[GROOVY-10734] STC doesn't resolve zero-argument method references in nested generics

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 4.0.4
• Fix Version/s: 4.0.5, 3.0.13
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Christopher Smith
• Created: 30/Aug/22 20:41
• Updated: 10/Feb/23 21:40
• Resolved: 03/Sep/22 16:30

Description

I have a rather mundane Streams pipeline trying to group some items by a particular property.

@CompileStatic
class GroovyExample {
    String category
    String title

    static Object organize(Collection<GroovyExample> examples) {
        examples.stream()
            .collect(groupingBy(GroovyExample::getCategory))
    }
}

This produces

Failed to find the expected method[getCategory(java.lang.Object)] in the type[GroovyExample]

This feels similar to GROOVY-9803 in that the apparent problem is a result of a nested generic call that, while unambiguous according to the JLS rules, doesn't get propagated tightly enough for the STC to correctly recognize that the target type is GroovyExample and thus the zero-argument method is the correct resolution.

Issue Links

• is related to: GROOVY-10054 STC: Cannot infer lambda parameter types for a stream collector
• is related to: GROOVY-10741 STC method pointer or reference to generated property method