Crashes when calling trait constructor from secondary constructor

[SrTobi]

minimized code

object Main {
  trait Test() {
    def this(x: Int) = this()
  }
}

scalaVersion := "0.22.0-bin-20200202-c2478a3-NIGHTLY"

Crash output (click arrow to expand)

sbt:dotty-example-project> compile
[info] Compiling 1 Scala source to /home/tobi/workspace/playground/dotty-test/target/scala-0.22/classes ...
Error while emitting Main.scala
[info] exception occurred while compiling /home/tobi/workspace/playground/dotty-test/src/main/scala/Main.scala
[error] ## Exception when compiling 1 sources to /home/tobi/workspace/playground/dotty-test/target/scala-0.22/classes
[error] java.lang.AssertionError: assertion failed: denotation module class <empty> invalid in run 1. ValidFor: Period(1..75, run = 2)
[error] dotty.DottyPredef$.assertFail(DottyPredef.scala:17)
[error] dotty.tools.dotc.core.Denotations$SingleDenotation.updateValidity(Denotations.scala:834)
[error] dotty.tools.dotc.core.Denotations$SingleDenotation.bringForward(Denotations.scala:863)
[error] dotty.tools.dotc.core.Denotations$SingleDenotation.current(Denotations.scala:918)
[error] dotty.tools.dotc.core.Symbols$Symbol.recomputeDenot(Symbols.scala:494)
[error] dotty.tools.dotc.core.Symbols$Symbol.computeDenot(Symbols.scala:489)
[error] dotty.tools.dotc.core.Symbols$Symbol.denot(Symbols.scala:483)
[error] dotty.tools.dotc.core.SymDenotations.stillValidInOwner(SymDenotations.scala:64)
[error] dotty.tools.dotc.core.Contexts$Context.stillValidInOwner(Contexts.scala:75)
[error] dotty.tools.dotc.core.SymDenotations.stillValid(SymDenotations.scala:60)
[error] dotty.tools.dotc.core.Contexts$Context.stillValid(Contexts.scala:75)
[error] dotty.tools.dotc.core.Denotations$SingleDenotation.bringForward(Denotations.scala:863)
[error] dotty.tools.dotc.core.Denotations$SingleDenotation.current(Denotations.scala:918)
[error] dotty.tools.dotc.core.Symbols$Symbol.recomputeDenot(Symbols.scala:494)
[error] dotty.tools.dotc.core.Symbols$Symbol.computeDenot(Symbols.scala:489)
[error] dotty.tools.dotc.core.Symbols$Symbol.denot(Symbols.scala:483)
[error] dotty.tools.dotc.core.SymDenotations.stillValidInOwner(SymDenotations.scala:64)
[error] dotty.tools.dotc.core.Contexts$Context.stillValidInOwner(Contexts.scala:75)
[error] dotty.tools.dotc.core.SymDenotations.stillValid(SymDenotations.scala:60)
[error] dotty.tools.dotc.core.Contexts$Context.stillValid(Contexts.scala:75)
[error] dotty.tools.dotc.core.Denotations$SingleDenotation.bringForward(Denotations.scala:863)
[error] dotty.tools.dotc.core.Denotations$SingleDenotation.current(Denotations.scala:918)
[error] dotty.tools.dotc.core.Symbols$Symbol.recomputeDenot(Symbols.scala:494)
[error] dotty.tools.dotc.core.Symbols$Symbol.computeDenot(Symbols.scala:489)
[error] dotty.tools.dotc.core.Symbols$Symbol.denot(Symbols.scala:483)
[error] dotty.tools.dotc.core.SymDenotations.stillValidInOwner(SymDenotations.scala:64)
[error] dotty.tools.dotc.core.Contexts$Context.stillValidInOwner(Contexts.scala:75)
[error] dotty.tools.dotc.core.SymDenotations.stillValid(SymDenotations.scala:60)
[error] dotty.tools.dotc.core.Contexts$Context.stillValid(Contexts.scala:75)
[error] dotty.tools.dotc.core.Denotations$SingleDenotation.bringForward(Denotations.scala:863)
[error] dotty.tools.dotc.core.Denotations$SingleDenotation.current(Denotations.scala:918)
[error] dotty.tools.dotc.core.Symbols$Symbol.recomputeDenot(Symbols.scala:494)
[error] dotty.tools.dotc.core.Symbols$Symbol.computeDenot(Symbols.scala:489)
[error] dotty.tools.dotc.core.Symbols$Symbol.denot(Symbols.scala:483)
[error] dotty.tools.dotc.core.Symbols$.toDenot(Symbols.scala:855)
[error] dotty.tools.dotc.core.MergeError.showSymbol(TypeErrors.scala:167)
[error] dotty.tools.dotc.core.MergeError.toMessage(TypeErrors.scala:188)
[error] dotty.tools.dotc.Driver.doCompile(Driver.scala:54)
[error] dotty.tools.dotc.Driver.process(Driver.scala:189)
[error] dotty.tools.dotc.Main.process(Main.scala)
[error] xsbt.CachedCompilerImpl.run(CachedCompilerImpl.java:69)
[error] xsbt.CompilerInterface.run(CompilerInterface.java:41)
[error] jdk.internal.reflect.GeneratedMethodAccessor15.invoke(Unknown Source)
[error] java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[error] java.base/java.lang.reflect.Method.invoke(Method.java:566)
[error] sbt.internal.inc.AnalyzingCompiler.call(AnalyzingCompiler.scala:248)
[error] sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:122)
[error] sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:95)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:91)
[error] scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
[error] sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:186)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$3(MixedAnalyzingCompiler.scala:82)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$3$adapted(MixedAnalyzingCompiler.scala:77)
[error] sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:215)
[error] sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:77)
[error] sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:146)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:343)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:343)
[error] sbt.internal.inc.Incremental$.doCompile(Incremental.scala:120)
[error] sbt.internal.inc.Incremental$.$anonfun$compile$4(Incremental.scala:100)
[error] sbt.internal.inc.IncrementalCommon.recompileClasses(IncrementalCommon.scala:180)
[error] sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:98)
[error] sbt.internal.inc.Incremental$.$anonfun$compile$3(Incremental.scala:102)
[error] sbt.internal.inc.Incremental$.manageClassfiles(Incremental.scala:155)
[error] sbt.internal.inc.Incremental$.compile(Incremental.scala:92)
[error] sbt.internal.inc.IncrementalCompile$.apply(Compile.scala:75)
[error] sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:348)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:301)
[error] sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:168)
[error] sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:248)
[error] sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:74)
[error] sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:1762)
[error] sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:1735)
[error] scala.Function1.$anonfun$compose$1(Function1.scala:49)
[error] sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:62)
[error] sbt.std.Transform$$anon$4.work(Transform.scala:67)
[error] sbt.Execute.$anonfun$submit$2(Execute.scala:281)
[error] sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:19)
[error] sbt.Execute.work(Execute.scala:290)
[error] sbt.Execute.$anonfun$submit$1(Execute.scala:281)
[error] sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:178)
[error] sbt.CompletionService$$anon$2.call(CompletionService.scala:37)
[error] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
[error] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
[error] java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
[error] java.base/java.lang.Thread.run(Thread.java:834)
[error]            
[error] stack trace is suppressed; run last Compile / compileIncremental for the full output
[error] (Compile / compileIncremental) java.lang.AssertionError: assertion failed: denotation module class <empty> invalid in run 1. ValidFor: Period(1..75, run = 2)

[nicolasstucki]

Same happens with

trait Test(x: Int) {
  def this() = this(3)
}

[nicolasstucki]

https://docs.scala-lang.org/sips/trait-parameters.html mentions that secondary constructors are not allowed

[SrTobi]

Yes. I found that out afterwards. Why is this forbidden btw? Is there a technical problem?

[nicolasstucki]

The wording in the SIP seems to indicate that this could be a potential extension.