Merge pull request #2662 from James-Ko/patch-1

Remove casts to IDisposable where unneeded

Author: stephentoub

src/System.Collections.Concurrent/src/System/Collections/Concurrent/ConcurrentDictionary.cs

@@ -1359,7 +1359,7 @@ bool IDictionary.Contains(object key)
         {
             if (key == null) throw new ArgumentNullException("key");
 
-            return (key is TKey) && ((ConcurrentDictionary<TKey, TValue>)this).ContainsKey((TKey)key);
+            return (key is TKey) && this.ContainsKey((TKey)key);
         }
 
         /// <summary>Provides an <see cref="T:System.Collections.Generics.IDictionaryEnumerator"/> for the

src/System.Console/src/System/IO/SyncTextReader.cs

@@ -16,7 +16,7 @@ internal sealed class SyncTextReader : TextReader
         public static SyncTextReader GetSynchronizedTextReader(TextReader reader)
         {
             Debug.Assert(reader != null);
-            return reader as SyncTextReader ?? 
+            return reader as SyncTextReader ??
                 new SyncTextReader(reader);
         }
 
@@ -31,8 +31,7 @@ protected override void Dispose(bool disposing)
             {
                 lock (_methodLock)
                 {
-                    // Explicitly pick up a potentially methodimpl'ed Dispose
-                    ((IDisposable)_in).Dispose();
+                    _in.Dispose();
                 }
             }
         }
@@ -87,7 +86,7 @@ public override String ReadToEnd()
 
         //
         // On SyncTextReader all APIs should run synchronously, even the async ones.
-        // No explicit locking is needed, as they all just delegate 
+        // No explicit locking is needed, as they all just delegate
         //
 
         public override Task<String> ReadLineAsync()

src/System.Console/src/System/IO/SyncTextWriter.cs

@@ -15,7 +15,7 @@ internal sealed class SyncTextWriter : TextWriter, IDisposable
         internal static SyncTextWriter GetSynchronizedTextWriter(TextWriter writer)
         {
             Debug.Assert(writer != null);
-            return writer as SyncTextWriter ?? 
+            return writer as SyncTextWriter ??
                 new SyncTextWriter(writer);
         }
 
@@ -47,8 +47,7 @@ protected override void Dispose(bool disposing)
             {
                 lock (_methodLock)
                 {
-                    // Explicitly pick up a potentially methodimpl'ed Dispose
-                    ((IDisposable)_out).Dispose();
+                    _out.Dispose();
                 }
             }
         }

src/System.Linq/src/System/Linq/Enumerable.cs

@@ -184,8 +184,11 @@ public override Iterator<TSource> Clone()
 
             public override void Dispose()
             {
-                if (_enumerator is IDisposable) ((IDisposable)_enumerator).Dispose();
-                _enumerator = null;
+                if (_enumerator != null)
+                {
+                    _enumerator.Dispose();
+                    _enumerator = null;
+                }
                 base.Dispose();
             }
 
@@ -347,8 +350,11 @@ public override Iterator<TResult> Clone()
 
             public override void Dispose()
             {
-                if (_enumerator is IDisposable) ((IDisposable)_enumerator).Dispose();
-                _enumerator = null;
+                if (_enumerator != null)
+                {
+                    _enumerator.Dispose();
+                    _enumerator = null;
+                }
                 base.Dispose();
             }
 

src/System.Xml.ReaderWriter/src/System/Xml/Core/XmlWrappingWriter.cs

@@ -197,7 +197,7 @@ protected override void Dispose(bool disposing)
         {
             if (disposing)
             {
-                ((IDisposable)writer).Dispose();
+                writer.Dispose();
             }
         }
     }