[GROOVY-10813] Cannot create method reference for print or println

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.13, 4.0.6
• Fix Version/s: 3.0.14, 4.0.7
• Component/s: Static compilation
• Assignee: Eric Milles
• Reporter: Eric Milles
• Created: 04/Nov/22 20:40
• Updated: 10/Feb/23 21:40
• Resolved: 28/Nov/22 16:35

Description

Consider the following:

@groovy.transform.CompileStatic
void p() {
  java.util.function.Consumer c = this::print
  c.accept('hello world!')
}
p()

Throws error "LambdaConversionException: Type mismatch in captured lambda parameter 0: expecting class script, found class java.lang.Object"

I was trying to print a stream element via "this::println". This fails also with "System.out::println" as well. I had to use closure syntax which works just fine. Lambda throws NPE: "Consumer c = obj -> print(obj)"

Issue Links

• relates to: GROOVY-10858 STC method reference return type checking
• links to: GitHub Pull Request #1824