@Override
  public void visitConstructor(ConstructorNode constructor) {
    // Groovy compiler generated constructor for example for joint compilation
    if (constructor.hasNoRealSourcePosition()) return;

    errorReporter.error(constructor,
"Constructors are not allowed; instead, define a 'setup()' or 'setupSpec()' method");
  }
Given the abstract syntax tree of a Groovy class representing a Spock
specification, builds an object model of the specification.

@author Peter Niederwieser
spock-core/src/main/java/org/spockframework/compiler/SpecParser.java