Inherit stdout/stderr for `cargo dev dogfood`
changelog: none
Prints progress as it happens and in colour, and will also show anything printed to stderr
Fixes#10609: Adds lint to detect construction of unit struct using `default`
Using `default` to construct a unit struct increases code complexity and adds a function call. This can be avoided by simply removing the call to `default` and simply construct by name.
changelog: [`default_constructed_unit_structs`]: detects construction of unit structs using `default`
fixes#10609
Currently a `{D,Subd}iagnosticMessage` can be created from any type that
impls `Into<String>`. That includes `&str`, `String`, and `Cow<'static,
str>`, which are reasonable. It also includes `&String`, which is pretty
weird, and results in many places making unnecessary allocations for
patterns like this:
```
self.fatal(&format!(...))
```
This creates a string with `format!`, takes a reference, passes the
reference to `fatal`, which does an `into()`, which clones the
reference, doing a second allocation. Two allocations for a single
string, bleh.
This commit changes the `From` impls so that you can only create a
`{D,Subd}iagnosticMessage` from `&str`, `String`, or `Cow<'static,
str>`. This requires changing all the places that currently create one
from a `&String`. Most of these are of the `&format!(...)` form
described above; each one removes an unnecessary static `&`, plus an
allocation when executed. There are also a few places where the existing
use of `&String` was more reasonable; these now just use `clone()` at
the call site.
As well as making the code nicer and more efficient, this is a step
towards possibly using `Cow<'static, str>` in
`{D,Subd}iagnosticMessage::{Str,Eager}`. That would require changing
the `From<&'a str>` impls to `From<&'static str>`, which is doable, but
I'm not yet sure if it's worthwhile.
new lint: `manual_while_let_some`
This PR implements the lint I suggested [on zulip](https://rust-lang.zulipchat.com/#narrow/stream/257328-clippy/topic/lint.20on.20while.20pop.20unwrap).
It looks for while loops like these:
```rs
let mut numbers = vec![0, 1, 2];
while !numbers.is_empty() {
let number = numbers.pop().unwrap();
// use `number`
}
```
and suggests replacing it with a while-let loop, like this:
```rs
let mut numbers = vec![0, 1, 2];
while let Some(number) = numbers.pop() {
// use `number`
}
```
... which is more concise and idiomatic.
It only looks for `Vec::pop()` calls in the first statement of the loop body in an attempt to not trigger FPs (as pop might only be called conditionally).
changelog: new lint [`manual_while_let_some`]
