checker: allow for `arr.any(opt_fn()?)`, add test

vlib/v/checker/fn.v

@@ -1726,6 +1726,10 @@ fn (mut c Checker) check_map_and_filter(is_map bool, elem_typ ast.Type, node ast
 			if is_map && arg_expr.return_type in [ast.void_type, 0] {
 				c.error('type mismatch, `$arg_expr.name` does not return anything', arg_expr.pos)
 			} else if !is_map && arg_expr.return_type != ast.bool_type {
+				if arg_expr.or_block.kind != .absent && arg_expr.return_type.has_flag(.optional)
+					&& arg_expr.return_type.clear_flag(.optional) == ast.bool_type {
+					return
+				}
 				c.error('type mismatch, `$arg_expr.name` must return a bool', arg_expr.pos)
 			}
 		}

vlib/v/tests/array_methods_test.v

@@ -30,3 +30,12 @@ fn test_array_eval_count() {
 	a4 = Counter{}
 	assert a4.new_arr('all() failed').all(it == 2) == false
 }
+
+fn opt_bool_fn() ?bool {
+	return true
+}
+
+fn test_any_called_with_opt_bool_fn() ? {
+	_ := [1, 2, 3].any(opt_bool_fn() ?)
+	assert true
+}