docs: private void checkPrimitiveBinding(List<ValidationMessage> errors, String path, String type, ElementDefinition elementContext, WrapperElement element) {
      if (!element.hasAttribute("value"))
        return;
  
      String value = element.getAttribute("value");
      // System.out.println("check "+value+" in "+path);
  
      // firstly, resolve the value set
      ElementDefinitionBindingComponent binding = elementContext.getBinding();
      if (binding.hasValueSet() && binding.getValueSet() instanceof Reference) {
        ValueSet vs = resolveBindingReference(binding.getValueSet());
        if (warning(errors, IssueType.CODEINVALID, element.line(), element.col(), path, vs != null, "ValueSet {0} not found", describeReference(binding.getValueSet()))) {
          ValidationResult vr = context.validateCode(null, value, null, vs);
        	if (!vr.isOk()) {
        		if (binding.getStrength() == BindingStrength.REQUIRED)
        			warning(errors, IssueType.CODEINVALID, element.line(), element.col(), path, false, "The value provided is not in the value set " + describeReference(binding.getValueSet()) + " (" + vs.getUrl() + ", and a code is required from this value set)");
        		else if (binding.getStrength() == BindingStrength.EXTENSIBLE)
        			warning(errors, IssueType.CODEINVALID, element.line(), element.col(), path, false, "The value provided is not in the value set " + describeReference(binding.getValueSet()) + " (" + vs.getUrl() + ", and a code should come from this value set unless it has no suitable code)");
        		else if (binding.getStrength() == BindingStrength.PREFERRED)
        			hint(errors, IssueType.CODEINVALID, element.line(), element.col(), path, false,  "The value provided is not in the value set " + describeReference(binding.getValueSet()) + " (" + vs.getUrl() + ", and a code is recommended to come from this value set)");
        	}
        }
      } else
        hint(errors, IssueType.CODEINVALID, element.line(), element.col(), path, false, "Binding has no source, so can't be checked");
    }