Description
I noticed while reading the code that reflect.(*rtype).MethodByName has been broken since Go 1.6 if an exported name happens to sort after an unexported method. This never happens when using pure ASCII, but can happen with non-ASCII uppercase letters.
Test case:
package main
import (
"fmt"
"reflect"
)
type I int
func (i I) ΦExported() {}
func (i I) unexported() {}
func main() {
t := reflect.TypeOf(I(0))
m, _ := t.MethodByName("ΦExported")
fmt.Println(m)
}
When run with Go 1.6 this prints
{ΦExported func(main.I) <func(main.I) Value> 1}
as it should. With Go 1.7 through 1.9rc1 it panics saying panic: reflect: Method index out of range.
The bug is that MethodByName walks through the methods by index, and then calls Method(index). But the index argument to Method is an index into the exported methods, not the index into all methods that MethodByName is using. It's the same value if all the exported methods happen to sort first, but of course is different if an exported method sorts after an unexported method.
Since this is not a regression, marking as 1.10.
CC @crawshaw