go errors rarely do what i expect

go_x509_error

package main

import (
	"crypto/x509"
	"fmt"
	"net/http"
)

func main() {
	if req, err := http.NewRequest("GET", "https://too.long.s3.amazonaws.com/index.html ", nil); err != nil {
		panic(err)

	} else if _, err = http.DefaultClient.Do(req); err != nil {
		if _, ok := err.(x509.HostnameError); ok {
			fmt.Println("i'm x509.HostnameError!")

		} else if _, ok = err.(x509.CertificateInvalidError); ok {
			fmt.Println("i'm x509.CertificateInvalidError")

		} else {
			panic(fmt.Errorf("WTF i can't be coerced into anything: %v!", err))
		}
	}
}

[david@foulplay x590test]$ gb build ./... 
cmd/x590test
[david@foulplay x590test]$ ../../../bin/x590test  
panic: WTF i can't be coerced into anything: Get https://too.long.s3.amazonaws.com/index.html%20: x509: certificate is valid for *.s3.amazonaws.com, s3.amazonaws.com, not too.long.s3.amazonaws.com!

goroutine 1 [running]:
panic(0x1d31a0, 0xc420427a50)
    /usr/local/go/src/runtime/panic.go:500 +0x18c
main.main()
    /Users/david/src/test1.7/src/cmd/x590test/m.go:21 +0x284