As I implied, I find the Haskell-like languages attractive. To the point that I am taking that approach in a toy language. But you are right, the cost of it is

As I implied, I find the Haskell-like languages attractive. To the point that I am taking that approach in a toy language. But you are right, the cost of it is pretty high - not just copy/paste, but it's tricky to parse, auto-formatting is harder, LSP support (changing code) is harder, renaming variables and functions is harder, etc. (Haskell-like languages are worse than Python because they don't always start a new indentation level on a new line, so renaming can change the indentation level.) So it's probably not worth it. And I will add, like the sibling commenter, I like the auto-format on save of Go. When writing Go, I'll type whatever, often on one line, and let the formatter take care of making it pretty.