diff --git a/interp/builtin.go b/interp/builtin.go
index d4a44abb1..0fad50c4e 100644
--- a/interp/builtin.go
+++ b/interp/builtin.go
@@ -70,6 +70,7 @@ func (r *Runner) builtinCode(ctx context.Context, pos syntax.Pos, name string, a
 			r.errf("set: %v\n", err)
 			return 2
 		}
+		r.updateExpandOpts()
 	case "shift":
 		n := 1
 		switch len(args) {
diff --git a/interp/interp.go b/interp/interp.go
index d6ec81893..151dab270 100644
--- a/interp/interp.go
+++ b/interp/interp.go
@@ -262,7 +262,6 @@ func Params(args ...string) func(*Runner) error {
 			args = args[1:]
 		}
 		r.Params = args
-		r.updateExpandOpts()
 		return nil
 	}
 }
@@ -501,6 +500,7 @@ func (r *Runner) Reset() {
 		Exec:        r.Exec,
 		Open:        r.Open,
 		KillTimeout: r.KillTimeout,
+		opts:        r.opts,
 
 		// emptied below, to reuse the space
 		Vars:      r.Vars,
diff --git a/interp/interp_test.go b/interp/interp_test.go
index 3bdebbd45..55918325b 100644
--- a/interp/interp_test.go
+++ b/interp/interp_test.go
@@ -2743,6 +2743,16 @@ func TestRunnerOpts(t *testing.T) {
 			"[[ $PWD == foo ]]",
 			"exit status 1",
 		},
+		{
+			opts(Params("foo")),
+			"echo $@",
+			"foo\n",
+		},
+		{
+			opts(Params("-u", "--", "foo")),
+			"echo $@; echo $unset",
+			"foo\nunset: unbound variable\nexit status 1",
+		},
 	}
 	p := syntax.NewParser()
 	for i, c := range cases {