Description of problem:
Given a DSL configuration containing
> [when]Foo with

{var} bars=Foo( bars == {var}

)

and a probably incorrect rule containing
> when
> Foo with

{var} bars

When this rule is expanded by org.drools.lang.dsl.DefaultExpander the expansion gets stuck in an infinite loop, probably substituting {var}

with

{var}

again and again.