[GROOVY-8839] Static compilation and array type parameter causing compile error

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.15
• Fix Version/s: 2.5.0
• Assignee: Unassigned
• Reporter: Eric Milles
• Created: 10/Oct/18 14:58
• Updated: 11/Oct/18 21:23
• Resolved: 11/Oct/18 15:16

Description

This seems related to GROOVY-8342 (and possibly GROOVY-8638 and GROOVY-7985). When using an array in a generics parameter, I get static compilation errors for return of a map and also for assignment of return value to a variable.

package r;
public class ResultHandle {}

package p
import groovy.transform.CompileStatic
import r.ResultHandle
@CompileStatic
class Issue {
  protected Map<String, ResultHandle[]> getResultsByType() {
    Map<String, ResultHandle[]> resultsByType = [:]
    // populate resultsByType
    return resultsByType
  }
}

When I build using Ant, I get the following error:

Buildfile: ...\Gr8\build.xml
-init:
-compile:
    [mkdir] Created dir: ...\Gr8\ant\JavaClasses
  [compile] Compiling 2 source files to ...\Gr8\ant\JavaClasses
  [compile] org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
  [compile] ...\Gr8\src\main\bugs\Groovy1234.groovy: 12: [Static type checking] - Incompatible generic argument types. Cannot assign java.util.LinkedHashMap <java.lang.String, [Lr.ResultHandle;> to: java.util.Map <String, ResultHandle[]>
  [compile]  @ line 12, column 12.
  [compile]        return resultsByType
  [compile]               ^
  [compile] 1 error

BUILD FAILED

Additionally, I would get an error if I assigned the result of the method to a typed variable, like this: Map<String, ResultHandle[]> resultsByType = getResultsByType()