Use .interfaceimpl type syntax

.gitignore

@@ -8,6 +8,7 @@ _ReSharper*/
 *.ReSharper
 *.patch
 .vs/
+.idea/
 /ILSpy.AddIn*/Packages/*
 /ILSpy.AddIn*/source.extension.vsixmanifest
 /ICSharpCode.Decompiler.Tests/TestCases/Disassembler/Pretty/*.dll

ICSharpCode.Decompiler.Tests/DisassemblerPrettyTestRunner.cs

@@ -64,6 +64,12 @@ namespace ICSharpCode.Decompiler.Tests
 			await Run(ilExpectedFile: Path.Combine(TestCasePath, "SortMembers.expected.il"), asmOptions: AssemblerOptions.SortedOutput);
 		}
 
+		[Test]
+		public async Task InterfaceImplAttributes()
+		{
+			await Run();
+		}
+
 		async Task Run([CallerMemberName] string testName = null, string ilExpectedFile = null, AssemblerOptions asmOptions = AssemblerOptions.None)
 		{
 			var ilInputFile = Path.Combine(TestCasePath, testName + ".il");

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

@@ -73,6 +73,7 @@
     <None Include="TestCases\Correctness\StackTests.il" />
     <None Include="TestCases\Correctness\StackTypes.il" />
     <None Include="TestCases\Correctness\Uninit.vb" />
+    <None Include="TestCases\Disassembler\Pretty\InterfaceImplAttributes.il" />
     <None Include="TestCases\Disassembler\Pretty\SortMembers.expected.il" />
     <None Include="TestCases\Disassembler\Pretty\SortMembers.il" />
     <None Include="TestCases\ILPretty\GuessAccessors.cs" />

ICSharpCode.Decompiler.Tests/TestCases/Disassembler/Pretty/InterfaceImplAttributes.il

@@ -0,0 +1,75 @@
+.assembly extern mscorlib
+{
+	.publickeytoken = (
+		b7 7a 5c 56 19 34 e0 89
+	)
+	.ver 4:0:0:0
+}
+.assembly InterfaceImplAttributes
+{
+	.custom instance void [mscorlib]System.Reflection.AssemblyFileVersionAttribute::.ctor(string) = (
+		01 00 07 31 2e 30 2e 30 2e 30 00 00
+	)
+	.hash algorithm 0x00008004 // SHA1
+	.ver 1:0:0:0
+}
+
+.module InterfaceImplAttributes.dll
+.imagebase 0x10000000
+.file alignment 0x00000200
+.stackreserve 0x00100000
+.subsystem 0x0003 // WindowsCui
+.corflags 0x00000001 // ILOnly
+
+.class private auto ansi '<Module>'
+{
+} // end of class <Module>
+
+.class public auto ansi beforefieldinit TestType
+	extends [mscorlib]System.Object
+	implements ITestInterfaceA
+{
+	.interfaceimpl type ITestInterfaceA
+	.custom instance void TestAttributeA::.ctor() = (
+		01 00 00 00
+	)
+
+	// Methods
+	.method public hidebysig specialname rtspecialname
+		instance void .ctor () cil managed
+	{
+		// Method begins at RVA 0x2050
+		// Header size: 1
+		// Code size: 7 (0x7)
+		.maxstack 8
+
+		IL_0000: ldarg.0
+		IL_0001: call instance void [mscorlib]System.Object::.ctor()
+		IL_0006: ret
+	} // end of method TestType::.ctor
+
+} // end of class TestType
+
+.class interface public auto ansi abstract ITestInterfaceA
+{
+} // end of class ITestInterfaceA
+
+.class public auto ansi beforefieldinit TestAttributeA
+	extends [mscorlib]System.Attribute
+{
+	// Methods
+	.method public hidebysig specialname rtspecialname
+		instance void .ctor () cil managed
+	{
+		// Method begins at RVA 0x2058
+		// Header size: 1
+		// Code size: 7 (0x7)
+		.maxstack 8
+
+		IL_0000: ldarg.0
+		IL_0001: call instance void [mscorlib]System.Attribute::.ctor()
+		IL_0006: ret
+	} // end of method TestAttributeA::.ctor
+
+} // end of class TestAttributeA
+

ICSharpCode.Decompiler/Disassembler/ReflectionDisassembler.cs

@@ -1577,7 +1577,6 @@ namespace ICSharpCode.Decompiler.Disassembler
 						output.Write("           ");
 					first = false;
 					var iface = module.Metadata.GetInterfaceImplementation(i);
-					WriteAttributes(module, iface.GetCustomAttributes());
 					iface.Interface.WriteTo(module, output, genericContext, ILNameSyntax.TypeName);
 				}
 				output.WriteLine();
@@ -1601,6 +1600,19 @@ namespace ICSharpCode.Decompiler.Disassembler
 				output.WriteLine(".size {0}", layout.Size);
 				output.WriteLine();
 			}
+			foreach (var ifaceHandle in interfaces)
+			{
+				var iface = module.Metadata.GetInterfaceImplementation(ifaceHandle);
+				var customAttributes = iface.GetCustomAttributes();
+				if (customAttributes.Count != 0)
+				{
+					output.Write(".interfaceimpl type ");
+					iface.Interface.WriteTo(module, output, genericContext, ILNameSyntax.TypeName);
+					output.WriteLine();
+					WriteAttributes(module, customAttributes);
+					output.WriteLine();
+				}
+			}
 			var nestedTypes = Process(module, typeDefinition.GetNestedTypes());
 			if (nestedTypes.Any())
 			{