AGREE ConstStatement and EqStatement Recursive Validation Check Required

[aaurandt]

Currently a cyclic expression is checked by performing the following (lines 1856-1865 specifically):

AGREE/com.rockwellcollins.atc.agree/src/com/rockwellcollins/atc/agree/validation/AgreeValidator.java

Lines 1846 to 1873 in 8d101f3

	@Check(CheckType.FAST)
	public void checkConstStatement(ConstStatement constStat) {
	TypeDef expected = AgreeTypeSystem.typeDefFromType(constStat.getType());
	TypeDef actual = AgreeTypeSystem.infer(constStat.getExpr());
	if (!AgreeTypeSystem.typesEqual(expected, actual)) {
	error(constStat, "The assumed type of constant statement '" + constStat.getName() + "' is '"
	+ nameOfTypeDef(expected) + "' but the actual type is '" + nameOfTypeDef(actual) + "'");
	}
	ExprCycleVisitor cycleVisitor = new ExprCycleVisitor();
	Set<EObject> cycleObjects = cycleVisitor.doSwitch(constStat.getExpr());
	if (cycleObjects == null) {
	throw new IllegalArgumentException("something went wrong with the cycle checker");
	}
	for (EObject obj : cycleObjects) {
	if (obj.equals(constStat)) {
	error(constStat.getExpr(), "Cyclic reference to variable '" + constStat.getName() + "'");
	}
	}
	for (Expr e : EcoreUtil2.getAllContentsOfType(constStat.getExpr(), Expr.class)) {
	if (!exprIsConstant(e)) {
	error(e, "Non-constant expression in constant declaration");
	return;
	}
	}
	}

The ExprCycleVisitor just goes down the AST, but it does not search for recursive loops. For example, the following code should produce an error, but it does not:

package TestPackage
public

system sys
	annex agree {**
		eq test1 : int = test2 + 10;
		eq test2 : int = test1 - 10;
	**};
end sys;

end TestPackage;