Due to the way expression parser is written, we need to resolve the
ambiguity between member access operators and dots used for punctuation
during lexing. The lexer uses a (totally bulletproof) heuristic to do
that: whenever '.' is followed by ' ' or '\n', it is considered a dot
and member access otherwise. While it works fine for prettified test
cases, non-prettified files often lack enter after a trailing dot
character. Since MemberAccess will always be invalid at that position,
explicitly treat trailing dot as a part of punctuation.
RecursiveASTVisitor was recursing into the subtrees of an old root if it
was changed in on_entry callback. Fix that by querying root pointer just
after on_entry callback returns. While on it, also use
`AK::TemporaryChange` instead of setting `m_current_subtree_pointer`
manually.
As it turns out, `FunctionCallCanonicalizationPass` was relying on being
able to replace tree on entry, and the bug in RecursiveASTVisitor made
the pass to not fully canonicalize nested function calls.
The changes to GenericASTPass.cpp alone are enough to fix the problem
but it is canonical (for some definition of canonicity) to only change
trees in on_leave. Therefore, the commit also switches
FunctionCallCanonicalizationPass to on_leave callback.
A test for this fix and one from the previous commit is also included.
We assume that variable shadowing is impossible, so then there is no
reason to keep distinct Declaration and Assignment operators after
ReferenceResolvingPass.
