Minimized code

//> using scala 3.6.2 def f(xs: List[Int]) = if x.nonEmpty then for x <- xs println(x)  end if end f

Output

-- [E040] Syntax Error: /home/amarki/snips/fordone.scala:7:0 ------------------- 7 | end if |^^^ |'<-' expected, but 'end of statement' found -- [E006] Not Found Error: /home/amarki/snips/fordone.scala:4:5 ---------------- 4 | if x.nonEmpty then | ^ | Not found: x | 

Expectation

The error on 6 is imprecise. In particular, I'd expect the correctly indented end if to "contain" the parse error.

It's not clear what the three carets correspond to. I have previously seen "encoded" names produce extra carets in messages, especially when synthetic, such as a x$1. This may be an example.

The original problem IRL was a long source file with many cascading errors due to missing definitions and subsequent errors on previous lines; the syntax error seen here was still shown first, as desired.

It looks like the precise error popped out in the middle of the cascade:

[error] 643 | if unapplied.is(CaseClass) then [error] | ^^^^ [error] | yield or do expected 

Before that, it is still really wanting the <-:

[error] 625 | warnings.result().sorta(_._2.span.point) [error] | ^ [error] | '<-' expected, but '.' found 

and

[error] 638 | case _ => [error] | ^^ [error] | '<-' expected, but '=>' found 

-Vprint:parser is too late to show what the for rewriting was trying to do:

package <empty> { def f(xs: List[Int]) = if x.nonEmpty then for x <- xs; println(x) <- _root_.scala.Predef.???; _ <- _root_.scala.Predef.??? do _root_.scala.Predef.??? } 

To the untrained eye, it wants an arrow because everything looks like a generator.

The pun is that the past tense of for ... do is fordone.