[GROOVY-7118] @Delegate for class that implements interface with Generic Method causes VerifyError

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3.7, 2.4.0-beta-3
• Fix Version/s: 2.4.0-rc-2
• Component/s: xforms
• Environment: JDK 1.80; JDK 1.7.0_60; ; Mac OS X
• Assignee: Paul King
• Reporter: John Engelman
• Created: 15/Oct/14 10:24
• Updated: 21/Jan/15 15:26
• Resolved: 05/Jan/15 05:01

Description

Using the @Delegate annotation on a class that implements an interface where the interface defines a generic method causes a runtime VerifyError.
This occurs regardless of the interface being defined in Java or Groovy.

Additionally it does not occur if the @Delegate instance does not implement an interface while still defining the same method.

Attached an example project that exhibits the error when trying to run Spock tests using './gradlew test'

java.lang.VerifyError: Bad return type
Exception Details:
  Location:
    foo/FooSpec.get(Ljava/lang/Class;)Ljava/lang/Throwable; @5: areturn
  Reason:
    Type 'java/lang/Object' (current frame, stack[0]) is not assignable to 'java/lang/Throwable' (from method signature)
  Current Frame:
    bci: @5
    flags: { }
    locals: { 'foo/FooSpec', 'java/lang/Class' }
    stack: { 'java/lang/Object' }
  Bytecode:
    0000000: 2a2b b601 07b0