Member predicate ConstantExprs::ExprEvaluator::allowVariableWithoutInitializer

When evaluating a syntactic subexpression of e, we may consider variable v even though it lacks an initializer. Normally, this is not sound, as uninitialized variables can contain arbitrary data (in fact, a query UninitialisedLocal.ql exists for finding that).

Subclasses may implement this predicate when needed.

predicate allowVariableWithoutInitializer(Expr e, Variable v)