Rollup of 3 pull requests

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -2997,12 +2997,25 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 span,
                 "use of `const` in the type system not defined as `type const`",
             );
-            if def_id.is_local() {
+            if let Some(local_def_id) = def_id.as_local() {
                 let name = tcx.def_path_str(def_id);
+                let (insertion_span, sugg) = match tcx.hir_node_by_def_id(local_def_id) {
+                    hir::Node::Item(item) if !item.vis_span.is_empty() => {
+                        (item.vis_span.shrink_to_hi(), " type")
+                    }
+                    hir::Node::ImplItem(impl_item)
+                        if let Some(vis_span) =
+                            impl_item.vis_span().filter(|span| !span.is_empty()) =>
+                    {
+                        (vis_span.shrink_to_hi(), " type")
+                    }
+                    _ => (tcx.def_span(def_id).shrink_to_lo(), "type "),
+                };
+
                 err.span_suggestion_verbose(
-                    tcx.def_span(def_id).shrink_to_lo(),
+                    insertion_span,
                     format!("add `type` before `const` for `{name}`"),
-                    format!("type "),
+                    sugg,
                     Applicability::MaybeIncorrect,
                 );
             } else {

library/core/src/fmt/num.rs

@@ -758,7 +758,7 @@ impl u128 {
     /// ```
     #[stable(feature = "int_format_into", since = "CURRENT_RUSTC_VERSION")]
     pub fn format_into(self, buf: &mut NumBuffer<Self>) -> &str {
-        let diff = buf.capacity() - U128_MAX_DEC_N;
+        let diff = buf.buf.len() - U128_MAX_DEC_N;
         // FIXME: Once const generics are better, use `NumberBufferTrait::BUF_SIZE` as generic const
         // for `fmt_u128_inner`.
         //
@@ -790,7 +790,7 @@ impl i128 {
     /// ```
     #[stable(feature = "int_format_into", since = "CURRENT_RUSTC_VERSION")]
     pub fn format_into(self, buf: &mut NumBuffer<Self>) -> &str {
-        let diff = buf.capacity() - U128_MAX_DEC_N;
+        let diff = buf.buf.len() - U128_MAX_DEC_N;
         // FIXME: Once const generics are better, use `NumberBufferTrait::BUF_SIZE` as generic const
         // for `fmt_u128_inner`.
         //

library/core/src/fmt/num_buffer.rs

@@ -3,9 +3,12 @@ use crate::mem::MaybeUninit;
 /// Trait used to describe the maximum number of digits in decimal base of the implemented integer.
 #[unstable(feature = "fmt_internals", issue = "none")]
 pub trait NumBufferTrait {
-    /// Maximum number of digits in decimal base of the implemented integer.
+    /// Used for initializing the `NumberBuffer` value.
     #[unstable(feature = "fmt_internals", issue = "none")]
-    const BUF_SIZE: usize;
+    const DEFAULT: Self::Buf;
+    /// The actual underlying type.
+    #[unstable(feature = "fmt_internals", issue = "none")]
+    type Buf: AsRef<[MaybeUninit<u8>]> + AsMut<[MaybeUninit<u8>]>;
 }
 
 macro_rules! impl_NumBufferTrait {
@@ -14,11 +17,13 @@ macro_rules! impl_NumBufferTrait {
             #[stable(feature = "int_format_into", since = "CURRENT_RUSTC_VERSION")]
             impl NumBufferTrait for $signed {
                 // `+ 2` and not `+ 1` to include the `-` character.
-                const BUF_SIZE: usize = $signed::MAX.ilog(10) as usize + 2;
+                const DEFAULT: Self::Buf = [MaybeUninit::<u8>::uninit(); $signed::MAX.ilog(10) as usize + 2];
+                type Buf = [MaybeUninit<u8>; $signed::MAX.ilog(10) as usize + 2];
             }
             #[stable(feature = "int_format_into", since = "CURRENT_RUSTC_VERSION")]
             impl NumBufferTrait for $unsigned {
-                const BUF_SIZE: usize = $unsigned::MAX.ilog(10) as usize + 1;
+                const DEFAULT: Self::Buf = [MaybeUninit::<u8>::uninit(); $unsigned::MAX.ilog(10) as usize + 1];
+                type Buf = [MaybeUninit<u8>; $unsigned::MAX.ilog(10) as usize + 1];
             }
         )*
     }
@@ -52,9 +57,7 @@ impl_NumBufferTrait! {
 /// ```
 #[stable(feature = "int_format_into", since = "CURRENT_RUSTC_VERSION")]
 pub struct NumBuffer<T: NumBufferTrait> {
-    // FIXME: Once const generics feature is working, use `T::BUF_SIZE` instead of 40.
-    pub(crate) buf: [MaybeUninit<u8>; 40],
-    // FIXME: Remove this field once we can actually use `T`.
+    pub(crate) buf: T::Buf,
     phantom: core::marker::PhantomData<T>,
 }
 
@@ -72,10 +75,6 @@ impl<T: NumBufferTrait> NumBuffer<T> {
     #[rustc_const_stable(feature = "int_format_into", since = "CURRENT_RUSTC_VERSION")]
     pub const fn new() -> Self {
         // FIXME: Once const generics feature is working, use `T::BUF_SIZE` instead of 40.
-        NumBuffer { buf: [MaybeUninit::<u8>::uninit(); 40], phantom: core::marker::PhantomData }
-    }
-
-    pub(crate) const fn capacity(&self) -> usize {
-        self.buf.len()
+        NumBuffer { buf: T::DEFAULT, phantom: core::marker::PhantomData }
     }
 }

library/std/src/sync/once_lock.rs

@@ -626,14 +626,7 @@ impl<T: fmt::Debug> fmt::Debug for OnceLock<T> {
 impl<T: Clone> Clone for OnceLock<T> {
     #[inline]
     fn clone(&self) -> OnceLock<T> {
-        let cell = Self::new();
-        if let Some(value) = self.get() {
-            match cell.set(value.clone()) {
-                Ok(()) => (),
-                Err(_) => unreachable!(),
-            }
-        }
-        cell
+        self.get().cloned().map_or_default(Self::from)
     }
 }
 

tests/ui/const-generics/mgca/suggest-pub-type_const.fixed

@@ -0,0 +1,53 @@
+//! Regression test for <https://github.com/rust-lang/rust/issues/157368>
+//! Tests suggesting `pub type const` instead of `type pub const`.
+//@ run-rustfix
+#![feature(min_generic_const_args, inherent_associated_types)]
+#![allow(dead_code)]
+
+mod impl_item {
+    pub struct Bar;
+    impl Bar {
+        pub type const PUBLIC: usize = 1;
+        pub(crate) type const RESTRICTED: usize = 1;
+        type const PRIVATE: usize = 1;
+    }
+
+    pub struct Foo1([u8; Bar::PUBLIC]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Foo2([u8; Bar::RESTRICTED]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Foo3([u8; Bar::PRIVATE]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+}
+
+mod top_level_item {
+    pub type const PUBLIC: usize = 1;
+    pub(crate) type const RESTRICTED: usize = 1;
+    type const PRIVATE: usize = 1;
+
+    pub struct Foo1([u8; PUBLIC]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Foo2([u8; RESTRICTED]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Foo3([u8; PRIVATE]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+}
+
+mod trait_item {
+    pub trait Foo {
+        type  const PUBLIC: usize;
+        //~^ ERROR: [E0449]
+        type  const RESTRICTED: usize;
+        //~^ ERROR: [E0449]
+        type const PRIVATE: usize;
+    }
+
+    pub struct Bar<T: Foo>([u8; T::PUBLIC]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Bar2<T: Foo>([u8; T::RESTRICTED]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Bar3<T: Foo>([u8; T::PRIVATE]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+}
+
+fn main() {}

tests/ui/const-generics/mgca/suggest-pub-type_const.rs

@@ -0,0 +1,53 @@
+//! Regression test for <https://github.com/rust-lang/rust/issues/157368>
+//! Tests suggesting `pub type const` instead of `type pub const`.
+//@ run-rustfix
+#![feature(min_generic_const_args, inherent_associated_types)]
+#![allow(dead_code)]
+
+mod impl_item {
+    pub struct Bar;
+    impl Bar {
+        pub const PUBLIC: usize = 1;
+        pub(crate) const RESTRICTED: usize = 1;
+        const PRIVATE: usize = 1;
+    }
+
+    pub struct Foo1([u8; Bar::PUBLIC]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Foo2([u8; Bar::RESTRICTED]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Foo3([u8; Bar::PRIVATE]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+}
+
+mod top_level_item {
+    pub const PUBLIC: usize = 1;
+    pub(crate) const RESTRICTED: usize = 1;
+    const PRIVATE: usize = 1;
+
+    pub struct Foo1([u8; PUBLIC]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Foo2([u8; RESTRICTED]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Foo3([u8; PRIVATE]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+}
+
+mod trait_item {
+    pub trait Foo {
+        pub const PUBLIC: usize;
+        //~^ ERROR: [E0449]
+        pub(crate) const RESTRICTED: usize;
+        //~^ ERROR: [E0449]
+        const PRIVATE: usize;
+    }
+
+    pub struct Bar<T: Foo>([u8; T::PUBLIC]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Bar2<T: Foo>([u8; T::RESTRICTED]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+    pub struct Bar3<T: Foo>([u8; T::PRIVATE]);
+    //~^ ERROR: use of `const` in the type system not defined as `type const`
+}
+
+fn main() {}

tests/ui/const-generics/mgca/suggest-pub-type_const.stderr

@@ -0,0 +1,118 @@
+error[E0449]: visibility qualifiers are not permitted here
+  --> $DIR/suggest-pub-type_const.rs:38:9
+   |
+LL |         pub const PUBLIC: usize;
+   |         ^^^ help: remove the qualifier
+   |
+   = note: trait items always share the visibility of their trait
+
+error[E0449]: visibility qualifiers are not permitted here
+  --> $DIR/suggest-pub-type_const.rs:40:9
+   |
+LL |         pub(crate) const RESTRICTED: usize;
+   |         ^^^^^^^^^^ help: remove the qualifier
+   |
+   = note: trait items always share the visibility of their trait
+
+error: use of `const` in the type system not defined as `type const`
+  --> $DIR/suggest-pub-type_const.rs:15:26
+   |
+LL |     pub struct Foo1([u8; Bar::PUBLIC]);
+   |                          ^^^^^^^^^^^
+   |
+help: add `type` before `const` for `impl_item::Bar::PUBLIC`
+   |
+LL |         pub type const PUBLIC: usize = 1;
+   |             ++++
+
+error: use of `const` in the type system not defined as `type const`
+  --> $DIR/suggest-pub-type_const.rs:17:26
+   |
+LL |     pub struct Foo2([u8; Bar::RESTRICTED]);
+   |                          ^^^^^^^^^^^^^^^
+   |
+help: add `type` before `const` for `impl_item::Bar::RESTRICTED`
+   |
+LL |         pub(crate) type const RESTRICTED: usize = 1;
+   |                    ++++
+
+error: use of `const` in the type system not defined as `type const`
+  --> $DIR/suggest-pub-type_const.rs:19:26
+   |
+LL |     pub struct Foo3([u8; Bar::PRIVATE]);
+   |                          ^^^^^^^^^^^^
+   |
+help: add `type` before `const` for `impl_item::Bar::PRIVATE`
+   |
+LL |         type const PRIVATE: usize = 1;
+   |         ++++
+
+error: use of `const` in the type system not defined as `type const`
+  --> $DIR/suggest-pub-type_const.rs:28:26
+   |
+LL |     pub struct Foo1([u8; PUBLIC]);
+   |                          ^^^^^^
+   |
+help: add `type` before `const` for `PUBLIC`
+   |
+LL |     pub type const PUBLIC: usize = 1;
+   |         ++++
+
+error: use of `const` in the type system not defined as `type const`
+  --> $DIR/suggest-pub-type_const.rs:30:26
+   |
+LL |     pub struct Foo2([u8; RESTRICTED]);
+   |                          ^^^^^^^^^^
+   |
+help: add `type` before `const` for `RESTRICTED`
+   |
+LL |     pub(crate) type const RESTRICTED: usize = 1;
+   |                ++++
+
+error: use of `const` in the type system not defined as `type const`
+  --> $DIR/suggest-pub-type_const.rs:32:26
+   |
+LL |     pub struct Foo3([u8; PRIVATE]);
+   |                          ^^^^^^^
+   |
+help: add `type` before `const` for `PRIVATE`
+   |
+LL |     type const PRIVATE: usize = 1;
+   |     ++++
+
+error: use of `const` in the type system not defined as `type const`
+  --> $DIR/suggest-pub-type_const.rs:45:33
+   |
+LL |     pub struct Bar<T: Foo>([u8; T::PUBLIC]);
+   |                                 ^^^^^^^^^
+   |
+help: add `type` before `const` for `Foo::PUBLIC`
+   |
+LL |         type pub const PUBLIC: usize;
+   |         ++++
+
+error: use of `const` in the type system not defined as `type const`
+  --> $DIR/suggest-pub-type_const.rs:47:34
+   |
+LL |     pub struct Bar2<T: Foo>([u8; T::RESTRICTED]);
+   |                                  ^^^^^^^^^^^^^
+   |
+help: add `type` before `const` for `Foo::RESTRICTED`
+   |
+LL |         type pub(crate) const RESTRICTED: usize;
+   |         ++++
+
+error: use of `const` in the type system not defined as `type const`
+  --> $DIR/suggest-pub-type_const.rs:49:34
+   |
+LL |     pub struct Bar3<T: Foo>([u8; T::PRIVATE]);
+   |                                  ^^^^^^^^^^
+   |
+help: add `type` before `const` for `Foo::PRIVATE`
+   |
+LL |         type const PRIVATE: usize;
+   |         ++++
+
+error: aborting due to 11 previous errors
+
+For more information about this error, try `rustc --explain E0449`.