The "tabify" and "untabify" commands do this in Emacs, and many languages have linters which can flag either (which you can then run, e.g. as a git pre-commit h

The "tabify" and "untabify" commands do this in Emacs, and many languages have linters which can flag either (which you can then run, e.g. as a git pre-commit hook). If spaces/tabs were just about nesting code blocks then this would all be a no-brainer, but vertical alignment can convey much more information than that (for example, splitting statements into semantically equivalent columns).