Oh actually I think that this example will fail in this updated case, a 2-element buffer is enough to encode any character in utf-16, so could you change it to a one-element buffer?

Gah, thank you for this. Agree with @alexcrichton 's suggestion.

The example still succeeds (at returning None) since the buffer is empty.
If I did just that the example would fail since encode_utf16() would return Some(1).
The first example already uses a buffer with length 1.

Do you mean changing both examples to use a different char that requires two u16s?

Ah yeah I wasn't sure if ß required two u16 elements or not, but yeah the example I believe intends to show one that requires two but the buffer is of length 1

I have changed both examples to use 𝕊 which requires two u16s. (and updated the buffer sizes and expected results accordingly.)

The build failure seems unrelated.

(Do I need to comment after adding commits?)

(Do I need to comment after adding commits?)

Yeah, GitHub doesn't notify us when you push :(

(I'll restart Travis just in case)

@bors: r+ d34c6ee

Thanks!