Fix encoding of anonymous struct

encode_compile.go

@@ -1116,7 +1116,7 @@ func encodeAnonymousStructFieldPairMap(tags structTags, named string, valueCode
 			isTaggedKey: f.isTaggedKey,
 		})
 		if f.next != nil && f.nextField != f.next && f.next.op.codeType() == codeStructField {
-			for k, v := range encodeAnonymousStructFieldPairMap(tags, named, f.next) {
+			for k, v := range encodeAnonymousFieldPairRecursively(tags, named, f.next) {
 				anonymousFields[k] = append(anonymousFields[k], v...)
 			}
 		}
@@ -1129,6 +1129,42 @@ func encodeAnonymousStructFieldPairMap(tags structTags, named string, valueCode
 	return anonymousFields
 }
 
+func encodeAnonymousFieldPairRecursively(tags structTags, named string, valueCode *opcode) map[string][]structFieldPair {
+	anonymousFields := map[string][]structFieldPair{}
+	f := valueCode
+	var prevAnonymousField *opcode
+	for {
+		if f.displayKey == "" {
+			if f.nextField == nil {
+				break
+			}
+			prevAnonymousField = f
+			f = f.nextField
+			continue
+		}
+
+		if strings.Contains(f.op.String(), "Anonymous") {
+			key := fmt.Sprintf("%s.%s", named, f.displayKey)
+			anonymousFields[key] = append(anonymousFields[key], structFieldPair{
+				prevField:   prevAnonymousField,
+				curField:    f,
+				isTaggedKey: f.isTaggedKey,
+			})
+			if f.next != nil && f.nextField != f.next && f.next.op.codeType() == codeStructField {
+				for k, v := range encodeAnonymousFieldPairRecursively(tags, named, f.next) {
+					anonymousFields[k] = append(anonymousFields[k], v...)
+				}
+			}
+		}
+		if f.nextField == nil {
+			break
+		}
+		prevAnonymousField = f
+		f = f.nextField
+	}
+	return anonymousFields
+}
+
 func encodeOptimizeConflictAnonymousFields(anonymousFields map[string][]structFieldPair) {
 	removedFields := map[*opcode]struct{}{}
 	for _, fieldPairs := range anonymousFields {

encode_test.go

@@ -409,6 +409,53 @@ func Test_Marshal(t *testing.T) {
 	})
 }
 
+func TestIssue116(t *testing.T) {
+	t.Run("first", func(t *testing.T) {
+		type Boo struct{ B string }
+		type Struct struct {
+			A   int
+			Boo *Boo
+		}
+		type Embedded struct {
+			Struct
+		}
+		b, err := json.Marshal(Embedded{Struct: Struct{
+			A:   1,
+			Boo: &Boo{B: "foo"},
+		}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		expected := `{"A":1,"Boo":{"B":"foo"}}`
+		actual := string(b)
+		if actual != expected {
+			t.Fatalf("expected %s but got %s", expected, actual)
+		}
+	})
+	t.Run("second", func(t *testing.T) {
+		type Boo struct{ B string }
+		type Struct struct {
+			A int
+			B *Boo
+		}
+		type Embedded struct {
+			Struct
+		}
+		b, err := json.Marshal(Embedded{Struct: Struct{
+			A: 1,
+			B: &Boo{B: "foo"},
+		}})
+		if err != nil {
+			t.Fatal(err)
+		}
+		actual := string(b)
+		expected := `{"A":1,"B":{"B":"foo"}}`
+		if actual != expected {
+			t.Fatalf("expected %s but got %s", expected, actual)
+		}
+	})
+}
+
 type marshalJSON struct{}
 
 func (*marshalJSON) MarshalJSON() ([]byte, error) {