Improve spans for indexing expressions
fixes#114388
Indexing is similar to method calls in having an arbitrary left-hand-side and then something on the right, which is the main part of the expression. Method calls already have a span for that right part, but indexing does not. This means that long method chains that use indexing have really bad spans, especially when the indexing panics and that span in coverted into a panic location.
This does the same thing as method calls for the AST and HIR, storing an extra span which is then put into the `fn_span` field in THIR.
r? compiler-errors
Indexing is similar to method calls in having an arbitrary
left-hand-side and then something on the right, which is the main part
of the expression. Method calls already have a span for that right part,
but indexing does not. This means that long method chains that use
indexing have really bad spans, especially when the indexing panics and
that span in coverted into a panic location.
This does the same thing as method calls for the AST and HIR, storing an
extra span which is then put into the `fn_span` field in THIR.
Perform OpaqueCast field projection on HIR, too.
fixes#105819
This is necessary for closure captures in 2021 edition, as they capture individual fields, not the full mentioned variables. So it may try to capture a field of an opaque (because the hidden type is known to be something with a field).
See https://github.com/rust-lang/rust/pull/99806 for when and why we added OpaqueCast to MIR.
[`slow_vector_initialization`]: catch `Vec::new()` followed by `.resize(len, 0)`
Closes#10938
changelog: [`slow_vector_initialization`]: catch `Vec::new()` followed by `.resize(len, 0)`
This is necessary for closure captures in 2021 edition, as they capture individual fields, not the full mentioned variables. So it may try to capture a field of an opaque (because the hidden type is known to be something with a field).
check that the types are equal in `SpanlessEq::eq_expr`
Fixes#11213
changelog: [`if_same_then_else`]: don't lint for integer literals of different types
Refactor some of `dereference.rs` to util functions
I've seen a few lints that need to be able to tell if changing the type of an expression would be a vaild suggestion. This extracts part of how that's done from `explicit_auto_deref`.
changelog: None
Allow `Self::cmp(self, other)` as a correct impl
Fixes#11178
Also no longer checks if the method name is *just* cmp, but the path. That was an oversight on my part ^^
r? `@xFrednet`
(and `@blyxyas` too!)
changelog: [`incorrect_partial_ord_impl_on_ord_type`]: Now allows non-method calls to `cmp` like `Self::cmp(self, other)`
Clippy had a false positive for with `ifs_same_cond` when two
if-let expressions have an `option_env!` macro. The fix is similar to the
`env!` macro fix.
The following example had a clippy error:
```rust
if let Some(env1) = option_env!("ENV1") {
// ...
} else if let Some(env2) = option_env!("ENV2") {
// ...
}
```
See https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=01b85c61b56ddd900117fb247af04824
changelog: Fix [`ifs_same_cond`] false positive when using `option_env!` in if-let expressions.
[`manual_filter_map`]: lint on `matches` and pattern matching
Fixes#8010
Previously this lint only worked specifically for a very limited set of methods on the filter call (`.filter(|opt| opt.is_some())` and `.filter(|res| res.is_ok())`). This PR extends it to also recognize `matches!` in the `filter` and pattern matching with `if let` or `match` in the `map`.
Example:
```rs
enum Enum {
A(i32),
B,
}
let _ = [Enum::A(123), Enum::B].into_iter()
.filter(|x| matches!(x, Enum::A(_)))
.map(|x| if let Enum::A(s) = x { s } else { unreachable!() });
```
Now suggests:
```diff
- .filter(|x| matches!(x, Enum::A(_))).map(if let Enum::A(s) = x { s } else { unreachable!() })
+ .filter_map(|x| match x { Enum::A(s) => Some(s), _ => None })
```
Adding this required a somewhat large change in code because it originally seemed to be specifically written with only method calls in the filter in mind, and `matches!` has different behavior in the map, so this new setup should make it possible to support more "generic" cases that need different handling for the filter and map calls.
changelog: [`manual_filter_map`]: lint on `matches` and pattern matching (and some internal refactoring)
It makes it sound like the `ExprKind` and `Rvalue` are supposed to represent all pointer related
casts, when in reality their just used to share a some enum variants. Make it clear there these
are only coercion to make it clear why only some pointer related "casts" are in the enum.
Move `TyCtxt::mk_x` to `Ty::new_x` where applicable
Part of rust-lang/compiler-team#616
turns out there's a lot of places we construct `Ty` this is a ridiculously huge PR :S
r? `@oli-obk`
Specialize `try_destructure_mir_constant` for its sole user (pretty printing)
We can't remove the query, as we need to invoke it from rustc_middle, but can only implement it in mir interpretation/const eval.
r? `@RalfJung` for a first round.
While we could move all the logic into pretty printing, that would end up duplicating a bit of code with const eval, which doesn't seem great either.
Don't lint manual_let_else in cases where ? would work
Don't lint `manual_let_else` where the question mark operator `?` would be sufficient, that is, mostly in cases like:
```Rust
let v = if let Some(v) = ex { v } else { return None };
```
Also, this PR emits the `question_mark` lint for `let...else` patterns that could be written with `?` (also, only `return None` like cases).
```
changelog: [`manual_let_else`]: don't lint in cases where question_mark already lints
changelog: [`question_mark`]: lint for `let Some(...) = ex else { return None };`
```
Fixes #8755
