unbalanced braces ( ... ) error when performing equalsIgnoreCase where LHS contains !. operator ----------------------------------------------------------------------------------------------- Key: DROOLS-82 URL: https://issues.jboss.org/browse/DROOLS-82 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Affects Versions: 5.5 Reporter: Marcin Grzejszczak Assignee: Mario Fusco Attachments: Test.zip GIVEN RULE: rule "Nested nested model rule - doesn't compile" dialect "mvel" when $model : Model( $nestedModel : nestedModel, $nestedNestedModel : nestedModel!.nestedNestedModel, "NestedNestedModelName".equalsIgnoreCase(nestedModel!.nestedNestedModel!.nestedNestedModelName) ) then System.out.println( "I'm a nested nested model! My name is [" + $nestedNestedModel.nestedNestedModelName +"] " ); end The following error occurs: Caused by: java.lang.RuntimeException: Unable to Analyse Expression "NestedNestedModelName".equalsIgnoreCase(nestedModel != null && "NestedNestedModelName".equalsIgnoreCase(nestedModel.nestedNestedModel != null && "NestedNestedModelName".equalsIgnoreCase(nestedModel.nestedNestedModel.nestedNestedModelName): [Error: unbalanced braces ( ... )] [Near : {... me".equalsIgnoreCase(nestedModel != null && "Neste ....}] ^ [Line: 6, Column: 4] : [Rule name='Nested nested model rule - doesn't compile'] at org.drools.container.spring.beans.KnowledgeBaseBeanFactory.afterPropertiesSet(KnowledgeBaseBeanFactory.java:121) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1477) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1417) ... 17 more The project needed to replicate the issue is attached to the issue