net/url: Parse improperly fixes url

[gopherbot]

by apoydence:

What happened?
 - net/url doesn't properly "correct" a malformed URL. 

x, _ := url.Parse("http:/localhost:9999/a")
println(x.String()) // outputs: http:///localhost:9999/a

What should have happened instead?
 - It should either output an error, or output "http://localhost:9999/a

Playground:
https://play.golang.org/p/HkSSHIxAPW

[bradfitz]

I'm not convinced we're doing anything wrong. I don't think we're obligated to return any specific or corrected output given malformed input.

Closing as invalid, but if I'm missing something compelling, please argue your case.