With `feature(never_type)`, it's not guaranteed that any variable with
type `!` isn't ever assigned to.

Signed-off-by: Freyskeyd <[email protected]>

Replace last impl with fold

attribute_to_string exists.

We always check against the length before indexing anyway.

There was only one callsite for each and this removes the
unwrap_or_default's on the comments argument

This also permits sharing the underlying code between pprust and
hir::print.

This function took too many arguments and are simple on the inside;
inlining them makes complexity go down.

hir::print's copy is unfortunately used from librustc_driver so inlining
it is not as straightforward.

This enforces that eof() must be called to get the String out, and
generally is better from an API perspective. No users of pretty printing
pre-allocate the buffer.

Presumably the code was from an older age of Rust and can now be written
much simpler.

These are somewhat ambiguous (beginning/end of what?) so it's better to
inline their one use into the code.

This is also easier to understand because the scan and print "tasks" are
separate, but previously were both called "print" or "pretty print."

It was always set to the string's length

Also moves it to pp::Printer from PrintState.

rustc_mir: treat DropAndReplace as Drop + Assign in qualify_consts.

This slipped through the cracks and never got implemented (thankfully that just meant it was overly conservative and didn't allow assignments that don't *actually* drop the previous value).
Fixes rust-lang#62273.

r? @oli-obk

…=pnkfelix

Sometimes generate storage statements for temporaries with type `!`

Closes rust-lang#62165
cc rust-lang#42371

…each, r=scottmcm

Use `fold` in `Iterator::last` default implementation

We already use it in all the other methods.  Consistency + potential perf is a pretty nice win!

…unaligned, r=rkruppe

rust-lang#62357: doc(ptr): add example for {read,write}_unaligned

related to rust-lang#62357

> With rust-lang#62323 the only example (that had UB and was thus invalid) in std::ptr::read_unaligned and std::ptr::write_unaligned is removed.

> We should add a valid example of using the aforementioned functions.

Signed-off-by: Freyskeyd <[email protected]>

…p, r=petrochenkov

Some more cleanups to syntax::print

All of these changes should be functionally equivalent to previous code.

Each commit mostly stands alone and this PR is easiest to review by-commit.