Fix #1940: Make sure that we use the correct .NET Core version, when there are multiple frameworks loaded in the current assembly list.

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -395,7 +395,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			settings.LoadInMemory = true;
 			var file = LoadPEFile(fileName, settings);
 			var resolver = new UniversalAssemblyResolver(fileName, settings.ThrowOnAssemblyResolveErrors,
-				file.Reader.DetectTargetFrameworkId(),
+				file.DetectTargetFrameworkId(),
 				settings.LoadInMemory ? PEStreamOptions.PrefetchMetadata : PEStreamOptions.Default,
 				settings.ApplyWindowsRuntimeProjections ? MetadataReaderOptions.ApplyWindowsRuntimeProjections : MetadataReaderOptions.None);
 			return new DecompilerTypeSystem(file, resolver);

ICSharpCode.Decompiler/CSharp/WholeProjectDecompiler.cs

@@ -296,7 +296,7 @@ namespace ICSharpCode.Decompiler.CSharp
 					break;
 			}
 
-			string targetFramework = module.Reader.DetectTargetFrameworkId();
+			string targetFramework = module.DetectTargetFrameworkId();
 			if (!string.IsNullOrEmpty(targetFramework)) {
 				string[] frameworkParts = targetFramework.Split(',');
 				result.TargetFrameworkIdentifier = frameworkParts.FirstOrDefault(a => !a.StartsWith("Version=", StringComparison.OrdinalIgnoreCase) && !a.StartsWith("Profile=", StringComparison.OrdinalIgnoreCase));

ICSharpCode.Decompiler/Metadata/DotNetCorePathFinderExtensions.cs

@@ -30,7 +30,13 @@ namespace ICSharpCode.Decompiler.Metadata
 	{
 		static readonly string RefPathPattern =
 			@"(Reference Assemblies[/\\]Microsoft[/\\]Framework[/\\](?<1>.NETFramework)[/\\]v(?<2>[^/\\]+)[/\\])" +
-			@"|(NuGetFallbackFolder[/\\](?<1>[^/\\]+)\\(?<2>[^/\\]+)([/\\].*)?[/\\]ref[/\\])";
+			@"|(NuGetFallbackFolder[/\\](?<1>[^/\\]+)\\(?<2>[^/\\]+)([/\\].*)?[/\\]ref[/\\])" +
+			@"|(shared[/\\](?<1>[^/\\]+)\\(?<2>[^/\\]+)([/\\].*)?[/\\])";
+
+		public static string DetectTargetFrameworkId(this PEFile assembly)
+		{
+			return DetectTargetFrameworkId(assembly.Reader, assembly.FileName);
+		}
 
 		public static string DetectTargetFrameworkId(this PEReader assembly, string assemblyPath = null)
 		{
@@ -67,9 +73,9 @@ namespace ICSharpCode.Decompiler.Metadata
 
 					if (type == ".NETFramework") {
 						return $".NETFramework,Version=v{version}";
-					} else if (type.Contains("netcore")) {
+					} else if (type.IndexOf("netcore", StringComparison.OrdinalIgnoreCase) >= 0) {
 						return $".NETCoreApp,Version=v{version}";
-					} else if (type.Contains("netstandard")) {
+					} else if (type.IndexOf("netstandard", StringComparison.OrdinalIgnoreCase) >= 0) {
 						return $".NETStandard,Version=v{version}";
 					}
 				}

ILSpy/AssemblyList.cs

@@ -39,7 +39,7 @@ namespace ICSharpCode.ILSpy
 		/// <summary>Dirty flag, used to mark modifications so that the list is saved later</summary>
 		bool dirty;
 
-		internal readonly ConcurrentDictionary<(string assemblyName, bool isWinRT), LoadedAssembly> assemblyLookupCache = new ConcurrentDictionary<(string assemblyName, bool isWinRT), LoadedAssembly>();
+		internal readonly ConcurrentDictionary<(string assemblyName, bool isWinRT, string targetFrameworkIdentifier), LoadedAssembly> assemblyLookupCache = new ConcurrentDictionary<(string assemblyName, bool isWinRT, string targetFrameworkIdentifier), LoadedAssembly>();
 		internal readonly ConcurrentDictionary<string, LoadedAssembly> moduleLookupCache = new ConcurrentDictionary<string, LoadedAssembly>();
 
 		/// <summary>

ILSpy/LoadedAssembly.cs

@@ -65,7 +65,7 @@ namespace ICSharpCode.ILSpy
 		public async Task<string> GetTargetFrameworkIdAsync()
 		{
 			var assembly = await GetPEFileAsync().ConfigureAwait(false);
-			return assembly.Reader.DetectTargetFrameworkId() ?? string.Empty;
+			return assembly.DetectTargetFrameworkId() ?? string.Empty;
 		}
 
 		public ReferenceLoadInfo LoadedAssemblyReferencesInfo { get; } = new ReferenceLoadInfo();
@@ -140,11 +140,15 @@ namespace ICSharpCode.ILSpy
 		public string Text {
 			get {
 				if (IsLoaded && !HasLoadError) {
-					var metadata = GetPEFileOrNull()?.Metadata;
+					PEFile module = GetPEFileOrNull();
+					var metadata = module?.Metadata;
 					string versionOrInfo = null;
 					if (metadata != null) {
 						if (metadata.IsAssembly) {
 							versionOrInfo = metadata.GetAssemblyDefinition().Version?.ToString();
+							var tfId = GetTargetFrameworkIdAsync().Result;
+							if (!string.IsNullOrEmpty(tfId))
+								versionOrInfo += ", " + tfId.Replace("Version=", " ");
 						} else {
 							versionOrInfo = ".netmodule";
 						}
@@ -277,14 +281,15 @@ namespace ICSharpCode.ILSpy
 			return debugInfoProvider;
 		}
 
-		public LoadedAssembly LookupReferencedAssembly(Decompiler.Metadata.IAssemblyReference reference)
+		public LoadedAssembly LookupReferencedAssembly(IAssemblyReference reference)
 		{
 			if (reference == null)
 				throw new ArgumentNullException(nameof(reference));
+			var tfm = GetTargetFrameworkIdAsync().Result;
 			if (reference.IsWindowsRuntime) {
-				return assemblyList.assemblyLookupCache.GetOrAdd((reference.Name, true), key => LookupReferencedAssemblyInternal(reference, true));
+				return assemblyList.assemblyLookupCache.GetOrAdd((reference.Name, true, tfm), key => LookupReferencedAssemblyInternal(reference, true, tfm));
 			} else {
-				return assemblyList.assemblyLookupCache.GetOrAdd((reference.FullName, false), key => LookupReferencedAssemblyInternal(reference, false));
+				return assemblyList.assemblyLookupCache.GetOrAdd((reference.FullName, false, tfm), key => LookupReferencedAssemblyInternal(reference, false, tfm));
 			}
 		}
 
@@ -308,19 +313,20 @@ namespace ICSharpCode.ILSpy
 		static readonly Dictionary<string, LoadedAssembly> loadingAssemblies = new Dictionary<string, LoadedAssembly>();
 		MyUniversalResolver universalResolver;
 
-		LoadedAssembly LookupReferencedAssemblyInternal(Decompiler.Metadata.IAssemblyReference fullName, bool isWinRT)
+		LoadedAssembly LookupReferencedAssemblyInternal(IAssemblyReference fullName, bool isWinRT, string tfm)
 		{
-			string GetName(Decompiler.Metadata.IAssemblyReference name) => isWinRT ? name.Name : name.FullName;
+			string key = tfm + ";" + (isWinRT ? fullName.Name : fullName.FullName);
 
 			string file;
 			LoadedAssembly asm;
 			lock (loadingAssemblies) {
 				foreach (LoadedAssembly loaded in assemblyList.GetAssemblies()) {
-					var reader = loaded.GetPEFileOrNull()?.Metadata;
+					var module = loaded.GetPEFileOrNull();
+					var reader = module?.Metadata;
 					if (reader == null || !reader.IsAssembly) continue;
 					var asmDef = reader.GetAssemblyDefinition();
-					var asmDefName = isWinRT ? reader.GetString(asmDef.Name) : reader.GetFullAssemblyName();
-					if (GetName(fullName).Equals(asmDefName, StringComparison.OrdinalIgnoreCase)) {
+					var asmDefName = loaded.GetTargetFrameworkIdAsync().Result + ";" + (isWinRT ? reader.GetString(asmDef.Name) : reader.GetFullAssemblyName());
+					if (key.Equals(asmDefName, StringComparison.OrdinalIgnoreCase)) {
 						LoadedAssemblyReferencesInfo.AddMessageOnce(fullName.FullName, MessageKind.Info, "Success - Found in Assembly List");
 						return loaded;
 					}