The iterators of LoopExp and LoopExpEval are not ordered, but the well-formedness constraints on them use ->at() which is only available for ordered collection. Usage of the AST property is subject to a variety of spelling, ordering and multiplicity inconsistencies.
Section 7.6.3 and 7.6.4 define extended variants of forAll and exists that have two iterators.
Figure 8.2 and Figure 13.3 show an unordered * multiplicity for LoopExp.iterator. The positioning of the VariableExp.referredVariable 0..1 multiplicity makes the diagram easy to mis-read.
Section 8.3.1 LoopExp defines iterator as "The iterator variables. These variables are, each in its turn, " implying an ordered collection.
Section 8.3.7 LoopExp [2] and [3] use iterator->forAll implying a collection.
Section 9.3 IteratorExpCS synthesized attributes use iterators->at(1) and at(2) requiring an ordered collection.
Section 9.3 IterateExpCS concrete syntax supports at most one iterator and one accumulator.
Section 9.3 IterateExpCS synthesized attributes use iterator.initExpression requiring a non-collection.
Figure 10.7 shows LoopExpEval.iterators as unordered 1..n.
Section 10.3.1 LoopExpEval defines iterators as "The names of the iterator variables".
Section 10.3.7 IterateExpEval [1] uses iterators->at(1) and iterators->at(2) implying an ordered collection with upper bound 2.
Section 10.3.7 LoopExpEval [1] has a two way if = 1 else, implying the upper bound is 2.
Section 10.3.7 LoopExpEval [3] uses iterators->at(1) and iterators->at(2) implying an ordered collection with upper bound 2.
Section 11.9.1 defines the mapping of forAll to iterate for multiple iterators, but IterateExpCS only supports a single iterator.