Fix #1083: add pattern for mcs auto events (version 4)

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

@@ -62,6 +62,8 @@
     <Compile Include="TestCases\Correctness\LINQRaytracer.cs" />
     <Compile Include="TestCases\Correctness\MiniJSON.cs" />
     <Compile Include="TestCases\Correctness\FloatingPointArithmetic.cs" />
+    <Compile Include="TestCases\ILPretty\Issue1038.cs" />
+    <None Include="TestCases\ILPretty\Issue1038.il" />
     <None Include="TestCases\ILPretty\Issue1047.cs" />
     <Compile Include="TestCases\ILPretty\Issue982.cs" />
     <Compile Include="TestCases\Pretty\AsyncMain.cs" />

ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs

@@ -54,6 +54,12 @@ namespace ICSharpCode.Decompiler.Tests
 			Run();
 		}
 
+		[Test]
+		public void Issue1038()
+		{
+			Run();
+		}
+
 		[Test]
 		public void Issue1047()
 		{

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue1038.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.ILPretty
+{
+	public class Issue1038<TK, TR> where TR : class, new()
+	{
+		public event Action<TK, TR> TestEvent = delegate {
+		};
+	}
+}

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue1038.il

@@ -0,0 +1,125 @@
+// Metadata version: v4.0.30319
+.assembly extern mscorlib
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+  .ver 4:0:0:0
+}
+.assembly extern System
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+  .ver 4:0:0:0
+}
+.assembly extern System.Core
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+  .ver 4:0:0:0
+}
+.assembly ConsoleApp11
+{
+  .ver 1:0:0:0
+}
+.module ConsoleApp11.exe
+// MVID: {B973FCD6-A9C4-48A9-8291-26DDC248E208}
+.imagebase 0x00400000
+.file alignment 0x00000200
+.stackreserve 0x00100000
+.subsystem 0x0003       // WINDOWS_CUI
+.corflags 0x00020003    //  ILONLY 32BITPREFERRED
+// Image base: 0x000001C4B6C90000
+
+.class public auto ansi beforefieldinit ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2<TK, class .ctor TR>
+{
+	// Fields
+	.field private class [System.Core]System.Action`2<!TK, !TR> TestEvent
+	.field private static class [System.Core]System.Action`2<!TK, !TR> '<>f__am$cache0'
+	.custom instance void [mscorlib]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 )
+
+	// Methods
+	.method public hidebysig specialname rtspecialname instance void .ctor () cil managed
+	{
+		.maxstack 8
+
+		ldarg.0
+		ldsfld class [System.Core]System.Action`2<!0, !1> class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2<!TK, !TR>::'<>f__am$cache0'
+		brtrue.s IL_0019
+
+		ldnull
+		ldftn void class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2<!TK, !TR>::'<TestEvent>m__0'(!0, !1)
+		newobj instance void class [System.Core]System.Action`2<!TK, !TR>::.ctor(object, native int)
+		stsfld class [System.Core]System.Action`2<!0, !1> class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2<!TK, !TR>::'<>f__am$cache0'
+
+		IL_0019: ldsfld class [System.Core]System.Action`2<!0, !1> class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2<!TK, !TR>::'<>f__am$cache0'
+		stfld class [System.Core]System.Action`2<!0, !1> class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2<!TK, !TR>::TestEvent
+		ret
+	}
+
+	.method public hidebysig specialname instance void add_TestEvent (class [System.Core]System.Action`2<!TK, !TR> 'value') cil managed 
+	{
+		.maxstack 3
+		.locals init (
+			[0] class [System.Core]System.Action`2<!TK, !TR>,
+			[1] class [System.Core]System.Action`2<!TK, !TR>
+		)
+
+		ldarg.0
+		ldfld class [System.Core]System.Action`2<!0, !1> class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2<!TK, !TR>::TestEvent
+		stloc.0
+			IL_0007: ldloc.0
+			stloc.1
+			ldarg.0
+			ldflda class [System.Core]System.Action`2<!0, !1> class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2<!TK, !TR>::TestEvent
+			ldloc.1
+			ldarg.1
+			call class [mscorlib]System.Delegate [mscorlib]System.Delegate::Combine(class [mscorlib]System.Delegate, class [mscorlib]System.Delegate)
+			castclass class [System.Core]System.Action`2<!TK, !TR>
+			ldloc.0
+			call !!0 [mscorlib]System.Threading.Interlocked::CompareExchange<class [System.Core]System.Action`2<!TK, !TR>>(!!0&, !!0, !!0)
+			stloc.0
+			ldloc.0
+			ldloc.1
+			bne.un IL_0007
+		ret
+	}
+
+	.method public hidebysig specialname instance void remove_TestEvent (class [System.Core]System.Action`2<!TK, !TR> 'value') cil managed 
+	{
+		.maxstack 3
+		.locals init (
+			[0] class [System.Core]System.Action`2<!TK, !TR>,
+			[1] class [System.Core]System.Action`2<!TK, !TR>
+		)
+
+		ldarg.0
+		ldfld class [System.Core]System.Action`2<!0, !1> class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2<!TK, !TR>::TestEvent
+		stloc.0
+			IL_0007: ldloc.0
+			stloc.1
+			ldarg.0
+			ldflda class [System.Core]System.Action`2<!0, !1> class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2<!TK, !TR>::TestEvent
+			ldloc.1
+			ldarg.1
+			call class [mscorlib]System.Delegate [mscorlib]System.Delegate::Remove(class [mscorlib]System.Delegate, class [mscorlib]System.Delegate)
+			castclass class [System.Core]System.Action`2<!TK, !TR>
+			ldloc.0
+			call !!0 [mscorlib]System.Threading.Interlocked::CompareExchange<class [System.Core]System.Action`2<!TK, !TR>>(!!0&, !!0, !!0)
+			stloc.0
+			ldloc.0
+			ldloc.1
+			bne.un IL_0007
+		ret
+	}
+
+	.method private hidebysig static void '<TestEvent>m__0' (!TK '', !TR '') cil managed
+	{
+		.custom instance void [mscorlib]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 )
+		.maxstack 8
+		ret
+	}
+
+	// Events
+	.event class [System.Core]System.Action`2<!TK, !TR> TestEvent
+	{
+		.addon instance void ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2::add_TestEvent(class [System.Core]System.Action`2<!0, !1>)
+		.removeon instance void ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue1038`2::remove_TestEvent(class [System.Core]System.Action`2<!0, !1>)
+	}
+}

ICSharpCode.Decompiler/CSharp/Transforms/PatternStatementTransform.cs

@@ -633,7 +633,46 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 				}
 			}
 		};
-		
+
+		static readonly Accessor automaticEventPatternV4MCS = new Accessor {
+			Attributes = { new Repeat(new AnyNode()) },
+			Body = new BlockStatement {
+				new AssignmentExpression {
+					Left = new NamedNode("var1", new IdentifierExpression(Pattern.AnyString)),
+					Operator = AssignmentOperatorType.Assign,
+					Right = new NamedNode(
+						"field",
+						new MemberReferenceExpression {
+								Target = new Choice { new ThisReferenceExpression(), new TypeReferenceExpression { Type = new AnyNode() } },
+								MemberName = Pattern.AnyString
+						}
+					)
+				},
+				new DoWhileStatement {
+					EmbeddedStatement = new BlockStatement {
+						new AssignmentExpression(new NamedNode("var2", new IdentifierExpression(Pattern.AnyString)), new IdentifierExpressionBackreference("var1")),
+						new AssignmentExpression {
+							Left = new IdentifierExpressionBackreference("var1"),
+							Right = new InvocationExpression(new MemberReferenceExpression(new TypeReferenceExpression(new TypePattern(typeof(System.Threading.Interlocked)).ToType()),
+								"CompareExchange",
+								new AstType[] { new AnyNode("type") }), // type argument+
+								new Expression[] { // arguments
+									new DirectionExpression { FieldDirection = FieldDirection.Ref, Expression = new Backreference("field") },
+									new CastExpression(new Backreference("type"), new InvocationExpression(new AnyNode("delegateCombine").ToExpression(), new IdentifierExpressionBackreference("var2"), new IdentifierExpression("value"))),
+									new IdentifierExpressionBackreference("var1")
+								}
+							)
+						}
+					},
+					Condition = new BinaryOperatorExpression {
+						Left = new CastExpression(new TypePattern(typeof(object)), new IdentifierExpressionBackreference("var1")),
+						Operator = BinaryOperatorType.InEquality,
+						Right = new IdentifierExpressionBackreference("var2")
+					},
+				}
+			}
+		};
+
 		bool CheckAutomaticEventMatch(Match m, CustomEventDeclaration ev, bool isAddAccessor)
 		{
 			if (!m.Success)
@@ -678,10 +717,22 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 			return true;
 		}
 
+		bool CheckAutomaticEventV4MCS(CustomEventDeclaration ev, out Match addMatch, out Match removeMatch)
+		{
+			addMatch = removeMatch = default(Match);
+			addMatch = automaticEventPatternV4MCS.Match(ev.AddAccessor);
+			if (!CheckAutomaticEventMatch(addMatch, ev, true))
+				return false;
+			removeMatch = automaticEventPatternV4MCS.Match(ev.RemoveAccessor);
+			if (!CheckAutomaticEventMatch(removeMatch, ev, false))
+				return false;
+			return true;
+		}
+
 		EventDeclaration TransformAutomaticEvents(CustomEventDeclaration ev)
 		{
 			Match m1, m2;
-			if (!CheckAutomaticEventV4(ev, out m1, out m2) && !CheckAutomaticEventV2(ev, out m1, out m2))
+			if (!CheckAutomaticEventV4(ev, out m1, out m2) && !CheckAutomaticEventV2(ev, out m1, out m2) && !CheckAutomaticEventV4MCS(ev, out m1, out m2))
 				return null;
 			RemoveCompilerGeneratedAttribute(ev.AddAccessor.Attributes, attributeTypesToRemoveFromAutoEvents);
 			EventDeclaration ed = new EventDeclaration();