Compiler shows warning for ArrayElementType (regression)

Steps to reproduce:
1. Have a source file which contains arrayelementtype metadata e.g.
[ArrayElementType="com.rma.command.Command"]
public var commands:Array;
2. compile in flexbuilder
3. or compile with mxmlc from command line

Actual Results:
Should compile fine

Expected Results:
Warnings in both command line and flashbuilder/flexbuilder
Also causes compiler to behave irratically

Stack of warning is:

Description Resource Path Location Type
flex2.compiler.as3.SignatureExtension.SignatureGenerationFailed[node='MetaData', level='warning', cause='flex2.compiler.as3.SignatureAssertionRuntimeException: Sanity Failed
at flex2.compiler.as3.SignatureEvaluator.ASSERT(SignatureEvaluator.java:369)
at flex2.compiler.as3.SignatureEvaluator.ASSERT_SANITY(SignatureEvaluator.java:347)
at flex2.compiler.as3.SignatureEvaluator.evaluate(SignatureEvaluator.java:1012)
at macromedia.asc.parser.MetaDataNode.evaluate(MetaDataNode.java:38)
at flash.swf.tools.as3.EvaluatorAdapter.evaluate(EvaluatorAdapter.java:338)
at flex2.compiler.as3.SignatureEvaluator.evaluate(SignatureEvaluator.java:1795)
at macromedia.asc.parser.StatementListNode.evaluate(StatementListNode.java:60)
at flex2.compiler.as3.SignatureEvaluator.evaluate(SignatureEvaluator.java:530)
at macromedia.asc.parser.ClassDefinitionNode.evaluate(ClassDefinitionNode.java:106)
at flash.swf.tools.as3.EvaluatorAdapter.evaluate(EvaluatorAdapter.java:338)
at flex2.compiler.as3.SignatureEvaluator.evaluate(SignatureEvaluator.java:1795)
at macromedia.asc.parser.StatementListNode.evaluate(StatementListNode.java:60)
at flex2.compiler.as3.SignatureEvaluator.evaluate(SignatureEvaluator.java:454)
at macromedia.asc.parser.ProgramNode.evaluate(ProgramNode.java:80)
at flex2.compiler.as3.SignatureExtension.generateSignature(SignatureExtension.java:270)
at flex2.compiler.as3.SignatureExtension.doSignatureGeneration(SignatureExtension.java:174)
at flex2.compiler.as3.SignatureExtension.parse1(SignatureExtension.java:137)
at flex2.compiler.as3.Compiler.parse1(Compiler.java:369)

', column='8', path='/Developer/source/met/spr_onm/flex/common/src/com/rma/command/CommandQueue.as', line='10'] CommandQueue.as common/src/com/rma/command line 10 Flex Problem

Workaround (if any):
Comment out the arrayelement type metadata I would like to just ignore the warning, but it seems to cause the compiler to sometimes 'hide' the classes that contain this metadata. The upshot of that is that it breaks any dependant classes.

Note this IS a duplicate of another issue with the same title, which appears to have regressed.