BUGFIX IDISP003 handle null forgiving operator.

Fix #211

Author: JohanLarsson

IDisposableAnalyzers.NetCoreTests/IDISP003DisposeBeforeReassigningTests/Valid.cs

@@ -36,6 +36,29 @@ public async ValueTask DisposeAsync()
             await _timer.DisposeAsync();
         }
     }
+}";
+            RoslynAssert.Valid(Analyzer, code);
+        }
+
+        [Test]
+        public static void NullableAnnotated()
+        {
+            var code = @"
+namespace N
+{
+    using System;
+    using System.IO;
+
+    class C
+    {
+        private IDisposable? _disposable;
+
+        void M()
+        {
+            _disposable!.Dispose();
+            _disposable = File.OpenRead(string.Empty);
+        }
+    }
 }";
             RoslynAssert.Valid(Analyzer, code);
         }

IDisposableAnalyzers/IDisposableAnalyzers.csproj

@@ -47,7 +47,7 @@
 
   <ItemGroup>
     <PackageReference Include="Gu.Analyzers" Version="1.6.7-dev" PrivateAssets="all" />
-    <PackageReference Include="Gu.Roslyn.Extensions" Version="0.12.6-dev" />
+    <PackageReference Include="Gu.Roslyn.Extensions" Version="0.12.7-dev" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.3.1" />
     <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="2.9.8" PrivateAssets="all" />
     <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.164" PrivateAssets="all" />

ValidCode.NetCore/Annotated.cs

@@ -0,0 +1,27 @@
+namespace ValidCode.NetCore
+{
+    using System;
+
+    sealed class Annotated : IDisposable
+    {
+        private IDisposable? _foo;
+        private bool _disposed;
+
+        public void Dispose()
+        {
+            if (this._disposed)
+            {
+                return;
+            }
+
+            this._disposed = true;
+            _foo?.Dispose();
+        }
+
+        void Reassign()
+        {
+            _foo!.Dispose();
+            _foo = new Disposable();
+        }
+    }
+}

ValidCode.NetCore/Disposable.cs

@@ -0,0 +1,11 @@
+namespace ValidCode.NetCore
+{
+    using System;
+
+    public sealed class Disposable : IDisposable
+    {
+        public void Dispose()
+        {
+        }
+    }
+}