[GROOVY-9267] Static compilation confuses generic type parameters

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 2.4.15, 2.5.8, 3.0.0-beta-3
• Component/s: Static compilation
• Assignee: Unassigned
• Reporter: Onni Koskinen
• Created: 04/Oct/19 07:58
• Updated: 04/Oct/19 15:36
• Resolved: 04/Oct/19 15:36

Description

Given the following snippet

import java.util.function.*

@groovy.transform.CompileStatic
class A {
    static <T> T f(Function<String, T> funcParam) {
        T result = funcParam.apply("hello")
        return result
    }
    
    static <TT> TT g(Function<String, TT> funcParam) {
        TT result = funcParam.apply("hello")
        return result
    }
}

def result1 = A.f({ String s -> s.length() })
def result2 = A.g({ String s -> s.length() })

assert result1.class == result2.class

one would assume the assertion to pass (with both results being of class Integer). Instead f's type parameter T is apparently confused with Function's type parameter of the same name and we get the following result: 

Assertion failed: 

assert result1.class == result2.class
       |       |     |  |       |
       '5'     |     |  5       class java.lang.Integer
               |     false
               class java.lang.String

	at ConsoleScript0.run(ConsoleScript0:19)

Originally encountered with Groovy 2.4.15 but also verified to be present on latest stable 2.5.8 as well as 3.0.0-beta-3.

 

Issue Links

• duplicates: GROOVY-8409 Static compilation with generic function wrapping BiFunction causes GroovyCastException