rustdoc: Remove fake_def_ids RefCell

[camelid]

No description provided.

[rust-highfive]

r? @GuillaumeGomez

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[camelid]

This may be worth a perf run since I had to remove the use of the Entry API due to borrowck errors, and as a result I think it will hash the CrateNum more times.

[jyn514]

r? @jyn514

[jyn514]

This may be worth a perf run since I had to remove the use of the Entry API due to borrowck errors, and as a result I think it will hash the CrateNum more times.

Can you post the error you get if you use entry instead? I'd prefer to keep using it if possible.

[camelid]

This may be worth a perf run since I had to remove the use of the Entry API due to borrowck errors, and as a result I think it will hash the CrateNum more times.

Can you post the error you get if you use entry instead? I'd prefer to keep using it if possible.

error[E0502]: cannot borrow `*self` as immutable because it is also borrowed as mutable
   --> src/librustdoc/core.rs:150:25
    |
144 |         let def_index = match self.fake_def_ids.entry(crate_num) {
    |                               ----------------- mutable borrow occurs here
...
150 |                         self.enter_resolver(|r| r.cstore().num_def_ids(crate_num))
    |                         ^^^^ immutable borrow occurs here
...
159 |                 e.insert(num_def_idx)
    |                 - mutable borrow later used here

[jyn514]

You can fix that by not going through the enter_resolver wrapper:

self.resolver.borrow_mut().access(|r| r.cstore().num_def_ids(crate_num))

[jyn514]

r=me with CI passing (remember to use r=jyn514)

[jyn514]

@bors r+

[bors]

📌 Commit 45673e2 has been approved by jyn514

[camelid]

Since this may have perf implications: @bors rollup=never

[jyn514]

Personally given how little perf impact #82305 had, I don't think this needs to be marked as rollup=never, especially since it only affects rustdoc and not rustc.

@bors rollup=maybe