Add support for the slnx solution file type

src/CommandLine/CommandLineHelpers.cs

@@ -21,7 +21,8 @@ public static bool IsGlobPatternForProject(string pattern)
     public static bool IsGlobPatternForSolution(string pattern)
     {
         return pattern.EndsWith(".sln", StringComparison.OrdinalIgnoreCase)
-            || pattern.EndsWith(".slnf", StringComparison.OrdinalIgnoreCase);
+            || pattern.EndsWith(".slnf", StringComparison.OrdinalIgnoreCase)
+            || pattern.EndsWith(".slnx", StringComparison.OrdinalIgnoreCase);
     }
 
     public static void WaitForKeyPress(string message = null)

src/CommandLine/Commands/MSBuildWorkspaceCommand.cs

@@ -414,7 +414,8 @@ private static bool IsSolutionFile(string path)
         string extension = Path.GetExtension(path);
 
         return string.Equals(extension, ".sln", StringComparison.OrdinalIgnoreCase)
-            || string.Equals(extension, ".slnf", StringComparison.OrdinalIgnoreCase);
+            || string.Equals(extension, ".slnf", StringComparison.OrdinalIgnoreCase)
+            || string.Equals(extension, ".slnx", StringComparison.OrdinalIgnoreCase);
     }
 
     protected class ConsoleProgressReporter : IProgress<ProjectLoadProgress>

src/CommandLine/Program.cs

@@ -868,7 +868,10 @@ private static bool TryParsePaths(IEnumerable<string> values, out ImmutableArray
 
         string directoryPath = Environment.CurrentDirectory;
 
-        if (!TryFindFile(Directory.EnumerateFiles(directoryPath, "*.sln", SearchOption.TopDirectoryOnly), out string solutionPath))
+        if (!TryFindFile(
+            Directory.EnumerateFiles(directoryPath, "*.sln", SearchOption.TopDirectoryOnly)
+                .Concat(Directory.EnumerateFiles(directoryPath, "*.slnx", SearchOption.TopDirectoryOnly)),
+            out string solutionPath))
         {
             WriteLine($"Multiple MSBuild solution files found in '{directoryPath}'", Verbosity.Quiet);
             return false;