Issue with compiling `@main` annotation when there is extra lines

Just to make sure it’s tracked here, I figured I’d create this and link it to the issue in Metals.

So I’ve been playing around with this a bit to see if I can consistently reproduce it, and I can. It’s very odd because it’s a certain combination of things based on empty lines. For example, if you create a new project with the Dotty g8 template and change the main method to be as follows at the top level:

Just one blank line, no package declaration. Bloop has no issue with this.

@main def main(): Unit = {
  println("Hello world!")
  println(msg)
}

def msg = "I was compiled by dotty :)"

Add one more empty line on top and you’ll get the following error:

This…

 
 
@main def main(): Unit = {
  println("Hello world!")
  println(msg)
}

def msg = "I was compiled by dotty :)"

Produces this:

❯ bloop run root
Compiling root (1 Scala source)
[E] [E1] src/main/scala/Main.scala:2:1
[E]      Found:    main
[E]      Required: scala.annotation.Annotation
[E]      L2: @main def main(): Unit = {
[E]          ^
[E] src/main/scala/Main.scala: L2 [E1]
Compiled root (224ms)
[E] Failed to compile 'root'

Add in a package declaration and make sure there is only one line between package declaration and main method, no issue.

package example

@main def main(): Unit = {
  println("Hello world!")
  println(msg)
}

def msg = "I was compiled by dotty :)"

If you add in another blank line, you’ll get the issue. The same thing happens if you add a blank line in at the top of the method.

package example

@main def main(): Unit = {

  println("Hello world!")
  println(msg)
}

def msg = "I was compiled by dotty :)"

All of the cases produce the same error from bloop. Note that all of these can be compile and ran with sbt with no issue.

[kpodsiad]

ok, I’ll try to reproduce it with the current bloop and then with your version. Will it be safe to close this and related issues if there aren’t any problems with compilation?

[ckipp01]

I’ll go ahead and close then. I haven’t looked back at this in a long time or noticed it so closing.