scala3 named tuple style pattern matching is not working

[shuttie]

Steps

Given code like this:

import language.experimental.namedTuples

object Main {
  case class StringField(name: String, value: String)

  def test(field: StringField) = field match {
    case StringField(name=name) => name
  }
}

and a scalafmt.conf file:

version = 3.8.4-RC4
runner.dialect = Scala35

with a build.sbt:

version := "0.1.0-SNAPSHOT"
scalaVersion := "3.6.2"
name := "sca-namedtuple-bug"
scalacOptions ++= Seq("-experimental")

Problem

Scalafmt fails formatting the code, but compiling works:

[info] welcome to sbt 1.10.7 (Gentoo Java 17.0.13)
[info] loading global plugins from /home/shutty/.sbt/1.0/plugins
[info] loading settings for project sca-namedtuple-bug-build from plugins.sbt...
[info] loading project definition from /home/shutty/private/code/sca-namedtuple-bug/project
[info] loading settings for project sca-namedtuple-bug from build.sbt...
[info] set current project to sca-namedtuple-bug (in build file:/home/shutty/private/code/sca-namedtuple-bug/)
[info] scalafmt: Formatting 1 Scala sources (/home/shutty/private/code/sca-namedtuple-bug)...
[error] org.scalafmt.sbt.ScalafmtSbtReporter$ScalafmtSbtError: scalafmt: /home/shutty/private/code/sca-namedtuple-bug/src/main/scala/Main.scala:7: error: [dialect scala35] `)` expected but `=` found
[error]     case StringField(name=name) => name
[error]                          ^ [/home/shutty/private/code/sca-namedtuple-bug/src/main/scala/Main.scala]
[error] (Compile / scalafmt) org.scalafmt.sbt.ScalafmtSbtReporter$ScalafmtSbtError: scalafmt: /home/shutty/private/code/sca-namedtuple-bug/src/main/scala/Main.scala:7: error: [dialect scala35] `)` expected but `=` found
[error]     case StringField(name=name) => name
[error]                          ^ [/home/shutty/private/code/sca-namedtuple-bug/src/main/scala/Main.scala]
[error] Total time: 1 s, completed Jan 3, 2025, 4:44:15 PM

Expectation

The latest version of scalafmt does not yet support scala36 syntax, but AFAIK named tuples are also available in the 3.5. Is there a way to have both named tuples AND scalafmt in the same project?

[kitbellew]

@shuttie when you were submitting this issue, did you have a chance to read through the issue template, perhaps? the section entitled "do not submit if", specifically.

[tgodzik]

Btw. we are working on it currently in the scalameta parser, @Florian3k should have a PR ready soon.

[shuttie]

@kitbellew yes I've read the issue template and saw the notice. But it's still unclear to me, if there's a way to triage beforehand to figure out if it's a scalameta or scalafmt issue? I have a reproducer for scalafmt, but not for scalameta, and I'm not using scalameta directly.

[kitbellew]

@kitbellew yes I've read the issue template and saw the notice. But it's still unclear to me, if there's a way to triage beforehand to figure out if it's a scalameta or scalafmt issue? I have a reproducer for scalafmt, but not for scalameta, and I'm not using scalameta directly.

the issue description explicitly emphasizes that anything related to your code (input) is a parser issue. so either you set your dialect incorrectly, or the parser has a bug.

also, you used sbt and not the scalafmt binary. also a requirement that was called out.