Allow downcasting from derived to base for valuetypes

xoofx · Sep 27, 2015 · 421c0be · 421c0be
1 parent cef6e29
commit 421c0be
Showing 1 changed file with 8 additions and 1 deletion.
diff --git a/src/Compilers/CSharp/Portable/Binder/Semantics/Conversions/ConversionsBase.cs b/src/Compilers/CSharp/Portable/Binder/Semantics/Conversions/ConversionsBase.cs
@@ -100,7 +100,7 @@ public static bool IsBaseClass(TypeSymbol derivedType, TypeSymbol baseType, ref
             Debug.Assert((object)baseType != null);
 
             // A base class has got to be a class. The derived type might be a struct, enum, or delegate.
-            if (!baseType.IsClassType())
+            if (!baseType.IsClassType() && !(derivedType.IsValueType && baseType.IsValueType))
             {
                 return false;
             }
@@ -1754,6 +1754,13 @@ private bool HasExplicitReferenceConversion(TypeSymbol source, TypeSymbol destin
                 return true;
             }
 
+            // Allow convert for valuetype
+            if (source.IsValueType && destination.IsValueType &&
+                IsBaseClass(source, destination, ref useSiteDiagnostics))
+            {
+                return true;
+            }
+
             return false;
         }