Incorrect diagnostic property in query expression

[TharushiJay]

Description:
Consider the diagnostic variable assignment is required at cursor position.

In the diagnostic properties which is used to derive the expected type, we get the bType incorrectly as xml<string> where it should be string[].

For a different case like x1.toBalString(), we get the type correctly as string in the diagnostic properties.

Steps to reproduce:

public function main() {
    xml x1 = xml `<book>The Lost World</book>`;

    from xml element in x1 select element.toBalString();
}

Affected Versions:
2201.2.0 (Swan Lake Update 2)

[pcnfernando]

As per the spec https://ballerina.io/spec/lang/master/#section_6.35,

If there is no contextually expected type, then the basic type of the value constructed is the basic type of expression following in; it is a compile-time error if the static type of this expression is not a subtype of one of the basic types that a query expression can construct.

The basic type the query being resolved to seem to be correct because x1 is a XML. But the constraint comes from the select clause, which is string in this case. Hence the type resolved would be xml<string>. But since we cannot constraint XML with string, we should get an error saying

[github-actions]

This issue is NOT closed with a proper Reason/ label. Make sure to add proper reason label before closing. Please add or leave a comment with the proper reason label now.

      - Reason/EngineeringMistake - The issue occurred due to a mistake made in the past.
      - Reason/Regression - The issue has introduced a regression.
      - Reason/MultipleComponentInteraction - Issue occured due to interactions in multiple components.
      - Reason/Complex - Issue occurred due to complex scenario.
      - Reason/Invalid - Issue is invalid.
      - Reason/Other - None of the above cases.

[SasinduDilshara]

This issue was reopened due to #40497

[github-actions]

This issue is NOT closed with a proper Reason/ label. Make sure to add proper reason label before closing. Please add or leave a comment with the proper reason label now.

      - Reason/EngineeringMistake - The issue occurred due to a mistake made in the past.
      - Reason/Regression - The issue has introduced a regression.
      - Reason/MultipleComponentInteraction - Issue occured due to interactions in multiple components.
      - Reason/Complex - Issue occurred due to complex scenario.
      - Reason/Invalid - Issue is invalid.
      - Reason/Other - None of the above cases.