Fix error handling in super with no __class__

Author: msimacek

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/superobject/SuperBuiltins.java

@@ -216,7 +216,7 @@ protected boolean isInBuiltinFunctionRoot() {
         protected ReadLocalVariableNode createRead(VirtualFrame frame) {
             FrameSlot slot = frame.getFrameDescriptor().findFrameSlot(SpecialAttributeNames.__CLASS__);
             if (slot == null) {
-                throw raise(PythonErrorType.RuntimeError, ErrorMessages.EMPTY_CLASS_CELL);
+                throw raise(PythonErrorType.RuntimeError, ErrorMessages.SUPER_NO_CLASS);
             }
             return ReadLocalVariableNode.create(slot);
         }
@@ -238,7 +238,7 @@ PNone initInPlace(VirtualFrame frame, SuperObject self, @SuppressWarnings("unuse
                 cls = getGetRefNode().execute((PCell) cls);
             }
             if (cls == PNone.NONE) {
-                throw raise(PythonErrorType.RuntimeError, ErrorMessages.EMPTY_CLASS_CELL, "super()");
+                throw raise(PythonErrorType.RuntimeError, ErrorMessages.SUPER_NO_CLASS);
             }
             return init(frame, self, cls, obj);
         }
@@ -276,7 +276,7 @@ private Object getClassFromTarget(VirtualFrame frame, PFrame target, HashingStor
             if (cls instanceof PCell) {
                 cls = getGetRefNode().execute((PCell) cls);
                 if (cls == null) {
-                    throw raise(PythonErrorType.RuntimeError, ErrorMessages.EMPTY_CLASS_CELL, "super()");
+                    throw raise(PythonErrorType.RuntimeError, ErrorMessages.SUPER_NO_CLASS);
                 }
             }
             return cls != null ? cls : PNone.NONE;

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/ErrorMessages.java

@@ -167,7 +167,7 @@ public abstract class ErrorMessages {
     public static final String DICT_UPDATE_SEQ_ELEM_HAS_LENGTH_2_REQUIRED = "dictionary update sequence element #%d has length %d; 2 is required";
     public static final String DIVISION_BY_ZERO = "division by zero";
     public static final String S_DIVISION_BY_ZERO = "%s division by zero";
-    public static final String EMPTY_CLASS_CELL = "%s: empty __class__ cell";
+    public static final String SUPER_NO_CLASS = "super(): no arguments";
     public static final String EMPTY_SEPARATOR = "empty separator";
     public static final String EMPTY_STR_FOR_COMPLEX = "empty string for complex()";
     public static final String END_MUST_BE_NONE_OR_STRING = "end must be None or a string, not %p";