making it defensive as I'm seeing the following stack trace while using this script:

 java.lang.NullPointerException
 	at org.codehaus.groovy.runtime.callsite.PojoMetaClassSite.checkCall(PojoMetaClassSite.java:54)
 	at org.codehaus.groovy.runtime.callsite.PojoMetaClassSite.call(PojoMetaClassSite.java:42)
 	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:112)
 	at dsld.IntelliJ$_run_closure1.doCall(IntelliJ.gdsl:15)
 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 	at java.lang.reflect.Method.invoke(Method.java:597)
 	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
 	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
 	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:272)
 	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:884)
 	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.callCurrent(PogoMetaClassSite.java:66)
 	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:141)
 	at dsld.IntelliJ$_run_closure1.doCall(IntelliJ.gdsl)
 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 	at java.lang.reflect.Method.invoke(Method.java:597)
 	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
 	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
 	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:272)
 	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:884)
 	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:39)
 	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:42)
 	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:54)
 	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:112)
 	at org.jetbrains.plugins.groovy.dsl.GroovyDslExecutor$_processVariants_closure16.doCall(GroovyDslExecutor.groovy:168)
 	at sun.reflect.GeneratedMethodAccessor290.invoke(Unknown Source)
 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 	at java.lang.reflect.Method.invoke(Method.java:597)
 	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
 	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
 	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:272)
 	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:884)
 	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.callCurrent(PogoMetaClassSite.java:66)
 	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:141)
 	at org.jetbrains.plugins.groovy.dsl.GroovyDslExecutor$_processVariants_closure16.doCall(GroovyDslExecutor.groovy)
 	at sun.reflect.GeneratedMethodAccessor289.invoke(Unknown Source)
 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 	at java.lang.reflect.Method.invoke(Method.java:597)
 	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
 	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
 	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:272)
 	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:884)
 	at groovy.lang.Closure.call(Closure.java:412)
 	at groovy.lang.Closure.call(Closure.java:406)
 	at org.codehaus.groovy.runtime.GroovyCategorySupport$ThreadCategoryInfo.use(GroovyCategorySupport.java:118)
 	at org.codehaus.groovy.runtime.GroovyCategorySupport.use(GroovyCategorySupport.java:257)
 	at org.codehaus.groovy.runtime.DefaultGroovyMethods.use(DefaultGroovyMethods.java:440)
 	at org.codehaus.groovy.runtime.dgm$883.invoke(Unknown Source)
 	at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoMetaMethodSiteNoUnwrapNoCoerce.invoke(PogoMetaMethodSite.java:308)
 	at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.callCurrent(PogoMetaMethodSite.java:52)
 	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:145)
 	at org.jetbrains.plugins.groovy.dsl.GroovyDslExecutor.processVariants(GroovyDslExecutor.groovy:167)
 	at org.jetbrains.plugins.groovy.dsl.GroovyDslScript.addGdslMembers(GroovyDslScript.java:90)
 	at org.jetbrains.plugins.groovy.dsl.GroovyDslScript.processExecutor(GroovyDslScript.java:69)
 	at org.jetbrains.plugins.groovy.dsl.GroovyDslFileIndex.processExecutors(GroovyDslFileIndex.java:248)
 	at org.jetbrains.plugins.groovy.lang.resolve.NonCodeMembersContributor.runContributors(NonCodeMembersContributor.java:108)
 	at org.jetbrains.plugins.groovy.lang.resolve.ResolveUtil.processNonCodeMembers(ResolveUtil.java:197)
 	at org.jetbrains.plugins.groovy.lang.resolve.ResolveUtil.processNonCodeMembers(ResolveUtil.java:187)
 	at org.jetbrains.plugins.groovy.lang.resolve.ResolveUtil.treeWalkUp(ResolveUtil.java:114)
 	at org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.GrReferenceResolveUtil.resolveImpl(GrReferenceResolveUtil.java:44)
 	at org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.GrReferenceExpressionImpl.resolveMethodOrProperty(GrReferenceExpressionImpl.java:240)
 	at org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.GrReferenceExpressionImpl.doPolyResolve(GrReferenceExpressionImpl.java:654)
 	at org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.GrReferenceExpressionImpl.access$100(GrReferenceExpressionImpl.java:73)
 	at org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.GrReferenceExpressionImpl$3.resolve(GrReferenceExpressionImpl.java:459)
 	at org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.GrReferenceExpressionImpl$3.resolve(GrReferenceExpressionImpl.java:457)
 	at com.intellij.psi.impl.source.resolve.ResolveCache$2.compute(ResolveCache.java:129)
 	at com.intellij.openapi.util.RecursionManager$2.doPreventingRecursion(RecursionManager.java:106)
 	at com.intellij.psi.impl.source.resolve.ResolveCache.a(ResolveCache.java:134)
 	at com.intellij.psi.impl.source.resolve.ResolveCache.resolveWithCaching(ResolveCache.java:145)
 	at org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.GrReferenceExpressionImpl.advancedResolve(GrReferenceExpressionImpl.java:763)
 	at org.jetbrains.plugins.groovy.annotator.GroovyAnnotator.visitReferenceExpression(GroovyAnnotator.java:187)
 	at org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.GrReferenceExpressionImpl.accept(GrReferenceExpressionImpl.java:346)
 	at org.jetbrains.plugins.groovy.annotator.GroovyAnnotator.annotate(GroovyAnnotator.java:128)
 	at com.intellij.codeInsight.daemon.impl.DefaultHighlightVisitor.a(DefaultHighlightVisitor.java:157)
 	at com.intellij.codeInsight.daemon.impl.DefaultHighlightVisitor.visit(DefaultHighlightVisitor.java:100)
 	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass$8.run(GeneralHighlightingPass.java:595)
 	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.a(GeneralHighlightingPass.java:773)
 	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.access$3600(GeneralHighlightingPass.java:80)
 	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass$10.run(GeneralHighlightingPass.java:779)
 	at com.intellij.codeInsight.daemon.impl.DefaultHighlightVisitor.analyze(DefaultHighlightVisitor.java:84)
 	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.a(GeneralHighlightingPass.java:776)
 	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.access$3600(GeneralHighlightingPass.java:80)
 	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass$10.run(GeneralHighlightingPass.java:779)
 	at com.intellij.codeInsight.daemon.impl.RefCountHolder.analyze(RefCountHolder.java:250)
 	at com.intellij.codeInsight.daemon.impl.analysis.HighlightVisitorImpl.analyze(HighlightVisitorImpl.java:135)
 	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.a(GeneralHighlightingPass.java:776)
 	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.a(GeneralHighlightingPass.java:641)
 	at com.intellij.codeInsight.daemon.impl.GeneralHighlightingPass.collectInformationWithProgress(GeneralHighlightingPass.java:203)
 	at com.intellij.codeInsight.daemon.impl.ProgressableTextEditorHighlightingPass.doCollectInformation(ProgressableTextEditorHighlightingPass.java:58)
 	at com.intellij.codeHighlighting.TextEditorHighlightingPass.collectInformation(TextEditorHighlightingPass.java:61)
 	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass$1$1.run(PassExecutorService.java:350)
 	at com.intellij.openapi.application.impl.ApplicationImpl.tryRunReadAction(ApplicationImpl.java:1049)
 	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass$1.run(PassExecutorService.java:342)
 	at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:218)
 	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.a(PassExecutorService.java:340)
 	at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.run(PassExecutorService.java:316)
 	at com.intellij.concurrency.JobUtil$3.call(JobUtil.java:134)
 	at com.intellij.concurrency.JobUtil$3.call(JobUtil.java:131)
 	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
 	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
 	at com.intellij.concurrency.PrioritizedFutureTask.access$101(PrioritizedFutureTask.java:31)
 	at com.intellij.concurrency.PrioritizedFutureTask$1.run(PrioritizedFutureTask.java:70)
 	at com.intellij.concurrency.PrioritizedFutureTask.run(PrioritizedFutureTask.java:113)
 	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
 	at java.lang.Thread.run(Thread.java:662)