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Description
Discussed in #17453
Originally posted by PeuTit May 10, 2023
Creating a new Play application with g8 and the play-scala-seed.g8 template.
sbt new playframework/play-scala-seed.g8 --branch 2.9.xI was testing the rewrite capabilities of the compiler with the following options:
scalacOptions ++= Seq(
"-rewrite",
"-indent",
)Launching a sbt shell & compiling the project, I'm facing the following errors:
[info] compiling 7 Scala sources and 1 Java source to /Users/titouan/Documents/work/perso/scala/test-tmp-play-scala3/target/scala-3.3.0-RC5/classes ...
[error] /Users/titouan/Documents/work/perso/scala/test-tmp-play-scala3/app/views/index.scala.html:4:28: Illegal start of toplevel definition
[error] <h1>Welcome to Play!</h1>
[error] ^
[error] /Users/titouan/Documents/work/perso/scala/test-tmp-play-scala3/app/views/main.scala.html:12:11: Illegal start of toplevel definition
[error] @* Here's where we render the page title `String`. *@
[error] ^
[error] /Users/titouan/Documents/work/perso/scala/test-tmp-play-scala3/app/views/main.scala.html:25:8: render is already defined as method render in /Users/titouan/Documents/work/perso/scala/test-tmp-play-scala3/target/scala-3.3.0-RC5/twirl/main/views/html/index.template.scala
[error]
[error] Note that overloaded methods must all be defined in the same group of toplevel definitions
[error] </html>
[error] ^
[error] /Users/titouan/Documents/work/perso/scala/test-tmp-play-scala3/app/views/index.scala.html:4:15: Not found: _display_:
[error] <h1>Welcome to Play!</h1>
[error] ^
[error] /Users/titouan/Documents/work/perso/scala/test-tmp-play-scala3/app/views/index.scala.html:5:2: Not found: apply
[error] }
[error] ^
[error] /Users/titouan/Documents/work/perso/scala/test-tmp-play-scala3/app/views/main.scala.html:11:9: Not found: _display_:
[error] <head>
[error] ^
[error] 6 errors found
[error] (Compile / compileIncremental) Compilation failed
[error] Total time: 1 s, completed May 10, 2023, 10:40:04 AM
Does anyone have ever faced this issue previously?
Actually, I was able to reproduce this. Interesting one. So what happens is that on the first compile it will take the Scala code that gets generated from the index.scala.html and attempt to rewrite it. It does this, but outputs invalid code. For example here is what your index.scala.html really looks like when passed to the compiler:
package views.html
import _root_.play.twirl.api.TwirlFeatureImports._
import _root_.play.twirl.api.TwirlHelperImports._
import _root_.play.twirl.api.Html
import _root_.play.twirl.api.JavaScript
import _root_.play.twirl.api.Txt
import _root_.play.twirl.api.Xml
import models._
import controllers._
import play.api.i18n._
import views.html._
import play.api.templates.PlayMagic._
import play.api.mvc._
import play.api.data._
object index extends _root_.play.twirl.api.BaseScalaTemplate[play.twirl.api.HtmlFormat.Appendable,_root_.play.twirl.api.Format[play.twirl.api.HtmlFormat.Appendable]](play.twirl.api.HtmlFormat) with _root_.play.twirl.api.Template0[play.twirl.api.HtmlFormat.Appendable] {
/**/
def apply/*1.2*/():play.twirl.api.HtmlFormat.Appendable = {
_display_ {
{
Seq[Any](format.raw/*2.1*/("""
"""),_display_(/*3.2*/main("Welcome to Play")/*3.25*/ {_display_(Seq[Any](format.raw/*3.27*/("""
"""),format.raw/*4.3*/("""<h1>Welcome to Play!</h1>
""")))}),format.raw/*5.2*/("""
"""))
}
}
}
def render(): play.twirl.api.HtmlFormat.Appendable = apply()
def f:(() => play.twirl.api.HtmlFormat.Appendable) = () => apply()
def ref: this.type = this
}
/*
-- GENERATED --
SOURCE: app/views/index.scala.html
HASH: f7d71d8a9f655317469a39627564796bcf2a545b
MATRIX: 722->1|818->4|845->6|876->29|915->31|944->34|1000->61
LINES: 21->1|26->2|27->3|27->3|27->3|28->4|29->5
-- GENERATED --
*/This then gets rewritten to
package views.html
import _root_.play.twirl.api.TwirlFeatureImports._
import _root_.play.twirl.api.TwirlHelperImports._
import _root_.play.twirl.api.Html
import _root_.play.twirl.api.JavaScript
import _root_.play.twirl.api.Txt
import _root_.play.twirl.api.Xml
import models._
import controllers._
import play.api.i18n._
import views.html._
import play.api.templates.PlayMagic._
import play.api.mvc._
import play.api.data._
object index extends _root_.play.twirl.api.BaseScalaTemplate[play.twirl.api.HtmlFormat.Appendable,_root_.play.twirl.api.Format[play.twirl.api.HtmlFormat.Appendable]](play.twirl.api.HtmlFormat) with _root_.play.twirl.api.Template0[play.twirl.api.HtmlFormat.Appendable]:
/**/
def apply/*1.2*/():play.twirl.api.HtmlFormat.Appendable =
_display_:
Seq[Any](format.raw/*2.1*/("""
"""),_display_(/*3.2*/main("Welcome to Play")/*3.25*/ {_display_(Seq[Any](format.raw/*3.27*/("""
"""),format.raw/*4.3*/("""<h1>Welcome to Play!</h1>
""")))}),format.raw/*5.2*/("""
"""))
def render(): play.twirl.api.HtmlFormat.Appendable = apply()
def f:(() => play.twirl.api.HtmlFormat.Appendable) = () => apply()
def ref: this.type = this
/*
-- GENERATED --
SOURCE: app/views/index.scala.html
HASH: f7d71d8a9f655317469a39627564796bcf2a545b
MATRIX: 722->1|818->4|845->6|876->29|915->31|944->34|1000->61
LINES: 21->1|26->2|27->3|27->3|27->3|28->4|29->5
-- GENERATED --
*/ Which has a whole handful of problems. The thing is, is that I don't even think we should be trying to rewrite these files, but I don't know if there is a good way to filter them out since Dotty I believe is just going to try and rewrite everything, whether it's generated code or not.