Fixed some more bugs and improved error messages.

3 files changed, 20 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/nsc/symtab/Types.scala b/src/compiler/scala/tools/nsc/symtab/Types.scala
index 6ab9822d15..2e805dd5e3 100644
--- a/src/compiler/scala/tools/nsc/symtab/Types.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Types.scala
@@ -1097,6 +1097,10 @@ trait Types requires SymbolTable {
       if (lobounds.forall(.<:<(tp)) && hibounds.forall(tp.<:<)) {
         inst = tp; true
       } else false;
+
+    override def toString() =
+      lobounds.mkString("[ _>:(", ",", ") ")+
+      hibounds.mkString("| _<:(", ",", ") | _= ")+ inst;
   }
 
   /** A prototype for mapping a function over all possible types
@@ -1240,7 +1244,11 @@ trait Types requires SymbolTable {
 		  case TypeRef(_, basesym, baseargs) =>
 //                    System.out.println("instantiating " + sym + " from " + basesym + " with " + basesym.typeParams + " and " + baseargs);//DEBUG
 		    if (basesym.typeParams.length != baseargs.length)
-                      assert(false, "asSeenFrom(" + pre + "," + clazz + ")" + sym + " " + basesym + " " + baseargs); //debug
+                      throw new TypeError(
+                        "something is wrong (wrong class file?): "+basesym+
+                        " with type parameters "+
+                        basesym.typeParams.map(.name).mkString("[",",","]")+
+                        " gets applied to arguments "+baseargs.mkString("(",",",")"))
 		    instParam(basesym.typeParams, baseargs);
 		  case _ =>
                     throwError
diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
index 1004b4b67d..5df8be1170 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
@@ -246,6 +246,7 @@ trait Infer requires Analyzer {
 	  errorTree(tree, sym.toString() + " cannot be accessed in " +
 		    (if (sym.isClassConstructor) context.enclClass.owner else pre.widen))
 	} else {
+          //System.out.println("check acc " + sym1 + ":" + sym1.tpe + " from " + pre);//DEBUG
           var owntype = pre.memberType(sym1);
           if (pre.isInstanceOf[SuperType])
             owntype = owntype.substSuper(pre, site.symbol.thisType);
@@ -295,8 +296,9 @@ trait Infer requires Analyzer {
     def protoTypeArgs(tparams: List[Symbol], formals: List[Type], restpe: Type,
 		      pt: Type): List[Type] = {
       /** Map type variable to its instance, or, if `variance' is covariant/contravariant,
-       *  to its upper/lower bound; */
+       *  to its upper/lower bound */
       def instantiateToBound(tvar: TypeVar, variance: int): Type = try {
+        //System.out.println("instantiate "+tvar+tvar.constr+" variance = "+variance);//DEBUG
 	if (tvar.constr.inst != NoType) {
 	  instantiate(tvar.constr.inst)
 	} else if ((variance & COVARIANT) != 0 && !tvar.constr.hibounds.isEmpty) {
@@ -305,6 +307,10 @@ trait Infer requires Analyzer {
 	} else if ((variance & CONTRAVARIANT) != 0 && !tvar.constr.lobounds.isEmpty) {
 	  tvar.constr.inst = lub(tvar.constr.lobounds);
 	  instantiate(tvar.constr.inst)
+        } else if (!tvar.constr.hibounds.isEmpty && !tvar.constr.lobounds.isEmpty &&
+                   glb(tvar.constr.hibounds) <:< lub(tvar.constr.lobounds)) {
+	  tvar.constr.inst = glb(tvar.constr.hibounds);
+	  instantiate(tvar.constr.inst)
 	} else {
 	  WildcardType
 	}
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 7d1b5a9c78..63edcdb412 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -567,10 +567,11 @@ trait Typers requires Analyzer {
                 error(parent.pos, "illegal inheritance; super"+superclazz+
                       "\n is not a subclass of the super"+ps.head.symbol+
                       "\n of the mixin " + psym);
-            } else if (settings.migrate.value)
+            } else if (settings.migrate.value) {
               error(parent.pos, migrateMsg+psym+" needs to be a declared as a trait")
-            else
-	      error(parent.pos, ""+psym+" is not declared to be a trait")
+            }else {
+	      error(parent.pos, ""+psym+" needs to be a trait be mixed in")
+            }
 	  else if (psym.hasFlag(FINAL))
 	    error(parent.pos, "illegal inheritance from final class")
 	  else if (!phase.erasedTypes && psym.isSealed &&