docs: @SuppressWarnings("static-method")
  	public Boolean toBooleanPrimitiveWrapperConstant(XExpression expression) {
  		if (expression instanceof XBooleanLiteral) {
  			return ((XBooleanLiteral) expression).isIsTrue() ? Boolean.TRUE : Boolean.FALSE;
  		}
  		if (expression instanceof XMemberFeatureCall) {
  			final XMemberFeatureCall call = (XMemberFeatureCall) expression;
  			final XExpression receiver = call.getMemberCallTarget();
  			if (receiver instanceof XFeatureCall) {
  				final XFeatureCall call2 = (XFeatureCall) receiver;
  				final String call2Identifier = call2.getConcreteSyntaxFeatureName();
  				if (Boolean.class.getSimpleName().equals(call2Identifier) || Boolean.class.getName().equals(call2Identifier)) {
  					final String callIdentifier = call.getConcreteSyntaxFeatureName();
  					if ("TRUE".equals(callIdentifier)) { //$NON-NLS-1$
  						return Boolean.TRUE;
  					} else if ("FALSE".equals(callIdentifier)) { //$NON-NLS-1$
  						return Boolean.FALSE;
  					}
  				}
  			}
  		}
  		return null;
  	}