Task overwriting throws exception (Gradle 1.9-rc-2)

In certain scenarios, Gradle 1.9-rc-2 is throwing exceptions when overwriting tasks. It appears it occurs if you overwrite a task that has already been overwritten:

repositories {
    // Use 'maven central' for resolving your dependencies.
    // You can declare any Maven/Ivy/file repository here.
  // In this section you declare the dependencies for your production and test code
dependencies {
    // We use the latest groovy 2.x version for building this library
    //compile 'org.codehaus.groovy:groovy:2.1.7'
      // We use the awesome Spock testing and specification framework
    //testCompile 'org.spockframework:spock-core:0.7-groovy-2.0'
    //testCompile 'junit:junit:4.11'
apply plugin: 'groovy'
  task clean(type: Delete, overwrite: true) {
    delete buildDir
  task clean(type: Delete, overwrite: true) {
    delete buildDir

Results in this message:

$ gradle tasks
  FAILURE: Build failed with an exception.
  * Where:
Build file '/Users/jengelman/workspace/personal/overwrite-test/build.gradle' line: 34
  * What went wrong:
A problem occurred evaluating root project 'overwrite-test'.
> Tried to remove model tasks.clean but it is not registered
  * Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
  Total time: 0.718 secs

Running this same command in Gradle 1.8 results in a successful build.

thanks for reporting this. Can you confirm that the issue is fixed with the 1.9 snapshot available at http://services.gradle.org/distributions-snapshots/gradle-1.9-20131030210600+0000-bin.zip ?

cheers, René