EAGLESIX-2651: FixedArity: use NaryExpressionBaseT

* also minor change to error text

lib/pipeline/expressions/FixedArityExpressionT.js

@@ -11,9 +11,9 @@
 var FixedArityExpressionT = module.exports = function FixedArityExpressionT(SubClass, nArgs) {
 
 	var FixedArityExpression = function FixedArityExpression() {
-		if (arguments.length !== 0) throw new Error((SubClass.opName || "(unspecified)") + ": zero args expected");
+		if (arguments.length !== 0) throw new Error(klass.name + "<" + SubClass.name + ">: zero args expected");
 		base.call(this);
-	}, klass = FixedArityExpression, base = require("./NaryExpressionT")(SubClass), proto = klass.prototype = Object.create(base.prototype, {constructor: {value: klass}});
+	}, klass = FixedArityExpression, base = require("./NaryExpressionBaseT")(SubClass), proto = klass.prototype = Object.create(base.prototype, {constructor: {value: klass}});
 
 	/**
 	 * Check that the number of args is what we expected

lib/pipeline/expressions/NaryExpressionBaseT.js

@@ -13,7 +13,7 @@ var NaryExpression = require("./NaryExpression");
 var NaryExpressionBaseT = module.exports = function NaryExpressionBaseT(SubClass) {
 
 	var NaryExpressionBase = function NaryExpressionBase() {
-		if (arguments.length !== 0) throw new Error("Zero args expected");
+		if (arguments.length !== 0) throw new Error(klass.name + "<" + SubClass.name + ">: zero args expected");
 		base.call(this);
 	}, klass = NaryExpressionBase, base = NaryExpression, proto = klass.prototype = Object.create(base.prototype, {constructor:{value:klass}});