diff --git a/compiler/parser.v b/compiler/parser.v
index b032f0e807..0438e150a9 100644
--- a/compiler/parser.v
+++ b/compiler/parser.v
@@ -1472,8 +1472,8 @@ fn (p mut Parser) var_decl() {
 		p.error('expected `=` or `:=`')
 	}
 	// all vars on left of `:=` already defined (or `_`)
-	if is_decl_assign && /*var_names.len > 1 &&*/ new_vars == 0 {
-		p.error_with_token_index('no new variables on left side of `:=`', var_token_idxs.last())
+	if is_decl_assign && var_names.len == 1 && var_names[0] == '_' {
+		p.error_with_token_index('use `=` instead of `:=`', var_token_idxs.last())
 	}
 	p.var_decl_name = if var_names.len > 1 { '_V_mret_'+var_names.join('_') } else { var_names[0] }
 	t := p.gen_var_decl(p.var_decl_name, is_static)