Missing span with unordered named params and varargs (causes crash with semantic db)

Minimized code

Compiling the following with the -Ysemanticdb flag enabled, causes an assertion error to be thrown by ExtractSemanticDB#localIdx.

// -Ysemanticdb
class Wrapper {

  def fct(p1: Int, p2: Int, extra: Int*): Int = ???

  fct(0, 0) // OK
  fct(p1 = 0, 0) // OK
  fct(0, p2 = 0) // OK
  fct(p1 = 0, p2 = 0) // OK
  fct(p2 = 0, p1 = 0) // java.lang.AssertionError: assertion failed: val extra$1 should have a span
}

Output (click arrow to expand)

``` exception occurred while compiling main.scala java.lang.AssertionError: assertion failed: val extra$1 should have a span while compiling main.scala Exception in thread "main" java.lang.AssertionError: assertion failed: val extra$1 should have a span at dotty.DottyPredef$.assertFail(DottyPredef.scala:17) at dotty.tools.dotc.semanticdb.ExtractSemanticDB$Extractor.localIdx$1(ExtractSemanticDB.scala:349) at dotty.tools.dotc.semanticdb.ExtractSemanticDB$Extractor.addSymName(ExtractSemanticDB.scala:370) at dotty.tools.dotc.semanticdb.ExtractSemanticDB$Extractor.symbolName(ExtractSemanticDB.scala:377) at dotty.tools.dotc.semanticdb.ExtractSemanticDB$Extractor.traverse(ExtractSemanticDB.scala:151) at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.apply(Trees.scala:1510) at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.apply(Trees.scala:1510) at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.fold$1(Trees.scala:1385) at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.apply(Trees.scala:1387) at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.foldOver(Trees.scala:1420) at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.traverseChildren(Trees.scala:1511) at dotty.tools.dotc.semanticdb.ExtractSemanticDB$Extractor.traverse(ExtractSemanticDB.scala:241) at dotty.tools.dotc.semanticdb.ExtractSemanticDB$Extractor.traverse$$anonfun$11(ExtractSemanticDB.scala:197) at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:15) at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:10) at scala.collection.immutable.List.foreach(List.scala:333) at dotty.tools.dotc.semanticdb.ExtractSemanticDB$Extractor.traverse(ExtractSemanticDB.scala:197) at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.apply(Trees.scala:1510) at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.apply(Trees.scala:1510) at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.foldOver(Trees.scala:1479) at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.traverseChildren(Trees.scala:1511) at dotty.tools.dotc.semanticdb.ExtractSemanticDB$Extractor.traverse(ExtractSemanticDB.scala:182) at dotty.tools.dotc.semanticdb.ExtractSemanticDB$Extractor.traverse$$anonfun$1(ExtractSemanticDB.scala:140) at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:15) at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:10) at scala.collection.immutable.List.foreach(List.scala:333) at dotty.tools.dotc.semanticdb.ExtractSemanticDB$Extractor.traverse(ExtractSemanticDB.scala:140) at dotty.tools.dotc.semanticdb.ExtractSemanticDB.run(ExtractSemanticDB.scala:47) at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:296) at scala.collection.immutable.List.map(List.scala:246) at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:297) at dotty.tools.dotc.Run.runPhases$4$$anonfun$4(Run.scala:180) at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:15) at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:10) at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323) at dotty.tools.dotc.Run.runPhases$5(Run.scala:190) at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:198) at dotty.runtime.function.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12) at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:64) at dotty.tools.dotc.Run.compileUnits(Run.scala:205) at dotty.tools.dotc.Run.compileSources(Run.scala:142) at dotty.tools.dotc.Run.compile(Run.scala:124) at dotty.tools.dotc.Driver.doCompile(Driver.scala:38) at dotty.tools.dotc.Driver.process(Driver.scala:195) at dotty.tools.dotc.Driver.process(Driver.scala:164) at dotty.tools.dotc.Driver.process(Driver.scala:176) at dotty.tools.dotc.Driver.main(Driver.scala:203) at dotty.tools.dotc.Main.main(Main.scala) ```

Note

This bug prevents metals from working correctly in the project that has the above code. I tried simply removing the assert in question from ExtractSemanticDB (and default to zero), and metals worked again. I'm not sure what is causing the missing span, but I do wonder if semantic DB should fail more gracefully here. Maybe a warning would be enough?

scala / scala3