Add unittests for issue 11360.

std/variant.d

@@ -514,10 +514,16 @@ private:
                 {
                     t[i] = variantArgs[i].get!T();
                 }
+
                 static if(is(ReturnType!A == void))
+                {
+                    (*zis)(t.expand);
                     *p = VariantN.init; // Uninitialized Variant.Uninitialized
+                }
                 else
+                {
                     *p = (*zis)(t.expand);
+                }
             }
             break;
 
@@ -1643,6 +1649,18 @@ unittest
     assertThrown!VariantException(Variant(A(3)) < Variant(A(4)));
 }
 
+// Handling of void function pointers / delegates, e.g. issue 11360
+unittest
+{
+    static void t1() { }
+    Variant v = &t1;
+    assert(v() == Variant.init);
+    
+    static int t2() { return 3; }
+    Variant v2 = &t2;
+    assert(v2() == 3);
+}
+
 /**
  * Applies a delegate or function to the given Algebraic depending on the held type,
  * ensuring that all types are handled by the visiting functions.