remove System.Runtime.Versioning.TargetFrameworkAttribute when exporting assembly as project

ICSharpCode.Decompiler/CSharp/Transforms/EscapeInvalidIdentifiers.cs

@@ -19,6 +19,7 @@
 using System;
 using System.Linq;
 using ICSharpCode.NRefactory.CSharp;
+using ICSharpCode.NRefactory.Semantics;
 
 namespace ICSharpCode.Decompiler.CSharp.Transforms
 {
@@ -54,4 +55,27 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 			}
 		}
 	}
+	
+	/// <summary>
+	/// This transform is used to remove assembly-attributes that are generated by the compiler,
+	/// thus don't need to be declared. (We have to remove them, in order to avoid conflicts while compiling.)
+	/// </summary>
+	/// <remarks>This transform is only enabled, when exporting a full assembly as project.</remarks>
+	public class RemoveCompilerGeneratedAssemblyAttributes : IAstTransform
+	{
+		public void Run(AstNode rootNode, TransformContext context)
+		{
+			foreach (var section in rootNode.Children.OfType<AttributeSection>()) {
+				if (section.AttributeTarget != "assembly")
+					continue;
+				foreach (var attribute in section.Attributes) {
+					var trr = attribute.Type.Annotation<TypeResolveResult>();
+					if (trr != null && trr.Type.FullName == "System.Runtime.Versioning.TargetFrameworkAttribute")
+						attribute.Remove();
+				}
+				if (section.Attributes.Count == 0)
+					section.Remove();
+			}
+		}
+	}
 }

ILSpy/Languages/CSharpLanguage.cs

@@ -492,6 +492,7 @@ namespace ICSharpCode.ILSpy
 			{
 				CSharpDecompiler decompiler = new CSharpDecompiler(ts, options.DecompilerSettings);
 				decompiler.AstTransforms.Add(new EscapeInvalidIdentifiers());
+				decompiler.AstTransforms.Add(new RemoveCompilerGeneratedAssemblyAttributes());
 				SyntaxTree syntaxTree = decompiler.DecompileModuleAndAssemblyAttributes();
 
 				string prop = "Properties";