Fix #2282: Finalizers must be void and cannot be declared in interfaces

ICSharpCode.Decompiler.Tests/TestCases/Pretty/InterfaceTests.cs

@@ -97,10 +97,19 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 				remove {
 				}
 			}
+			public int Finalize()
+			{
+				return 0;
+			}
 			void IA.Method()
 			{
 				throw new NotImplementedException();
 			}
 		}
+
+		internal interface IInterfacesCannotDeclareDtors
+		{
+			int Finalize();
+		}
 	}
 }

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -1127,9 +1127,13 @@ namespace ICSharpCode.Decompiler.CSharp
 						{
 							// A method introduced in a class or struct hides all non-method base class members with the same name, and all
 							// base class methods with the same signature (method name and parameter count, modifiers, and types).
-							if (baseType.GetMembers(m => m.SymbolKind != SymbolKind.Indexer && m.Name == entity.Name && lookup.IsAccessible(m, true))
-									.Any(m => m.SymbolKind != SymbolKind.Method || (((IMethod)entity).TypeParameters.Count == ((IMethod)m).TypeParameters.Count
-																					&& parameterListComparer.Equals(((IMethod)entity).Parameters, ((IMethod)m).Parameters))))
+							if (baseType.GetMembers(m => m.SymbolKind != SymbolKind.Indexer
+													&& m.SymbolKind != SymbolKind.Constructor
+													&& m.SymbolKind != SymbolKind.Destructor
+													&& m.Name == entity.Name && lookup.IsAccessible(m, true))
+								.Any(m => m.SymbolKind != SymbolKind.Method ||
+									(((IMethod)entity).TypeParameters.Count == ((IMethod)m).TypeParameters.Count
+										&& parameterListComparer.Equals(((IMethod)entity).Parameters, ((IMethod)m).Parameters))))
 							{
 								return true;
 							}

ICSharpCode.Decompiler/TypeSystem/Implementation/MetadataMethod.cs

@@ -82,8 +82,8 @@ namespace ICSharpCode.Decompiler.TypeSystem.Implementation
 			}
 			else if ((attributes & finalizerAttributes) == finalizerAttributes)
 			{
-				string name = this.Name;
-				if (name == "Finalize" && Parameters.Count == 0)
+				if (Name == "Finalize" && Parameters.Count == 0 && ReturnType.IsKnownType(KnownTypeCode.Void)
+					&& (DeclaringTypeDefinition as MetadataTypeDefinition)?.Kind == TypeKind.Class)
 				{
 					this.symbolKind = SymbolKind.Destructor;
 				}