Port clippy away from compiletest to ui_test
Reasons to do this:
* runs completely on stable Rust
* is easier to extend with new features
* has its own dogfood test suite, so changes can be tested in [the `ui_test` repo](https://github.com/oli-obk/ui_test)
* supports dependencies from crates.io without having to manually fiddle with command line flags
* supports `ui-cargo`, `ui`, `ui-toml` out of the box, no need to find and run the tests ourselves
One thing that is a big difference to `compiletest` is that if a test emits *any* error, you need to mark all of them with `//~ ERROR:` annotations. Since many clippy tests did not have annotations, I changed many lints to be `warn` in their test so that only the `stderr` output is tested.
TODO:
* [ ] check that this still works as a subtree in the rustc repo
changelog: none
<!-- changelog_checked -->
Note: at present the latest changes needed for clippy are only available as a git dependency, but I expect to publish a new crates.io version soon
Check if `if` conditions always evaluate to true in `never_loop`
This fixes the example provided in #11004, but it shouldn't be closed as this is still an issue on like
```rust
let x = true;
if x { /* etc */ }`
```
This also makes `clippy_utils::consts::constant` handle `ConstBlock` and `DropTemps`.
changelog: [`never_loop`]: Check if `if` conditions always evaluate to true
Lint `mem_forget` if any fields are `Drop`
Closes#9298
I think this way of doing it (`needs_drop`) should be fine.
---
changelog: Enhancement: [`mem_forget`]: Now lints on types with fields that implement `Drop`
[#10996](https://github.com/rust-lang/rust-clippy/pull/10996)
[`format_push_string`]: look through `match` and `if` expressions
Closes#9493.
changelog: [`format_push_string`]: look through `match` and `if` expressions
[`get_unwrap`]: include a borrow in the suggestion if argument is not an integer literal
Fixes#9909
I have to say, I don't really understand what the previous logic was trying to do, but this fixes the linked bug.
It was checking if the argument passed to `.get()` can be parsed as a usize (i.e. if it's an integer literal, probably?), and if not, it wouldn't include a borrow? I don't know how we came to that conclusion, but that logic doesn't work:
```rs
let slice = &[1, 2];
let _r: &i32 = slice.get({ 1 }).unwrap();
// previous suggestion: slice[{ 1 }]
// the suggestion should be: &slice[{ 1 }]
```
Here the argument passed to it isn't an integer literal, but it should still include a borrow, because it would otherwise change the type from `&i32` to `i32`.
The exception is that if the parent of the `get().unwrap()` expr is a dereference or a method call or the like, we don't need an explicit borrow because it's automatically inserted by the compiler
changelog: [`get_unwrap`]: include a borrow in the suggestion if argument is not an integer literal
Don't lint [`iter_nth_zero`] in `next`
Closes#9820
This also *slightlyy* modifies the output of `iter_nth`, as I noticed the types' names weren't in backticks
changelog: [`iter_nth_zero`]: No longer lints in implementations of `Iterator::next`
[`single_match`]: don't lint if block contains comments
Fixes#8634
It now ignores matches with a comment in the "else" arm
changelog: [`single_match`]: don't lint if block contains comments
[`redundant_closure_call`]: handle nested closures
Fixes#9956.
This ended up being a much larger change than I'd thought, and I ended up having to pretty much rewrite it as a late lint pass, because it needs access to certain things that I don't think are available in early lint passes (e.g. getting the parent expr). I think this'll be required to fi-x #10922 anyway, so this is probably fine.
(edit: had to write "fi-x" because "fix" makes github think that this PR fixes it, which it doesn't 😅 )
Previously, it would suggest changing `(|| || 42)()()` to `|| 42()`, which is a type error (it needs parens: `(|| 42)()`). In my opinion, though, the suggested fix should have really been `42`, so that's what this PR changes.
changelog: [`redundant_closure_call`]: handle nested closures and rewrite as a late lint pass
Fix false positive of [self_named_module_files] and [mod_module_files]
changelog: [self_named_module_files] [mod_module_files]: No longer lints dependencies located in subdirectory of workspace
fixes#8887
---
First time contributor here, just read contribution guide today.
I have several questions:
1. ~Is it the correct way to use environment variable `CARGO_HOME` to get the location of cargo home directory?~
(Edit: Code no longer uses CARGO_HOME)
2. How to setup test for this PR? This involves multiple files and `CARGO_HOME` setup. ~Not sure how to do this.~
~Edit: Working on tests right now~ A workspace_test has been added
[`arithmetic_side_effects`] Fix#10792Fix#10792
```
changelog: [`arithmetic_side_effects`]: Retrieve field values of structures that are in constant environments
```
