Fix #2389: missing extern keyword for properties and events.

ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -191,7 +191,7 @@
     <Compile Include="TestCases\Pretty\CustomAttributeConflicts.cs" />
     <Compile Include="TestCases\Pretty\DynamicTests.cs" />
     <Compile Include="TestCases\Pretty\Issue1080.cs" />
-    <Compile Include="TestCases\Pretty\MemberTests.cs" />
+    <None Include="TestCases\Pretty\MemberTests.cs" />
     <Compile Include="TestCases\Pretty\NamedArguments.cs" />
     <Compile Include="TestCases\Pretty\QualifierTests.cs" />
     <Compile Include="TestCases\Pretty\RefLocalsAndReturns.cs" />

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

@@ -30,11 +30,13 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 #if ROSLYN
 			public int this[int index] => 0;
 #else
+			#pragma warning disable format
 			public int this[int index] {
 				get {
 					return 0;
 				}
 			}
+			#pragma warning restore format
 #endif
 		}
 
@@ -49,11 +51,19 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 		private volatile int volatileField = 3;
 		private static volatile int staticVolatileField = 4;
 
+		public extern int ExternGetOnly { get; }
+		public extern int ExternSetOnly { set; }
+		public extern int ExternProperty { get; set; }
+
+		public extern event EventHandler Event;
+
 		public void UseVolatileFields()
 		{
 			Console.WriteLine(volatileField + staticVolatileField);
 			volatileField++;
 			staticVolatileField++;
 		}
+
+		public extern void ExternMethod();
 	}
 }

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -1735,14 +1735,21 @@ namespace ICSharpCode.Decompiler.CSharp
 					getter = ((IndexerDeclaration)propertyDecl).Getter;
 					setter = ((IndexerDeclaration)propertyDecl).Setter;
 				}
-				if (property.CanGet && property.Getter.HasBody)
+
+				bool getterHasBody = property.CanGet && property.Getter.HasBody;
+				bool setterHasBody = property.CanSet && property.Setter.HasBody;
+				if (getterHasBody)
 				{
 					DecompileBody(property.Getter, getter, decompileRun, decompilationContext);
 				}
-				if (property.CanSet && property.Setter.HasBody)
+				if (setterHasBody)
 				{
 					DecompileBody(property.Setter, setter, decompileRun, decompilationContext);
 				}
+				if (!getterHasBody && !setterHasBody && !property.IsAbstract && property.DeclaringType.Kind != TypeKind.Interface)
+				{
+					propertyDecl.Modifiers |= Modifiers.Extern;
+				}
 				var accessorHandle = (MethodDefinitionHandle)(property.Getter ?? property.Setter).MetadataToken;
 				var accessor = metadata.GetMethodDefinition(accessorHandle);
 				if (!accessorHandle.GetMethodImplementations(metadata).Any() && accessor.HasFlag(System.Reflection.MethodAttributes.Virtual) == accessor.HasFlag(System.Reflection.MethodAttributes.NewSlot))
@@ -1768,14 +1775,20 @@ namespace ICSharpCode.Decompiler.CSharp
 				{
 					eventDecl.Name = ev.Name.Substring(lastDot + 1);
 				}
-				if (ev.CanAdd && ev.AddAccessor.HasBody)
+				bool adderHasBody = ev.CanAdd && ev.AddAccessor.HasBody;
+				bool removerHasBody = ev.CanRemove && ev.RemoveAccessor.HasBody;
+				if (adderHasBody)
 				{
 					DecompileBody(ev.AddAccessor, ((CustomEventDeclaration)eventDecl).AddAccessor, decompileRun, decompilationContext);
 				}
-				if (ev.CanRemove && ev.RemoveAccessor.HasBody)
+				if (removerHasBody)
 				{
 					DecompileBody(ev.RemoveAccessor, ((CustomEventDeclaration)eventDecl).RemoveAccessor, decompileRun, decompilationContext);
 				}
+				if (!adderHasBody && !removerHasBody && !ev.IsAbstract && ev.DeclaringType.Kind != TypeKind.Interface)
+				{
+					eventDecl.Modifiers |= Modifiers.Extern;
+				}
 				var accessor = metadata.GetMethodDefinition((MethodDefinitionHandle)(ev.AddAccessor ?? ev.RemoveAccessor).MetadataToken);
 				if (accessor.HasFlag(System.Reflection.MethodAttributes.Virtual) == accessor.HasFlag(System.Reflection.MethodAttributes.NewSlot))
 				{

ICSharpCode.Decompiler/CSharp/Transforms/PatternStatementTransform.cs

@@ -986,7 +986,8 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 		{
 			if (!ev.PrivateImplementationType.IsNull)
 				return null;
-			if (!ev.Modifiers.HasFlag(Modifiers.Abstract))
+			const Modifiers withoutBody = Modifiers.Abstract | Modifiers.Extern;
+			if ((ev.Modifiers & withoutBody) == 0 && ev.GetSymbol() is IEvent symbol && symbol.DeclaringType.Kind != TypeKind.Interface)
 			{
 				if (!CheckAutomaticEventV4AggressivelyInlined(ev) && !CheckAutomaticEventV4(ev) && !CheckAutomaticEventV2(ev) && !CheckAutomaticEventV4MCS(ev))
 					return null;