Jade Compiler Exception

unable to evaluate [non.existing.query()] - JexlException de.neuland.jade4j.expression.JexlExpressionHandler.evaluateExpression@53![13,20]: 'non.existing.query();' attempting to call method on null in ../compiler/exceptions/error.jade:9

In ../compiler/exceptions/error.jade at line 9.

5    body {
6      color: orange;
7    }
8  body
9    h1= non.existing.query()
10    ul
11      li At vero eos
12      li Lorem ipsum dolor

Generated Output pretty raw

<html><head><title>broken