Rollup merge of #4509 - sinkuu:redundant_clone_fix, r=llogiq

Fix false-positive of redundant_clone and move to clippy::perf

This PR introduces dataflow analysis to `redundant_clone` lint to filter out borrowed variables, which had been incorrectly detected.

Depends on https://github.com/rust-lang/rust/pull/64207.

changelog: Moved `redundant_clone` lint to `perf` group

# What this lint catches

## `clone`/`to_owned`

```rust
let s = String::new();
let t = s.clone();
```

```rust
// MIR
_1 = String::new();
_2 = &_1;
_3 = clone(_2); // (*)
```

We can turn this `clone` call into a move if

1. `_2` is the sole borrow of `_1` at the statement `(*)`
2. `_1` is not used hereafter

## `Deref` + type-specific `to_owned` method

```rust
let s = std::path::PathBuf::new();
let t = s.to_path_buf();
```

```rust
// MIR
_1 = PathBuf::new();
_2 = &1;
_3 = call deref(_2);
_4 = _3;                         // Copies borrow
StorageDead(_2);
_5 = Path::to_path_buf(_4); // (*)
```

We can turn this `to_path_buf` call into a move if

1. `_3` `_4` are the sole borrow of `_1` at `(*)`
2. `_1` is not used hereafter

# What this PR introduces

1. `MaybeStorageLive` that determines whether a local lives at a particular location
2. `PossibleBorrowerVisitor` that constructs [`TransitiveRelation`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_data_structures/transitive_relation/struct.TransitiveRelation.html) of possible borrows, e.g. visiting `_2 = &1; _3 = &_2:` will result in `_3 -> _2 -> _1` relation. Then `_3` and `_2` will be counted as possible borrowers of `_1` in the sole-borrow analysis above.

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/ui/map_clone.fixed b/tests/ui/map_clone.fixed
index c8b9bc04944..2029c81d0d5 100644
--- a/tests/ui/map_clone.fixed
+++ b/tests/ui/map_clone.fixed
@@ -1,7 +1,7 @@
 // run-rustfix
 #![warn(clippy::all, clippy::pedantic)]
 #![allow(clippy::iter_cloned_collect)]
-#![allow(clippy::clone_on_copy)]
+#![allow(clippy::clone_on_copy, clippy::redundant_clone)]
 #![allow(clippy::missing_docs_in_private_items)]
 #![allow(clippy::redundant_closure_for_method_calls)]