Also show constraint on SO

Author: odersky

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

@@ -195,7 +195,7 @@ object Inferencing {
         case tp =>
           foldOver(x, tp)
       catch case ex: Throwable =>
-        handleRecursive("traverse ", s"${tp.show}" , ex)
+        handleRecursive("traverse ", s"${tp.show} in ${ctx.typerState.constraint.show}" , ex)
 
 
     def process(tp: Type): Boolean =