Member predicate BlockStmt::mayBeGloballyImpure

Holds if it is possible that this statement is globally impure.

Similar to mayBeImpure(), except that mayBeGloballyImpure() does not consider modifications to temporary local variables to be impure. That is, if you call a function in which mayBeGloballyImpure() doesn’t hold for any statement, then the function as a whole will have no side-effects, even if it mutates its own fresh stack variables.