use PlaceRef abstractions more consistently

[henryboisdequin]

Addresses this comment
Associated issue: #80647

r? @RalfJung

[henryboisdequin]

@rustbot label: +C-cleanup +A-mir +T-compiler

[henryboisdequin]

@RalfJung Update:

• Addressed all of your comments (but not pushed yet)
• I'm currently changing visit_projection and all of its associated functions to take a PlaceRef

[henryboisdequin]

@rustbot label: +S-waiting-on-author -S-waiting-on-review

[henryboisdequin]

@RalfJung Nearly finished but I still have some errors and don't know how to resolve them. The current code is pushed, as you can see. Here are the errors:

error[E0308]: mismatched types
--> compiler/rustc_middle/src/mir/visit.rs:154:34
|
68 | / macro_rules! make_mir_visitor {
69 | | ($visitor_trait_name:ident, $($mutability:ident)?) => {
70 | | pub trait $visitor_trait_name<'tcx> {
71 | | // Override these, and call `self.super_xxx` to revert back to the
... |
154 | | self.super_place(place_ref, context, location);
| | ^^^^^^^^^ expected struct `mir::PlaceRef`, found `&mut mir::PlaceRef<'tcx>`
... |
929 | | }
930 | | }
| |_- in this expansion of `make_mir_visitor!`
...
1084 | make_mir_visitor!(Visitor,);
| ---------------------------- in this macro invocation
error[E0308]: mismatched types
--> compiler/rustc_middle/src/mir/visit.rs:383:29
|
68 | / macro_rules! make_mir_visitor {
69 | | ($visitor_trait_name:ident, $($mutability:ident)?) => {
70 | | pub trait $visitor_trait_name<'tcx> {
71 | | // Override these, and call `self.super_xxx` to revert back to the
... |
383 | | &mut place.as_ref(),
| | ^^^^^^^^^^^^^^^^^^^ expected struct `mir::PlaceRef`, found `&mir::Place<'_>`
... |
929 | | }
930 | | }
| |_- in this expansion of `make_mir_visitor!`
...
1084 | make_mir_visitor!(Visitor,);
| ---------------------------- in this macro invocation
|
= note: expected mutable reference `&mut mir::PlaceRef<'tcx>`
found mutable reference `&mut &mir::Place<'_>`
error[E0308]: mismatched types
--> compiler/rustc_middle/src/mir/visit.rs:390:29
|
68 | / macro_rules! make_mir_visitor {
69 | | ($visitor_trait_name:ident, $($mutability:ident)?) => {
70 | | pub trait $visitor_trait_name<'tcx> {
71 | | // Override these, and call `self.super_xxx` to revert back to the
... |
390 | | &mut place.as_ref(),
| | ^^^^^^^^^^^^^^^^^^^ expected struct `mir::PlaceRef`, found `&mir::Place<'_>`
... |
929 | | }
930 | | }
| |_- in this expansion of `make_mir_visitor!`
...
1084 | make_mir_visitor!(Visitor,);
| ---------------------------- in this macro invocation
|
= note: expected mutable reference `&mut mir::PlaceRef<'tcx>`
found mutable reference `&mut &mir::Place<'_>`
error[E0308]: mismatched types
--> compiler/rustc_middle/src/mir/visit.rs:383:29
|
68 | / macro_rules! make_mir_visitor {
69 | | ($visitor_trait_name:ident, $($mutability:ident)?) => {
70 | | pub trait $visitor_trait_name<'tcx> {
71 | | // Override these, and call `self.super_xxx` to revert back to the
... |
383 | | &mut place.as_ref(),
| | ^^^^^^^^^^^^^^^^^^^ expected struct `mir::PlaceRef`, found `&mir::Place<'_>`
... |
929 | | }
930 | | }
| |_- in this expansion of `make_mir_visitor!`
...
1085 | make_mir_visitor!(MutVisitor, mut);
| ----------------------------------- in this macro invocation
|
= note: expected mutable reference `&mut mir::PlaceRef<'tcx>`
found mutable reference `&mut &mir::Place<'_>`
error[E0308]: mismatched types
--> compiler/rustc_middle/src/mir/visit.rs:390:29
|
68 | / macro_rules! make_mir_visitor {
69 | | ($visitor_trait_name:ident, $($mutability:ident)?) => {
70 | | pub trait $visitor_trait_name<'tcx> {
71 | | // Override these, and call `self.super_xxx` to revert back to the
... |
390 | | &mut place.as_ref(),
| | ^^^^^^^^^^^^^^^^^^^ expected struct `mir::PlaceRef`, found `&mir::Place<'_>`
... |
929 | | }
930 | | }
| |_- in this expansion of `make_mir_visitor!`
...
1085 | make_mir_visitor!(MutVisitor, mut);
| ----------------------------------- in this macro invocation
|
= note: expected mutable reference `&mut mir::PlaceRef<'tcx>`
found mutable reference `&mut &mir::Place<'_>`
error: aborting due to 5 previous errors
For more information about this error, try `rustc --explain E0308`.
error: could not compile `rustc_middle`

I'm not really sure why they are happening or how to fix them. Help would be appreciated!

[RalfJung]

@henryboisdequin thanks! I'll take a look, but I can't promise I'll do that before next weekend. In the mean time, you could also ask on the Rust Zulip; there might be people there that can help you.

[henryboisdequin]

@RalfJung on Zulip I and a couple of others discussed that it would be impossible to replace &mut Place with &mut PlaceRef in a mutable visitor. To make such a change, we would require a lot more refactoring which I think should be done in another PR. In this PR, it just addresses your comment. I'll start working on the other PR!

Oops: #80647 (comment)

[henryboisdequin]

@rustbot label -S-waiting-on-author +S-waiting-on-review

[henryboisdequin]

@RalfJungvisit_projection now takes a PlaceRef

[RalfJung]

Awesome, thanks a lot. :)
Let's see if CI passes, then I'll r+.

[RalfJung]

@bors r+

[bors]

📌 Commit a9c6188 has been approved by RalfJung

[camelid]

Associated issue: #80647

Should this PR close that issue, or no?

[henryboisdequin]

Associated issue: #80647

Should this PR close that issue, or no?

@RalfJung What do you think?

[RalfJung]

No it should not close the issue, there's still more cleanup left to be done.