Allow 'is' as a valid null check on parameters

* CheckParametersNullityInVisibleMethodsRule.cs: Allow 'is' as a valid
null check on parameters

* Test/CheckParametersNullityInVisibleMethodsTest.cs: Test case for
above, provided by Iristyle

2 files changed, 42 insertions, 0 deletions

diff --git a/gendarme/rules/Gendarme.Rules.Correctness/CheckParametersNullityInVisibleMethodsRule.cs b/gendarme/rules/Gendarme.Rules.Correctness/CheckParametersNullityInVisibleMethodsRule.cs
index 6b06a731..c5e0e647 100644
--- a/gendarme/rules/Gendarme.Rules.Correctness/CheckParametersNullityInVisibleMethodsRule.cs
+++ b/gendarme/rules/Gendarme.Rules.Correctness/CheckParametersNullityInVisibleMethodsRule.cs
@@ -157,6 +157,9 @@ namespace Gendarme.Rules.Correctness {
 				next = next.Next;
 				nc = next.OpCode.Code;
 				break;
+			case Code.Isinst:
+				has_null_check.Set (parameter.GetSequence ());
+				return;
 			}
 
 			if (null_compare.Get (nc)) {
diff --git a/gendarme/rules/Gendarme.Rules.Correctness/Test/CheckParametersNullityInVisibleMethodsTest.cs b/gendarme/rules/Gendarme.Rules.Correctness/Test/CheckParametersNullityInVisibleMethodsTest.cs
index 302c1f91..65307c4e 100644
--- a/gendarme/rules/Gendarme.Rules.Correctness/Test/CheckParametersNullityInVisibleMethodsTest.cs
+++ b/gendarme/rules/Gendarme.Rules.Correctness/Test/CheckParametersNullityInVisibleMethodsTest.cs
@@ -755,5 +755,44 @@ namespace Tests.Rules.Correctness {
 		{
 			AssertRuleSuccess<CheckParametersNullityInVisibleMethodsTest> ("ChecksObjectAndMember");                        
 		}
+
+		// test case from Iristyle
+		// https://github.com/Iristyle/mono-tools/commit/d27c6d10ccebde1d1c3d600279fc35802581f266
+		public void ReassignsRefBeforeCheck (ref object test)
+		{
+			//uncommenting this line makes the test succeed
+			//if (null == test) { throw new ArgumentNullException("test"); }
+
+			//follow this general pattern because of FxCop false positive on CA1062
+			//http://connect.microsoft.com/VisualStudio/feedback/details/560099/ca1062-false-positive-with-byref-arguments
+			object testCopy = test;
+			
+			if (null == testCopy)
+				throw new ArgumentNullException ("test");
+			test = testCopy;
+		}
+
+		[Test]
+		[Ignore ("by design the rule only checks parameter arguments, not variables, fields, return value...")]
+		public void ParameterAssignedToVariableBeforeCheck ()
+		{
+			AssertRuleSuccess<CheckParametersNullityInVisibleMethodsTest> ("ReassignsRefBeforeCheck");
+		}
+
+		// test case provided by Iristyle - bnc665193
+		// https://github.com/Iristyle/mono-tools/commit/5afbd0a3ef746ff6fdb3db4e1be53995c1734be4
+		public void ChecksIsType (Exception ex)
+		{
+			//only non-nulls may pass
+			if (ex is ArgumentException) {
+				ex.ToString ();
+			}            
+		}
+
+		[Test]
+		public void AllowsIsCheck ()
+		{
+			AssertRuleSuccess<CheckParametersNullityInVisibleMethodsTest> ("ChecksIsType");
+		}
 	}
 }