[GROOVY-6358] @CompileStatic doesn't determine correct type for return from generic static method

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.1.7
• Fix Version/s: 2.3.1
• Component/s: Static compilation
• Assignee: Cédric Champeau
• Reporter: Adam Brown
• Created: 23/Sep/13 16:05
• Updated: 20/May/14 05:31
• Resolved: 16/May/14 12:34

Description

The following code produces the compilation error:

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
bad.groovy: 20: [Static type checking] - Cannot assign value of type java.lang.Object to variable of type Ifc
 @ line 20, column 16.
   	    Ifc ifc = Generator.create(Ifc)
                  ^

1 error

import groovy.transform.CompileStatic
import java.lang.reflect.Method

interface Ifc {
	void method()
}

@CompileStatic
class Generator {
	static <T> T create (Class<T> clazz) {
	    return clazz.methods.collectEntries { Method method ->
	        [ (method.name) : { println "${method.name} called"} ]
	    }.asType(clazz)
	}
}

@CompileStatic
class User {
	static void main() {
	    Ifc ifc = Generator.create(Ifc)
	    ifc.method()
	}
}

User.main()

Without the @CompileStatic on the User class, the code compiles and runs as expected.