void () { myFixture.configureByText(XmlFileType.INSTANCE, """ <schema xmlns="http://www.w3.org/2001/XMLSchema"\s xmlns:x="http://www.w3.org/2001/XMLSchema" <warning descr="Namespace declaration is never used">xmlns:y="http://www.w3.org/2001/XMLSchema"</warning>> <element name="a" default="x:y"/> </schema>"""); myFixture.testHighlighting(); }