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Auto merge of #126128 - oli-obk:method_ice, r=lcnr 

Consistently use subtyping in method resolution

fixes #126062

An earlier version of this PR modified how we compute variance, but the root cause was an inconsistency between the usage of `eq` and `sub`, where we assumed that the latter passing implies the former will pass.

r? `@compiler-errors`
This commit is contained in:
bors 2024-06-17 12:08:17 +00:00
parent 3baa20b783 3e6e6b190d
commit 9b584a6f6f
16 changed files with 108 additions and 118 deletions
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9
compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
View File

@ -750,16 +750,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
/// Resolves an associated value path into a base type and associated constant, or method
/// resolution. The newly resolved definition is written into `type_dependent_defs`.
#[instrument(level = "trace", skip(self), ret)]
pub fn resolve_ty_and_res_fully_qualified_call(
&self,
qpath: &'tcx QPath<'tcx>,
hir_id: HirId,
span: Span,
) -> (Res, Option<LoweredTy<'tcx>>, &'tcx [hir::PathSegment<'tcx>]) {
debug!(
"resolve_ty_and_res_fully_qualified_call: qpath={:?} hir_id={:?} span={:?}",
qpath, hir_id, span
);
let (ty, qself, item_segment) = match *qpath {
QPath::Resolved(ref opt_qself, path) => {
return (
@ -1417,10 +1414,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// This also occurs for an enum variant on a type alias.
let impl_ty = self.normalize(span, tcx.type_of(impl_def_id).instantiate(tcx, args));
let self_ty = self.normalize(span, self_ty);
match self.at(&self.misc(span), self.param_env).eq(
match self.at(&self.misc(span), self.param_env).sub(
DefineOpaqueTypes::Yes,
impl_ty,
self_ty,
impl_ty,
) {
Ok(ok) => self.register_infer_ok_obligations(ok),
Err(_) => {

11
tests/crashes/126062.rs
View File

@ -1,11 +0,0 @@
//@ known-bug: rust-lang/rust#126062
struct Fail<T>(Fail);
impl<T> Fail<i32> {
const C: () = panic!();
}
fn f<T>() {
if false {
let _val = &Fail::<T>::C;
}
}

10
tests/ui/associated-consts/wrong-projection-self-ty-invalid-bivariant-arg.rs Normal file
View File

@ -0,0 +1,10 @@
struct Fail<T>;
//~^ ERROR: type parameter `T` is never used
impl Fail<i32> {
const C: () = ();
}
fn main() {
Fail::<()>::C
}

12
tests/ui/associated-consts/wrong-projection-self-ty-invalid-bivariant-arg.stderr Normal file
View File

@ -0,0 +1,12 @@
error[E0392]: type parameter `T` is never used
--> $DIR/wrong-projection-self-ty-invalid-bivariant-arg.rs:1:13
|
LL | struct Fail<T>;
| ^ unused type parameter
|
= help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData`
= help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0392`.

17
tests/ui/associated-consts/wrong-projection-self-ty-invalid-bivariant-arg2.rs Normal file
View File

@ -0,0 +1,17 @@
trait Proj {
type Assoc;
}
impl<T> Proj for T {
type Assoc = T;
}
struct Fail<T: Proj<Assoc = U>, U>(T);
impl Fail<i32, i32> {
const C: () = ();
}
fn main() {
Fail::<i32, u32>::C
//~^ ERROR: type mismatch
}

20
tests/ui/associated-consts/wrong-projection-self-ty-invalid-bivariant-arg2.stderr Normal file
View File

@ -0,0 +1,20 @@
error[E0271]: type mismatch resolving `<i32 as Proj>::Assoc == u32`
--> $DIR/wrong-projection-self-ty-invalid-bivariant-arg2.rs:15:5
|
LL | Fail::<i32, u32>::C
| ^^^^^^^^^^^^^^^^ type mismatch resolving `<i32 as Proj>::Assoc == u32`
|
note: expected this to be `u32`
--> $DIR/wrong-projection-self-ty-invalid-bivariant-arg2.rs:5:18
|
LL | type Assoc = T;
| ^
note: required by a bound in `Fail`
--> $DIR/wrong-projection-self-ty-invalid-bivariant-arg2.rs:8:21
|
LL | struct Fail<T: Proj<Assoc = U>, U>(T);
| ^^^^^^^^^ required by this bound in `Fail`
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0271`.

19
tests/ui/coercion/coerce-issue-49593-box-never-windows.nofallback.stderr
View File

@ -1,19 +0,0 @@
error[E0277]: the trait bound `(): std::error::Error` is not satisfied
--> $DIR/coerce-issue-49593-box-never-windows.rs:18:53
|
LL | /* *mut $0 is coerced to Box<dyn Error> here */ Box::<_ /* ! */>::new(x)
| ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `()`
|
= note: required for the cast from `Box<()>` to `Box<(dyn std::error::Error + 'static)>`
error[E0277]: the trait bound `(): std::error::Error` is not satisfied
--> $DIR/coerce-issue-49593-box-never-windows.rs:23:49
|
LL | /* *mut $0 is coerced to *mut Error here */ raw_ptr_box::<_ /* ! */>(x)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `()`
|
= note: required for the cast from `*mut ()` to `*mut (dyn std::error::Error + 'static)`
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0277`.

58
tests/ui/coercion/coerce-issue-49593-box-never-windows.rs
View File

@ -1,58 +0,0 @@
//@ revisions: nofallback fallback
//@ only-windows - the number of `Error` impls is platform-dependent
//@[fallback] check-pass
//@[nofallback] check-fail
#![feature(never_type)]
#![cfg_attr(fallback, feature(never_type_fallback))]
#![allow(unreachable_code)]
use std::error::Error;
use std::mem;
fn raw_ptr_box<T>(t: T) -> *mut T {
panic!()
}
fn foo(x: !) -> Box<dyn Error> {
/* *mut $0 is coerced to Box<dyn Error> here */ Box::<_ /* ! */>::new(x)
//[nofallback]~^ ERROR trait bound `(): std::error::Error` is not satisfied
}
fn foo_raw_ptr(x: !) -> *mut dyn Error {
/* *mut $0 is coerced to *mut Error here */ raw_ptr_box::<_ /* ! */>(x)
//[nofallback]~^ ERROR trait bound `(): std::error::Error` is not satisfied
}
fn no_coercion(d: *mut dyn Error) -> *mut dyn Error {
/* an unsize coercion won't compile here, and it is indeed not used
because there is nothing requiring the _ to be Sized */
d as *mut _
}
trait Xyz {}
struct S;
struct T;
impl Xyz for S {}
impl Xyz for T {}
fn foo_no_never() {
let mut x /* : Option<S> */ = None;
let mut first_iter = false;
loop {
if !first_iter {
let y: Box<dyn Xyz>
= /* Box<$0> is coerced to Box<Xyz> here */ Box::new(x.unwrap());
}
x = Some(S);
first_iter = true;
}
let mut y : Option<S> = None;
// assert types are equal
mem::swap(&mut x, &mut y);
}
fn main() {
}

11
tests/ui/coercion/coerce-issue-49593-box-never.fallback.stderr Normal file
View File

@ -0,0 +1,11 @@
error[E0277]: the trait bound `(): std::error::Error` is not satisfied
--> $DIR/coerce-issue-49593-box-never.rs:18:5
|
LL | Box::<_ /* ! */>::new(x)
| ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `()`
|
= note: required for the cast from `Box<()>` to `Box<(dyn std::error::Error + 'static)>`
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0277`.

12
tests/ui/coercion/coerce-issue-49593-box-never.nofallback.stderr
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@ -1,16 +1,16 @@
error[E0277]: the trait bound `(): std::error::Error` is not satisfied
--> $DIR/coerce-issue-49593-box-never.rs:18:53
--> $DIR/coerce-issue-49593-box-never.rs:18:5
|
LL | /* *mut $0 is coerced to Box<dyn Error> here */ Box::<_ /* ! */>::new(x)
| ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `()`
LL | Box::<_ /* ! */>::new(x)
| ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `()`
|
= note: required for the cast from `Box<()>` to `Box<(dyn std::error::Error + 'static)>`
error[E0277]: the trait bound `(): std::error::Error` is not satisfied
--> $DIR/coerce-issue-49593-box-never.rs:23:49
--> $DIR/coerce-issue-49593-box-never.rs:24:5
|
LL | /* *mut $0 is coerced to *mut Error here */ raw_ptr_box::<_ /* ! */>(x)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `()`
LL | raw_ptr_box::<_ /* ! */>(x)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `()`
|
= note: required for the cast from `*mut ()` to `*mut (dyn std::error::Error + 'static)`

20
tests/ui/coercion/coerce-issue-49593-box-never.rs
View File

@ -1,7 +1,5 @@
//@ revisions: nofallback fallback
//@ ignore-windows - the number of `Error` impls is platform-dependent
//@[fallback] check-pass
//@[nofallback] check-fail
//@check-fail
#![feature(never_type)]
#![cfg_attr(fallback, feature(never_type_fallback))]
@ -15,18 +13,21 @@ fn raw_ptr_box<T>(t: T) -> *mut T {
}
fn foo(x: !) -> Box<dyn Error> {
/* *mut $0 is coerced to Box<dyn Error> here */ Box::<_ /* ! */>::new(x)
//[nofallback]~^ ERROR trait bound `(): std::error::Error` is not satisfied
// Subtyping during method resolution will generate new inference vars and
// subtype them. Thus fallback will not fall back to `!`, but `()` instead.
Box::<_ /* ! */>::new(x)
//~^ ERROR trait bound `(): std::error::Error` is not satisfied
}
fn foo_raw_ptr(x: !) -> *mut dyn Error {
/* *mut $0 is coerced to *mut Error here */ raw_ptr_box::<_ /* ! */>(x)
/* *mut $0 is coerced to *mut Error here */
raw_ptr_box::<_ /* ! */>(x)
//[nofallback]~^ ERROR trait bound `(): std::error::Error` is not satisfied
}
fn no_coercion(d: *mut dyn Error) -> *mut dyn Error {
/* an unsize coercion won't compile here, and it is indeed not used
because there is nothing requiring the _ to be Sized */
because there is nothing requiring the _ to be Sized */
d as *mut _
}
@ -49,10 +50,9 @@ fn foo_no_never() {
first_iter = true;
}
let mut y : Option<S> = None;
let mut y: Option<S> = None;
// assert types are equal
mem::swap(&mut x, &mut y);
}
fn main() {
}
fn main() {}

2
tests/ui/const-generics/generic_arg_infer/issue-91614.stderr
View File

@ -15,7 +15,7 @@ note: required by a bound in `Mask::<T, N>::splat`
--> $SRC_DIR/core/src/../../portable-simd/crates/core_simd/src/masks.rs:LL:COL
help: consider giving `y` an explicit type, where the type for type parameter `T` is specified
|
LL | let y: Mask<_, N> = Mask::<_, _>::splat(false);
LL | let y: Mask<T, N> = Mask::<_, _>::splat(false);
| ++++++++++++
error: aborting due to 1 previous error

2
tests/ui/inference/need_type_info/type-alias-indirect.stderr
View File

@ -2,7 +2,7 @@ error[E0282]: type annotations needed
--> $DIR/type-alias-indirect.rs:14:5
|
LL | IndirectAlias::new();
| ^^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the type alias `IndirectAlias`
| ^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the type alias `IndirectAlias`
error: aborting due to 1 previous error

6
tests/ui/inference/need_type_info/type-alias.stderr
View File

@ -2,19 +2,19 @@ error[E0282]: type annotations needed
--> $DIR/type-alias.rs:12:5
|
LL | DirectAlias::new()
| ^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T`
| ^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the type alias `DirectAlias`
error[E0282]: type annotations needed
--> $DIR/type-alias.rs:18:5
|
LL | IndirectAlias::new();
| ^^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the type alias `IndirectAlias`
| ^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the type alias `IndirectAlias`
error[E0282]: type annotations needed
--> $DIR/type-alias.rs:32:5
|
LL | DirectButWithDefaultAlias::new();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the type alias `DirectButWithDefaultAlias`
error: aborting due to 3 previous errors

1
tests/ui/suggestions/mut-borrow-needed-by-trait.rs
View File

@ -17,6 +17,7 @@ fn main() {
let fp = BufWriter::new(fp);
//~^ ERROR the trait bound `&dyn std::io::Write: std::io::Write` is not satisfied
//~| ERROR the trait bound `&dyn std::io::Write: std::io::Write` is not satisfied
//~| ERROR the trait bound `&dyn std::io::Write: std::io::Write` is not satisfied
writeln!(fp, "hello world").unwrap(); //~ ERROR the method
}

16
tests/ui/suggestions/mut-borrow-needed-by-trait.stderr
View File

@ -10,6 +10,16 @@ LL | let fp = BufWriter::new(fp);
note: required by a bound in `BufWriter::<W>::new`
--> $SRC_DIR/std/src/io/buffered/bufwriter.rs:LL:COL
error[E0277]: the trait bound `&dyn std::io::Write: std::io::Write` is not satisfied
--> $DIR/mut-borrow-needed-by-trait.rs:17:14
|
LL | let fp = BufWriter::new(fp);
| ^^^^^^^^^ the trait `std::io::Write` is not implemented for `&dyn std::io::Write`
|
= note: `std::io::Write` is implemented for `&mut dyn std::io::Write`, but not for `&dyn std::io::Write`
note: required by a bound in `BufWriter`
--> $SRC_DIR/std/src/io/buffered/bufwriter.rs:LL:COL
error[E0277]: the trait bound `&dyn std::io::Write: std::io::Write` is not satisfied
--> $DIR/mut-borrow-needed-by-trait.rs:17:14
|
@ -21,13 +31,13 @@ note: required by a bound in `BufWriter`
--> $SRC_DIR/std/src/io/buffered/bufwriter.rs:LL:COL
error[E0599]: the method `write_fmt` exists for struct `BufWriter<&dyn Write>`, but its trait bounds were not satisfied
--> $DIR/mut-borrow-needed-by-trait.rs:21:14
--> $DIR/mut-borrow-needed-by-trait.rs:22:14
|
LL | writeln!(fp, "hello world").unwrap();
| ---------^^---------------- method cannot be called on `BufWriter<&dyn Write>` due to unsatisfied trait bounds
|
note: must implement `io::Write`, `fmt::Write`, or have a `write_fmt` method
--> $DIR/mut-borrow-needed-by-trait.rs:21:14
--> $DIR/mut-borrow-needed-by-trait.rs:22:14
|
LL | writeln!(fp, "hello world").unwrap();
| ^^
@ -35,7 +45,7 @@ LL | writeln!(fp, "hello world").unwrap();
`&dyn std::io::Write: std::io::Write`
which is required by `BufWriter<&dyn std::io::Write>: std::io::Write`
error: aborting due to 3 previous errors
error: aborting due to 4 previous errors
Some errors have detailed explanations: E0277, E0599.
For more information about an error, try `rustc --explain E0277`.