New scheme

Author: odersky

compiler/src/dotty/tools/dotc/Compiler.scala

@@ -83,7 +83,6 @@ class Compiler {
          new PatternMatcher) ::      // Compile pattern matches
     List(new TestRecheck.Pre) ::     // Test only: run rechecker, enabled under -Yrecheck-test
     List(new TestRecheck) ::         // Test only: run rechecker, enabled under -Yrecheck-test
-    List(new cc.AddTryOwners) ::     // Add symbols as owners of try blocks, enabled under captureChecking
     List(new cc.Setup) ::            // Preparations for check captures phase, enabled under captureChecking
     List(new cc.CheckCaptures) ::    // Check captures, enabled under captureChecking
     List(new ElimOpaque,             // Turn opaque into normal aliases

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -437,7 +437,7 @@ object desugar {
   private def toDefParam(tparam: TypeDef, keepAnnotations: Boolean): TypeDef = {
     var mods = tparam.rawMods
     if (!keepAnnotations) mods = mods.withAnnotations(Nil)
-    tparam.withMods(mods & EmptyFlags | Param)
+    tparam.withMods(mods & (EmptyFlags | Sealed) | Param)
   }
   private def toDefParam(vparam: ValDef, keepAnnotations: Boolean, keepDefault: Boolean): ValDef = {
     var mods = vparam.rawMods