Overloaded or recursive method test needs return type

[allanrenucci]

This doesn't compile:

import Test.test

object Test {
  def test = "  " * 10
}

[info] Running dotty.tools.dotc.Main -d out tests/allan/Test.scala -classpath dotty-library_2.12-0.4.0-bin-SNAPSHOT-nonbootstrapped.jar
-- [E043] Syntax Error: tests/allan/Test.scala:4:13 ----------------------------
4 |  def test = "  " * 10
  |             ^^^^
  |             overloaded or recursive method test needs return type

Dotty is confused by the import

[odersky]

The error message could be better, but this is a true cyclic reference, so an error should be reported. The cyclic reference is:

• in the body of test, we need to find an implicit on " " that provides the *.
• we search the imports for any implicits
• to search the import, we compute the member denotation of Test.test.
• the denotations needs a type, which causes the return type of test to be computed again.

scalac avoids this because it does not compute types when taking members. But we do not want to go back there.

[odersky]

Remedy: Provide an explicit return type. That's good practice anyway.

[smarter]

How come the following works with Dotty then?

import Test._

object Test {
  def test = "  " * 10
}

[odersky]

It scans for all implicit members of Test before trying to compute any of them.

[odersky]

I think there's no way to amke the cyclic error go away. So we need to work on the reporting side. test is neither overloaded nor recursive, so the error message should say something like:

"trying to follow acyclic reference when type-checking method test. Please add an explicit return type."

[Blaisorblade]

Fixed by #4729, closing.