docs: @Check
  	@SuppressWarnings("checkstyle:nestedifdepth")
  	public void checkDefaultSkillAnnotation(SarlCapacity capacity) {
  		final String annotationId = DefaultSkill.class.getName();
  		final XAnnotation annotation = IterableExtensions.findFirst(capacity.getAnnotations(), it -> {
  			return Strings.equal(annotationId, it.getAnnotationType().getIdentifier());
  		});
  		if (annotation != null) {
  			final XExpression expr = annotation.getValue();
  			if (expr instanceof XTypeLiteral) {
  				final XTypeLiteral typeLiteral = (XTypeLiteral) expr;
  				final JvmType type = typeLiteral.getType();
  				if (type != null && !type.eIsProxy()) {
  					final LightweightTypeReference reference = toLightweightTypeReference(type, capacity);
  					// Validating by the annotation value's type.
  					if (this.inheritanceHelper.isSarlSkill(reference)) {
  						final EObject element = this.associations.getPrimaryJvmElement(capacity);
  						assert element instanceof JvmType;
  						if (!reference.isSubtypeOf((JvmType) element)) {
  							error(MessageFormat.format(
  									Messages.SARLValidator_71,
  									capacity.getName(), type.getSimpleName()),
  									expr,
  									null,
  									ValidationMessageAcceptor.INSIGNIFICANT_INDEX,
  									INVALID_DEFAULT_SKILL_ANNOTATION);
  						}
  						return;
  					}
  				}
  			}
  			error(Messages.SARLValidator_88,
  					expr,
  					null,
  					ValidationMessageAcceptor.INSIGNIFICANT_INDEX,
  					INVALID_DEFAULT_SKILL_ANNOTATION);
  		}
  	}