Add suggestion for some #[deprecated] items

library/alloc/src/lib.rs

@@ -118,6 +118,7 @@
 #![feature(const_waker)]
 #![feature(core_intrinsics)]
 #![feature(core_panic)]
+#![feature(deprecated_suggestion)]
 #![feature(dispatch_from_dyn)]
 #![feature(error_generic_member_access)]
 #![feature(error_in_core)]

library/alloc/src/slice.rs

@@ -592,7 +592,7 @@ impl<T> [T] {
     /// ```
     #[rustc_allow_incoherent_impl]
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[deprecated(since = "1.3.0", note = "renamed to join")]
+    #[deprecated(since = "1.3.0", note = "renamed to join", suggestion = "join")]
     pub fn connect<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
     where
         Self: Join<Separator>,

library/core/src/mem/mod.rs

@@ -413,7 +413,7 @@ pub const unsafe fn size_of_val_raw<T: ?Sized>(val: *const T) -> usize {
 #[inline]
 #[must_use]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[deprecated(note = "use `align_of` instead", since = "1.2.0")]
+#[deprecated(note = "use `align_of` instead", since = "1.2.0", suggestion = "align_of")]
 pub fn min_align_of<T>() -> usize {
     intrinsics::min_align_of::<T>()
 }
@@ -436,7 +436,7 @@ pub fn min_align_of<T>() -> usize {
 #[inline]
 #[must_use]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[deprecated(note = "use `align_of_val` instead", since = "1.2.0")]
+#[deprecated(note = "use `align_of_val` instead", since = "1.2.0", suggestion = "align_of_val")]
 pub fn min_align_of_val<T: ?Sized>(val: &T) -> usize {
     // SAFETY: val is a reference, so it's a valid raw pointer
     unsafe { intrinsics::min_align_of_val(val) }

library/core/src/str/mod.rs

@@ -993,7 +993,7 @@ impl str {
 
     /// An iterator over the lines of a string.
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[deprecated(since = "1.4.0", note = "use lines() instead now")]
+    #[deprecated(since = "1.4.0", note = "use lines() instead now", suggestion = "lines")]
     #[inline]
     #[allow(deprecated)]
     pub fn lines_any(&self) -> LinesAny<'_> {

tests/ui/deprecation/issue-84637-deprecated-associated-function.fixed

@@ -6,4 +6,6 @@ fn main() {
     let _foo = str::trim_start("   aoeu"); //~ ERROR use of deprecated method `core::str::<impl str>::trim_left`: superseded by `trim_start` [deprecated]
 
     let _bar = "   aoeu".trim_start(); //~ ERROR use of deprecated method `core::str::<impl str>::trim_left`: superseded by `trim_start` [deprecated]
+
+    let _baz = ["a", "b"].join(" "); //~ ERROR use of deprecated method `std::slice::<impl [T]>::connect`: renamed to join [deprecated]
 }

tests/ui/deprecation/issue-84637-deprecated-associated-function.rs

@@ -6,4 +6,6 @@ fn main() {
     let _foo = str::trim_left("   aoeu"); //~ ERROR use of deprecated method `core::str::<impl str>::trim_left`: superseded by `trim_start` [deprecated]
 
     let _bar = "   aoeu".trim_left(); //~ ERROR use of deprecated method `core::str::<impl str>::trim_left`: superseded by `trim_start` [deprecated]
+
+    let _baz = ["a", "b"].connect(" "); //~ ERROR use of deprecated method `std::slice::<impl [T]>::connect`: renamed to join [deprecated]
 }

tests/ui/deprecation/issue-84637-deprecated-associated-function.stderr

@@ -25,5 +25,16 @@ help: replace the use of the deprecated method
 LL |     let _bar = "   aoeu".trim_start();
    |                          ~~~~~~~~~~
 
-error: aborting due to 2 previous errors
+error: use of deprecated method `std::slice::<impl [T]>::connect`: renamed to join
+  --> $DIR/issue-84637-deprecated-associated-function.rs:10:27
+   |
+LL |     let _baz = ["a", "b"].connect(" ");
+   |                           ^^^^^^^
+   |
+help: replace the use of the deprecated method
+   |
+LL |     let _baz = ["a", "b"].join(" ");
+   |                           ~~~~
+
+error: aborting due to 3 previous errors