diff --git a/entc/gen/internal/bindata.go b/entc/gen/internal/bindata.go
index d625fd48f..da4915bcd 100644
--- a/entc/gen/internal/bindata.go
+++ b/entc/gen/internal/bindata.go
@@ -121,7 +121,7 @@ func (fi bindataFileInfo) Sys() interface{} {
 	return nil
 }
 
-var _templateBaseTmpl = 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+var _templateBaseTmpl = 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
 func templateBaseTmplBytes() ([]byte, error) {
 	return bindataRead(
@@ -136,7 +136,7 @@ func templateBaseTmpl() (*asset, error) {
 		return nil, err
 	}
 
-	info := bindataFileInfo{name: "template/base.tmpl", size: 4707, mode: os.FileMode(420), modTime: time.Unix(1, 0)}
+	info := bindataFileInfo{name: "template/base.tmpl", size: 4698, mode: os.FileMode(420), modTime: time.Unix(1, 0)}
 	a := &asset{bytes: bytes, info: info}
 	return a, nil
 }
@@ -881,7 +881,7 @@ func templateHeaderTmpl() (*asset, error) {
 	return a, nil
 }
 
-var _templateImportTmpl = []byte("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\xff\x84\x53\xcd\x6a\xdc\x4c\x10\x3c\xaf\x9e\xa2\x10\x7b\xb0\xcd\xe7\x91\x3f\xdf\x62\xf0\xc1\x18\x1b\x0c\x21\x18\xec\x7b\x98\x9d\x69\x49\x8d\xa5\x69\x65\xa6\xd7\x89\x11\x7a\xf7\x30\x5a\x6d\x76\xcd\x12\x72\x52\xb5\xaa\xfa\x67\xfa\x67\x1c\xab\x8b\xe2\x5e\x86\x8f\xc8\x4d\xab\xb8\xbe\xfa\xff\xcb\xe5\x10\x29\x51\x50\x3c\x5a\x47\x1b\x91\x37\x3c\x05\x67\x70\xd7\x75\x98\x45\x09\x99\x8f\xef\xe4\x4d\xf1\xda\x72\x42\x92\x6d\x74\x04\x27\x9e\xc0\x09\x1d\x3b\x0a\x89\x3c\xb6\xc1\x53\x84\xb6\x84\xbb\xc1\xba\x96\x70\x6d\xae\xf6\x2c\x6a\xd9\x06\x5f\x70\x98\xf9\xaf\x4f\xf7\x0f\xdf\x5e\x1e\x50\x73\x47\x58\xfe\x45\x11\x85\xe7\x48\x4e\x25\x7e\x40\x6a\xe8\x51\x32\x8d\x44\xa6\xb8\xa8\xa6\xa9\x28\xc6\x11\x9e\x6a\x0e\x84\x92\xfb\x41\xa2\x96\x98\xa6\x62\x07\x71\x56\xac\xca\xba\xd7\xb2\x58\x95\x4e\x82\xd2\xaf\x19\x52\x8c\x12\x53\x46\xbd\xd5\x36\x7f\x93\x46\x27\xe1\x7d\x81\x1c\x9a\x99\x55\xee\xa9\x2c\x56\xe3\x78\x89\xea\x02\xdc\x04\x89\x84\x86\x02\x45\xe5\xd0\x40\x02\x9a\x68\x87\x16\x69\x20\xc7\x35\xd7\x0e\x4a\xfd\xd0\x59\xa5\x84\xb9\xb8\xd9\x95\x6b\x04\x51\x9c\xd1\x0f\xac\xcd\xbd\x84\x9a\x1b\xf3\x6c\xdd\x9b\x6d\x08\xeb\x3d\x3a\xcf\x45\xaf\x56\xe5\x38\x9e\x8a\xa6\xa9\x1a\x22\x79\x76\x56\x73\x39\x7f\x15\xcd\xbf\x0f\x76\x96\xe6\xfc\x3f\x59\xdb\x83\xfe\xc5\xb5\xd4\x5b\xec\xd2\xcd\xa1\xcc\x91\x96\x82\xdf\x31\xd9\x88\x36\xe4\x12\xbf\xff\x87\x75\x8d\x9b\x5b\xac\xcd\x23\x53\xe7\xd3\xe2\x7b\x88\x5d\x9b\xd7\x8f\x81\xcc\xf3\x5b\xf3\x6c\xb5\x5d\xe8\x4f\xb1\x4f\x83\xef\x8d\x63\x5c\x36\xac\xed\x76\x63\x9c\xf4\x55\xbd\xac\x1f\x07\xb7\xdd\x58\x95\x58\x51\x98\x87\xf7\x2f\x4d\xe5\xd9\x76\xe4\x74\x19\xdc\xf2\xfa\x17\x95\xb8\x6b\xcb\xe9\xe3\x96\x5d\xb9\xb9\x85\x79\x9a\x61\x3a\xea\xce\x9e\x3d\xed\xd1\x67\xfc\x67\xf4\xfb\x35\x4c\x95\xf5\x9e\x95\x25\xd8\xae\xc4\x3a\xcb\xce\xf3\xb2\x2e\x2e\x45\xbe\x3d\xdc\x1d\xdc\xb4\xb5\x0a\x67\x03\x36\x04\x79\xa7\x18\xd9\x93\xcf\xe7\x20\x71\x3e\x24\x81\xf5\x1e\x87\x98\x58\xd2\x64\x66\xd8\x0d\x3d\x99\x79\xeb\x4e\x2e\xe2\x73\x29\xd3\x34\x8e\x14\xfc\x34\x15\xbf\x03\x00\x00\xff\xff\x2e\x6e\xc7\x74\xff\x03\x00\x00")
+var _templateImportTmpl = []byte("\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\xff\x84\x53\x4f\x4b\xe4\x4e\x10\x3d\x4f\x3e\x45\x11\xe6\xa0\xf2\xb3\xe3\xcf\xdb\x0a\x1e\x44\x14\x84\x65\x11\xf4\xbe\xf4\x74\x57\x92\xc2\xa4\x2b\x5b\x5d\xe3\x2a\x21\xdf\x7d\xe9\x4e\xc6\x99\x61\x58\xf6\x94\xd7\xfd\x5e\xfd\x49\xf5\xab\x71\xac\x2e\x8a\x7b\x1e\x3e\x85\x9a\x56\xe1\xfa\xea\xff\x6f\x97\x83\x60\xc4\xa0\xf0\x68\x1d\x6e\x98\xdf\xe0\x29\x38\x03\x77\x5d\x07\x59\x14\x21\xf1\xf2\x8e\xde\x14\xaf\x2d\x45\x88\xbc\x15\x87\xe0\xd8\x23\x50\x84\x8e\x1c\x86\x88\x1e\xb6\xc1\xa3\x80\xb6\x08\x77\x83\x75\x2d\xc2\xb5\xb9\xda\xb1\x50\xf3\x36\xf8\x82\x42\xe6\xbf\x3f\xdd\x3f\xfc\x78\x79\x80\x9a\x3a\x84\xe5\x4e\x98\x15\x3c\x09\x3a\x65\xf9\x04\xae\x41\x0f\x8a\xa9\x20\x9a\xe2\xa2\x9a\xa6\xa2\x18\x47\xf0\x58\x53\x40\x28\xa9\x1f\x58\xb4\x84\x69\x2a\x66\x08\x67\xc5\xaa\xac\x7b\x2d\x8b\x55\xe9\x38\x28\x7e\x64\x88\x22\x2c\x31\xa1\xde\x6a\x9b\xbe\x51\xc5\x71\x78\x5f\x20\x85\x26\xb3\x4a\x3d\x96\xc5\x6a\x1c\x2f\xa1\xba\x00\x6a\x02\x0b\x42\x83\x01\x45\x29\x34\xc0\x01\x1a\xb1\x43\x0b\x71\x40\x47\x35\xd5\x0e\x14\xfb\xa1\xb3\x8a\x11\x72\x73\x39\x94\x6a\x08\xac\x70\x86\xbf\x60\x6d\xee\x39\xd4\xd4\x98\x67\xeb\xde\x6c\x83\xb0\xde\xa1\xf3\xd4\xf4\x6a\x55\x8e\xe3\xa9\x68\x9a\xaa\x41\xd0\x93\xb3\x9a\xda\xf9\xab\x28\x5f\xef\xcf\x49\x9a\xea\xff\x26\x6d\xf7\xfa\x17\xd7\x62\x6f\x61\x2e\x97\x53\x99\x03\x2d\x06\x3f\x33\xe9\x20\x36\xa4\x16\x7f\xfe\x07\xeb\x1a\x6e\x6e\x61\x6d\x1e\x09\x3b\x1f\x97\xd8\x7d\xee\xda\xbc\x7e\x0e\x68\x9e\xdf\x9a\x67\xab\xed\x42\x1f\xe5\x3e\x4d\xbe\x3b\x1c\xe2\xb2\x21\x6d\xb7\x1b\xe3\xb8\xaf\xea\xc5\x7e\x14\xdc\x76\x63\x95\xa5\xc2\x90\x1f\xef\x5f\x9a\xca\x93\xed\xd0\xcd\x5a\xee\x6c\x68\x0c\x4b\x53\x7d\x54\x1f\x5f\xcf\x7e\x30\x95\x17\x65\x99\xc7\x75\xfa\xd3\x8b\x87\x6e\x6e\xc1\x3c\x65\x18\x0f\xa6\xb6\x63\x4f\x67\x77\x8c\xbf\x2c\xb1\xb3\x67\xac\xac\xf7\xa4\xc4\xc1\x76\x25\xac\x93\xec\x3c\x99\x78\x09\x29\xd2\x4e\xc2\xdd\x3e\x4c\x5b\xab\xe0\x6c\x80\x0d\x02\xbf\xa3\x08\x79\xf4\x69\x4d\x58\xf2\x82\x31\x58\xef\x61\x9f\x13\x96\x32\x89\x19\x66\x33\x44\x93\xdd\x78\xb2\x29\xc7\xad\x4c\xd3\x38\x62\xf0\xd3\x54\xfc\x09\x00\x00\xff\xff\xa5\x33\x84\x1e\x17\x04\x00\x00")
 
 func templateImportTmplBytes() ([]byte, error) {
 	return bindataRead(
@@ -896,7 +896,7 @@ func templateImportTmpl() (*asset, error) {
 		return nil, err
 	}
 
-	info := bindataFileInfo{name: "template/import.tmpl", size: 1023, mode: os.FileMode(420), modTime: time.Unix(1, 0)}
+	info := bindataFileInfo{name: "template/import.tmpl", size: 1047, mode: os.FileMode(420), modTime: time.Unix(1, 0)}
 	a := &asset{bytes: bytes, info: info}
 	return a, nil
 }
diff --git a/entc/gen/template/base.tmpl b/entc/gen/template/base.tmpl
index 317a7f50f..3f34e4da3 100644
--- a/entc/gen/template/base.tmpl
+++ b/entc/gen/template/base.tmpl
@@ -66,13 +66,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("{{ $pkg }}: %s not found", e.label)
+	return "{{ $pkg }}: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -90,13 +90,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("{{ $pkg }}: %s not singular", e.label)
+	return "{{ $pkg }}: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -106,13 +106,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("{{ $pkg }}: %s edge was not loaded", e.edge)
+	return "{{ $pkg }}: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -125,7 +125,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("{{ $pkg }}: constraint failed: %s", e.msg)
+	return "{{ $pkg }}: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -135,8 +135,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 {{/* expand error types and global helpers. */}}
diff --git a/entc/gen/template/import.tmpl b/entc/gen/template/import.tmpl
index 042084222..7c61d7b82 100644
--- a/entc/gen/template/import.tmpl
+++ b/entc/gen/template/import.tmpl
@@ -28,6 +28,7 @@ import (
 	{{- end }}
 	"github.com/facebookincubator/ent"
 	"github.com/facebookincubator/ent/dialect"
+	"golang.org/x/xerrors"
 	{{- with $.Storage }}
 		{{- range $_, $import := .Imports }}
 			"{{ $import }}"
diff --git a/entc/integration/config/ent/ent.go b/entc/integration/config/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/entc/integration/config/ent/ent.go
+++ b/entc/integration/config/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/entc/integration/customid/ent/ent.go b/entc/integration/customid/ent/ent.go
index 5da69707e..c2b57d713 100644
--- a/entc/integration/customid/ent/ent.go
+++ b/entc/integration/customid/ent/ent.go
@@ -15,6 +15,7 @@ import (
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
 	"github.com/google/uuid"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -95,13 +96,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -119,13 +120,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -135,13 +136,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -154,7 +155,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -164,8 +165,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/entc/integration/ent/ent.go b/entc/integration/ent/ent.go
index e9566cdec..f92791107 100644
--- a/entc/integration/ent/ent.go
+++ b/entc/integration/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/entc/integration/gremlin/ent/ent.go b/entc/integration/gremlin/ent/ent.go
index 13e2108c5..73c520322 100644
--- a/entc/integration/gremlin/ent/ent.go
+++ b/entc/integration/gremlin/ent/ent.go
@@ -15,6 +15,7 @@ import (
 	"github.com/facebookincubator/ent/dialect/gremlin/encoding/graphson"
 	"github.com/facebookincubator/ent/dialect/gremlin/graph/dsl"
 	"github.com/facebookincubator/ent/dialect/gremlin/graph/dsl/__"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -142,13 +143,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -166,13 +167,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -182,13 +183,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -201,7 +202,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -211,8 +212,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 // Code implements the dsl.Node interface.
diff --git a/entc/integration/idtype/ent/ent.go b/entc/integration/idtype/ent/ent.go
index b31a5bfb7..02119bb11 100644
--- a/entc/integration/idtype/ent/ent.go
+++ b/entc/integration/idtype/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/entc/integration/json/ent/ent.go b/entc/integration/json/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/entc/integration/json/ent/ent.go
+++ b/entc/integration/json/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/entc/integration/migrate/entv1/ent.go b/entc/integration/migrate/entv1/ent.go
index 740bcf60c..29884006f 100644
--- a/entc/integration/migrate/entv1/ent.go
+++ b/entc/integration/migrate/entv1/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("entv1: %s not found", e.label)
+	return "entv1: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("entv1: %s not singular", e.label)
+	return "entv1: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("entv1: %s edge was not loaded", e.edge)
+	return "entv1: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("entv1: constraint failed: %s", e.msg)
+	return "entv1: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/entc/integration/migrate/entv2/ent.go b/entc/integration/migrate/entv2/ent.go
index 623d5795d..f1b8104eb 100644
--- a/entc/integration/migrate/entv2/ent.go
+++ b/entc/integration/migrate/entv2/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("entv2: %s not found", e.label)
+	return "entv2: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("entv2: %s not singular", e.label)
+	return "entv2: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("entv2: %s edge was not loaded", e.edge)
+	return "entv2: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("entv2: constraint failed: %s", e.msg)
+	return "entv2: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/entc/integration/template/ent/ent.go b/entc/integration/template/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/entc/integration/template/ent/ent.go
+++ b/entc/integration/template/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/edgeindex/ent/ent.go b/examples/edgeindex/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/edgeindex/ent/ent.go
+++ b/examples/edgeindex/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/entcpkg/ent/ent.go b/examples/entcpkg/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/entcpkg/ent/ent.go
+++ b/examples/entcpkg/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/m2m2types/ent/ent.go b/examples/m2m2types/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/m2m2types/ent/ent.go
+++ b/examples/m2m2types/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/m2mbidi/ent/ent.go b/examples/m2mbidi/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/m2mbidi/ent/ent.go
+++ b/examples/m2mbidi/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/m2mrecur/ent/ent.go b/examples/m2mrecur/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/m2mrecur/ent/ent.go
+++ b/examples/m2mrecur/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/o2m2types/ent/ent.go b/examples/o2m2types/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/o2m2types/ent/ent.go
+++ b/examples/o2m2types/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/o2mrecur/ent/ent.go b/examples/o2mrecur/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/o2mrecur/ent/ent.go
+++ b/examples/o2mrecur/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/o2o2types/ent/ent.go b/examples/o2o2types/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/o2o2types/ent/ent.go
+++ b/examples/o2o2types/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/o2obidi/ent/ent.go b/examples/o2obidi/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/o2obidi/ent/ent.go
+++ b/examples/o2obidi/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/o2orecur/ent/ent.go b/examples/o2orecur/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/o2orecur/ent/ent.go
+++ b/examples/o2orecur/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/start/ent/ent.go b/examples/start/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/start/ent/ent.go
+++ b/examples/start/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/examples/traversal/ent/ent.go b/examples/traversal/ent/ent.go
index f6486aece..92e23bee0 100644
--- a/examples/traversal/ent/ent.go
+++ b/examples/traversal/ent/ent.go
@@ -14,6 +14,7 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
+	"golang.org/x/xerrors"
 )
 
 // Order applies an ordering on either graph traversal or sql selector.
@@ -94,13 +95,13 @@ type NotFoundError struct {
 
 // Error implements the error interface.
 func (e *NotFoundError) Error() string {
-	return fmt.Sprintf("ent: %s not found", e.label)
+	return "ent: " + e.label + " not found"
 }
 
 // IsNotFound returns a boolean indicating whether the error is a not found error.
 func IsNotFound(err error) bool {
-	_, ok := err.(*NotFoundError)
-	return ok
+	var e *NotFoundError
+	return xerrors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -118,13 +119,13 @@ type NotSingularError struct {
 
 // Error implements the error interface.
 func (e *NotSingularError) Error() string {
-	return fmt.Sprintf("ent: %s not singular", e.label)
+	return "ent: " + e.label + " not singular"
 }
 
 // IsNotSingular returns a boolean indicating whether the error is a not singular error.
 func IsNotSingular(err error) bool {
-	_, ok := err.(*NotSingularError)
-	return ok
+	var e *NotSingularError
+	return xerrors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -134,13 +135,13 @@ type NotLoadedError struct {
 
 // Error implements the error interface.
 func (e *NotLoadedError) Error() string {
-	return fmt.Sprintf("ent: %s edge was not loaded", e.edge)
+	return "ent: " + e.edge + " edge was not loaded"
 }
 
 // IsNotLoaded returns a boolean indicating whether the error is a not loaded error.
 func IsNotLoaded(err error) bool {
-	_, ok := err.(*NotLoadedError)
-	return ok
+	var e *NotLoadedError
+	return xerrors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -153,7 +154,7 @@ type ConstraintError struct {
 
 // Error implements the error interface.
 func (e ConstraintError) Error() string {
-	return fmt.Sprintf("ent: constraint failed: %s", e.msg)
+	return "ent: constraint failed: " + e.msg
 }
 
 // Unwrap implements the errors.Wrapper interface.
@@ -163,8 +164,8 @@ func (e *ConstraintError) Unwrap() error {
 
 // IsConstraintError returns a boolean indicating whether the error is a constraint failure.
 func IsConstraintError(err error) bool {
-	_, ok := err.(*ConstraintError)
-	return ok
+	var e *ConstraintError
+	return xerrors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {
diff --git a/go.mod b/go.mod
index 8d7088bd2..565f54a50 100644
--- a/go.mod
+++ b/go.mod
@@ -27,4 +27,5 @@ require (
 	go.opencensus.io v0.22.0
 	golang.org/x/sync v0.0.0-20190423024810-112230192c58
 	golang.org/x/tools v0.0.0-20191012152004-8de300cfc20a
+	golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7
 )
diff --git a/go.sum b/go.sum
index 3d07792eb..60341ef46 100644
--- a/go.sum
+++ b/go.sum
@@ -35,8 +35,6 @@ github.com/lib/pq v1.2.0 h1:LXpIM/LZ5xGFhOpXAQUIMM1HdyqzVYM13zNdjCEEcA0=
 github.com/lib/pq v1.2.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
 github.com/mattn/go-runewidth v0.0.4 h1:2BvfKmzob6Bmd4YsL0zygOqfdFnK7GR4QL06Do4/p7Y=
 github.com/mattn/go-runewidth v0.0.4/go.mod h1:LwmH8dsx7+W8Uxz3IHJYH5QSwggIsqBzpuz5H//U1FU=
-github.com/mattn/go-sqlite3 v1.10.0 h1:jbhqpg7tQe4SupckyijYiy0mJJ/pRyHvXf7JdWK860o=
-github.com/mattn/go-sqlite3 v1.10.0/go.mod h1:FPy6KqzDD04eiIsT53CuJW3U88zkxoIYsOqkbpncsNc=
 github.com/mattn/go-sqlite3 v1.11.0 h1:LDdKkqtYlom37fkvqs8rMPFKAMe8+SgjbwZ6ex1/A/Q=
 github.com/mattn/go-sqlite3 v1.11.0/go.mod h1:FPy6KqzDD04eiIsT53CuJW3U88zkxoIYsOqkbpncsNc=
 github.com/mitchellh/mapstructure v1.1.2 h1:fmNYVwqnSfB9mZU6OS2O6GsXM+wcskZDuKQzvN1EDeE=
@@ -91,10 +89,9 @@ golang.org/x/tools v0.0.0-20181030221726-6c7e314b6563/go.mod h1:n7NCudcB/nEzxVGm
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3HoIrodX9oNMXvdceNzlUR8zjMvY=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
-golang.org/x/tools v0.0.0-20190514171724-faff00d7e7f6 h1:MfRv9P1q9msQtpNPKv0olEj2ueVViE36KqlG4Br8bAs=
-golang.org/x/tools v0.0.0-20190514171724-faff00d7e7f6/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
 golang.org/x/tools v0.0.0-20191012152004-8de300cfc20a h1:TwMENskLwU2NnWBzrJGEWHqSiGUkO/B4rfyhwqDxDYQ=
 golang.org/x/tools v0.0.0-20191012152004-8de300cfc20a/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7 h1:9zdDQZ7Thm29KFXgAX/+yaf3eVbP7djjWp/dXAppNCc=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/appengine v1.4.0 h1:/wp5JvzpHIxhs/dumFmF7BXTf3Z+dd4uXta4kVyO508=