@NotNull private Collection<PsiElement> getDeclarationsByDescriptor( @NotNull DeclarationDescriptor declarationDescriptor) { Collection<PsiElement> declarations; if (declarationDescriptor instanceof PackageViewDescriptor) { final PackageViewDescriptor aPackage = (PackageViewDescriptor) declarationDescriptor; Collection<JetFile> files = trace.get(BindingContext.PACKAGE_TO_FILES, aPackage.getFqName()); if (files == null) { return Collections .emptyList(); // package can be defined out of Kotlin sources, e. g. in library or Java // code } declarations = Collections2.transform( files, new Function<JetFile, PsiElement>() { @Override public PsiElement apply(@Nullable JetFile file) { assert file != null : "File is null for aPackage " + aPackage; return file.getPackageDirective().getNameIdentifier(); } }); } else { declarations = Collections.singletonList( BindingContextUtils.descriptorToDeclaration( trace.getBindingContext(), declarationDescriptor)); } return declarations; }