1,17 +1,17 @@
 package exec
 
 import (
+	"fmt"
 	"math"
 	"reflect"
 
-	"github.com/neelance/graphql-go/errors"
 	"github.com/neelance/graphql-go/internal/schema"
 )
 
 type scalar struct {
 	name        string
 	reflectType reflect.Type
-	coerceInput func(input interface{}) (interface{}, *errors.QueryError)
+	coerceInput func(input interface{}) (interface{}, error)
 }
 
 func (*scalar) Kind() string       { return "SCALAR" }
@@ -21,10 +21,10 @@ var builtinScalars = []*scalar{
 	&scalar{
 		name:        "Int",
 		reflectType: reflect.TypeOf(int32(0)),
-		coerceInput: func(input interface{}) (interface{}, *errors.QueryError) {
+		coerceInput: func(input interface{}) (interface{}, error) {
 			i := input.(int)
 			if i < math.MinInt32 || i > math.MaxInt32 {
-				return nil, errors.Errorf("not a 32-bit integer: %d", i)
+				return nil, fmt.Errorf("not a 32-bit integer: %d", i)
 			}
 			return int32(i), nil
 		},
@@ -32,28 +32,28 @@ var builtinScalars = []*scalar{
 	&scalar{
 		name:        "Float",
 		reflectType: reflect.TypeOf(float64(0)),
-		coerceInput: func(input interface{}) (interface{}, *errors.QueryError) {
+		coerceInput: func(input interface{}) (interface{}, error) {
 			return input, nil // TODO
 		},
 	},
 	&scalar{
 		name:        "String",
 		reflectType: reflect.TypeOf(""),
-		coerceInput: func(input interface{}) (interface{}, *errors.QueryError) {
+		coerceInput: func(input interface{}) (interface{}, error) {
 			return input, nil // TODO
 		},
 	},
 	&scalar{
 		name:        "Boolean",
 		reflectType: reflect.TypeOf(true),
-		coerceInput: func(input interface{}) (interface{}, *errors.QueryError) {
+		coerceInput: func(input interface{}) (interface{}, error) {
 			return input, nil // TODO
 		},
 	},
 	&scalar{
 		name:        "ID",
 		reflectType: reflect.TypeOf(""),
-		coerceInput: func(input interface{}) (interface{}, *errors.QueryError) {
+		coerceInput: func(input interface{}) (interface{}, error) {
 			return input, nil // TODO
 		},
 	},
diff --git a/internal/query/query.go b/internal/query/query.go
index 6131a72524e..588f7b55e93 100644
--- a/internal/query/query.go
+++ b/internal/query/query.go
@@ -89,7 +89,7 @@ func Parse(queryString string, resolver common.Resolver) (doc *Document, err *er
 		for _, v := range op.Vars.Fields {
 			t, err := common.ResolveType(v.Type, resolver)
 			if err != nil {
-				return nil, err
+				return nil, errors.Errorf("%s", err)
 			}
 			v.Type = t
 		}
diff --git a/internal/schema/schema.go b/internal/schema/schema.go
index 9b3235c5c97..4a034adce4d 100644
--- a/internal/schema/schema.go
+++ b/internal/schema/schema.go
@@ -86,7 +86,7 @@ func New() *Schema {
 	}
 }
 
-func (s *Schema) Parse(schemaString string) *errors.QueryError {
+func (s *Schema) Parse(schemaString string) error {
 	sc := &scanner.Scanner{
 		Mode: scanner.ScanIdents | scanner.ScanInts | scanner.ScanFloats | scanner.ScanStrings,
 	}
@@ -151,7 +151,7 @@ func (s *Schema) Parse(schemaString string) *errors.QueryError {
 	return nil
 }
 
-func resolveNamedType(s *Schema, t NamedType) *errors.QueryError {
+func resolveNamedType(s *Schema, t NamedType) error {
 	switch t := t.(type) {
 	case *Object:
 		for _, f := range t.Fields {
@@ -173,7 +173,7 @@ func resolveNamedType(s *Schema, t NamedType) *errors.QueryError {
 	return nil
 }
 
-func resolveField(s *Schema, f *Field) *errors.QueryError {
+func resolveField(s *Schema, f *Field) error {
 	t, err := common.ResolveType(f.Type, s.Resolve)
 	if err != nil {
 		return err
@@ -182,7 +182,7 @@ func resolveField(s *Schema, f *Field) *errors.QueryError {
 	return resolveInputObject(s, &f.Args)
 }
 
-func resolveInputObject(s *Schema, io *common.InputMap) *errors.QueryError {
+func resolveInputObject(s *Schema, io *common.InputMap) error {
 	for _, f := range io.Fields {
 		t, err := common.ResolveType(f.Type, s.Resolve)
 		if err != nil {