void (@NotNull XmlAttributeValue value) { PsiReference[] references = value.getReferences(); for (PsiReference reference : references) { if (reference instanceof SchemaPrefixReference) { if (!XML.equals(((SchemaPrefixReference)reference).getNamespacePrefix()) && reference.resolve() == null) { holder.registerProblem(reference, XmlAnalysisBundle.message("xml.inspections.unbound.namespace", ((SchemaPrefixReference)reference).getNamespacePrefix()), ProblemHighlightType.LIKE_UNKNOWN_SYMBOL); } } } }