Hi @rajshivu,
This is not really what we were looking for. Your approach replaces the variables return and _ with $result, which is incorrect and causes the tests to fail.

To allow $result to represent return values of methods, you need to modify the grammar to allow identifiers to start with $, substitute the variable $result with _ (similarly to return), and finally add some tests to check if your implementation is correct.

Also, if you have any suggestions other than $result, which is not very idiomatic for Java, feel free to let us know!

Hey @rajshivu,
Almost there. Your implementation is not quite correct yet. Currently what you're doing is replacing all return and $result variables with _ in the CreateASTVisitor. That way, the following code passes, when it shouldn't:

void test() {
  @Refinement("$result > 0") // $result is replaced with `_`, which refers to `x`, so it passes
  int x = 1;
}

Actually, $result or return should only be allowed on refinements that target methods, such as:

@Refinement("$result > 0")
int test() {
  return 1;
}

So, we don't actually want to modify the CreateASTVisitor. Instead, we want to modify the MethodsFunctionsChecker. More specifically, the handleFunctionRefinements, and add an additional case for $result, similarly to return:

private Predicate handleFunctionRefinements(RefinedFunction f, CtElement method, List<CtParameter<?>> params) throws LJError {
  // ...
  ret = ret.substituteVariable("return", Keys.WILDCARD);
  ret = ret.substituteVariable("$result", Keys.WILDCARD); // ADD THIS
  f.setRefReturn(ret);
  // ...
}

Finally, please add tests to liquidjava-example/src/main/java/testSuite, not liquidjava-example/src/main/java/testMultiple. For tests that should pass, they must include "Correct" in their file name, whereas for tests that should fail, they should include "Error", along with the expected error in the first line of the file as a comment. To run the tests locally, you can run mvn test.