dillon1000/react

Detect hoisting where the reference is a reassignment

Our logic to detect hoisting relies on Babel's `isReferencedIdentifier()` to 
determine whether a reference to an identifier is a reference or a declaration. 
The idea is that we want to find references to variables that may be hoistable, 
before the declaration — the definition of hoisting. But due to the bug in 
isReferencedIdentifier, we skipped over reassignments of hoisted variables. The 
hack here checks if an identifier is a direct child of an AssignmentExpression, 
ensuring we visit reassignments.