Imported Upstream version 6.0.0.172

Former-commit-id: f3cc9b82f3e5bd8f0fd3ebc098f789556b44e9cd

mcs/class/corlib/System.IO/PathInternal.NotSupported.cs

@@ -0,0 +1,20 @@
+namespace System.IO
+{
+    internal static partial class PathInternal
+    {
+        internal const char DirectorySeparatorChar = '\0';
+        internal const char AltDirectorySeparatorChar = '\0';
+        internal const char VolumeSeparatorChar = '\0';
+        internal const char PathSeparator = '\0';
+
+        internal const string DirectorySeparatorCharAsString = "";
+        internal const string ParentDirectoryPrefix = "";
+
+        internal static int GetRootLength(ReadOnlySpan<char> path) => throw new PlatformNotSupportedException ();
+        internal static bool IsDirectorySeparator(char c) => throw new PlatformNotSupportedException ();
+        internal static string NormalizeDirectorySeparators(string path) => throw new PlatformNotSupportedException ();
+        internal static bool IsPartiallyQualified(ReadOnlySpan<char> path) => throw new PlatformNotSupportedException ();
+        internal static bool IsEffectivelyEmpty(string path) => throw new PlatformNotSupportedException ();
+        internal static bool IsEffectivelyEmpty(ReadOnlySpan<char> path) => throw new PlatformNotSupportedException ();
+    }
+}