Fix layout replace for unit layouts (#588)

src/lua/util.rs

@@ -761,8 +761,8 @@ pub fn textwrap<'a>(util: Table<'a>, lua: &Lua) -> Result<Table<'a>> {
 /// ```
 pub fn layout_replace<'a>(util: Table<'a>, lua: &Lua) -> Result<Table<'a>> {
     let func = lua.create_function(
-        move |lua, (layout, target, replacement): (Table, Value, Value)| {
-            let layout: Layout = lua.from_value(Value::Table(layout))?;
+        move |lua, (layout, target, replacement): (Value, Value, Value)| {
+            let layout: Layout = lua.from_value(layout)?;
             let target: Layout = lua.from_value(target)?;
             let replacement: Layout = lua.from_value(replacement)?;
 

src/ui.rs

@@ -1615,5 +1615,11 @@ mod tests {
             }
             _ => panic!("Unexpected layout"),
         }
+
+        let res = Layout::Table.replace(&Layout::Table, &Layout::Selection);
+        assert_eq!(res, Layout::Selection);
+
+        let res = Layout::Table.replace(&Layout::Nothing, &Layout::Selection);
+        assert_eq!(res, Layout::Table);
     }
 }