diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 181c4d3a75..2fb693f3df 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -93,11 +93,15 @@ pub fn (c mut Checker) infix_expr(infix_expr ast.InfixExpr) table.Type {
 	if !c.table.check(right_type, left_type) {
 		left := c.table.get_type_symbol(left_type)
 		right := c.table.get_type_symbol(right_type)
-		// array << elm
+		// `array << elm`
 		// the expressions have different types (array_x and x)
 		if left.kind == .array && infix_expr.op == .left_shift {
 			return table.void_type
 		}
+		// `elm in array`
+		if right.kind == .array && infix_expr.op == .key_in {
+			return table.bool_type
+		}
 		// if !c.table.check(&infix_expr.right_type, &infix_expr.right_type) {
 		// c.error('infix expr: cannot use `$infix_expr.right_type.name` as `$infix_expr.left_type.name`', infix_expr.pos)
 		c.error('infix expr: cannot use `$right.name` (right) as `$left.name`', infix_expr.pos)
@@ -378,7 +382,7 @@ pub fn (c mut Checker) expr(node ast.Expr) table.Type {
 			return it.typ
 		}
 		ast.None {
-			return  table.none_type
+			return table.none_type
 		}
 		else {}
 	}
diff --git a/vlib/v/table/table.v b/vlib/v/table/table.v
index 267cdcd581..777c3b1f0e 100644
--- a/vlib/v/table/table.v
+++ b/vlib/v/table/table.v
@@ -395,6 +395,11 @@ pub fn (t &Table) check(got, expected Type) bool {
 	if exp_type_sym.name == 'array' || got_type_sym.name == 'array' {
 		return true
 	}
+	// TODO
+	// accept [] when an expected type is an array
+	if got_type_sym.kind == .array && got_type_sym.name == 'array_void' && exp_type_sym.kind == .array {
+		return true
+	}
 	if got_idx != exp_idx {
 		// && got.typ.name != expected.typ.name*/
 		return false