[Mono-bugs] [Bug 81041][Min] New - missing CS0019: reject == operator for object vs. generic type argument

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Changed by atsushi at ximian.com.

http://bugzilla.ximian.com/show_bug.cgi?id=81041

--- shadow/81041	2007-03-05 15:35:31.000000000 -0500
+++ shadow/81041.tmp.30833	2007-03-05 15:35:31.000000000 -0500
@@ -0,0 +1,74 @@
+Bug#: 81041
+Product: Mono: Compilers
+Version: 1.0
+OS: 
+OS Details: 
+Status: NEW   
+Resolution: 
+Severity: 
+Priority: Minor
+Component: C#
+AssignedTo: rharinath at novell.com                            
+ReportedBy: atsushi at ximian.com               
+QAContact: mono-bugs at ximian.com
+TargetMilestone: ---
+URL: 
+Cc: 
+Summary: missing CS0019: reject == operator for object vs. generic type argument
+
+With gmcs, the example below does not cause CS0019 (no applicable ==
+operator) error.
+
+--------
+public class Test
+{
+        public static void Main ()
+        {
+                KVP<string,int> p = new KVP<string,int> ();
+                int i;
+                p.TryGet ("", out i);
+        }
+}
+
+public class KVP<K,V>
+{
+        V vvv;
+
+        public bool TryGet (K k, out V v)
+        {
+                object tmp = vvv;
+                if (tmp == default (V))
+                        v = default (V);
+                else
+                        v = (V) tmp;
+                return true;
+        }
+}
+--------
+
+I read ECMA 334 section 14.9.6 (Reference type equality operators) and I
+think the below term should apply here:
+
+"Otherwise, if either A or B is a type parameter that is not known to be a
+reference type (§25.7), then no reference type equality operator is
+applicable."
+
+
+Actual Results:
+
+no error.
+
+Expected Results:
+
+$ csc test.cs -nologo
+test.cs(18,7): error CS0019: Operator '==' cannot be applied to operands of
+type 'object' and 'V'
+
+How often does this happen? 
+
+consistently.
+
+Additional Information:
+
+The compiled assembly, when executed, causes invalid IL on mono, and
+strangely no error on .net ...