#2622: Fix crash in ExpressionBuilder when decompiling object initializer composed of readonly properties.

Author: siegfriedpammer

ICSharpCode.Decompiler.Tests/TestCases/Correctness/InitializerTests.cs

@@ -391,7 +391,43 @@ public static void Bug270_NestedInitialisers()
 
 		}
 
+#if CS60
+		class Issue2622a
+		{
+			public class C
+			{
+				public ServiceHost M()
+				{
+					return new ServiceHost(typeof(EWSService), null) {
+						Description = { Endpoints = { [0] = { Behaviors = { new EwsWebHttpBehavior() } } } }
+					};
+				}
+			}
+
+			class EWSService { }
+
+			public class ServiceHost
+			{
+				public ServiceHost(Type type, object x) { }
+
+				public Descr Description { get; }
+			}
+
+			public class Descr
+			{
+				public List<EP> Endpoints { get; }
+			}
+
+			public class EP
+			{
+				public List<Beh> Behaviors { get; }
+			}
+
+			public abstract class Beh { }
 
+			public class EwsWebHttpBehavior : Beh { }
+		}
+#endif
 
 		class Issue855
 		{

ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs

@@ -3305,18 +3305,9 @@ TranslatedExpression MakeInitializerAssignment(InitializedObjectResolveResult rr
 			}
 			if (valuePath.Indices?.Length > 0)
 			{
-				Expression index;
-				if (memberPath.Member is IProperty property)
-				{
-					index = new CallBuilder(this, typeSystem, settings)
-						.BuildDictionaryInitializerExpression(valuePath.OpCode, property.Setter, rr, GetIndices(valuePath.Indices, indexVariables).ToList());
-				}
-				else
-				{
-					index = new IndexerExpression(null, GetIndices(valuePath.Indices, indexVariables).Select(i => Translate(i).Expression));
-				}
+				Expression index = new IndexerExpression(null, GetIndices(valuePath.Indices, indexVariables).Select(i => Translate(i).Expression));
 				return new AssignmentExpression(index, value)
-					.WithRR(new MemberResolveResult(rr, memberPath.Member))
+					.WithRR(new MemberResolveResult(rr, valuePath.Member))
 					.WithoutILInstruction();
 			}
 			else