Improve DotNetCorePathFinderExtensions.DetectTargetFrameworkId to properly detect framework version of GAC assemblies.

ICSharpCode.Decompiler/Metadata/DotNetCorePathFinderExtensions.cs

@@ -29,9 +29,11 @@ namespace ICSharpCode.Decompiler.Metadata
 	public static class DotNetCorePathFinderExtensions
 	{
 		static readonly string RefPathPattern =
-			@"(Reference Assemblies[/\\]Microsoft[/\\]Framework[/\\](?<1>.NETFramework)[/\\]v(?<2>[^/\\]+)[/\\])" +
+			@"(Reference Assemblies[/\\]Microsoft[/\\]Framework[/\\](?<type>.NETFramework)[/\\]v(?<version>[^/\\]+)[/\\])" +
-			@"|(NuGetFallbackFolder[/\\](?<1>[^/\\]+)\\(?<2>[^/\\]+)([/\\].*)?[/\\]ref[/\\])" +
+			@"|((?<type>Microsoft\.NET)[/\\]assembly[/\\]GAC_(MSIL|32|64)[/\\])" +
-			@"|(shared[/\\](?<1>[^/\\]+)\\(?<2>[^/\\]+)([/\\].*)?[/\\])";
+			@"|((?<type>Microsoft\.NET)[/\\]Framework(64)?[/\\](?<version>[^/\\]+)[/\\])" +
+			@"|(NuGetFallbackFolder[/\\](?<type>[^/\\]+)\\(?<version>[^/\\]+)([/\\].*)?[/\\]ref[/\\])" +
+			@"|(shared[/\\](?<type>[^/\\]+)\\(?<version>[^/\\]+)([/\\].*)?[/\\])";
 
 		public static string DetectTargetFrameworkId(this PEFile assembly)
 		{
@@ -68,16 +70,20 @@ namespace ICSharpCode.Decompiler.Metadata
 				var pathMatch = Regex.Match(assemblyPath, RefPathPattern, 
 					RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.ExplicitCapture);
 				if (pathMatch.Success) {
-					var type = pathMatch.Groups[1].Value;
+					var type = pathMatch.Groups["type"].Value;
-					var version = pathMatch.Groups[2].Value;
+					var version = pathMatch.Groups["version"].Value;
+					if (string.IsNullOrEmpty(version))
+						version = reader.MetadataVersion;
 
-					if (type == ".NETFramework") {
+					if (type == "Microsoft.NET" || type == ".NETFramework") {
-						return $".NETFramework,Version=v{version}";
+						return $".NETFramework,Version=v{version.TrimStart('v').Substring(0, 3)}";
 					} else if (type.IndexOf("netcore", StringComparison.OrdinalIgnoreCase) >= 0) {
 						return $".NETCoreApp,Version=v{version}";
 					} else if (type.IndexOf("netstandard", StringComparison.OrdinalIgnoreCase) >= 0) {
 						return $".NETStandard,Version=v{version}";
 					}
+				} else {
+					return $".NETFramework,Version={reader.MetadataVersion.Substring(0, 4)}";
 				}
 			}