7535: Extract function assist r=cpud36 a=cpud36
This PR adds `extract function/method` assist. closes#5409.
# Supported features
Assist should support extracting from expressions(`1`, `2 + 2`, `loop { }`) and from a series of statements, e.g.:
```rust
foo();
$0bar();
baz();$0
quix();
```
Assist also supports extracting parameters, like:
```rust
fn foo() -> i32 {
let n = 1;
$0n + 1$0
}
// -
fn foo() -> i32 {
let n = 1;
fun_name(n)
}
fn fun_name(n: i32) -> i32 {
n + 1
}
```
Extracting methods also generally works.
Assist allows referencing outer variables, both mutably and immutably, and handles handles access to variables local to extracted function:
```rust
fn foo() {
let mut n = 1;
let mut m = 2;
let mut moved_v = Vec::new();
let mut ref_mut_v = Vec::new();
$0
n += 1;
let k = 1;
moved_v.push(n);
let r = &mut m;
ref_mut_v.push(*r);
let h = 3;
$0
n = ref_mut_v.len() + k;
n -= h + m;
}
// -
fn foo() {
let mut n = 1;
let mut m = 2;
let mut moved_v = Vec::new();
let mut ref_mut_v = Vec::new();
let (k, h) = fun_name(&mut n, moved_v, &mut m, &mut ref_mut_v);
n = ref_mut_v.len() + k;
n -= h + m;
}
fn fun_name(n: &mut i32, mut moved_v: Vec<i32>, m: &mut i32, ref_mut_v: &mut Vec<i32>) -> (i32, i32) {
*n += 1;
let k = 1;
moved_v.push(*n);
let r = m;
ref_mut_v.push(*r);
let h = 3;
(k, h)
}
```
So we handle both input and output paramters
# Showcase
# Working with non-`Copy` types
Consider the following example:
```rust
fn foo() {
let v = Vec::new();
$0
let n = v.len();
$0
let is_empty = v.is_empty();
}
```
`v` must be a parameter to extracted function.
The question is, what type should it have.
It could be `v: Vec<i32>`, or `v: &Vec<i32>`.
The former is incorrect for `Vec<i32>`, but the later is silly for `i32`.
To resolve this we need to know if the type implements `Copy` trait.
I didn't find any api available from assists to query this.
`hir_ty::method_resolution::implements` seems relevant, but is isn't publicly re-exported from `hir`.
# Star(`*`) token and pointer dereference
If I understand correctly, in order to create expression like `*p`, one should use `ast::make::expr_prefix(T![*], ...)`, which
in turn calls `token(T![*])`.
`token` does not have star in `tokens::SOURCE_FILE`, so this panics.
I had to add `*` to `SOURCE_FILE` to make it work.
Correct me if this is not intended way to do this.
# Lowering access `value -> mut ref -> shared ref`
Consider the following example:
```rust
fn foo() {
let v = Vec::new();
$0 let n = v.len(); $0
}
```
`v` is not used after extracted function body, so both `v: &Vec<i32>` and `v: Vec<i32>` would work.
Currently the later would be chosen.
We can however check the body of extracted function and conclude that `v: &Vec<i32>` is sufficient.
Using `v: &Vec<i32>`(that is a minimal required access level) might be a better default.
I am unsure.
# Cleanup
The assist seems to be reasonably handling most of common cases.
If there are no concerns with code it produces(i.e. with test cases), I will start cleaning up
[edit]
added showcase
Co-authored-by: Vladyslav Katasonov <cpud47@gmail.com>
7559: Make `ModPath`'s representation private r=jonas-schievink a=jonas-schievink
This lets us switch out the `Vec` for something more efficient
bors r+
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>
7557: Intern `TypeRef`s in the containing `ItemTree` r=jonas-schievink a=jonas-schievink
This reduces the memory used by `ItemTreeQuery` by ~20%. As it turns out, `TypeRef` is very heavy, and is used a lot in `ItemTree`:
* Many types are frequently repeated throughout the same file. This is what this PR addresses by storing identical `TypeRef`s only once per `ItemTree`.
* The vast majority of `TypeRef` consist of a plain path with only a single element. "Type anchors" like in `<Ty>::func` are used incredibly rarely, and even multi-segment paths are much rarer than single-segment paths.
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>
7555: Expander: store a LocalModuleId, not ModuleId r=jonas-schievink a=jonas-schievink
It already stores the DefMap containing the module, so having
a full ModuleId is unnecessary and makes it easier to mix things up
bors r+
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>
7554: Don't keep the parent DefMap alive via Arc r=jonas-schievink a=jonas-schievink
This seems like it could easily leak a lot of memory since we don't
currently run GC
bors r+
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>
7547: Split out ItemScope::dump from DefMap::dump r=jonas-schievink a=jonas-schievink
This is helpful for more targeted debugging
bors r+
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>
7543: Grammar fixes r=Kushagra-0801 a=Kushagra-0801
I think line 235 is still wrong, but I am not sure.
Is the `crated/tt` in line 252 supposed to be `crates/tt`?
Co-authored-by: Kushagra Gupta <39802979+Kushagra-0801@users.noreply.github.com>
7541: Use block_def_map in body lowering (third time's the charm) r=jonas-schievink a=jonas-schievink
After https://github.com/rust-analyzer/rust-analyzer/pull/7380 and https://github.com/rust-analyzer/rust-analyzer/pull/7506 both had to be reverted, this should have finally resolved all remaining bugs.
Most importantly, the optimization to skip `block_def_map` computation when the block contains no inner items was fixed (which fortunately was simpler than expected).
I've ran `analysis-stats` on libstd locally, which works fine, and also ran this PR locally for a short while without issues.
Note that this *still* has no (or almost no) user-facing impact, because the rest of r-a still relies on some local item support hacks.
bors r+
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>
