@Override
  public void visitField(FieldNode gField) {
    PropertyNode owner = spec.getAst().getProperty(gField.getName());
    if (gField.isStatic()) return;

    Field field = new Field(spec, gField, fieldCount++);
    field.setShared(AstUtil.hasAnnotation(gField, Shared.class));
    field.setOwner(owner);
    spec.getFields().add(field);
  }
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