Since #3320 non-breaking spaces are preserved in Markdown prose, but they still aren’t preserved in inline code, which would have been useful to avoid line breaks in things like x = 2.

In the listings below ␣ represents a regular space, and • represents a non-breaking space.

Prettier 1.18.2
Playground link

--parser markdown

Input:

normal␣space

non-breaking•space

`normal␣space`

`non-breaking•space`

Output:

normal␣space

non-breaking•space

`normal␣space`

`non-breaking␣space`

Expected behavior:

normal␣space

non-breaking•space

`normal␣space`

`non-breaking•space`