Merge pull request #2841 from ElektroKill/fix/foreach-issue-2199

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

@@ -114,6 +114,8 @@
     <Compile Include="TestAssemblyResolver.cs" />
     <None Include="TestCases\VBPretty\VBAutomaticEvents.vb" />
     <Compile Include="TestCases\VBPretty\VBAutomaticEvents.cs" />
+    <Compile Include="TestCases\VBPretty\VBNonGenericForEach.cs" />
+    <None Include="TestCases\VBPretty\VBNonGenericForEach.vb" />
     <Compile Include="TypeSystem\ReflectionHelperTests.cs" />
     <None Include="TestCases\Pretty\MetadataAttributes.cs" />
     <None Include="TestCases\Correctness\ComInterop.cs" />

ICSharpCode.Decompiler.Tests/TestCases/VBPretty/VBNonGenericForEach.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections;
+using System.Runtime.CompilerServices;
+
+public class VBNonGenericForEach
+{
+	public static void M()
+	{
+		ArrayList arrayList = new ArrayList();
+		foreach (object item in arrayList)
+		{
+#if ROSLYN && OPT
+			Console.WriteLine(RuntimeHelpers.GetObjectValue(RuntimeHelpers.GetObjectValue(item)));
+#else
+			object objectValue = RuntimeHelpers.GetObjectValue(item);
+			Console.WriteLine(RuntimeHelpers.GetObjectValue(objectValue));
+#endif
+		}
+	}
+}

ICSharpCode.Decompiler.Tests/TestCases/VBPretty/VBNonGenericForEach.vb

@@ -0,0 +1,11 @@
+Imports System
+Imports System.Collections
+
+Public Class VBNonGenericForEach
+	Public Shared Sub M()
+		Dim collection = New ArrayList
+		For Each element In collection
+			Console.WriteLine(element)
+		Next
+	End Sub
+End Class

ICSharpCode.Decompiler.Tests/VBPrettyTestRunner.cs

@@ -131,6 +131,12 @@ namespace ICSharpCode.Decompiler.Tests
 			await Run(options: options | CompilerOptions.Library);
 		}
 
+		[Test]
+		public async Task VBNonGenericForEach([ValueSource(nameof(defaultOptions))] CompilerOptions options)
+		{
+			await Run(options: options | CompilerOptions.Library);
+		}
+
 		async Task Run([CallerMemberName] string testName = null, CompilerOptions options = CompilerOptions.UseDebug, DecompilerSettings settings = null)
 		{
 			var vbFile = Path.Combine(TestCasePath, testName + ".vb");

ICSharpCode.Decompiler/IL/Transforms/UsingTransform.cs

@@ -1,4 +1,4 @@
-// Copyright (c) 2017 Siegfried Pammer
+// 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
@@ -316,7 +316,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 					// reference types have a null check.
 					if (!checkInst.MatchIfInstruction(out var condition, out var disposeInst))
 						return false;
-					if (!MatchNullCheckOrTypeCheck(condition, ref objVar, disposeTypeCode))
+					if (!MatchNullCheckOrTypeCheck(condition, ref objVar, disposeTypeCode, out var isInlinedIsInst))
 						return false;
 					if (!(disposeInst is Block disposeBlock) || disposeBlock.Instructions.Count != 1)
 						return false;
@@ -333,6 +333,8 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 						return false;
 					if (target.MatchBox(out var newTarget, out var type) && type.Equals(objVar.Type))
 						target = newTarget;
+					else if (isInlinedIsInst && target.MatchIsInst(out newTarget, out type) && type.IsKnownType(disposeTypeCode))
+						target = newTarget;
 					disposeCall = cv;
 				}
 				else if (objVar.Type.Kind == TypeKind.Struct && objVar.Type.IsByRefLike)
@@ -381,10 +383,16 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			}
 		}
 
-		bool MatchNullCheckOrTypeCheck(ILInstruction condition, ref ILVariable objVar, KnownTypeCode disposeType)
+		bool MatchNullCheckOrTypeCheck(ILInstruction condition, ref ILVariable objVar, KnownTypeCode disposeType, out bool isInlinedIsInst)
 		{
+			isInlinedIsInst = false;
 			if (condition.MatchCompNotEquals(out var left, out var right))
 			{
+				if (left.MatchIsInst(out var arg, out var type) && type.IsKnownType(disposeType))
+				{
+					isInlinedIsInst = true;
+					left = arg;
+				}
 				if (!left.MatchLdLoc(objVar) || !right.MatchLdNull())
 					return false;
 				return true;