incr.comp.: Fix two problems with HIR hashing.
Fixes https://github.com/rust-lang/rust/issues/45469.
This PR fixes two small problems:
* Overflow checks are always enabled in a constant context, so we need to hash spans of potentially overflowing operations. (Eventually I'd like to handle spans differently so we don't have to make HIR hashing know so much about things like this.)
* The HIR map collector had a bug where it would assign the `DepNode::Hir` instead of the corresponding `DepNode::HirBody` in some nested contexts.
r? @nikomatsakis
Fix duplicate display of error E0502
Ref. Repeated "mutable/immutable borrow" error messages #42106.
This PR modifies the return type of [`report_error_if_loan_conflicts_with_restriction`](0f0f5db465/src/librustc_borrowck/borrowck/check_loans.rs (L398-L403)) so the result can be checked in [`report_error_if_loans_conflict`](0f0f5db465/src/librustc_borrowck/borrowck/check_loans.rs (L377-L396)). This is done to prevent displaying a duplicate of the error message E0502 which is referenced in #42106.
The output of compiling:
```rust
fn do_something<T>(collection: &mut Vec<T>) {
let _a = &collection;
collection.swap(1, 2);
}
fn main() {}
```
is now
```bash
$ rustc src/test/compile-fail/issue-42106.rs
error[E0502]: cannot borrow `*collection` as mutable because `collection` is also borrowed as immutable
--> src/test/compile-fail/issue-42106.rs:13:5
|
12 | let _a = &collection;
| ---------- immutable borrow occurs here
13 | collection.swap(1, 2);
| ^^^^^^^^^^ mutable borrow occurs here
14 | }
| - immutable borrow ends here
error: aborting due to 2 previous errors
```
r? @estebank
Improve std::process module docs
Addresses part of #29370
I've changed the first `cat` example to a "Hello World" example involving echo, and I've also added another example showing how to pipe output. I'm still working on the module-level description.
For now, I'd like feedback on the examples.
r? @steveklabnik
Update the book for a fix to the print button
Fixes#45552.
Brings in recent improvements in the text that we've made recently as well.
r? @steveklabnik
