[GROOVY-6215] Problem with @TypeChecked and switch statements

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.1.5
• Fix Version/s: 2.1.6
• Component/s: Compiler
• Assignee: Cédric Champeau
• Reporter: Jeff Brown
• Created: 24/Jun/13 11:24
• Updated: 10/Jul/13 04:42
• Resolved: 26/Jun/13 10:06

Description

Demo.groovy

import groovy.transform.CompileStatic

@CompileStatic
class Demo {

    def processNumber(int x) {
        def value = getValueForNumber(x)
        value
    }

    def getValueForNumber(int x) {
        def valueToReturn
        switch(x) {
            case 1:
                valueToReturn = 'One'
                break
            case 2:
                valueToReturn = []
                valueToReturn << 'Two'
                break
        }
        valueToReturn
    }

    static void main(args) {
        def demo = new Demo()
        println demo.processNumber(1)
        println demo.processNumber(2)
        println demo.processNumber(3)
    }
}

That code will throw a ClassCastException.

 $ groovy Demo
Caught: org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'One' with class 'java.lang.String' to class 'java.util.List'
org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'One' with class 'java.lang.String' to class 'java.util.List'
	at Demo.processNumber(Demo.groovy:7)
	at Demo.main(Demo.groovy:27)

The compiler is generating the following code for the processNumber method:

 @TypeChecked.TypeCheckingInfo(inferredType="AAlDbGFzc05vZGUAABBMamF2YS91dGlsL0xpc3Q7AQAAAAEBAAAJQ2xhc3NOb2RlAAASTGphdmEvbGFuZy9PYmplY3Q7AQAAAAEBAAAJQ2xhc3NOb2RlAAADTEU7Af////8A/////wAAAAABAAlDbGFzc05vZGUAABJMamF2YS9sYW5nL09iamVjdDsA/////w==", version=1)
  public Object processNumber(int x)
  {
    List value = (List)ScriptBytecodeAdapter.castToType(getValueForNumber(x), List.class);
    return value; return null;
  }

It appears that the compiler is picking up the type from whatever the last case statement is.