Eta expansion val f = mymethod (i.e., no applied argument lists) shows spurious error about trailing "_"

[deanwampler]

Compiler version

scala 3.0.0-M3

Minimized code

In the REPL, try this:

def cat1(s1: String)(s2: String) = s1 + s2
val fcat1 = cat1

Output

1 |val fcat1 = cat1
  |            ^^^^
  |            The syntax `<function> _` is no longer supported;
  |            you can simply leave out the trailing ` _`

By accident, I noticed you get exactly the same error message if you type def fcat1 = cat1.

Expectation

It accepts the definition of fcat1, as described in the automatic eta expansion docs, https://dotty.epfl.ch/docs/reference/changed-features/eta-expansion.html

[griggt]

Is this only with -source 3.1 ?

[odersky]

Seems to be only under 3.1

[deanwampler]

Yes, I'm using -source 3.1.