Merge pull request #927 from icsharpcode/initializer_pretty_fix

Initializer

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

@@ -66,6 +66,7 @@
     <Compile Include="TestCases\Correctness\Using.cs" />
     <Compile Include="TestCases\ILPretty\Issue379.cs" />
     <Compile Include="TestCases\Pretty\FixProxyCalls.cs" />
+    <Compile Include="TestCases\Pretty\InitializerTests.cs" />
     <None Include="TestCases\ILPretty\Issue646.cs" />
     <Compile Include="TestCases\Pretty\Async.cs" />
     <Compile Include="TestCases\Pretty\CheckedUnchecked.cs" />

ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs

@@ -188,6 +188,12 @@ namespace ICSharpCode.Decompiler.Tests
 			Run(cscOptions: cscOptions, asmOptions: AssemblerOptions.UseOwnDisassembler);
 		}
 
+		[Test]
+		public void InitializerTests([ValueSource("defaultOptions")] CompilerOptions cscOptions)
+		{
+			Run(cscOptions: cscOptions);
+		}
+
 		[Test]
 		public void FixProxyCalls([Values(CompilerOptions.None, CompilerOptions.Optimize, CompilerOptions.UseRoslyn)] CompilerOptions cscOptions)
 		{

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

@@ -0,0 +1,484 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Threading;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
+{
+	public class InitializerTests
+	{
+		#region Types and helpers
+		public class C
+		{
+			public int Z;
+			public S Y;
+			public List<S> L;
+		}
+
+		public struct S
+		{
+			public int A;
+			public int B;
+
+			public S(int a)
+			{
+				this.A = a;
+				this.B = 0;
+			}
+		}
+
+		private enum MyEnum
+		{
+			a = 0,
+			b = 1
+		}
+
+		private enum MyEnum2
+		{
+			c = 0,
+			d = 1
+		}
+
+		private class Data
+		{
+			public List<MyEnum2> FieldList = new List<MyEnum2>();
+			public MyEnum a {
+				get;
+				set;
+			}
+			public MyEnum b {
+				get;
+				set;
+			}
+			public List<MyEnum2> PropertyList {
+				get;
+				set;
+			}
+
+			public Data MoreData {
+				get;
+				set;
+			}
+
+			public StructData NestedStruct {
+				get;
+				set;
+			}
+
+			public Data this[int i] {
+				get {
+					return null;
+				}
+				set {
+				}
+			}
+
+			public Data this[int i, string j] {
+				get {
+					return null;
+				}
+				set {
+				}
+			}
+
+			public event EventHandler TestEvent;
+		}
+
+		private struct StructData
+		{
+			public int Field;
+			public int Property {
+				get;
+				set;
+			}
+
+			public Data MoreData {
+				get;
+				set;
+			}
+
+			public StructData(int initialValue)
+			{
+				this = default(StructData);
+				this.Field = initialValue;
+				this.Property = initialValue;
+			}
+		}
+
+		// Helper methods used to ensure initializers used within expressions work correctly
+		private static void X(object a, object b)
+		{
+		}
+
+		private static object Y()
+		{
+			return null;
+		}
+
+		public static void TestCall(int a, Thread thread)
+		{
+
+		}
+
+		public static C TestCall(int a, C c)
+		{
+			return c;
+		}
+		#endregion
+
+		public C Test1()
+		{
+			C c = new C();
+			c.L = new List<S>();
+			c.L.Add(new S(1));
+			return c;
+		}
+
+		public C Test1Alternative()
+		{
+			return InitializerTests.TestCall(1, new C {
+				L = new List<S> {
+					new S(1)
+				}
+			});
+		}
+
+		public C Test2()
+		{
+			C c = new C();
+			c.Z = 1;
+			c.Z = 2;
+			return c;
+		}
+
+		public C Test3()
+		{
+			C c = new C();
+			c.Y = new S(1);
+			c.Y.A = 2;
+			return c;
+		}
+
+		public C Test3b()
+		{
+			return InitializerTests.TestCall(0, new C {
+				Z = 1,
+				Y = {
+					A = 2
+				}
+			});
+		}
+
+		public C Test4()
+		{
+			C c = new C();
+			c.Y.A = 1;
+			c.Z = 2;
+			c.Y.B = 3;
+			return c;
+		}
+
+
+		public static void CollectionInitializerList()
+		{
+			InitializerTests.X(InitializerTests.Y(), new List<int> {
+				1,
+				2,
+				3
+			});
+		}
+
+		public static object RecursiveCollectionInitializer()
+		{
+			List<object> list = new List<object>();
+			list.Add(list);
+			return list;
+		}
+
+		public static void CollectionInitializerDictionary()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Dictionary<string, int> {
+			{
+				"First",
+				1
+			},
+			{
+				"Second",
+				2
+			},
+			{
+				"Third",
+				3
+			}
+		  });
+		}
+
+		public static void CollectionInitializerDictionaryWithEnumTypes()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Dictionary<MyEnum, MyEnum2> {
+			{
+				MyEnum.a,
+				MyEnum2.c
+			},
+			{
+				MyEnum.b,
+				MyEnum2.d
+			}
+		  });
+		}
+
+		public static void NotACollectionInitializer()
+		{
+			List<int> list = new List<int>();
+			list.Add(1);
+			list.Add(2);
+			list.Add(3);
+			InitializerTests.X(InitializerTests.Y(), list);
+		}
+
+		public static void ObjectInitializer()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				a = MyEnum.a
+			});
+		}
+
+		public static void NotAnObjectInitializer()
+		{
+			Data data = new Data();
+			data.a = MyEnum.a;
+			InitializerTests.X(InitializerTests.Y(), data);
+		}
+
+		public static void NotAnObjectInitializerWithEvent()
+		{
+			Data data = new Data();
+			data.TestEvent += delegate(object sender, EventArgs e) {
+				Console.WriteLine();
+			};
+			InitializerTests.X(InitializerTests.Y(), data);
+		}
+
+		public static void ObjectInitializerAssignCollectionToField()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				a = MyEnum.a,
+				FieldList = new List<MyEnum2> {
+					MyEnum2.c,
+					MyEnum2.d
+				}
+			});
+		}
+
+		public static void ObjectInitializerAddToCollectionInField()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				a = MyEnum.a,
+				FieldList = {
+					MyEnum2.c,
+					MyEnum2.d
+				}
+			});
+		}
+
+		public static void ObjectInitializerAssignCollectionToProperty()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				a = MyEnum.a,
+				PropertyList = new List<MyEnum2> {
+					MyEnum2.c,
+					MyEnum2.d
+				}
+			});
+		}
+
+		public static void ObjectInitializerAddToCollectionInProperty()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				a = MyEnum.a,
+				PropertyList = {
+					MyEnum2.c,
+					MyEnum2.d
+				}
+			});
+		}
+
+		public static void ObjectInitializerWithInitializationOfNestedObjects()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				MoreData = {
+					a = MyEnum.a,
+					MoreData = {
+						a = MyEnum.b
+					}
+				}
+			});
+		}
+
+		private static int GetInt()
+		{
+			return 1;
+		}
+
+		private static string GetString()
+		{
+			return "Test";
+		}
+
+#if !LEGACY_CSC
+		public static void SimpleDictInitializer()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				MoreData = {
+					a = MyEnum.a,
+					[2] = null
+				}
+			});
+		}
+
+		public static void MixedObjectAndDictInitializer()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				MoreData = {
+					a = MyEnum.a,
+					[InitializerTests.GetInt()] = {
+						a = MyEnum.b,
+						FieldList = {
+							MyEnum2.c
+						},
+						[InitializerTests.GetInt(), InitializerTests.GetString()] = new Data(),
+						[2] = null
+					}
+				}
+			});
+		}
+#endif
+
+		public static void ObjectInitializerWithInitializationOfDeeplyNestedObjects()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				a = MyEnum.b,
+				MoreData = {
+				  a = MyEnum.a,
+				  MoreData = {
+						MoreData = {
+							MoreData = {
+								MoreData = {
+									MoreData = {
+										MoreData = {
+											a = MyEnum.b
+										}
+									}
+								}
+							}
+						}
+					}
+			  }
+			});
+		}
+
+		public static void CollectionInitializerInsideObjectInitializers()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				MoreData = new Data {
+					a = MyEnum.a,
+					b = MyEnum.b,
+					PropertyList = {
+						MyEnum2.c
+					}
+				}
+			});
+		}
+
+		public static void NotAStructInitializer_DefaultConstructor()
+		{
+			StructData structData = default(StructData);
+			structData.Field = 1;
+			structData.Property = 2;
+			InitializerTests.X(InitializerTests.Y(), structData);
+		}
+
+		public static void StructInitializer_DefaultConstructor()
+		{
+			InitializerTests.X(InitializerTests.Y(), new StructData {
+				Field = 1,
+				Property = 2
+			});
+		}
+
+		public static void NotAStructInitializer_ExplicitConstructor()
+		{
+			StructData structData = new StructData(0);
+			structData.Field = 1;
+			structData.Property = 2;
+			InitializerTests.X(InitializerTests.Y(), structData);
+		}
+
+		public static void StructInitializer_ExplicitConstructor()
+		{
+			InitializerTests.X(InitializerTests.Y(), new StructData(0) {
+				Field = 1,
+				Property = 2
+			});
+		}
+
+		public static void StructInitializerWithInitializationOfNestedObjects()
+		{
+			InitializerTests.X(InitializerTests.Y(), new StructData {
+				MoreData = {
+					a = MyEnum.a,
+					FieldList = {
+						MyEnum2.c,
+						MyEnum2.d
+					}
+				}
+			});
+		}
+
+		public static void StructInitializerWithinObjectInitializer()
+		{
+			InitializerTests.X(InitializerTests.Y(), new Data {
+				NestedStruct = new StructData(2) {
+					Field = 1,
+					Property = 2
+				}
+			});
+		}
+
+		public static void Bug270_NestedInitialisers()
+		{
+			NumberFormatInfo[] source = null;
+
+			InitializerTests.TestCall(0, new Thread(InitializerTests.Bug270_NestedInitialisers) {
+				Priority = ThreadPriority.BelowNormal,
+				CurrentCulture = new CultureInfo(0) {
+					DateTimeFormat = new DateTimeFormatInfo {
+						ShortDatePattern = "ddmmyy"
+					},
+					NumberFormat = (from format in source
+									where format.CurrencySymbol == "$"
+									select format).First()
+				}
+			});
+		}
+	}
+}

ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs

@@ -1440,11 +1440,10 @@ namespace ICSharpCode.Decompiler.CSharp
 				if (currentPath == null) {
 					currentPath = info.Path;
 				} else {
-					int firstDifferenceIndex = Math.Min(currentPath.Count, info.Path.Count);
+					int minLen = Math.Min(currentPath.Count, info.Path.Count);
-					int index = 0;
+					int firstDifferenceIndex = 0;
-					while (index < firstDifferenceIndex && info.Path[index] == currentPath[index])
+					while (firstDifferenceIndex < minLen && info.Path[firstDifferenceIndex] == currentPath[firstDifferenceIndex])
-						index++;
+						firstDifferenceIndex++;
-					firstDifferenceIndex = index;
 					while (elementsStack.Count - 1 > firstDifferenceIndex) {
 						var methodElement = currentPath[elementsStack.Count - 1];
 						var pathElement = currentPath[elementsStack.Count - 2];

ICSharpCode.Decompiler/CSharp/OutputVisitor/CSharpOutputVisitor.cs

@@ -90,6 +90,7 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 			Space(policy.SpaceBeforeBracketComma);
 			// TODO: Comma policy has changed.
 			writer.WriteToken(Roles.Comma, ",");
+			isAfterSpace = false;
 			Space(!noSpaceAfterComma && policy.SpaceAfterBracketComma);
 			// TODO: Comma policy has changed.
 		}
@@ -194,6 +195,7 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 		
 		#region Write tokens
 		protected bool isAtStartOfLine = true;
+		protected bool isAfterSpace;
 		
 		/// <summary>
 		/// Writes a keyword, and all specials up to
@@ -207,18 +209,21 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 		{
 			writer.WriteKeyword(tokenRole, token);
 			isAtStartOfLine = false;
+			isAfterSpace = false;
 		}
 		
 		protected virtual void WriteIdentifier(Identifier identifier)
 		{
 			writer.WriteIdentifier(identifier);
 			isAtStartOfLine = false;
+			isAfterSpace = false;
 		}
 		
 		protected virtual void WriteIdentifier(string identifier)
 		{
 			AstType.Create(identifier).AcceptVisitor(this);
 			isAtStartOfLine = false;
+			isAfterSpace = false;
 		}
 		
 		protected virtual void WriteToken(TokenRole tokenRole)
@@ -230,6 +235,7 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 		{
 			writer.WriteToken(tokenRole, token);
 			isAtStartOfLine = false;
+			isAfterSpace = false;
 		}
 		
 		protected virtual void LPar()
@@ -260,8 +266,9 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 		/// </summary>
 		protected virtual void Space(bool addSpace = true)
 		{
-			if (addSpace) {
+			if (addSpace && !isAfterSpace) {
 				writer.Space();
+				isAfterSpace = true;
 			}
 		}
 		
@@ -269,6 +276,7 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 		{
 			writer.NewLine();
 			isAtStartOfLine = true;
+			isAfterSpace = false;
 		}
 		
 		protected virtual void OpenBrace(BraceStyle style)
@@ -278,7 +286,7 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 				case BraceStyle.EndOfLine:
 				case BraceStyle.BannerStyle:
 					if (!isAtStartOfLine)
-						writer.Space();
+						Space();
 					writer.WriteToken(Roles.LBrace, "{");
 					break;
 				case BraceStyle.EndOfLineWithoutSpace:
@@ -937,6 +945,7 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 		{
 			StartNode(primitiveExpression);
 			writer.WritePrimitiveValue(primitiveExpression.Value, primitiveExpression.UnsafeLiteralValue);
+			isAfterSpace = false;
 			EndNode(primitiveExpression);
 		}
 		#endregion

ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj

@@ -276,6 +276,7 @@
     <Compile Include="IL\ILAstWritingOptions.cs" />
     <Compile Include="IL\SequencePoint.cs" />
     <Compile Include="IL\Instructions\CallIndirect.cs" />
+    <Compile Include="IL\Instructions\DefaultValue.cs" />
     <Compile Include="IL\Transforms\EarlyExpressionTransforms.cs" />
     <Compile Include="IL\Transforms\ProxyCallReplacer.cs" />
     <Compile Include="IL\Instructions\StringToInt.cs" />

ICSharpCode.Decompiler/IL/ILReader.cs

@@ -1011,7 +1011,9 @@ namespace ICSharpCode.Decompiler.IL
 
 		ILInstruction InitObj(ILInstruction target, IType type)
 		{
-			return new StObj(target, new DefaultValue(type), type);
+			var value = new DefaultValue(type);
+			value.ILStackWasEmpty = currentStack.IsEmpty;
+			return new StObj(target, value, type);
 		}
 		
 		private ILInstruction DecodeConstrainedCall()

ICSharpCode.Decompiler/IL/Instructions/DefaultValue.cs

@@ -0,0 +1,33 @@
+// Copyright (c) 2017 Siegfried Pammer
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace ICSharpCode.Decompiler.IL
+{
+	partial class DefaultValue
+	{
+		/// <summary>
+		/// Gets whether the IL stack was empty at the point of this instruction.
+		/// (not counting the argument of the instruction itself)
+		/// </summary>
+		public bool ILStackWasEmpty;
+	}
+}

ICSharpCode.Decompiler/IL/Transforms/AssignVariableNames.cs

@@ -196,6 +196,14 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 					proposedName = proposedNameForLoads[0];
 				}
 			}
+			if (string.IsNullOrEmpty(proposedName) && variable.Kind == VariableKind.StackSlot) {
+				var proposedNameForStoresFromNewObj = variable.StoreInstructions.OfType<StLoc>()
+					.Select(expr => GetNameByType(GuessType(variable.Type, expr.Value, context)))
+					.Except(currentFieldNames).ToList();
+				if (proposedNameForStoresFromNewObj.Count == 1) {
+					proposedName = proposedNameForStoresFromNewObj[0];
+				}
+			}
 			if (string.IsNullOrEmpty(proposedName)) {
 				proposedName = GetNameByType(variable.Type);
 			}
@@ -349,6 +357,25 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 				return char.ToLower(name[0]) + name.Substring(1);
 		}
 
+		internal static IType GuessType(IType variableType, ILInstruction inst, ILTransformContext context)
+		{
+			if (!variableType.IsKnownType(KnownTypeCode.Object))
+				return variableType;
+
+			switch (inst) {
+				case NewObj newObj:
+					return newObj.Method.DeclaringType;
+				case Call call:
+					return call.Method.ReturnType;
+				case CallVirt callVirt:
+					return callVirt.Method.ReturnType;
+				case CallIndirect calli:
+					return calli.ReturnType;
+				default:
+					return context.TypeSystem.Compilation.FindType(inst.ResultType.ToKnownTypeCode());
+			}
+		}
+
 		internal static string GenerateForeachVariableName(ILFunction function, ILInstruction valueContext, ILVariable existingVariable = null)
 		{
 			if (function == null)

ICSharpCode.Decompiler/IL/Transforms/EarlyExpressionTransforms.cs

@@ -104,6 +104,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 				var newObj = new NewObj(inst.Method);
 				newObj.ILRange = inst.ILRange;
 				newObj.Arguments.AddRange(inst.Arguments.Skip(1));
+				newObj.ILStackWasEmpty = inst.ILStackWasEmpty;
 				var expr = new StObj(inst.Arguments[0], newObj, inst.Method.DeclaringType);
 				inst.ReplaceWith(expr);
 				return expr;

ICSharpCode.Decompiler/IL/Transforms/TransformCollectionAndObjectInitializers.cs

@@ -20,6 +20,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using ICSharpCode.Decompiler.TypeSystem;
+using ICSharpCode.Decompiler.Util;
 
 namespace ICSharpCode.Decompiler.IL.Transforms
 {
@@ -45,7 +46,6 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			ILInstruction inst = body.Instructions[pos];
 			// Match stloc(v, newobj)
 			if (inst.MatchStLoc(out var v, out var initInst) && (v.Kind == VariableKind.Local || v.Kind == VariableKind.StackSlot)) {
-				Block initializerBlock = null;
 				IType instType;
 				switch (initInst) {
 					case NewObj newObjInst:
@@ -65,49 +65,55 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 						instType = newObjInst.Method.DeclaringType;
 						break;
 					case DefaultValue defaultVal:
+						if (defaultVal.ILStackWasEmpty && v.Kind == VariableKind.Local && !context.Function.Method.IsConstructor) {
+							// on statement level (no other expressions on IL stack),
+							// prefer to keep local variables (but not stack slots),
+							// unless we are in a constructor (where inlining object initializers might be critical
+							// for the base ctor call)
+							return false;
+						}
 						instType = defaultVal.Type;
 						break;
-					case Block existingInitializer:
-						if (existingInitializer.Type == BlockType.CollectionInitializer || existingInitializer.Type == BlockType.ObjectInitializer) {
-							initializerBlock = existingInitializer;
-							var value = ((StLoc)initializerBlock.Instructions[0]).Value;
-							if (value is NewObj no)
-								instType = no.Method.DeclaringType;
-							else
-								instType = ((DefaultValue)value).Type;
-							break;
-						}
-						return false;
 					default:
 						return false;
 				}
 				int initializerItemsCount = 0;
-				var blockType = initializerBlock?.Type ?? BlockType.CollectionInitializer;
+				var blockType = BlockType.CollectionInitializer;
-				var possibleIndexVariables = new Dictionary<ILVariable, (int Index, ILInstruction Value)>();
+				possibleIndexVariables = new Dictionary<ILVariable, (int Index, ILInstruction Value)>();
+				currentPath = new List<AccessPathElement>();
+				isCollection = false;
+				pathStack = new Stack<HashSet<AccessPathElement>>();
+				pathStack.Push(new HashSet<AccessPathElement>());
 				// Detect initializer type by scanning the following statements
 				// each must be a callvirt with ldloc v as first argument
 				// if the method is a setter we're dealing with an object initializer
 				// if the method is named Add and has at least 2 arguments we're dealing with a collection/dictionary initializer
 				while (pos + initializerItemsCount + 1 < body.Instructions.Count
-					&& IsPartOfInitializer(body.Instructions, pos + initializerItemsCount + 1, v, instType, ref blockType, possibleIndexVariables)) {
+					&& IsPartOfInitializer(body.Instructions, pos + initializerItemsCount + 1, v, instType, ref blockType)) {
 					initializerItemsCount++;
 				}
+				// Do not convert the statements into an initializer if there's an incompatible usage of the initializer variable
+				// directly after the possible initializer.
+				if (IsMethodCallOnVariable(body.Instructions[pos + initializerItemsCount + 1], v))
+					return false;
+				// Calculate the correct number of statements inside the initializer:
+				// All index variables that were used in the initializer have Index set to -1.
+				// We fetch the first unused variable from the list and remove all instructions after its
+				// first usage (i.e. the init store) from the initializer.
 				var index = possibleIndexVariables.Where(info => info.Value.Index > -1).Min(info => (int?)info.Value.Index);
 				if (index != null) {
 					initializerItemsCount = index.Value - pos - 1;
 				}
+				// The initializer would be empty, there's nothing to do here.
 				if (initializerItemsCount <= 0)
 					return false;
 				context.Step("CollectionOrObjectInitializer", inst);
-				ILVariable finalSlot;
+				// Create a new block and final slot (initializer target variable)
-				if (initializerBlock == null) {
+				var initializerBlock = new Block(blockType);
-					initializerBlock = new Block(blockType);
+				ILVariable finalSlot = context.Function.RegisterVariable(VariableKind.InitializerTarget, v.Type);
-					finalSlot = context.Function.RegisterVariable(VariableKind.InitializerTarget, v.Type);
+				initializerBlock.FinalInstruction = new LdLoc(finalSlot);
-					initializerBlock.FinalInstruction = new LdLoc(finalSlot);
+				initializerBlock.Instructions.Add(new StLoc(finalSlot, initInst.Clone()));
-					initializerBlock.Instructions.Add(new StLoc(finalSlot, initInst.Clone()));
+				// Move all instructions to the initializer block.
-				} else {
-					finalSlot = ((LdLoc)initializerBlock.FinalInstruction).Variable;
-				}
 				for (int i = 1; i <= initializerItemsCount; i++) {
 					switch (body.Instructions[i + pos]) {
 						case CallInstruction call:
@@ -139,20 +145,67 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			return true;
 		}
 
-		bool IsPartOfInitializer(InstructionCollection<ILInstruction> instructions, int pos, ILVariable target, IType rootType, ref BlockType blockType, Dictionary<ILVariable, (int Index, ILInstruction Value)> possibleIndexVariables)
+		bool IsMethodCallOnVariable(ILInstruction inst, ILVariable variable)
+		{
+			if (inst.MatchLdLocRef(variable))
+				return true;
+			if (inst is CallInstruction call && call.Arguments.Count > 0 && !call.Method.IsStatic)
+				return IsMethodCallOnVariable(call.Arguments[0], variable);
+			if (inst.MatchLdFld(out var target, out _) || inst.MatchStFld(out target, out _, out _) || inst.MatchLdFlda(out target, out _))
+				return IsMethodCallOnVariable(target, variable);
+			return false;
+		}
+
+		Dictionary<ILVariable, (int Index, ILInstruction Value)> possibleIndexVariables;
+		List<AccessPathElement> currentPath;
+		bool isCollection;
+		Stack<HashSet<AccessPathElement>> pathStack;
+
+		bool IsPartOfInitializer(InstructionCollection<ILInstruction> instructions, int pos, ILVariable target, IType rootType, ref BlockType blockType)
 		{
+			// Include any stores to local variables that are single-assigned and do not reference the initializer-variable
+			// in the list of possible index variables.
+			// Index variables are used to implement dictionary initializers.
 			if (instructions[pos] is StLoc stloc && stloc.Variable.Kind == VariableKind.Local && stloc.Variable.IsSingleDefinition) {
 				if (stloc.Value.Descendants.OfType<IInstructionWithVariableOperand>().Any(ld => ld.Variable == target && (ld is LdLoc || ld is LdLoca)))
 					return false;
 				possibleIndexVariables.Add(stloc.Variable, (stloc.ChildIndex, stloc.Value));
 				return true;
 			}
-			(var kind, var path, var values, var targetVariable) = AccessPathElement.GetAccessPath(instructions[pos], rootType, possibleIndexVariables);
+			(var kind, var newPath, var values, var targetVariable) = AccessPathElement.GetAccessPath(instructions[pos], rootType, possibleIndexVariables);
+			if (kind == AccessPathKind.Invalid || target != targetVariable)
+				return false;
+			// Treat last element separately:
+			// Can either be an Add method call or property setter.
+			var lastElement = newPath.Last();
+			newPath.RemoveLast();
+			// Compare new path with current path:
+			int minLen = Math.Min(currentPath.Count, newPath.Count);
+			int firstDifferenceIndex = 0;
+			while (firstDifferenceIndex < minLen && newPath[firstDifferenceIndex] == currentPath[firstDifferenceIndex])
+				firstDifferenceIndex++;
+			while (currentPath.Count > firstDifferenceIndex) {
+				isCollection = false;
+				currentPath.RemoveAt(currentPath.Count - 1);
+				pathStack.Pop();
+			}
+			while (currentPath.Count < newPath.Count) {
+				AccessPathElement newElement = newPath[currentPath.Count];
+				currentPath.Add(newElement);
+				if (isCollection || !pathStack.Peek().Add(newElement))
+					return false;
+				pathStack.Push(new HashSet<AccessPathElement>());
+			}
 			switch (kind) {
 				case AccessPathKind.Adder:
-					return target == targetVariable;
+					isCollection = true;
+					if (pathStack.Peek().Count != 0)
+						return false;
+					return true;
 				case AccessPathKind.Setter:
-					if (values.Count == 1 && target == targetVariable) {
+					if (isCollection || !pathStack.Peek().Add(lastElement))
+						return false;
+					if (values.Count == 1) {
 						blockType = BlockType.ObjectInitializer;
 						return true;
 					}
@@ -183,7 +236,8 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 
 		public override string ToString() => $"[{Member}, {Indices}]";
 
-		public static (AccessPathKind Kind, List<AccessPathElement> Path, List<ILInstruction> Values, ILVariable Target) GetAccessPath(ILInstruction instruction, IType rootType, Dictionary<ILVariable, (int Index, ILInstruction Value)> possibleIndexVariables = null)
+		public static (AccessPathKind Kind, List<AccessPathElement> Path, List<ILInstruction> Values, ILVariable Target) GetAccessPath(
+			ILInstruction instruction, IType rootType, Dictionary<ILVariable, (int Index, ILInstruction Value)> possibleIndexVariables = null)
 		{
 			List<AccessPathElement> path = new List<AccessPathElement>();
 			ILVariable target = null;
@@ -203,6 +257,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 							var isGetter = property?.Getter == method;
 							var indices = call.Arguments.Skip(1).Take(call.Arguments.Count - (isGetter ? 1 : 2)).ToArray();
 							if (possibleIndexVariables != null) {
+								// Mark all index variables as used
 								foreach (var index in indices.OfType<IInstructionWithVariableOperand>()) {
 									if (possibleIndexVariables.TryGetValue(index.Variable, out var info))
 										possibleIndexVariables[index.Variable] = (-1, info.Value);
@@ -224,17 +279,18 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 							}
 						}
 						break;
-					case LdObj ldobj:
+					case LdObj ldobj: {
 						if (ldobj.Target is LdFlda ldflda) {
 							path.Insert(0, new AccessPathElement(ldflda.Field));
 							instruction = ldflda.Target;
 							break;
 						}
 						goto default;
-					case StObj stobj:
+					}
-						if (stobj.Target is LdFlda ldflda2) {
+					case StObj stobj: {
-							path.Insert(0, new AccessPathElement(ldflda2.Field));
+						if (stobj.Target is LdFlda ldflda) {
-							instruction = ldflda2.Target;
+							path.Insert(0, new AccessPathElement(ldflda.Field));
+							instruction = ldflda.Target;
 							if (values == null) {
 								values = new List<ILInstruction>(new[] { stobj.Value });
 								kind = AccessPathKind.Setter;
@@ -242,6 +298,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 							break;
 						}
 						goto default;
+					}
 					case LdLoc ldloc:
 						target = ldloc.Variable;
 						instruction = null;
@@ -250,6 +307,10 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 						target = ldloca.Variable;
 						instruction = null;
 						break;
+					case LdFlda ldflda:
+						path.Insert(0, new AccessPathElement(ldflda.Field));
+						instruction = ldflda.Target;
+						break;
 					default:
 						kind = AccessPathKind.Invalid;
 						instruction = null;
@@ -313,7 +374,8 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 
 		public bool Equals(AccessPathElement other)
 		{
-			return other.Member.Equals(this.Member) && (other.Indices == this.Indices || other.Indices.SequenceEqual(this.Indices, ILInstructionMatchComparer.Instance));
+			return other.Member.Equals(this.Member)
+				&& (other.Indices == this.Indices || other.Indices.SequenceEqual(this.Indices, ILInstructionMatchComparer.Instance));
 		}
 
 		public static bool operator ==(AccessPathElement lhs, AccessPathElement rhs)
@@ -337,12 +399,14 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 				return true;
 			if (x == null || y == null)
 				return false;
-			return x.Match(y).Success;
+			return SemanticHelper.IsPure(x.Flags)
+				&& SemanticHelper.IsPure(y.Flags)
+				&& x.Match(y).Success;
 		}
 
 		public int GetHashCode(ILInstruction obj)
 		{
-			return obj.GetHashCode();
+			throw new NotSupportedException();
 		}
 	}
 }

ICSharpCode.Decompiler/Util/CollectionExtensions.cs

@@ -190,5 +190,12 @@ namespace ICSharpCode.Decompiler.Util
 				return maxElement;
 			}
 		}
+
+		public static void RemoveLast<T>(this IList<T> list)
+		{
+			if (list == null)
+				throw new ArgumentNullException(nameof(list));
+			list.RemoveAt(list.Count - 1);
+		}
 	}
 }