Incremental compilation fails in Hero SDK when mx:Legend is present.

Steps to reproduce:
1. Create a new Flex project in Flash Builder.
2. Make sure Flex SDK 18510 or later is being used.
3. Add <mx:Legend /> to the main application.
4. Save.

Actual Results:

Compilation errors.
Error 1046: type was not found or was not a compile time constant [mx.core]::IChildList.
Error 1046: type was not found or was not a compile time constant [mx.core]::IContainer.
Could not resolve <mx:Legend> into a component implementation

In the developer environment, the compiler fires an assertion:

"There is a problem in one of the compiler algorithms. Please use --conservative=true to compiler. Also please file a bug report."

And as suggested, putting -conservative true fixes the issue.

Expected Results:

No compilation errors.

Workaround:

Use -conservative true.

Notes:

• My understanding is that charts have been refactored recently, this may be related to that.