@elextr, I'm not entirely sure what's the protocol for syncing parser changes from upstream, but I submitted this fix to universal-ctags and it was accepted (universal-ctags/ctags#1734).
I've made another commit on this branch pulling in the relevant changes. The improvements can be reviewed using this [Ruby test file](https://raw.githubusercontent.com/masatake/ctags/68ea0f84f69fecaebb27ce11461...) - using various assignments with blocks no longer breaks the symbols tree.