[Mono-bugs] [Bug 79843][Maj] New - Valid delegate assignation not regarded as valid

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Changed by ymotara at deloitte.co.za.

http://bugzilla.ximian.com/show_bug.cgi?id=79843

--- shadow/79843	2006-11-06 06:54:29.000000000 -0500
+++ shadow/79843.tmp.13973	2006-11-06 06:54:29.000000000 -0500
@@ -0,0 +1,68 @@
+Bug#: 79843
+Product: Mono: Compilers
+Version: 1.1
+OS: GNU/Linux [Other]
+OS Details: 
+Status: NEW   
+Resolution: 
+Severity: 
+Priority: Major
+Component: C#
+AssignedTo: rharinath at novell.com                            
+ReportedBy: ymotara at deloitte.co.za               
+QAContact: mono-bugs at ximian.com
+TargetMilestone: ---
+URL: 
+Cc: 
+Summary: Valid delegate assignation not regarded as valid
+
+Description of Problem:
+When the method assigned to a delegate returns an interface type that is
+convertible to the type-signature return of the delegate, the assignation
+is rejected with the error CS0407.
+
+Steps to reproduce the problem:
+1. Create test file "test.cs" as follows:
+
+delegate IInterface testDelegate(IInterface x);
+interface IInterface {
+   int ID { get; }
+}
+class concrete : IInterface {
+   public int ID { get { return 0; } }
+}
+class Program {
+   private concrete getConcrete(IInterface z) {
+      return new concrete();
+   }
+   public static void Main(string[] args) {
+      Program p = new Program();
+      testDelegate x = new testDelegate(p.getConcrete);
+      // also fails on:
+      // testDelegate x = p.getConcrete;
+      // also fails on:
+      // testDelegate x = (testDelegate)p.getConcrete;
+      x(new concrete());
+   }
+}
+
+2. Try to compile test file.
+3. Observe error.
+
+Actual Results:
+Running "gmcs test.cs" results in the following output:
+test.cs(18,24): error CS0407: `concrete Program.getConcrete(IInterface)'
+has the wrong return type to match the delegate `IInterface
+testDelegate(IInterface)'
+Compilation failed: 1 error(s), 0 warnings
+
+Expected Results:
+The compilation should succeed: delegates are supposed to allow covariance.
+ csc compiles the code just fine; unless there is a bug in that compiler,
+the bug exists in gmcs.
+
+How often does this happen? 
+100% of the time.
+
+Additional Information:
+Tested against version 1.1.18 on both Gentoo and Ubuntu.