diff --git a/vlib/v/checker/check_types.v b/vlib/v/checker/check_types.v
index 75a9c39dcf..7c808eb5a3 100644
--- a/vlib/v/checker/check_types.v
+++ b/vlib/v/checker/check_types.v
@@ -102,7 +102,7 @@ pub fn (mut c Checker) check_basic(got table.Type, expected table.Type) bool {
 		return true
 	}
 	// sum type
-	if c.check_sumtype_compatibility(got, expected) {
+	if c.table.sumtype_has_variant(expected, got) {
 		return true
 	}
 	// fn type
@@ -386,10 +386,6 @@ pub fn (mut c Checker) string_inter_lit(mut node ast.StringInterLiteral) table.T
 	return table.string_type
 }
 
-pub fn (c &Checker) check_sumtype_compatibility(a table.Type, b table.Type) bool {
-	return c.table.sumtype_has_variant(a, b) || c.table.sumtype_has_variant(b, a)
-}
-
 pub fn (mut c Checker) infer_fn_types(f table.Fn, mut call_expr ast.CallExpr) {
 	gt_name := 'T'
 	mut typ := table.void_type
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 079af02403..9da730bced 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -3874,7 +3874,7 @@ pub fn (mut c Checker) if_expr(mut node ast.IfExpr) table.Type {
 				expr_type := c.expr(infix.left)
 				if left_sym.kind == .interface_ {
 					c.type_implements(right_expr.typ, expr_type, branch.pos)
-				} else if !c.check_types(expr_type, right_expr.typ) {
+				} else if !c.check_types(right_expr.typ, expr_type) {
 					expect_str := c.table.type_to_str(right_expr.typ)
 					expr_str := c.table.type_to_str(expr_type)
 					c.error('cannot use type `$expect_str` as type `$expr_str`', branch.pos)