Auto merge of rust-lang#100982 - fee1-dead-contrib:const-impl-requires-const-trait, r=oli-obk

Require `#[const_trait]` on `Trait` for `impl const Trait`

r? `@oli-obk`

Author: bors

alloc/src/boxed.rs

@@ -2037,8 +2037,7 @@ impl<T: ?Sized, A: Allocator> AsMut<T> for Box<T, A> {
  *  could have a method to project a Pin<T> from it.
  */
 #[stable(feature = "pin", since = "1.33.0")]
-#[rustc_const_unstable(feature = "const_box", issue = "92521")]
-impl<T: ?Sized, A: Allocator> const Unpin for Box<T, A> where A: 'static {}
+impl<T: ?Sized, A: Allocator> Unpin for Box<T, A> where A: 'static {}
 
 #[unstable(feature = "generator_trait", issue = "43122")]
 impl<G: ?Sized + Generator<R> + Unpin, R, A: Allocator> Generator<R> for Box<G, A>

core/src/alloc/mod.rs

@@ -107,6 +107,7 @@ impl fmt::Display for AllocError {
 ///
 /// [*currently allocated*]: #currently-allocated-memory
 #[unstable(feature = "allocator_api", issue = "32838")]
+#[const_trait]
 pub unsafe trait Allocator {
     /// Attempts to allocate a block of memory.
     ///

core/src/borrow.rs

@@ -154,6 +154,7 @@
 /// [`String`]: ../../std/string/struct.String.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Borrow"]
+#[const_trait]
 pub trait Borrow<Borrowed: ?Sized> {
     /// Immutably borrows from an owned value.
     ///
@@ -184,6 +185,7 @@ pub trait Borrow<Borrowed: ?Sized> {
 /// an underlying type by providing a mutable reference. See [`Borrow<T>`]
 /// for more information on borrowing as another type.
 #[stable(feature = "rust1", since = "1.0.0")]
+#[const_trait]
 pub trait BorrowMut<Borrowed: ?Sized>: Borrow<Borrowed> {
     /// Mutably borrows from an owned value.
     ///

core/src/cmp.rs

@@ -204,20 +204,10 @@ use self::Ordering::*;
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(alias = "==")]
 #[doc(alias = "!=")]
-#[cfg_attr(
-    bootstrap,
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} == {Rhs}`"
-    )
-)]
-#[cfg_attr(
-    not(bootstrap),
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} == {Rhs}`",
-        append_const_msg,
-    )
+#[rustc_on_unimplemented(
+    message = "can't compare `{Self}` with `{Rhs}`",
+    label = "no implementation for `{Self} == {Rhs}`",
+    append_const_msg
 )]
 #[const_trait]
 #[rustc_diagnostic_item = "PartialEq"]
@@ -1076,20 +1066,10 @@ impl const PartialOrd for Ordering {
 #[doc(alias = "<")]
 #[doc(alias = "<=")]
 #[doc(alias = ">=")]
-#[cfg_attr(
-    bootstrap,
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
-    )
-)]
-#[cfg_attr(
-    not(bootstrap),
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
-        append_const_msg,
-    )
+#[rustc_on_unimplemented(
+    message = "can't compare `{Self}` with `{Rhs}`",
+    label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
+    append_const_msg
 )]
 #[const_trait]
 #[rustc_diagnostic_item = "PartialOrd"]

core/src/convert/mod.rs

@@ -155,6 +155,7 @@ pub const fn identity<T>(x: T) -> T {
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "AsRef")]
+#[const_trait]
 pub trait AsRef<T: ?Sized> {
     /// Converts this type into a shared reference of the (usually inferred) input type.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -197,6 +198,7 @@ pub trait AsRef<T: ?Sized> {
 /// [`Box<T>`]: ../../std/boxed/struct.Box.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "AsMut")]
+#[const_trait]
 pub trait AsMut<T: ?Sized> {
     /// Converts this type into a mutable reference of the (usually inferred) input type.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -273,6 +275,7 @@ pub trait AsMut<T: ?Sized> {
 /// [`Vec`]: ../../std/vec/struct.Vec.html
 #[rustc_diagnostic_item = "Into"]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[const_trait]
 pub trait Into<T>: Sized {
     /// Converts this type into the (usually inferred) input type.
     #[must_use]
@@ -368,6 +371,7 @@ pub trait Into<T>: Sized {
     all(_Self = "&str", T = "std::string::String"),
     note = "to coerce a `{T}` into a `{Self}`, use `&*` as a prefix",
 ))]
+#[const_trait]
 pub trait From<T>: Sized {
     /// Converts to this type from the input type.
     #[lang = "from"]
@@ -392,6 +396,7 @@ pub trait From<T>: Sized {
 /// [`Into`], see there for details.
 #[rustc_diagnostic_item = "TryInto"]
 #[stable(feature = "try_from", since = "1.34.0")]
+#[const_trait]
 pub trait TryInto<T>: Sized {
     /// The type returned in the event of a conversion error.
     #[stable(feature = "try_from", since = "1.34.0")]
@@ -468,6 +473,7 @@ pub trait TryInto<T>: Sized {
 /// [`try_from`]: TryFrom::try_from
 #[rustc_diagnostic_item = "TryFrom"]
 #[stable(feature = "try_from", since = "1.34.0")]
+#[const_trait]
 pub trait TryFrom<T>: Sized {
     /// The type returned in the event of a conversion error.
     #[stable(feature = "try_from", since = "1.34.0")]

core/src/default.rs

@@ -99,6 +99,7 @@
 /// ```
 #[cfg_attr(not(test), rustc_diagnostic_item = "Default")]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(bootstrap), const_trait)]
 pub trait Default: Sized {
     /// Returns the "default value" for a type.
     ///

core/src/iter/traits/collect.rs

@@ -228,6 +228,7 @@ pub trait FromIterator<A>: Sized {
 #[rustc_diagnostic_item = "IntoIterator"]
 #[rustc_skip_array_during_method_dispatch]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[const_trait]
 pub trait IntoIterator {
     /// The type of the elements being iterated over.
     #[stable(feature = "rust1", since = "1.0.0")]

core/src/lib.rs

@@ -141,6 +141,7 @@
 #![feature(const_str_from_utf8_unchecked_mut)]
 #![feature(const_swap)]
 #![feature(const_trait_impl)]
+#![feature(const_try)]
 #![feature(const_type_id)]
 #![feature(const_type_name)]
 #![feature(const_default_impls)]

core/src/ops/arith.rs

@@ -65,38 +65,15 @@
 /// ```
 #[lang = "add"]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[cfg_attr(
-    bootstrap,
-    rustc_on_unimplemented(
-        on(
-            all(_Self = "{integer}", Rhs = "{float}"),
-            message = "cannot add a float to an integer",
-        ),
-        on(
-            all(_Self = "{float}", Rhs = "{integer}"),
-            message = "cannot add an integer to a float",
-        ),
-        message = "cannot add `{Rhs}` to `{Self}`",
-        label = "no implementation for `{Self} + {Rhs}`"
-    )
-)]
-#[cfg_attr(
-    not(bootstrap),
-    rustc_on_unimplemented(
-        on(
-            all(_Self = "{integer}", Rhs = "{float}"),
-            message = "cannot add a float to an integer",
-        ),
-        on(
-            all(_Self = "{float}", Rhs = "{integer}"),
-            message = "cannot add an integer to a float",
-        ),
-        message = "cannot add `{Rhs}` to `{Self}`",
-        label = "no implementation for `{Self} + {Rhs}`",
-        append_const_msg,
-    )
+#[rustc_on_unimplemented(
+    on(all(_Self = "{integer}", Rhs = "{float}"), message = "cannot add a float to an integer",),
+    on(all(_Self = "{float}", Rhs = "{integer}"), message = "cannot add an integer to a float",),
+    message = "cannot add `{Rhs}` to `{Self}`",
+    label = "no implementation for `{Self} + {Rhs}`",
+    append_const_msg
 )]
 #[doc(alias = "+")]
+#[const_trait]
 pub trait Add<Rhs = Self> {
     /// The resulting type after applying the `+` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -201,9 +178,11 @@ add_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented(
     message = "cannot subtract `{Rhs}` from `{Self}`",
-    label = "no implementation for `{Self} - {Rhs}`"
+    label = "no implementation for `{Self} - {Rhs}`",
+    append_const_msg
 )]
 #[doc(alias = "-")]
+#[const_trait]
 pub trait Sub<Rhs = Self> {
     /// The resulting type after applying the `-` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -333,6 +312,7 @@ sub_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
     label = "no implementation for `{Self} * {Rhs}`"
 )]
 #[doc(alias = "*")]
+#[const_trait]
 pub trait Mul<Rhs = Self> {
     /// The resulting type after applying the `*` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -466,6 +446,7 @@ mul_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
     label = "no implementation for `{Self} / {Rhs}`"
 )]
 #[doc(alias = "/")]
+#[const_trait]
 pub trait Div<Rhs = Self> {
     /// The resulting type after applying the `/` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -568,6 +549,7 @@ div_impl_float! { f32 f64 }
     label = "no implementation for `{Self} % {Rhs}`"
 )]
 #[doc(alias = "%")]
+#[const_trait]
 pub trait Rem<Rhs = Self> {
     /// The resulting type after applying the `%` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -682,6 +664,7 @@ rem_impl_float! { f32 f64 }
 #[lang = "neg"]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(alias = "-")]
+#[const_trait]
 pub trait Neg {
     /// The resulting type after applying the `-` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -755,6 +738,7 @@ neg_impl! { isize i8 i16 i32 i64 i128 f32 f64 }
 )]
 #[doc(alias = "+")]
 #[doc(alias = "+=")]
+#[const_trait]
 pub trait AddAssign<Rhs = Self> {
     /// Performs the `+=` operation.
     ///
@@ -822,6 +806,7 @@ add_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 )]
 #[doc(alias = "-")]
 #[doc(alias = "-=")]
+#[const_trait]
 pub trait SubAssign<Rhs = Self> {
     /// Performs the `-=` operation.
     ///
@@ -880,6 +865,7 @@ sub_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 )]
 #[doc(alias = "*")]
 #[doc(alias = "*=")]
+#[const_trait]
 pub trait MulAssign<Rhs = Self> {
     /// Performs the `*=` operation.
     ///
@@ -938,6 +924,7 @@ mul_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 )]
 #[doc(alias = "/")]
 #[doc(alias = "/=")]
+#[const_trait]
 pub trait DivAssign<Rhs = Self> {
     /// Performs the `/=` operation.
     ///
@@ -999,6 +986,7 @@ div_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 )]
 #[doc(alias = "%")]
 #[doc(alias = "%=")]
+#[const_trait]
 pub trait RemAssign<Rhs = Self> {
     /// Performs the `%=` operation.
     ///

core/src/ops/bit.rs

@@ -31,6 +31,7 @@
 #[lang = "not"]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(alias = "!")]
+#[const_trait]
 pub trait Not {
     /// The resulting type after applying the `!` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -143,6 +144,7 @@ impl const Not for ! {
     message = "no implementation for `{Self} & {Rhs}`",
     label = "no implementation for `{Self} & {Rhs}`"
 )]
+#[const_trait]
 pub trait BitAnd<Rhs = Self> {
     /// The resulting type after applying the `&` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -244,6 +246,7 @@ bitand_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} | {Rhs}`",
     label = "no implementation for `{Self} | {Rhs}`"
 )]
+#[const_trait]
 pub trait BitOr<Rhs = Self> {
     /// The resulting type after applying the `|` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -345,6 +348,7 @@ bitor_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} ^ {Rhs}`",
     label = "no implementation for `{Self} ^ {Rhs}`"
 )]
+#[const_trait]
 pub trait BitXor<Rhs = Self> {
     /// The resulting type after applying the `^` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -445,6 +449,7 @@ bitxor_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} << {Rhs}`",
     label = "no implementation for `{Self} << {Rhs}`"
 )]
+#[const_trait]
 pub trait Shl<Rhs = Self> {
     /// The resulting type after applying the `<<` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -564,6 +569,7 @@ shl_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 isize i128 }
     message = "no implementation for `{Self} >> {Rhs}`",
     label = "no implementation for `{Self} >> {Rhs}`"
 )]
+#[const_trait]
 pub trait Shr<Rhs = Self> {
     /// The resulting type after applying the `>>` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -692,6 +698,7 @@ shr_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize }
     message = "no implementation for `{Self} &= {Rhs}`",
     label = "no implementation for `{Self} &= {Rhs}`"
 )]
+#[const_trait]
 pub trait BitAndAssign<Rhs = Self> {
     /// Performs the `&=` operation.
     ///
@@ -764,6 +771,7 @@ bitand_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} |= {Rhs}`",
     label = "no implementation for `{Self} |= {Rhs}`"
 )]
+#[const_trait]
 pub trait BitOrAssign<Rhs = Self> {
     /// Performs the `|=` operation.
     ///
@@ -836,6 +844,7 @@ bitor_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} ^= {Rhs}`",
     label = "no implementation for `{Self} ^= {Rhs}`"
 )]
+#[const_trait]
 pub trait BitXorAssign<Rhs = Self> {
     /// Performs the `^=` operation.
     ///
@@ -906,6 +915,7 @@ bitxor_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} <<= {Rhs}`",
     label = "no implementation for `{Self} <<= {Rhs}`"
 )]
+#[const_trait]
 pub trait ShlAssign<Rhs = Self> {
     /// Performs the `<<=` operation.
     ///
@@ -989,6 +999,7 @@ shl_assign_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize }
     message = "no implementation for `{Self} >>= {Rhs}`",
     label = "no implementation for `{Self} >>= {Rhs}`"
 )]
+#[const_trait]
 pub trait ShrAssign<Rhs = Self> {
     /// Performs the `>>=` operation.
     ///