'Unexpected token: "NEWLINE"' (in a line which has been commented out)

I’m receiving

In asdf.cr:206:9

 206 | #foo= SomeModule.bar @asdf, qwer, uiop
Error: unexpected token: "NEWLINE"

If relevant: the line is within a method, but not within any other block.

And I have no clue why this happens, what the compiler is trying to tell me, or where to start trying to solve this

Somewhat unexpected: if I add a newline before, then the error also follows (so compiler still complains about the line which is commented out, and not about the new, obvious empty line, directly above it)

It was a missing ) dozens of lines earlier (which I only found by counting ( and ), because luckily my last changes involved a lot of those so I had there some suspicion).