Saxon

java.lang.UnsupportedOperationException: Cannot copy a variable reference whose binding is unknown

at net.sf.saxon.expr.GlobalVariableReference.copy(GlobalVariableReference.java:43)

at net.sf.saxon.expr.AdjacentTextNodeMerger.copy(AdjacentTextNodeMerger.java:186)

at net.sf.saxon.expr.Atomizer.copy(Atomizer.java:348)

at net.sf.saxon.expr.AtomicSequenceConverter.copy(AtomicSequenceConverter.java:290)

at net.sf.saxon.expr.SystemFunctionCall.copy(SystemFunctionCall.java:306)

at net.sf.saxon.expr.instruct.ValueOf.copy(ValueOf.java:218)

at net.sf.saxon.style.XSLTemplate.compileTemplateRule(XSLTemplate.java:731)

at net.sf.saxon.style.XSLTemplate.compileDeclaration(XSLTemplate.java:648)

at net.sf.saxon.style.PrincipalStylesheetModule.compile(PrincipalStylesheetModule.java:1242)

at net.sf.saxon.style.Compilation.compilePackage(Compilation.java:322)

at net.sf.saxon.style.StylesheetModule.loadStylesheet(StylesheetModule.java:252)

at net.sf.saxon.style.Compilation.compileSingletonPackage(Compilation.java:113)

at net.sf.saxon.s9api.XsltCompiler.compile(XsltCompiler.java:838)

at net.sf.saxon.Transform.doTransform(Transform.java:753)

at net.sf.saxon.Transform.main(Transform.java:82)

Fatal error during transformation: java.lang.UnsupportedOperationException: Cannot copy a variable reference whose binding is unknown