[GROOVY-7721] Static type checking fails when compiling against a Java8 interface with inherited methods

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.0
• Fix Version/s: 3.0.0-alpha-1, 2.5.0-beta-2, 2.4.13, 2.6.0-alpha-2
• Component/s: Static compilation, Static Type Checker
• Assignee: Daniel Sun
• Reporter: Peter Gromov
• Created: 28/Dec/15 14:25
• Updated: 14/Sep/17 02:07
• Resolved: 13/Sep/17 15:09

Description

Create classes.java:

interface I {
    R[] method();
}

interface I2 extends I {
    R2[] method();
}

interface R {}
interface R2 extends R {}

compile it with JDK 8 javac.

Then create usage.groovy:

import groovy.transform.CompileStatic

@CompileStatic
class Gr {
    R2[] x(I2 i) {
       return i.method();
    }
}

Compile it with groovyc (also run with Java8) with the classes from previous compilation in the classpath. Compilation fails:

usage.groovy: 6: [Static type checking] - Reference to method is ambiguous. Cannot choose between [R2[] I2#method(), R[] I2#method()]
 @ line 6, column 15.
          return i.method();
                 ^

1 error

Originally reported as https://youtrack.jetbrains.com/issue/IDEA-148973

Issue Links

• is related to: GROOVY-7849 Incompatible covariant array return type
• links to: GitHub Pull Request #599