This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
This fixes the issue when the current line offset is actually for next range.
Maintain a current code range with current line offset and cache next file/line
offset. Update file/line offset after finishing current range.
Differential Revision: https://reviews.llvm.org/D123151
