Gradle 2.14-rc-1 Shadow issue

build.gradle

task shadow(type: ShadowJar) {
  transform(GroovyExtensionModuleTransformer) //this is the line in the script that errors
}

ShadowJar.java

public class ShadowJar extends CopySpec {
  
    public <T extends Transformer> ShadowSpec transform(Class<T> clazz) throws InstantiationException, IllegalAccessException {
      //..
    }

    public <T extends Transformer> ShadowSpec transform(Class<T> clazz, Action<T> configure) throws InstantiationException, IllegalAccessException {
      //..
    }
}

stacktrace

Caused by: java.lang.IllegalArgumentException: argument type mismatch
	at org.gradle.internal.metaobject.BeanDynamicObject$MetaClassAdapter.invokeMethod(BeanDynamicObject.java:342)
	at org.gradle.internal.metaobject.BeanDynamicObject.invokeMethod(BeanDynamicObject.java:153)
	at org.gradle.internal.metaobject.CompositeDynamicObject.invokeMethod(CompositeDynamicObject.java:98)
	at org.gradle.internal.metaobject.ConfigureDelegate.invokeMethod(ConfigureDelegate.java:58)
	at build_8kqk7sdz791ni980spg9qwrl3$_run_closure1.doCall(/private/var/folders/wd/bt6km58d1g3ffqsg41hgmxp80000gn/T/junit3750280684062064164/build.gradle:19)
	at org.gradle.api.internal.ClosureBackedAction.execute(ClosureBackedAction.java:67)
	at org.gradle.util.ConfigureUtil.configureSelf(ConfigureUtil.java:136)
	at org.gradle.api.internal.AbstractTask.configure(AbstractTask.java:522)
	at org.gradle.api.internal.project.AbstractProject.task(AbstractProject.java:943)
	at org.gradle.internal.metaobject.BeanDynamicObject$MetaClassAdapter.invokeMethod(BeanDynamicObject.java:342)
	at org.gradle.internal.metaobject.BeanDynamicObject.invokeMethod(BeanDynamicObject.java:153)
	at org.gradle.internal.metaobject.CompositeDynamicObject.invokeMethod(CompositeDynamicObject.java:98)
	at org.gradle.internal.metaobject.AbstractDynamicObject.invokeMethod(AbstractDynamicObject.java:163)
	at org.gradle.groovy.scripts.BasicScript.methodMissing(BasicScript.java:79)
	at build_8kqk7sdz791ni980spg9qwrl3.run(/private/var/folders/wd/bt6km58d1g3ffqsg41hgmxp80000gn/T/junit3750280684062064164/build.gradle:14)
	at org.gradle.groovy.scripts.internal.DefaultScriptRunnerFactory$ScriptRunnerImpl.run(DefaultScriptRunnerFactory.java:91)