[GROOVY-9374] Type-inference fails for tap on inner classes with type checking

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.5.9
• Fix Version/s: 3.0.0
• Environment: Groovy 2.5.9. on Zulu JDK 11.0.3; Linux
• Assignee: Eric Milles
• Reporter: Jan Hackel
• Created: 27/Jan/20 13:17
• Updated: 14/Sep/20 18:48
• Resolved: 04/Feb/20 20:31

Description

The following code will not compile with Groovy 2.5.9. It produces an error "[Static type checking] - Cannot assign value of type java.lang.Object to variable of type java.time.LocalDate". Same thing happens for instance fields.

A workaround is to qualify the source field either by this or by class name.

import groovy.transform.CompileStatic
import java.time.LocalDate

@CompileStatic
class TapTypeChecking {

  private static final LocalDate DATE = LocalDate.of(2020, 2, 1)

  static Inner inner() {
    return new Inner().tap {
      someDate = DATE
    }
  }

  static class Inner {

    LocalDate someDate
  }
}