use non-pointer receiver for Marshal* methods

genmethod.go

@@ -48,7 +48,7 @@ func writeFunction(w io.Writer, fs *token.FileSet, fn Function) {
 func genUnmarshalJSON(mtyp *marshalerType) Function {
 	var (
 		m        = newMarshalMethod(mtyp)
-		recv     = m.receiver()
+		recv     = m.receiver(true)
 		input    = Name(m.scope.newIdent("input"))
 		intertyp = m.intermediateType(m.scope.newIdent(m.mtyp.orig.Obj().Name() + "JSON"))
 		dec      = Name(m.scope.newIdent("dec"))
@@ -80,7 +80,7 @@ func genUnmarshalJSON(mtyp *marshalerType) Function {
 func genMarshalJSON(mtyp *marshalerType) Function {
 	var (
 		m        = newMarshalMethod(mtyp)
-		recv     = m.receiver()
+		recv     = m.receiver(false)
 		intertyp = m.intermediateType(m.scope.newIdent(m.mtyp.orig.Obj().Name() + "JSON"))
 		enc      = Name(m.scope.newIdent("enc"))
 		json     = Name(m.scope.parent.packageName("encoding/json"))
@@ -108,7 +108,7 @@ func genMarshalJSON(mtyp *marshalerType) Function {
 func genUnmarshalYAML(mtyp *marshalerType) Function {
 	var (
 		m         = newMarshalMethod(mtyp)
-		recv      = m.receiver()
+		recv      = m.receiver(true)
 		unmarshal = Name(m.scope.newIdent("unmarshal"))
 		intertyp  = m.intermediateType(m.scope.newIdent(m.mtyp.orig.Obj().Name() + "YAML"))
 		dec       = Name(m.scope.newIdent("dec"))
@@ -136,7 +136,7 @@ func genUnmarshalYAML(mtyp *marshalerType) Function {
 func genMarshalYAML(mtyp *marshalerType) Function {
 	var (
 		m        = newMarshalMethod(mtyp)
-		recv     = m.receiver()
+		recv     = m.receiver(false)
 		intertyp = m.intermediateType(m.scope.newIdent(m.mtyp.orig.Obj().Name() + "YAML"))
 		enc      = Name(m.scope.newIdent("enc"))
 	)
@@ -154,9 +154,13 @@ func genMarshalYAML(mtyp *marshalerType) Function {
 	return fn
 }
 
-func (m *marshalMethod) receiver() Receiver {
+func (m *marshalMethod) receiver(pointer bool) Receiver {
 	letter := strings.ToLower(m.mtyp.name[:1])
-	return Receiver{Name: m.scope.newIdent(letter), Type: Star{Value: Name(m.mtyp.name)}}
+	r := Receiver{Name: m.scope.newIdent(letter), Type: Name(m.mtyp.name)}
+	if pointer {
+		r.Type = Star{Value: r.Type}
+	}
+	return r
 }
 
 func (m *marshalMethod) intermediateType(name string) Struct {

internal/tests/mapconv/output.go

@@ -7,7 +7,7 @@ import (
 	"errors"
 )
 
-func (x *X) MarshalJSON() ([]byte, error) {
+func (x X) MarshalJSON() ([]byte, error) {
 	type XJSON struct {
 		Map   map[replacedString]replacedInt
 		Named namedMap2
@@ -56,7 +56,7 @@ func (x *X) UnmarshalJSON(input []byte) error {
 	return nil
 }
 
-func (x *X) MarshalYAML() (interface{}, error) {
+func (x X) MarshalYAML() (interface{}, error) {
 	type XYAML struct {
 		Map   map[replacedString]replacedInt
 		Named namedMap2

internal/tests/nameclash/output.go

@@ -9,7 +9,7 @@ import (
 	json0 "github.com/fjl/gencodec/internal/clashjson"
 )
 
-func (y *Y) MarshalJSON() ([]byte, error) {
+func (y Y) MarshalJSON() ([]byte, error) {
 	type YJSON0 struct {
 		Foo    *json0.Foo   `optional:"true"`
 		Foo2   *json0.Foo   `optional:"true"`
@@ -58,7 +58,7 @@ func (y *Y) UnmarshalJSON(input []byte) error {
 	return nil
 }
 
-func (y *Y) MarshalYAML() (interface{}, error) {
+func (y Y) MarshalYAML() (interface{}, error) {
 	type YYAML struct {
 		Foo    *json0.Foo   `optional:"true"`
 		Foo2   *json0.Foo   `optional:"true"`

internal/tests/sliceconv/output.go

@@ -7,7 +7,7 @@ import (
 	"errors"
 )
 
-func (x *X) MarshalJSON() ([]byte, error) {
+func (x X) MarshalJSON() ([]byte, error) {
 	type XJSON struct {
 		Slice []replacedInt
 		Named namedSlice2
@@ -56,7 +56,7 @@ func (x *X) UnmarshalJSON(input []byte) error {
 	return nil
 }
 
-func (x *X) MarshalYAML() (interface{}, error) {
+func (x X) MarshalYAML() (interface{}, error) {
 	type XYAML struct {
 		Slice []replacedInt
 		Named namedSlice2