`equals` should be marked as `infix` for Scala 3.4

[soronpo]

Scala 3.4 introduces warnings on alphanumeric method application in infix positioning if such methods are not explicitly marked with infix. I think equals should be marked as infix, as it is naturally used in infix positioning.

Compiler version

3.4.nightly

Minimized code

val x = 1 equals 1

Output

Alphanumeric method equals is not declared infix; it should not be used as infix operator.
Instead, use method syntax .equals(...) or backticked identifier `equals`.
The latter can be rewritten automatically under -rewrite -source 3.4-migration.

Expectation

No warnings.

[nicolasstucki]

Not sure if it might be intended to be written as

val x = 1 `equals` 1

I would have found it more natural to use

val x = 1 == 1

[odersky]

What about eq, ne? It would be great if someone could make a proposal which stdlib methods should be implicitly treated as infix. (Could be none). Maybe start a discussion on contributors? Who would like to do that?

[odersky]

I won't take the lead on this. Waiting for proposals to be made.

[nicolasstucki]

What about eq, ne?

eq and ne seem to already be treated as infix.

def x(a: AnyRef, b: AnyRef) =
  a equals b // warn
  a eq b
  a ne b

[nicolasstucki]

Maybe start a discussion on contributors? Who would like to do that?

@soronpo could you start the dicussion on contributors?

[som-snytt]

Ironically, I've started writing x.eq(y) after seeing it here.

[soronpo]

would have found it more natural to use

val x = 1 == 1

When using strictEquality, it's not that straightforward for all cases.

Maybe start a discussion on contributors? Who would like to do that?

@soronpo could you start the dicussion on contributors?

Yes, I will do so.

[soronpo]

https://contributors.scala-lang.org/t/which-stdlib-functions-and-types-should-be-marked-as-infix/6436

[soronpo]

Is there a way to get statistics from the OpenCB about infix linter warnings?