Imported Upstream version 5.18.0.142

Former-commit-id: 7467d4b717762eeaf652d77f1486dd11ffb1ff1f

mcs/errors/cs0280.cs

@@ -0,0 +1,22 @@
+// CS0280: `C.Fixable.GetPinnableReference(int)' has the wrong signature to be used in extensible fixed statement
+// Line: 11
+// Compiler options: -unsafe -langversion:latest -warnaserror
+
+using System;
+
+unsafe class C
+{
+	public static void Main ()
+	{
+		fixed (int* p = new Fixable ()) {
+		}
+	}
+
+	struct Fixable
+	{
+		public ref int GetPinnableReference (int i = 1)
+		{
+			throw new NotImplementedException ();
+		}
+	}
+}