Fix the invalid error for readonly record types

.github/CODEOWNERS

@@ -4,4 +4,4 @@
 # See: https://help.github.com/articles/about-codeowners/
 
 # These owners will be the default owners for everything in the repo.
-*       @gimantha @MaryamZi @hasithaa
+*       @gimantha @MaryamZi @hasithaa @SasinduDilshara

ballerina/tests/from_json_string_test.bal

@@ -60,6 +60,37 @@ isolated function testSimpleJsonStringToRecord() returns Error? {
     test:assertEquals(recC.get("b"), 1);
 }
 
+type ReadOnlyUser readonly & record {|
+    int id;
+|};
+
+@test:Config
+isolated function testSimpleJsonStringToRecord2() returns Error? {
+    string user = string `{"id": 4012}`;
+    ReadOnlyUser r = check parseString(user);
+    test:assertEquals(r, {id: 4012});
+}
+
+public type UserId readonly & int;
+
+public type UserName readonly & record {
+    string firstname;
+    string lastname;
+};
+
+type ReadOnlyUser2 readonly & record {|
+    UserId id;
+    UserName name;
+    int age;
+|};
+
+@test:Config
+isolated function testSimpleJsonStringToRecord3() returns Error? {
+    string user = string `{"id": 4012, "name": {"firstname": "John", "lastname": "Doe"}, "age": 27}`;
+    ReadOnlyUserRecord2 r = check parseString(user);
+    test:assertEquals(r, {id: 4012, age: 27, name: {firstname: "John", lastname: "Doe"}});
+}
+
 @test:Config
 isolated function testSimpleJsonStringToRecordWithProjection() returns Error? {
     string str = string `{"a": "hello", "b": 1}`;

ballerina/tests/from_json_test.bal

@@ -67,6 +67,55 @@ isolated function testSimpleJsonToRecord() returns Error? {
     test:assertEquals(recC.get("b"), 1);
 }
 
+type ReadOnlyUserRecord readonly & record {|
+    int id;
+|};
+
+@test:Config
+isolated function testSimpleJsonToRecord2() returns Error? {
+    json user = {id: 4012};
+    ReadOnlyUserRecord r = check parseAsType(user);
+    test:assertEquals(r, {id: 4012});
+}
+
+public type ReadonlyUserId readonly & int;
+
+public type ReadonlyUserName readonly & record {
+    string firstname;
+    string lastname;
+};
+
+type ReadOnlyUserRecord2 readonly & record {|
+    ReadonlyUserId id;
+    ReadonlyUserName name;
+    int age;
+|};
+
+@test:Config
+isolated function testSimpleJsonToRecord3() returns Error? {
+    json user = {id: 4012, name: {firstname: "John", lastname: "Doe"}, age: 27};
+    ReadOnlyUserRecord2 r = check parseAsType(user);
+    test:assertEquals(r, {id: 4012, age: 27, name: {firstname: "John", lastname: "Doe"}});
+}
+
+type UserRecord3 ReadOnlyUserRecord2;
+
+@test:Config
+isolated function testSimpleJsonToRecord4() returns Error? {
+    json user = {id: 4012, name: {firstname: "John", lastname: "Doe"}, age: 27};
+    UserRecord3 r = check parseAsType(user);
+    test:assertEquals(r, {id: 4012, age: 27, name: {firstname: "John", lastname: "Doe"}});
+}
+
+@test:Config
+isolated function testSimpleJsonToRecord5() returns Error? {
+    ReadonlyUserName username = {firstname: "John", lastname: "Doe"};
+    record{string firstname; string lastname;} nameRec = username;
+    json user = {id: 4012, name: nameRec.toJson(), age: 27};
+    ReadOnlyUserRecord2 r = check parseAsType(user);
+    test:assertEquals(r, {id: 4012, age: 27, name: {firstname: "John", lastname: "Doe"}});
+}
+
 @test:Config
 isolated function testSimpleJsonToRecordWithProjection() returns Error? {
     json j = {"a": "hello", "b": 1};

native/src/main/java/io/ballerina/lib/data/jsondata/json/JsonParser.java

@@ -249,7 +249,7 @@ public Object execute(Reader reader, BMap<BString, Object> options, Type type) t
                 }
                 case TypeTags.INTERSECTION_TAG -> {
                     Type effectiveType = ((IntersectionType) type).getEffectiveType();
-                    if (!SymbolFlags.isFlagOn(SymbolFlags.READONLY, effectiveType.getFlags())) {
+                    if (!effectiveType.isReadOnly()) {
                         throw DiagnosticLog.error(DiagnosticErrorCode.UNSUPPORTED_TYPE, type);
                     }
 

native/src/main/java/io/ballerina/lib/data/jsondata/json/JsonTraverse.java

@@ -158,7 +158,7 @@ private Object traverseJson(Object json, Type type) {
                 }
                 case TypeTags.INTERSECTION_TAG -> {
                     Type effectiveType = ((IntersectionType) referredType).getEffectiveType();
-                    if (!SymbolFlags.isFlagOn(SymbolFlags.READONLY, effectiveType.getFlags())) {
+                    if (!effectiveType.isReadOnly()) {
                         throw DiagnosticLog.error(DiagnosticErrorCode.UNSUPPORTED_TYPE, type);
                     }
                     for (Type constituentType : ((IntersectionType) referredType).getConstituentTypes()) {