Remove casts to imported anonymous types and add a validation to disallow the same

[MaryamZi]

Purpose

$title, as a temporary fix for #28262.

Not sure if we can write a test for either change.

Check List

• Read the Contributing Guide
• Updated Change Log
• Checked Tooling Support (#)
• Added necessary tests
  • Unit Tests
  • Spec Conformance Tests
  • Integration Tests
  • Ballerina By Example Tests
• Increased Test Coverage
• Added necessary documentation
  • API documentation
  • Module documentation in Module.md files
  • Ballerina By Examples

[rdhananjaya]

Out of curiosity, what happens if we don't have this conversion here? Issues in jvm codegen or does it get re-added somehow via desugaring the desugared constructs?

[MaryamZi]

So the type of expr ($result$) here is the union of a record and nil - record {|T value;|}?. Although semantically it is invalid to do $result$.value in such a scenario, desugaring proceeds as a field access on a record union due to the check at https://github.com/ballerina-platform/ballerina-lang/blob/master/compiler/ballerina-lang/src/main/java/org/wso2/ballerinalang/compiler/desugar/Desugar.java#L5171. And then at org.wso2.ballerinalang.compiler.bir.codegen.JvmInstructionGen#generateMapLoadIns we don't seem to be adding a cast so probably works as is there?

[KRVPerera]

Better if we can add a positive test case which was failing previously with anonemous type cast.

[MaryamZi]

Better if we can add a positive test case which was failing previously with anonemous type cast.

Any suggestions on how we can add such a test?

There are several conditions that needs to be met. For example if we consider using foreach with an array

1. need to have two compatible lang.array versions where both have different names for the anonymous types
2. need to build the JAR using the pack with one version and then run it using a pack with the other

[MaryamZi]

Better if we can add a positive test case which was failing previously with anonemous type cast.

Any suggestions on how we can add such a test?

There are several conditions that needs to be met. For example if we consider using foreach with an array

1. need to have two compatible lang.array versions where both have different names for the anonymous types
2. need to build the JAR using the pack with one version and then run it using a pack with the other

Will go ahead and merge this for now, will add a test in a separate PR if we can figure out a way to test this.