Provide better spans for the match arm without tail expression
Resolves#75418.
Applied the same logic in the `if`-`else` type mismatch case.
r? @estebank
Currently, the def span of a funtion encompasses the entire function
signature and body. However, this is usually unnecessarily verbose - when we are
pointing at an entire function in a diagnostic, we almost always want to
point at the signature. The actual contents of the body tends to be
irrelevant to the diagnostic we are emitting, and just takes up
additional screen space.
This commit changes the `def_span` of all function items (freestanding
functions, `impl`-block methods, and `trait`-block methods) to be the
span of the signature. For example, the function
```rust
pub fn foo<T>(val: T) -> T { val }
```
now has a `def_span` corresponding to `pub fn foo<T>(val: T) -> T`
(everything before the opening curly brace).
Trait methods without a body have a `def_span` which includes the
trailing semicolon. For example:
```rust
trait Foo {
fn bar();
}```
the function definition `Foo::bar` has a `def_span` of `fn bar();`
This makes our diagnostic output much shorter, and emphasizes
information that is relevant to whatever diagnostic we are reporting.
We continue to use the full span (including the body) in a few of
places:
* MIR building uses the full span when building source scopes.
* 'Outlives suggestions' use the full span to sort the diagnostics being
emitted.
* The `#[rustc_on_unimplemented(enclosing_scope="in this scope")]`
attribute points the entire scope body.
* The 'unconditional recursion' lint uses the full span to show
additional context for the recursive call.
All of these cases work only with local items, so we don't need to
add anything extra to crate metadata.
To separate the astconv.rs file, I split it into its own module with a
subtrait called GenericAstConv. This subtrait handles methods related to
generics, be it types or lifetimes.
typeck: Add bounds module and Bounds struct
bounds: Run fmt, add documentation
generic_astconv: Add subtrait GenericAstConv
Some methods of AstConv deal exclusively with Generics. Therefore, it
makes sense to have them in their own trait. Some other methods from
AstConv might be added to it later
generic_astconv: Add more methods from AstConv
Add check_generic_arg_count_for_call() and check_generic_arg_count()
astconv: Add module for clarity
generic: Rename GenericAstConv -> AstConvGeneric
generic: add more methods to AstConvGeneric
astconv: Remove AstConvGeneric trait, add impl dyn AstConv in other
module
astconv: Add errors module to handle AstConv complaints
fmt: format code in astconv/
astconv: Remove old file
astconv: Fix visibility on GenericArgPosition
astconv: Fix visibility on GenericArgPosition
astconv: Fix function visibility on other originally private functions
Add explanation for `&mut self` method call when expecting `-> Self`
When a user tries to use a method as if it returned a new value of the
same type as its receiver, we will emit a type error. Try to detect this
and provide extra explanation that the method modifies the receiver
in-place.
This has confused people in the wild, like in
https://users.rust-lang.org/t/newbie-why-the-commented-line-stops-the-snippet-from-compiling/47322
Reference lang items during AST lowering
Fixes#60607 and fixes#61019.
This PR introduces `QPath::LangItem` to the HIR and uses it in AST lowering instead of constructing a `hir::Path` from a slice of symbols:
- Credit for much of this work goes to @matthewjasper, I basically just [rebased their earlier work](a227c706b7 (diff-c0f791ead38d2d02916faaad0f56f41d)).
- ~~Changes to Clippy might not be correct, they compile but attempting to run tests through `./x.py` produced failures which appeared spurious, so I didn't run any clippy tests.~~
- Changes to save analysis might not be correct - tests pass but I don't have a lot of confidence in those changes being correct.
- I've used `GenericBounds::LangItemTrait` rather than changing `PolyTraitRef`, as suggested by @matthewjasper [in this comment](a227c706b7 (r40107992)) but I'd prefer that be left for a follow-up.
- I've split things into smaller commits fairly arbitrarily to make the diff easier to review, each commit should compile but might not pass tests until the final commit.
r? @oli-obk
cc @matthewjasper
This commit simplifies `is_range_literal` by checking for
`QPath::LangItem` containing range-related lang items, rather than using
a heuristic.
Co-authored-by: Matthew Jasper <mjjasper1@gmail.com>
Signed-off-by: David Wood <david@davidtw.co>
This commit introduces `QPath::LangItem` to the HIR and uses it in AST
lowering instead of constructing a `hir::Path` from a slice of symbols.
This might be better for performance, but is also much cleaner as the
previous approach is fragile. In addition, it resolves a bug (#61019)
where an extern crate imported as "std" would result in the paths
created during AST lowering being resolved incorrectly (or not at all).
Co-authored-by: Matthew Jasper <mjjasper1@gmail.com>
Signed-off-by: David Wood <david@davidtw.co>
merge `as_local_hir_id` with `local_def_id_to_hir_id`
`as_local_hir_id` was defined as just calling `local_def_id_to_hir_id` and I think that having two different ways to call the same method is somewhat confusing.
Don't really care about which of these 2 methods we want to keep.
Does this require an MCP, considering that these methods are fairly frequently used?
Do not emit E0228 when it is implied by E0106
Emit E0288 (lifetime bound for trait object cannot be deduced) only on bare trait objects. When the trait object is in the form of `&dyn Trait`, E0106 (missing lifetime specifier) will have been emitted, making the former redundant.
Emit E0288 (lifetime bound for trait object cannot be deduced) only on
bare trait objects. When the trait object is in the form of
`&dyn Trait`, E0106 (missing lifetime specifier) will have been emitted,
making the former redundant.
Add basic test
And also run fmt which is where the other changes are from
Fix mut issues
These only appear when running tests, so resolved by adding mut
Swap order of forget
Add pub and rm guard impl
Add explicit type to guard
Add safety note
Change guard type from T to S
It should never have been T, as it guards over [MaybeUninit<S>; N]
Also add feature to test
Fix regionck failure when converting Index to IndexMut
Fixes#74933
Consider an overloaded index expression `base[index]`. Without knowing whether it will be mutated, this will initially be desugared into `<U as Index<T>>::index(&base, index)` for some `U` and `T`. Let `V` be the `expr_ty_adjusted` of `index`.
If this expression ends up being used in any mutable context (or used in a function call with `&mut self` receiver before #72280), we will need to fix it up. The current code will rewrite it to `<U as IndexMut<V>>::index_mut(&mut base, index)`. In most cases this is fine as `V` will be equal to `T`, however this is not always true when `V/T` are references, as they may have different region.
This issue is quite subtle before #72280 as this code path is only used to fixup function receivers, but after #72280 we've made this a common path.
The solution is basically just rewrite it to `<U as IndexMut<T>>::index_mut(&mut base, index)`. `T` can retrieved in the fixup path using `node_substs`.
Tweak conditions for E0026 and E0769
When we have a tuple struct used with struct we don't want to suggest using the (valid) struct syntax with numeric field names. Instead we want to suggest the expected syntax.
Given
```rust
fn main() {
match MyOption::MySome(42) {
MyOption::MySome { x: 42 } => (),
_ => (),
}
}
```
We now emit E0769 "tuple variant `MyOption::MySome` written as struct variant" instead of E0026 "variant `MyOption::MySome` does not have a field named `x`".
Remove restriction on type parameters preceding consts w/ feature const-generics
Removed the restriction on type parameters preceding const parameters when the feature const-generics is enabled.
Builds on #74676, which deals with unsorted generic parameters. This just lifts the check in lowering the AST to HIR that permits consts and types to be reordered with respect to each other. Lifetimes still must precede both
This change is not intended for min-const-generics, and is gated behind the `#![feature(const_generics)]`.
One thing is that it also permits type parameters without a default to come after consts, which I expected to not work, and was hoping to get more guidance on whether that should be permitted or how to prevent it otherwise.
I did not go through the RFC process for this pull request because there was prior work to get this feature added. In the previous PR that was cited, work was done to enable this change.
r? @lcnr
When we have a tuple struct used with struct we don't want to suggest using
the (valid) struct syntax with numeric field names. Instead we want to
suggest the expected syntax.
Given
```rust
fn main() {
match MyOption::MySome(42) {
MyOption::MySome { x: 42 } => (),
_ => (),
}
}
```
We now emit E0769 "tuple variant `MyOption::MySome` written as struct variant"
instead of E0026 "variant `MyOption::MySome` does not have a field named `x`".
Updated tests and error msgs
Update stderr from test
Update w/ lcnr comments
Change some tests around, and also updated Ord implementation for ParamKindOrd
Update w/ nits from lcnr
By moving `{known,used}_attrs` from `SessionGlobals` to `Session`. This
means they are accessed via the `Session`, rather than via TLS. A few
`Attr` methods and `librustc_ast` functions are now methods of
`Session`.
All of this required passing a `Session` to lots of functions that didn't
already have one. Some of these functions also had arguments removed, because
those arguments could be accessed directly via the `Session` argument.
`contains_feature_attr()` was dead, and is removed.
Some functions were moved from `librustc_ast` elsewhere because they now need
to access `Session`, which isn't available in that crate.
- `entry_point_type()` --> `librustc_builtin_macros`
- `global_allocator_spans()` --> `librustc_metadata`
- `is_proc_macro_attr()` --> `Session`
This runs _just_ enough of typeck that later queries don't panic.
Because this is in the same part of the compiler that errors on `impl
Trait`, this special-cases impl Trait for rustdoc and no one else.
Everything is fine.
