We have presented the symbolic composition on simple cases. For more complex programs, the result of this transformation could possibly be a ill-formed attribute grammar, because of the following remarks, essentially corresponding to the constraints introduced by Giegerich and Ganzinger about descriptional composition for classical attribute grammars.
The projections in symbolic composition must be performed only on terms that
participate to the construction of the intermediate data structure. This
is the problem of determining the set 
, which corresponds to the
Ganzinger and Giegerich's separation between syntactic and semantic domains.
This induces that the complete construction of the intermediate data structure
ought to be available, and must not be hidden. Moreover, in the resulting
attribute grammar, each attribute occurrence must be defined only once. Such
problem could arise with some non-linear terms.
The Ganzinger and Giegerich's constraints could be used in a first approach to resolve these problems. Nevertheless, our special context of type-checked functional programs permits to reformulate the resolution of these problems in terms of a particular static analysis. From our point of view, the information required by the composition mechanism must be determined separately. This independence had allowed us to present our symbolic composition, even if the problem of static analysis in functional context constitutes an interesting study, not tackled in this paper.