Fix problems related to t0039

This test case exercised several problems:

1.)2.) Two ways to run into a cyclic references. Fixed by
 - assuming an early info when completing a typedef, similarly to what is done for a classdef
 - doing wellformed bounds checking in a later phase.

Failure to check whether arguments correspond to F-bounds.
 - a substitution was missing.

1 files changed, 8 insertions, 3 deletions

diff --git a/src/dotty/tools/dotc/core/SymDenotations.scala b/src/dotty/tools/dotc/core/SymDenotations.scala
index 5fbf6c2c4..bbe5cf986 100644
--- a/src/dotty/tools/dotc/core/SymDenotations.scala
+++ b/src/dotty/tools/dotc/core/SymDenotations.scala
@@ -145,9 +145,14 @@ object SymDenotations {
       if (myFlags is Touched) throw new CyclicReference(this)
       myFlags |= Touched
 
-      completions.println(s"completing ${this.debugString}")
-      completer.complete(this)
-      completions.println(s"completed ${this.debugString}")
+      // completions.println(s"completing ${this.debugString}")
+      try completer.complete(this)
+      catch {
+      case ex: CyclicReference =>
+        completions.println(s"error while completing ${this.debugString}")
+        throw ex
+      }
+      // completions.println(s"completed ${this.debugString}")
     }
 
     protected[dotc] final def info_=(tp: Type) = {