reflect: add test for variadic reflect.Type.Method

For #41737

Change-Id: Id065880dd7da54dec1b45662c202aeb7f8397c60
Reviewed-on: https://go-review.googlesource.com/c/go/+/258819
Trust: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Cherry Zhang <[email protected]>

Author: ianlancetaylor

src/reflect/all_test.go

@@ -2405,8 +2405,14 @@ func TestVariadicMethodValue(t *testing.T) {
 	points := []Point{{20, 21}, {22, 23}, {24, 25}}
 	want := int64(p.TotalDist(points[0], points[1], points[2]))
 
+	// Variadic method of type.
+	tfunc := TypeOf((func(Point, ...Point) int)(nil))
+	if tt := TypeOf(p).Method(4).Type; tt != tfunc {
+		t.Errorf("Variadic Method Type from TypeOf is %s; want %s", tt, tfunc)
+	}
+
 	// Curried method of value.
-	tfunc := TypeOf((func(...Point) int)(nil))
+	tfunc = TypeOf((func(...Point) int)(nil))
 	v := ValueOf(p).Method(4)
 	if tt := v.Type(); tt != tfunc {
 		t.Errorf("Variadic Method Type is %s; want %s", tt, tfunc)