diff --git a/library/std/src/os/windows/io/handle.rs b/library/std/src/os/windows/io/handle.rs index ee30cc8be6b57..e4de52612ef62 100644 --- a/library/std/src/os/windows/io/handle.rs +++ b/library/std/src/os/windows/io/handle.rs @@ -76,7 +76,7 @@ pub struct OwnedHandle { /// `NULL`. This ensures that such FFI calls cannot start using the handle without /// checking for `NULL` first. /// -/// This type concerns any value other than `NULL` to be valid, including `INVALID_HANDLE_VALUE`. +/// This type considers any value other than `NULL` to be valid, including `INVALID_HANDLE_VALUE`. /// This is because APIs that use `NULL` as their sentry value don't treat `INVALID_HANDLE_VALUE` /// as special. /// @@ -96,7 +96,7 @@ pub struct HandleOrNull(OwnedHandle); /// `INVALID_HANDLE_VALUE`. This ensures that such FFI calls cannot start using the handle without /// checking for `INVALID_HANDLE_VALUE` first. /// -/// This type concerns any value other than `INVALID_HANDLE_VALUE` to be valid, including `NULL`. +/// This type considers any value other than `INVALID_HANDLE_VALUE` to be valid, including `NULL`. /// This is because APIs that use `INVALID_HANDLE_VALUE` as their sentry value may return `NULL` /// under `windows_subsystem = "windows"` or other situations where I/O devices are detached. /// @@ -143,17 +143,17 @@ impl BorrowedHandle<'_> { } impl TryFrom for OwnedHandle { - type Error = (); + type Error = NullHandleError; #[inline] - fn try_from(handle_or_null: HandleOrNull) -> Result { + fn try_from(handle_or_null: HandleOrNull) -> Result { let owned_handle = handle_or_null.0; if owned_handle.handle.is_null() { // Don't call `CloseHandle`; it'd be harmless, except that it could // overwrite the `GetLastError` error. forget(owned_handle); - Err(()) + Err(NullHandleError(())) } else { Ok(owned_handle) } @@ -201,23 +201,59 @@ impl OwnedHandle { } impl TryFrom for OwnedHandle { - type Error = (); + type Error = InvalidHandleError; #[inline] - fn try_from(handle_or_invalid: HandleOrInvalid) -> Result { + fn try_from(handle_or_invalid: HandleOrInvalid) -> Result { let owned_handle = handle_or_invalid.0; if owned_handle.handle == c::INVALID_HANDLE_VALUE { // Don't call `CloseHandle`; it'd be harmless, except that it could // overwrite the `GetLastError` error. forget(owned_handle); - Err(()) + Err(InvalidHandleError(())) } else { Ok(owned_handle) } } } +/// This is the error type used by [`HandleOrNull`] when attempting to convert +/// into a handle, to indicate that the value is null. +// The empty field prevents constructing this, and allows extending it in the future. +#[unstable(feature = "io_safety", issue = "87074")] +#[derive(Debug, Clone, PartialEq, Eq)] +pub struct NullHandleError(()); + +#[unstable(feature = "io_safety", issue = "87074")] +impl fmt::Display for NullHandleError { + fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { + "A HandleOrNull could not be converted to a handle because it was null".fmt(fmt) + } +} + +#[unstable(feature = "io_safety", issue = "87074")] +impl crate::error::Error for NullHandleError {} + +/// This is the error type used by [`HandleOrInvalid`] when attempting to +/// convert into a handle, to indicate that the value is +/// `INVALID_HANDLE_VALUE`. +// The empty field prevents constructing this, and allows extending it in the future. +#[unstable(feature = "io_safety", issue = "87074")] +#[derive(Debug, Clone, PartialEq, Eq)] +pub struct InvalidHandleError(()); + +#[unstable(feature = "io_safety", issue = "87074")] +impl fmt::Display for InvalidHandleError { + fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { + "A HandleOrInvalid could not be converted to a handle because it was INVALID_HANDLE_VALUE" + .fmt(fmt) + } +} + +#[unstable(feature = "io_safety", issue = "87074")] +impl crate::error::Error for InvalidHandleError {} + impl AsRawHandle for BorrowedHandle<'_> { #[inline] fn as_raw_handle(&self) -> RawHandle { diff --git a/src/test/ui/coercion/coerce-issue-49593-box-never-windows.nofallback.stderr b/src/test/ui/coercion/coerce-issue-49593-box-never-windows.nofallback.stderr new file mode 100644 index 0000000000000..ab9cc707aa0be --- /dev/null +++ b/src/test/ui/coercion/coerce-issue-49593-box-never-windows.nofallback.stderr @@ -0,0 +1,39 @@ +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 here */ Box::<_ /* ! */>::new(x) + | ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `()` + | + = help: the following other types implement trait `std::error::Error`: + ! + &'a T + AccessError + AddrParseError + Arc + BorrowError + BorrowMutError + Box + and 45 others + = note: required for the cast to the object type `dyn std::error::Error` + +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 `()` + | + = help: the following other types implement trait `std::error::Error`: + ! + &'a T + AccessError + AddrParseError + Arc + BorrowError + BorrowMutError + Box + and 45 others + = note: required for the cast to the object type `(dyn std::error::Error + 'static)` + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0277`. diff --git a/src/test/ui/coercion/coerce-issue-49593-box-never-windows.rs b/src/test/ui/coercion/coerce-issue-49593-box-never-windows.rs new file mode 100644 index 0000000000000..95d3935caa9ef --- /dev/null +++ b/src/test/ui/coercion/coerce-issue-49593-box-never-windows.rs @@ -0,0 +1,58 @@ +// 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) -> *mut T { + panic!() +} + +fn foo(x: !) -> Box { + /* *mut $0 is coerced to Box 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 */ = None; + let mut first_iter = false; + loop { + if !first_iter { + let y: Box + = /* Box<$0> is coerced to Box here */ Box::new(x.unwrap()); + } + + x = Some(S); + first_iter = true; + } + + let mut y : Option = None; + // assert types are equal + mem::swap(&mut x, &mut y); +} + +fn main() { +} diff --git a/src/test/ui/coercion/coerce-issue-49593-box-never.nofallback.stderr b/src/test/ui/coercion/coerce-issue-49593-box-never.nofallback.stderr index 1b1ce67cb0c1f..1daa91f025a89 100644 --- a/src/test/ui/coercion/coerce-issue-49593-box-never.nofallback.stderr +++ b/src/test/ui/coercion/coerce-issue-49593-box-never.nofallback.stderr @@ -1,5 +1,5 @@ error[E0277]: the trait bound `(): std::error::Error` is not satisfied - --> $DIR/coerce-issue-49593-box-never.rs:17:53 + --> $DIR/coerce-issue-49593-box-never.rs:18:53 | LL | /* *mut $0 is coerced to Box here */ Box::<_ /* ! */>::new(x) | ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `()` @@ -17,7 +17,7 @@ LL | /* *mut $0 is coerced to Box here */ Box::<_ /* ! */>::new(x = note: required for the cast to the object type `dyn std::error::Error` error[E0277]: the trait bound `(): std::error::Error` is not satisfied - --> $DIR/coerce-issue-49593-box-never.rs:22:49 + --> $DIR/coerce-issue-49593-box-never.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 `()` diff --git a/src/test/ui/coercion/coerce-issue-49593-box-never.rs b/src/test/ui/coercion/coerce-issue-49593-box-never.rs index 7a4324bd5adce..16efb65acb2b6 100644 --- a/src/test/ui/coercion/coerce-issue-49593-box-never.rs +++ b/src/test/ui/coercion/coerce-issue-49593-box-never.rs @@ -1,4 +1,5 @@ // revisions: nofallback fallback +// ignore-windows - the number of `Error` impls is platform-dependent //[fallback] check-pass //[nofallback] check-fail