NPE (fatal) when using bound var to non-existing field in eval

rule foo
when
Integer( $i : noSuchValue )
eval( $i > 0 )
then
end

Exception in thread "main" java.lang.NullPointerException
at org.drools.rule.builder.dialect.java.DeclarationTypeFixer.fix(DeclarationTypeFixer.java:9)
at org.drools.rule.builder.dialect.java.AbstractJavaRuleBuilder.createVariableContext(AbstractJavaRuleBuilder.java:95)
at org.drools.rule.builder.dialect.java.JavaEvalBuilder.build(JavaEvalBuilder.java:79)
at org.drools.rule.builder.dialect.java.JavaEvalBuilder.build(JavaEvalBuilder.java:40)
at org.drools.rule.builder.GroupElementBuilder.build(GroupElementBuilder.java:65)
at org.drools.rule.builder.RuleBuilder.build(RuleBuilder.java:81)
at org.drools.compiler.PackageBuilder.addRule(PackageBuilder.java:1648)
at org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:699)
at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:317)
at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:495)
at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:28)