You should be able to do something like:

var bound = ptr.bindMemory(to: ContentType.self).baseAddress!

to get an UnsafeMutablePointer<ContentType> from the UnsafeMutableRawBufferPointer that you have.

Comment by Erik Aigner (JIRA)

If it would compile. The new version does not compile at all!

Comment by Erik Aigner (JIRA)

Writing

data.withUnsafeMutableBytes { ptr in
    // do stuff
}

will generate a deprecation warning.

Explicitly writing (the new method signature)

data.withUnsafeMutableBytes { (ptr: UnsafeMutableRawBufferPointer) -> Int32 in
    // do stuff
}

will generate a compile error.

Right. It's generating a compile error because you've changed the type of ptr such that it no longer matches the code you have in // do stuff. I'm giving you a way that you can convert it to the type that does match your code.

Comment by Erik Aigner (JIRA)

Oh, I see what's going on.

Xcode did output the error on the wrong line, so i thought the type mismatch was referring
to the closure parameter, not to passing the pointer to the call inside the closure.

Retagging this as a diagnostics bug, then. cc @xedin

Yeah, we should figure out some way to provide more sophisticated fixits for cases like this (in the short term, even a long comment explaining what to do would be a big help).