entc/gen: define method receiver on enum fields (#580)

Signed-off-by: Alex Snast <alexsn@fb.com>

entc/gen/template/meta.tmpl

@@ -106,19 +106,19 @@ const (
 			{{-  end }}
 		)
 
-		func (s {{ $enum }}) String() string {
-			return string(s)
+		{{ $receiver := receiver $f.BuilderField -}}
+		func ({{ $receiver }} {{ $enum }}) String() string {
+			return string({{ $receiver }})
 		}
 
 		{{ $name := $f.Validator -}}
-		{{ $arg := receiver $f.BuilderField }}
-		// {{ $name }} is a validator for the "{{ $arg }}" field enum values. It is called by the builders before save.
-		func {{ $name }}({{ $arg }} {{ $enum }}) error {
-			switch {{ $arg }} {
+		// {{ $name }} is a validator for the "{{ $receiver }}" field enum values. It is called by the builders before save.
+		func {{ $name }}({{ $receiver }} {{ $enum }}) error {
+			switch {{ $receiver }} {
 				case {{ range $i, $e := $f.Enums }}{{ if ne $i 0 }},{{ end }}{{ $f.StructField }}{{ pascal $e }}{{ end }}:
 					return nil
 				default:
-					return fmt.Errorf("{{ $.Package }}: invalid enum value for {{ $f.Name }} field: %q", {{ $arg }})
+					return fmt.Errorf("{{ $.Package }}: invalid enum value for {{ $f.Name }} field: %q", {{ $receiver }})
 			}
 		}
 	{{ end }}

entc/integration/ent/user/user.go

@@ -167,8 +167,8 @@ const (
 	RoleAdmin Role = "admin"
 )
 
-func (s Role) String() string {
-	return string(s)
+func (r Role) String() string {
+	return string(r)
 }
 
 // RoleValidator is a validator for the "r" field enum values. It is called by the builders before save.

entc/integration/gremlin/ent/user/user.go

@@ -100,8 +100,8 @@ const (
 	RoleAdmin Role = "admin"
 )
 
-func (s Role) String() string {
-	return string(s)
+func (r Role) String() string {
+	return string(r)
 }
 
 // RoleValidator is a validator for the "r" field enum values. It is called by the builders before save.

entc/integration/privacy/ent/galaxy/galaxy.go

@@ -67,8 +67,8 @@ const (
 	TypeIrregular    Type = "irregular"
 )
 
-func (s Type) String() string {
-	return string(s)
+func (_type Type) String() string {
+	return string(_type)
 }
 
 // TypeValidator is a validator for the "_type" field enum values. It is called by the builders before save.