Merge pull request #2090 from dotty-staging/fix/ParSetLike

Fix #2089: Error when compiling ParSetLike, ParSet, SetLike, in this order

Author: odersky

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -1080,6 +1080,13 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
               (if (isVarPattern(arg)) desugar.patternVar(arg) else arg, tparam.paramBounds)
             else
               (arg, WildcardType)
+          if (tpt1.symbol.isClass)
+            tparam match {
+              case tparam: Symbol =>
+                // This is needed to get the test `compileParSetSubset` to work
+                tparam.ensureCompleted()
+              case _ =>
+            }
           typed(desugaredArg, argPt)
         }
         args.zipWithConserve(tparams)(typedArg(_, _)).asInstanceOf[List[Tree]]

compiler/test/dotc/tests.scala

@@ -225,6 +225,10 @@ class tests extends CompilerTest {
         |../scala-scala/src/library/scala/collection/generic/GenSeqFactory.scala""".stripMargin)
   @Test def compileIndexedSeq = compileLine("../scala-scala/src/library/scala/collection/immutable/IndexedSeq.scala")
   @Test def compileParSetLike = compileLine("../scala-scala/src/library/scala/collection/parallel/mutable/ParSetLike.scala")
+  @Test def compileParSetSubset = compileLine(
+      """../scala-scala/src/library/scala/collection/parallel/mutable/ParSetLike.scala
+        |../scala-scala/src/library/scala/collection/parallel/mutable/ParSet.scala
+        |../scala-scala/src/library/scala/collection/mutable/SetLike.scala""".stripMargin)(scala2mode ++ defaultOptions)
 
   @Test def dotty = {
     dottyBootedLib