Declaration of SymbolRef is confusing and embarrassing to percept the code easily, especially when working along with symbolic regions, values, expressions (SVal, SymbolVal, SymbolData, etc.). Every time it takes time to recall a correct aliasing in mind. Rename SymbolRef to SymExprRef would have a benefit.
using SymbolRef = const SymExpr *;
using SymExprRef = const SymExpr *;
P.S. In some files you can see bigger chunks than one-word-renaming. It is just auto-formatting changes.