Bug in ANTLR grammar generation when invoking expression rules directly

[chseidl]

There is a bug when referencing a meta class whose syntax rule is marked as expression rule from outside of another expression rule. In this case, the generated ANTLR syntax holds a reference to a syntax rule with the name as would be expected for a non-expression rule. However, expression rules use a different naming convention (and actually hierarchicals tructuring of rule due to the expression nature) so that the ANTLR grammar rule cannot be resolved.

The use case may actually be avalid concern, e.g., when using an aotmic expression rule within another statement (say an integer literal atomix expression also to initialize a constant's value that should not support arbitrary expressions).

Example code for above use case illustrating the example will be sent to the developers.