Merge from rustc

25 files changed, 169 insertions, 227 deletions

diff --git a/src/tools/clippy/clippy_lints/src/casts/cast_ref_to_mut.rs b/src/tools/clippy/clippy_lints/src/casts/cast_ref_to_mut.rs
deleted file mode 100644
index 15f2f81f407..00000000000
--- a/src/tools/clippy/clippy_lints/src/casts/cast_ref_to_mut.rs
+++ /dev/null
@@ -1,26 +0,0 @@
-use clippy_utils::diagnostics::span_lint;
-use if_chain::if_chain;
-use rustc_hir::{Expr, ExprKind, MutTy, Mutability, TyKind, UnOp};
-use rustc_lint::LateContext;
-use rustc_middle::ty;
-
-use super::CAST_REF_TO_MUT;
-
-pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
-    if_chain! {
-        if let ExprKind::Unary(UnOp::Deref, e) = &expr.kind;
-        if let ExprKind::Cast(e, t) = &e.kind;
-        if let TyKind::Ptr(MutTy { mutbl: Mutability::Mut, .. }) = t.kind;
-        if let ExprKind::Cast(e, t) = &e.kind;
-        if let TyKind::Ptr(MutTy { mutbl: Mutability::Not, .. }) = t.kind;
-        if let ty::Ref(..) = cx.typeck_results().node_type(e.hir_id).kind();
-        then {
-            span_lint(
-                cx,
-                CAST_REF_TO_MUT,
-                expr.span,
-                "casting `&T` to `&mut T` may cause undefined behavior, consider instead using an `UnsafeCell`",
-            );
-        }
-    }
-}
diff --git a/src/tools/clippy/clippy_lints/src/casts/mod.rs b/src/tools/clippy/clippy_lints/src/casts/mod.rs
index cfeb75eed3b..0c175372aab 100644
--- a/src/tools/clippy/clippy_lints/src/casts/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/mod.rs
@@ -9,7 +9,6 @@ mod cast_possible_truncation;
 mod cast_possible_wrap;
 mod cast_precision_loss;
 mod cast_ptr_alignment;
-mod cast_ref_to_mut;
 mod cast_sign_loss;
 mod cast_slice_different_sizes;
 mod cast_slice_from_raw_parts;
@@ -332,41 +331,6 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for casts of `&T` to `&mut T` anywhere in the code.
-    ///
-    /// ### Why is this bad?
-    /// It’s basically guaranteed to be undefined behavior.
-    /// `UnsafeCell` is the only way to obtain aliasable data that is considered
-    /// mutable.
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// fn x(r: &i32) {
-    ///     unsafe {
-    ///         *(r as *const _ as *mut _) += 1;
-    ///     }
-    /// }
-    /// ```
-    ///
-    /// Instead consider using interior mutability types.
-    ///
-    /// ```rust
-    /// use std::cell::UnsafeCell;
-    ///
-    /// fn x(r: &UnsafeCell<i32>) {
-    ///     unsafe {
-    ///         *r.get() += 1;
-    ///     }
-    /// }
-    /// ```
-    #[clippy::version = "1.33.0"]
-    pub CAST_REF_TO_MUT,
-    correctness,
-    "a cast of reference to a mutable pointer"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
     /// Checks for expressions where a character literal is cast
     /// to `u8` and suggests using a byte literal instead.
     ///
@@ -680,7 +644,6 @@ impl_lint_pass!(Casts => [
     CAST_POSSIBLE_TRUNCATION,
     CAST_POSSIBLE_WRAP,
     CAST_LOSSLESS,
-    CAST_REF_TO_MUT,
     CAST_PTR_ALIGNMENT,
     CAST_SLICE_DIFFERENT_SIZES,
     UNNECESSARY_CAST,
@@ -747,7 +710,6 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
             }
         }
 
-        cast_ref_to_mut::check(cx, expr);
         cast_ptr_alignment::check(cx, expr);
         char_lit_as_u8::check(cx, expr);
         ptr_as_ptr::check(cx, expr, &self.msrv);
diff --git a/src/tools/clippy/clippy_lints/src/declared_lints.rs b/src/tools/clippy/clippy_lints/src/declared_lints.rs
index 0ae95b045e0..212e809d4c5 100644
--- a/src/tools/clippy/clippy_lints/src/declared_lints.rs
+++ b/src/tools/clippy/clippy_lints/src/declared_lints.rs
@@ -81,7 +81,6 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::casts::CAST_POSSIBLE_WRAP_INFO,
     crate::casts::CAST_PRECISION_LOSS_INFO,
     crate::casts::CAST_PTR_ALIGNMENT_INFO,
-    crate::casts::CAST_REF_TO_MUT_INFO,
     crate::casts::CAST_SIGN_LOSS_INFO,
     crate::casts::CAST_SLICE_DIFFERENT_SIZES_INFO,
     crate::casts::CAST_SLICE_FROM_RAW_PARTS_INFO,
diff --git a/src/tools/clippy/clippy_lints/src/renamed_lints.rs b/src/tools/clippy/clippy_lints/src/renamed_lints.rs
index 7c2a100efda..4cb41830023 100644
--- a/src/tools/clippy/clippy_lints/src/renamed_lints.rs
+++ b/src/tools/clippy/clippy_lints/src/renamed_lints.rs
@@ -31,6 +31,7 @@ pub static RENAMED_LINTS: &[(&str, &str)] = &[
     ("clippy::stutter", "clippy::module_name_repetitions"),
     ("clippy::to_string_in_display", "clippy::recursive_format_impl"),
     ("clippy::zero_width_space", "clippy::invisible_characters"),
+    ("clippy::cast_ref_to_mut", "cast_ref_to_mut"),
     ("clippy::clone_double_ref", "suspicious_double_ref_op"),
     ("clippy::drop_bounds", "drop_bounds"),
     ("clippy::drop_copy", "dropping_copy_types"),
diff --git a/src/tools/clippy/tests/ui/cast_ref_to_mut.rs b/src/tools/clippy/tests/ui/cast_ref_to_mut.rs
deleted file mode 100644
index c48a734ba32..00000000000
--- a/src/tools/clippy/tests/ui/cast_ref_to_mut.rs
+++ /dev/null
@@ -1,31 +0,0 @@
-#![warn(clippy::cast_ref_to_mut)]
-#![allow(clippy::no_effect, clippy::borrow_as_ptr)]
-
-extern "C" {
-    // N.B., mutability can be easily incorrect in FFI calls -- as
-    // in C, the default is mutable pointers.
-    fn ffi(c: *mut u8);
-    fn int_ffi(c: *mut i32);
-}
-
-fn main() {
-    let s = String::from("Hello");
-    let a = &s;
-    unsafe {
-        let num = &3i32;
-        let mut_num = &mut 3i32;
-        // Should be warned against
-        (*(a as *const _ as *mut String)).push_str(" world");
-        *(a as *const _ as *mut _) = String::from("Replaced");
-        *(a as *const _ as *mut String) += " world";
-        // Shouldn't be warned against
-        println!("{}", *(num as *const _ as *const i16));
-        println!("{}", *(mut_num as *mut _ as *mut i16));
-        ffi(a.as_ptr() as *mut _);
-        int_ffi(num as *const _ as *mut _);
-        int_ffi(&3 as *const _ as *mut _);
-        let mut value = 3;
-        let value: *const i32 = &mut value;
-        *(value as *const i16 as *mut i16) = 42;
-    }
-}
diff --git a/src/tools/clippy/tests/ui/cast_ref_to_mut.stderr b/src/tools/clippy/tests/ui/cast_ref_to_mut.stderr
deleted file mode 100644
index aacd99437d9..00000000000
--- a/src/tools/clippy/tests/ui/cast_ref_to_mut.stderr
+++ /dev/null
@@ -1,22 +0,0 @@
-error: casting `&T` to `&mut T` may cause undefined behavior, consider instead using an `UnsafeCell`
-  --> $DIR/cast_ref_to_mut.rs:18:9
-   |
-LL |         (*(a as *const _ as *mut String)).push_str(" world");
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: `-D clippy::cast-ref-to-mut` implied by `-D warnings`
-
-error: casting `&T` to `&mut T` may cause undefined behavior, consider instead using an `UnsafeCell`
-  --> $DIR/cast_ref_to_mut.rs:19:9
-   |
-LL |         *(a as *const _ as *mut _) = String::from("Replaced");
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: casting `&T` to `&mut T` may cause undefined behavior, consider instead using an `UnsafeCell`
-  --> $DIR/cast_ref_to_mut.rs:20:9
-   |
-LL |         *(a as *const _ as *mut String) += " world";
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 3 previous errors
-
diff --git a/src/tools/clippy/tests/ui/modulo_one.stderr b/src/tools/clippy/tests/ui/modulo_one.stderr
index 04ecdef5e99..83a76f81d4e 100644
--- a/src/tools/clippy/tests/ui/modulo_one.stderr
+++ b/src/tools/clippy/tests/ui/modulo_one.stderr
@@ -2,7 +2,7 @@ error: this operation will panic at runtime
   --> $DIR/modulo_one.rs:11:5
    |
 LL |     i32::MIN % (-1); // also caught by rustc
-   |     ^^^^^^^^^^^^^^^ attempt to compute the remainder of `i32::MIN % -1_i32`, which would overflow
+   |     ^^^^^^^^^^^^^^^ attempt to compute `i32::MIN % -1_i32`, which would overflow
    |
    = note: `#[deny(unconditional_panic)]` on by default
 
@@ -10,13 +10,13 @@ error: this operation will panic at runtime
   --> $DIR/modulo_one.rs:21:5
    |
 LL |     INT_MIN % NEG_ONE; // also caught by rustc
-   |     ^^^^^^^^^^^^^^^^^ attempt to compute the remainder of `i64::MIN % -1_i64`, which would overflow
+   |     ^^^^^^^^^^^^^^^^^ attempt to compute `i64::MIN % -1_i64`, which would overflow
 
 error: this operation will panic at runtime
   --> $DIR/modulo_one.rs:22:5
    |
 LL |     INT_MIN % STATIC_NEG_ONE; // ONLY caught by rustc
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^ attempt to compute the remainder of `i64::MIN % -1_i64`, which would overflow
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^ attempt to compute `i64::MIN % -1_i64`, which would overflow
 
 error: any number modulo 1 will be 0
   --> $DIR/modulo_one.rs:8:5
diff --git a/src/tools/clippy/tests/ui/rename.fixed b/src/tools/clippy/tests/ui/rename.fixed
index 53ac65473b8..f7854b89ee4 100644
--- a/src/tools/clippy/tests/ui/rename.fixed
+++ b/src/tools/clippy/tests/ui/rename.fixed
@@ -29,6 +29,7 @@
 #![allow(clippy::recursive_format_impl)]
 #![allow(clippy::invisible_characters)]
 #![allow(suspicious_double_ref_op)]
+#![allow(cast_ref_to_mut)]
 #![allow(drop_bounds)]
 #![allow(dropping_copy_types)]
 #![allow(dropping_references)]
@@ -76,6 +77,7 @@
 #![warn(clippy::module_name_repetitions)]
 #![warn(clippy::recursive_format_impl)]
 #![warn(clippy::invisible_characters)]
+#![warn(cast_ref_to_mut)]
 #![warn(suspicious_double_ref_op)]
 #![warn(drop_bounds)]
 #![warn(dropping_copy_types)]
diff --git a/src/tools/clippy/tests/ui/rename.rs b/src/tools/clippy/tests/ui/rename.rs
index 722c0b3eb27..fa347d395ef 100644
--- a/src/tools/clippy/tests/ui/rename.rs
+++ b/src/tools/clippy/tests/ui/rename.rs
@@ -29,6 +29,7 @@
 #![allow(clippy::recursive_format_impl)]
 #![allow(clippy::invisible_characters)]
 #![allow(suspicious_double_ref_op)]
+#![allow(cast_ref_to_mut)]
 #![allow(drop_bounds)]
 #![allow(dropping_copy_types)]
 #![allow(dropping_references)]
@@ -76,6 +77,7 @@
 #![warn(clippy::stutter)]
 #![warn(clippy::to_string_in_display)]
 #![warn(clippy::zero_width_space)]
+#![warn(clippy::cast_ref_to_mut)]
 #![warn(clippy::clone_double_ref)]
 #![warn(clippy::drop_bounds)]
 #![warn(clippy::drop_copy)]
diff --git a/src/tools/clippy/tests/ui/rename.stderr b/src/tools/clippy/tests/ui/rename.stderr
index 1ff83917660..9dffe51e5d7 100644
--- a/src/tools/clippy/tests/ui/rename.stderr
+++ b/src/tools/clippy/tests/ui/rename.stderr
@@ -1,5 +1,5 @@
 error: lint `clippy::almost_complete_letter_range` has been renamed to `clippy::almost_complete_range`
-  --> $DIR/rename.rs:50:9
+  --> $DIR/rename.rs:51:9
    |
 LL | #![warn(clippy::almost_complete_letter_range)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::almost_complete_range`
@@ -7,292 +7,298 @@ LL | #![warn(clippy::almost_complete_letter_range)]
    = note: `-D renamed-and-removed-lints` implied by `-D warnings`
 
 error: lint `clippy::blacklisted_name` has been renamed to `clippy::disallowed_names`
-  --> $DIR/rename.rs:51:9
+  --> $DIR/rename.rs:52:9
    |
 LL | #![warn(clippy::blacklisted_name)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_names`
 
 error: lint `clippy::block_in_if_condition_expr` has been renamed to `clippy::blocks_in_if_conditions`
-  --> $DIR/rename.rs:52:9
+  --> $DIR/rename.rs:53:9
    |
 LL | #![warn(clippy::block_in_if_condition_expr)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::blocks_in_if_conditions`
 
 error: lint `clippy::block_in_if_condition_stmt` has been renamed to `clippy::blocks_in_if_conditions`
-  --> $DIR/rename.rs:53:9
+  --> $DIR/rename.rs:54:9
    |
 LL | #![warn(clippy::block_in_if_condition_stmt)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::blocks_in_if_conditions`
 
 error: lint `clippy::box_vec` has been renamed to `clippy::box_collection`
-  --> $DIR/rename.rs:54:9
+  --> $DIR/rename.rs:55:9
    |
 LL | #![warn(clippy::box_vec)]
    |         ^^^^^^^^^^^^^^^ help: use the new name: `clippy::box_collection`
 
 error: lint `clippy::const_static_lifetime` has been renamed to `clippy::redundant_static_lifetimes`
-  --> $DIR/rename.rs:55:9
+  --> $DIR/rename.rs:56:9
    |
 LL | #![warn(clippy::const_static_lifetime)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::redundant_static_lifetimes`
 
 error: lint `clippy::cyclomatic_complexity` has been renamed to `clippy::cognitive_complexity`
-  --> $DIR/rename.rs:56:9
+  --> $DIR/rename.rs:57:9
    |
 LL | #![warn(clippy::cyclomatic_complexity)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::cognitive_complexity`
 
 error: lint `clippy::derive_hash_xor_eq` has been renamed to `clippy::derived_hash_with_manual_eq`
-  --> $DIR/rename.rs:57:9
+  --> $DIR/rename.rs:58:9
    |
 LL | #![warn(clippy::derive_hash_xor_eq)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::derived_hash_with_manual_eq`
 
 error: lint `clippy::disallowed_method` has been renamed to `clippy::disallowed_methods`
-  --> $DIR/rename.rs:58:9
+  --> $DIR/rename.rs:59:9
    |
 LL | #![warn(clippy::disallowed_method)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_methods`
 
 error: lint `clippy::disallowed_type` has been renamed to `clippy::disallowed_types`
-  --> $DIR/rename.rs:59:9
+  --> $DIR/rename.rs:60:9
    |
 LL | #![warn(clippy::disallowed_type)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_types`
 
 error: lint `clippy::eval_order_dependence` has been renamed to `clippy::mixed_read_write_in_expression`
-  --> $DIR/rename.rs:60:9
+  --> $DIR/rename.rs:61:9
    |
 LL | #![warn(clippy::eval_order_dependence)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::mixed_read_write_in_expression`
 
 error: lint `clippy::identity_conversion` has been renamed to `clippy::useless_conversion`
-  --> $DIR/rename.rs:61:9
+  --> $DIR/rename.rs:62:9
    |
 LL | #![warn(clippy::identity_conversion)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::useless_conversion`
 
 error: lint `clippy::if_let_some_result` has been renamed to `clippy::match_result_ok`
-  --> $DIR/rename.rs:62:9
+  --> $DIR/rename.rs:63:9
    |
 LL | #![warn(clippy::if_let_some_result)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::match_result_ok`
 
 error: lint `clippy::integer_arithmetic` has been renamed to `clippy::arithmetic_side_effects`
-  --> $DIR/rename.rs:63:9
+  --> $DIR/rename.rs:64:9
    |
 LL | #![warn(clippy::integer_arithmetic)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::arithmetic_side_effects`
 
 error: lint `clippy::logic_bug` has been renamed to `clippy::overly_complex_bool_expr`
-  --> $DIR/rename.rs:64:9
+  --> $DIR/rename.rs:65:9
    |
 LL | #![warn(clippy::logic_bug)]
    |         ^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::overly_complex_bool_expr`
 
 error: lint `clippy::new_without_default_derive` has been renamed to `clippy::new_without_default`
-  --> $DIR/rename.rs:65:9
+  --> $DIR/rename.rs:66:9
    |
 LL | #![warn(clippy::new_without_default_derive)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::new_without_default`
 
 error: lint `clippy::option_and_then_some` has been renamed to `clippy::bind_instead_of_map`
-  --> $DIR/rename.rs:66:9
+  --> $DIR/rename.rs:67:9
    |
 LL | #![warn(clippy::option_and_then_some)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::bind_instead_of_map`
 
 error: lint `clippy::option_expect_used` has been renamed to `clippy::expect_used`
-  --> $DIR/rename.rs:67:9
+  --> $DIR/rename.rs:68:9
    |
 LL | #![warn(clippy::option_expect_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::expect_used`
 
 error: lint `clippy::option_map_unwrap_or` has been renamed to `clippy::map_unwrap_or`
-  --> $DIR/rename.rs:68:9
+  --> $DIR/rename.rs:69:9
    |
 LL | #![warn(clippy::option_map_unwrap_or)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::option_map_unwrap_or_else` has been renamed to `clippy::map_unwrap_or`
-  --> $DIR/rename.rs:69:9
+  --> $DIR/rename.rs:70:9
    |
 LL | #![warn(clippy::option_map_unwrap_or_else)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::option_unwrap_used` has been renamed to `clippy::unwrap_used`
-  --> $DIR/rename.rs:70:9
+  --> $DIR/rename.rs:71:9
    |
 LL | #![warn(clippy::option_unwrap_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::unwrap_used`
 
 error: lint `clippy::ref_in_deref` has been renamed to `clippy::needless_borrow`
-  --> $DIR/rename.rs:71:9
+  --> $DIR/rename.rs:72:9
    |
 LL | #![warn(clippy::ref_in_deref)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::needless_borrow`
 
 error: lint `clippy::result_expect_used` has been renamed to `clippy::expect_used`
-  --> $DIR/rename.rs:72:9
+  --> $DIR/rename.rs:73:9
    |
 LL | #![warn(clippy::result_expect_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::expect_used`
 
 error: lint `clippy::result_map_unwrap_or_else` has been renamed to `clippy::map_unwrap_or`
-  --> $DIR/rename.rs:73:9
+  --> $DIR/rename.rs:74:9
    |
 LL | #![warn(clippy::result_map_unwrap_or_else)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::result_unwrap_used` has been renamed to `clippy::unwrap_used`
-  --> $DIR/rename.rs:74:9
+  --> $DIR/rename.rs:75:9
    |
 LL | #![warn(clippy::result_unwrap_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::unwrap_used`
 
 error: lint `clippy::single_char_push_str` has been renamed to `clippy::single_char_add_str`
-  --> $DIR/rename.rs:75:9
+  --> $DIR/rename.rs:76:9
    |
 LL | #![warn(clippy::single_char_push_str)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::single_char_add_str`
 
 error: lint `clippy::stutter` has been renamed to `clippy::module_name_repetitions`
-  --> $DIR/rename.rs:76:9
+  --> $DIR/rename.rs:77:9
    |
 LL | #![warn(clippy::stutter)]
    |         ^^^^^^^^^^^^^^^ help: use the new name: `clippy::module_name_repetitions`
 
 error: lint `clippy::to_string_in_display` has been renamed to `clippy::recursive_format_impl`
-  --> $DIR/rename.rs:77:9
+  --> $DIR/rename.rs:78:9
    |
 LL | #![warn(clippy::to_string_in_display)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::recursive_format_impl`
 
 error: lint `clippy::zero_width_space` has been renamed to `clippy::invisible_characters`
-  --> $DIR/rename.rs:78:9
+  --> $DIR/rename.rs:79:9
    |
 LL | #![warn(clippy::zero_width_space)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::invisible_characters`
 
+error: lint `clippy::cast_ref_to_mut` has been renamed to `cast_ref_to_mut`
+  --> $DIR/rename.rs:80:9
+   |
+LL | #![warn(clippy::cast_ref_to_mut)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `cast_ref_to_mut`
+
 error: lint `clippy::clone_double_ref` has been renamed to `suspicious_double_ref_op`
-  --> $DIR/rename.rs:79:9
+  --> $DIR/rename.rs:81:9
    |
 LL | #![warn(clippy::clone_double_ref)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `suspicious_double_ref_op`
 
 error: lint `clippy::drop_bounds` has been renamed to `drop_bounds`
-  --> $DIR/rename.rs:80:9
+  --> $DIR/rename.rs:82:9
    |
 LL | #![warn(clippy::drop_bounds)]
    |         ^^^^^^^^^^^^^^^^^^^ help: use the new name: `drop_bounds`
 
 error: lint `clippy::drop_copy` has been renamed to `dropping_copy_types`
-  --> $DIR/rename.rs:81:9
+  --> $DIR/rename.rs:83:9
    |
 LL | #![warn(clippy::drop_copy)]
    |         ^^^^^^^^^^^^^^^^^ help: use the new name: `dropping_copy_types`
 
 error: lint `clippy::drop_ref` has been renamed to `dropping_references`
-  --> $DIR/rename.rs:82:9
+  --> $DIR/rename.rs:84:9
    |
 LL | #![warn(clippy::drop_ref)]
    |         ^^^^^^^^^^^^^^^^ help: use the new name: `dropping_references`
 
 error: lint `clippy::for_loop_over_option` has been renamed to `for_loops_over_fallibles`
-  --> $DIR/rename.rs:83:9
+  --> $DIR/rename.rs:85:9
    |
 LL | #![warn(clippy::for_loop_over_option)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `for_loops_over_fallibles`
 
 error: lint `clippy::for_loop_over_result` has been renamed to `for_loops_over_fallibles`
-  --> $DIR/rename.rs:84:9
+  --> $DIR/rename.rs:86:9
    |
 LL | #![warn(clippy::for_loop_over_result)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `for_loops_over_fallibles`
 
 error: lint `clippy::for_loops_over_fallibles` has been renamed to `for_loops_over_fallibles`
-  --> $DIR/rename.rs:85:9
+  --> $DIR/rename.rs:87:9
    |
 LL | #![warn(clippy::for_loops_over_fallibles)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `for_loops_over_fallibles`
 
 error: lint `clippy::forget_copy` has been renamed to `forgetting_copy_types`
-  --> $DIR/rename.rs:86:9
+  --> $DIR/rename.rs:88:9
    |
 LL | #![warn(clippy::forget_copy)]
    |         ^^^^^^^^^^^^^^^^^^^ help: use the new name: `forgetting_copy_types`
 
 error: lint `clippy::forget_ref` has been renamed to `forgetting_references`
-  --> $DIR/rename.rs:87:9
+  --> $DIR/rename.rs:89:9
    |
 LL | #![warn(clippy::forget_ref)]
    |         ^^^^^^^^^^^^^^^^^^ help: use the new name: `forgetting_references`
 
 error: lint `clippy::into_iter_on_array` has been renamed to `array_into_iter`
-  --> $DIR/rename.rs:88:9
+  --> $DIR/rename.rs:90:9
    |
 LL | #![warn(clippy::into_iter_on_array)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `array_into_iter`
 
 error: lint `clippy::invalid_atomic_ordering` has been renamed to `invalid_atomic_ordering`
-  --> $DIR/rename.rs:89:9
+  --> $DIR/rename.rs:91:9
    |
 LL | #![warn(clippy::invalid_atomic_ordering)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_atomic_ordering`
 
 error: lint `clippy::invalid_ref` has been renamed to `invalid_value`
-  --> $DIR/rename.rs:90:9
+  --> $DIR/rename.rs:92:9
    |
 LL | #![warn(clippy::invalid_ref)]
    |         ^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_value`
 
 error: lint `clippy::invalid_utf8_in_unchecked` has been renamed to `invalid_from_utf8_unchecked`
-  --> $DIR/rename.rs:91:9
+  --> $DIR/rename.rs:93:9
    |
 LL | #![warn(clippy::invalid_utf8_in_unchecked)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_from_utf8_unchecked`
 
 error: lint `clippy::let_underscore_drop` has been renamed to `let_underscore_drop`
-  --> $DIR/rename.rs:92:9
+  --> $DIR/rename.rs:94:9
    |
 LL | #![warn(clippy::let_underscore_drop)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `let_underscore_drop`
 
 error: lint `clippy::mem_discriminant_non_enum` has been renamed to `enum_intrinsics_non_enums`
-  --> $DIR/rename.rs:93:9
+  --> $DIR/rename.rs:95:9
    |
 LL | #![warn(clippy::mem_discriminant_non_enum)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `enum_intrinsics_non_enums`
 
 error: lint `clippy::panic_params` has been renamed to `non_fmt_panics`
-  --> $DIR/rename.rs:94:9
+  --> $DIR/rename.rs:96:9
    |
 LL | #![warn(clippy::panic_params)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `non_fmt_panics`
 
 error: lint `clippy::positional_named_format_parameters` has been renamed to `named_arguments_used_positionally`
-  --> $DIR/rename.rs:95:9
+  --> $DIR/rename.rs:97:9
    |
 LL | #![warn(clippy::positional_named_format_parameters)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `named_arguments_used_positionally`
 
 error: lint `clippy::temporary_cstring_as_ptr` has been renamed to `temporary_cstring_as_ptr`
-  --> $DIR/rename.rs:96:9
+  --> $DIR/rename.rs:98:9
    |
 LL | #![warn(clippy::temporary_cstring_as_ptr)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `temporary_cstring_as_ptr`
 
 error: lint `clippy::unknown_clippy_lints` has been renamed to `unknown_lints`
-  --> $DIR/rename.rs:97:9
+  --> $DIR/rename.rs:99:9
    |
 LL | #![warn(clippy::unknown_clippy_lints)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `unknown_lints`
 
 error: lint `clippy::unused_label` has been renamed to `unused_labels`
-  --> $DIR/rename.rs:98:9
+  --> $DIR/rename.rs:100:9
    |
 LL | #![warn(clippy::unused_label)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `unused_labels`
 
-error: aborting due to 49 previous errors
+error: aborting due to 50 previous errors
 
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index a799d93ce25..923b2e63f2e 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -1939,6 +1939,17 @@ impl<'test> TestCx<'test> {
         // Use a single thread for efficiency and a deterministic error message order
         rustc.arg("-Zthreads=1");
 
+        // Hide libstd sources from ui tests to make sure we generate the stderr
+        // output that users will see.
+        // Without this, we may be producing good diagnostics in-tree but users
+        // will not see half the information.
+        //
+        // This also has the benefit of more effectively normalizing output between different
+        // compilers, so that we don't have to know the `/rustc/$sha` output to normalize after the
+        // fact.
+        rustc.arg("-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX");
+        rustc.arg("-Ztranslate-remapped-path-to-local-path=no");
+
         // Optionally prevent default --sysroot if specified in test compile-flags.
         if !self.props.compile_flags.iter().any(|flag| flag.starts_with("--sysroot")) {
             // In stage 0, make sure we use `stage0-sysroot` instead of the bootstrap sysroot.
@@ -2014,13 +2025,6 @@ impl<'test> TestCx<'test> {
                 rustc.arg("-Ccodegen-units=1");
                 // Hide line numbers to reduce churn
                 rustc.arg("-Zui-testing");
-                // Hide libstd sources from ui tests to make sure we generate the stderr
-                // output that users will see.
-                // Without this, we may be producing good diagnostics in-tree but users
-                // will not see half the information.
-                rustc.arg("-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX");
-                rustc.arg("-Ztranslate-remapped-path-to-local-path=no");
-
                 rustc.arg("-Zdeduplicate-diagnostics=no");
                 // FIXME: use this for other modes too, for perf?
                 rustc.arg("-Cstrip=debuginfo");
@@ -3732,28 +3736,13 @@ impl<'test> TestCx<'test> {
             normalize_path(&remapped_parent_dir, "$DIR");
         }
 
-        let source_bases = &[
-            // Source base on the current filesystem (calculated as parent of `tests/$suite`):
-            Some(self.config.src_base.parent().unwrap().parent().unwrap().into()),
-            // Source base on the sysroot (from the src components downloaded by `download-rustc`):
-            Some(self.config.sysroot_base.join("lib").join("rustlib").join("src").join("rust")),
-            // Virtual `/rustc/$sha` remapped paths (if `remap-debuginfo` is enabled):
-            option_env!("CFG_VIRTUAL_RUST_SOURCE_BASE_DIR").map(PathBuf::from),
-            // Virtual `/rustc/$sha` coming from download-rustc:
-            std::env::var_os("FAKE_DOWNLOAD_RUSTC_PREFIX").map(PathBuf::from),
-            // Tests using -Zsimulate-remapped-rust-src-base should use this fake path
-            Some("/rustc/FAKE_PREFIX".into()),
-        ];
-        for base_dir in source_bases {
-            if let Some(base_dir) = base_dir {
-                // Paths into the libstd/libcore
-                normalize_path(&base_dir.join("library"), "$SRC_DIR");
-                // `ui-fulldeps` tests can show paths to the compiler source when testing macros from
-                // `rustc_macros`
-                // eg. /home/user/rust/compiler
-                normalize_path(&base_dir.join("compiler"), "$COMPILER_DIR");
-            }
-        }
+        let base_dir = Path::new("/rustc/FAKE_PREFIX");
+        // Paths into the libstd/libcore
+        normalize_path(&base_dir.join("library"), "$SRC_DIR");
+        // `ui-fulldeps` tests can show paths to the compiler source when testing macros from
+        // `rustc_macros`
+        // eg. /home/user/rust/compiler
+        normalize_path(&base_dir.join("compiler"), "$COMPILER_DIR");
 
         // Paths into the build directory
         let test_build_dir = &self.config.build_base;
diff --git a/src/tools/miri/src/diagnostics.rs b/src/tools/miri/src/diagnostics.rs
index 14931baaadf..8c788c915fe 100644
--- a/src/tools/miri/src/diagnostics.rs
+++ b/src/tools/miri/src/diagnostics.rs
@@ -3,6 +3,8 @@ use std::num::NonZeroU64;
 
 use log::trace;
 
+use rustc_const_eval::ReportErrorExt;
+use rustc_errors::DiagnosticMessage;
 use rustc_span::{source_map::DUMMY_SP, SpanData, Symbol};
 use rustc_target::abi::{Align, Size};
 
@@ -83,7 +85,21 @@ impl fmt::Display for TerminationInfo {
     }
 }
 
-impl MachineStopType for TerminationInfo {}
+impl fmt::Debug for TerminationInfo {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{self}")
+    }
+}
+
+impl MachineStopType for TerminationInfo {
+    fn diagnostic_message(&self) -> DiagnosticMessage {
+        self.to_string().into()
+    }
+    fn add_args(
+        self: Box<Self>,
+        _: &mut dyn FnMut(std::borrow::Cow<'static, str>, rustc_errors::DiagnosticArgValue<'static>),
+    ) {}
+}
 
 /// Miri specific diagnostics
 pub enum NonHaltingDiagnostic {
@@ -302,8 +318,32 @@ pub fn report_error<'tcx, 'mir>(
 
     let stacktrace = ecx.generate_stacktrace();
     let (stacktrace, was_pruned) = prune_stacktrace(stacktrace, &ecx.machine);
-    e.print_backtrace();
-    msg.insert(0, e.to_string());
+    let (e, backtrace) = e.into_parts();
+    backtrace.print_backtrace();
+
+    // We want to dump the allocation if this is `InvalidUninitBytes`. Since `add_args` consumes
+    // the `InterpError`, we extract the variables it before that.
+    let extra = match e {
+        UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some((alloc_id, access)))) => {
+            Some((alloc_id, access))
+        }
+        _ => None
+    };
+
+    // FIXME(fee1-dead), HACK: we want to use the error as title therefore we can just extract the
+    // label and arguments from the InterpError.
+    let e = {
+        let handler = &ecx.tcx.sess.parse_sess.span_diagnostic;
+        let mut diag = ecx.tcx.sess.struct_allow("");
+        let msg = e.diagnostic_message();
+        e.add_args(handler, &mut diag);
+        let s = handler.eagerly_translate_to_string(msg, diag.args());
+        diag.cancel();
+        s
+    };
+
+    msg.insert(0, e);
+
     report_msg(
         DiagLevel::Error,
         if let Some(title) = title { format!("{title}: {}", msg[0]) } else { msg[0].clone() },
@@ -332,15 +372,12 @@ pub fn report_error<'tcx, 'mir>(
     }
 
     // Extra output to help debug specific issues.
-    match e.kind() {
-        UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some((alloc_id, access)))) => {
-            eprintln!(
-                "Uninitialized memory occurred at {alloc_id:?}{range:?}, in this allocation:",
-                range = access.uninit,
-            );
-            eprintln!("{:?}", ecx.dump_alloc(*alloc_id));
-        }
-        _ => {}
+    if let Some((alloc_id, access)) = extra {
+        eprintln!(
+            "Uninitialized memory occurred at {alloc_id:?}{range:?}, in this allocation:",
+            range = access.uninit,
+        );
+        eprintln!("{:?}", ecx.dump_alloc(alloc_id));
     }
 
     None
@@ -438,12 +475,15 @@ pub fn report_msg<'tcx>(
         // Add visual separator before backtrace.
         err.note(if extra_span { "BACKTRACE (of the first span):" } else { "BACKTRACE:" });
     }
+
+    let (mut err, handler) = err.into_diagnostic().unwrap();
+    
     // Add backtrace
     for (idx, frame_info) in stacktrace.iter().enumerate() {
         let is_local = machine.is_local(frame_info);
         // No span for non-local frames and the first frame (which is the error site).
         if is_local && idx > 0 {
-            err.span_note(frame_info.span, frame_info.to_string());
+            err.eager_subdiagnostic(handler, frame_info.as_note(machine.tcx));
         } else {
             let sm = sess.source_map();
             let span = sm.span_to_embeddable_string(frame_info.span);
@@ -451,7 +491,7 @@ pub fn report_msg<'tcx>(
         }
     }
 
-    err.emit();
+    handler.emit_diagnostic(&mut err);
 }
 
 impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
diff --git a/src/tools/miri/src/eval.rs b/src/tools/miri/src/eval.rs
index 43d8f221ce3..1e9d48be65e 100644
--- a/src/tools/miri/src/eval.rs
+++ b/src/tools/miri/src/eval.rs
@@ -422,8 +422,9 @@ pub fn eval_entry<'tcx>(
     let mut ecx = match create_ecx(tcx, entry_id, entry_type, &config) {
         Ok(v) => v,
         Err(err) => {
-            err.print_backtrace();
-            panic!("Miri initialization error: {}", err.kind())
+            let (kind, backtrace) = err.into_parts();
+            backtrace.print_backtrace();
+            panic!("Miri initialization error: {kind:?}")
         }
     };
 
diff --git a/src/tools/miri/src/helpers.rs b/src/tools/miri/src/helpers.rs
index a2b49e6f219..f1190265239 100644
--- a/src/tools/miri/src/helpers.rs
+++ b/src/tools/miri/src/helpers.rs
@@ -164,9 +164,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         // We don't give a span -- this isn't actually used directly by the program anyway.
         let const_val = this
             .eval_global(cid, None)
-            .unwrap_or_else(|err| panic!("failed to evaluate required Rust item: {path:?}\n{err}"));
+            .unwrap_or_else(|err| panic!("failed to evaluate required Rust item: {path:?}\n{err:?}"));
         this.read_scalar(&const_val.into())
-            .unwrap_or_else(|err| panic!("failed to read required Rust item: {path:?}\n{err}"))
+            .unwrap_or_else(|err| panic!("failed to read required Rust item: {path:?}\n{err:?}"))
     }
 
     /// Helper function to get a `libc` constant as a `Scalar`.
diff --git a/src/tools/miri/src/lib.rs b/src/tools/miri/src/lib.rs
index 893a4dbd4c8..f711f01f323 100644
--- a/src/tools/miri/src/lib.rs
+++ b/src/tools/miri/src/lib.rs
@@ -43,6 +43,7 @@
 
 extern crate rustc_apfloat;
 extern crate rustc_ast;
+extern crate rustc_errors;
 #[macro_use]
 extern crate rustc_middle;
 extern crate rustc_const_eval;
diff --git a/src/tools/miri/tests/fail/intrinsics/copy_overlapping.rs b/src/tools/miri/tests/fail/intrinsics/copy_overlapping.rs
index 3df881bd43c..9c73bdc17be 100644
--- a/src/tools/miri/tests/fail/intrinsics/copy_overlapping.rs
+++ b/src/tools/miri/tests/fail/intrinsics/copy_overlapping.rs
@@ -10,6 +10,6 @@ fn main() {
     unsafe {
         let a = data.as_mut_ptr();
         let b = a.wrapping_offset(1) as *mut _;
-        copy_nonoverlapping(a, b, 2); //~ ERROR: copy_nonoverlapping called on overlapping ranges
+        copy_nonoverlapping(a, b, 2); //~ ERROR: `copy_nonoverlapping` called on overlapping ranges
     }
 }
diff --git a/src/tools/miri/tests/fail/intrinsics/copy_overlapping.stderr b/src/tools/miri/tests/fail/intrinsics/copy_overlapping.stderr
index cdb3da74ca9..13a76aae730 100644
--- a/src/tools/miri/tests/fail/intrinsics/copy_overlapping.stderr
+++ b/src/tools/miri/tests/fail/intrinsics/copy_overlapping.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: copy_nonoverlapping called on overlapping ranges
+error: Undefined Behavior: `copy_nonoverlapping` called on overlapping ranges
   --> $DIR/copy_overlapping.rs:LL:CC
    |
 LL |         copy_nonoverlapping(a, b, 2);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ copy_nonoverlapping called on overlapping ranges
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `copy_nonoverlapping` called on overlapping ranges
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.stderr
index a31b929d7a7..0b9cda62b33 100644
--- a/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.stderr
+++ b/src/tools/miri/tests/fail/intrinsics/ptr_offset_from_oob.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: out-of-bounds offset_from: ALLOC has size 4, so pointer at offset 10 is out-of-bounds
+error: Undefined Behavior: out-of-bounds `offset_from`: ALLOC has size 4, so pointer at offset 10 is out-of-bounds
   --> $DIR/ptr_offset_from_oob.rs:LL:CC
    |
 LL |     unsafe { end_ptr.offset_from(end_ptr) };
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds offset_from: ALLOC has size 4, so pointer at offset 10 is out-of-bounds
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds `offset_from`: ALLOC has size 4, so pointer at offset 10 is out-of-bounds
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/src/tools/miri/tests/fail/modifying_constants.rs b/src/tools/miri/tests/fail/modifying_constants.rs
index 2783ebd155f..40ba31dad8f 100644
--- a/src/tools/miri/tests/fail/modifying_constants.rs
+++ b/src/tools/miri/tests/fail/modifying_constants.rs
@@ -1,6 +1,8 @@
 // This should fail even without validation/SB
 //@compile-flags: -Zmiri-disable-validation -Zmiri-disable-stacked-borrows
 
+#![allow(cast_ref_to_mut)]
+
 fn main() {
     let x = &1; // the `&1` is promoted to a constant, but it used to be that only the pointer is marked static, not the pointee
     let y = unsafe { &mut *(x as *const i32 as *mut i32) };
diff --git a/src/tools/miri/tests/fail/stacked_borrows/shr_frozen_violation1.rs b/src/tools/miri/tests/fail/stacked_borrows/shr_frozen_violation1.rs
index d1322dc6e57..8cd59b3550d 100644
--- a/src/tools/miri/tests/fail/stacked_borrows/shr_frozen_violation1.rs
+++ b/src/tools/miri/tests/fail/stacked_borrows/shr_frozen_violation1.rs
@@ -1,3 +1,5 @@
+#![allow(cast_ref_to_mut)]
+
 fn foo(x: &mut i32) -> i32 {
     *x = 5;
     unknown_code(&*x);
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/builtin_attr.rs b/src/tools/rust-analyzer/crates/hir-def/src/builtin_attr.rs
index f7c1e683d0d..142b1229019 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/builtin_attr.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/builtin_attr.rs
@@ -196,10 +196,6 @@ pub const INERT_ATTRIBUTES: &[BuiltinAttribute] = &[
     ungated!(recursion_limit, CrateLevel, template!(NameValueStr: "N"), FutureWarnFollowing),
     ungated!(type_length_limit, CrateLevel, template!(NameValueStr: "N"), FutureWarnFollowing),
     gated!(
-        const_eval_limit, CrateLevel, template!(NameValueStr: "N"), ErrorFollowing,
-        const_eval_limit, experimental!(const_eval_limit)
-    ),
-    gated!(
         move_size_limit, CrateLevel, template!(NameValueStr: "N"), ErrorFollowing,
         large_assignments, experimental!(move_size_limit)
     ),
diff --git a/src/tools/rust-installer/combine-installers.sh b/src/tools/rust-installer/combine-installers.sh
index bee5319fd55..01e5a00af4a 100755
--- a/src/tools/rust-installer/combine-installers.sh
+++ b/src/tools/rust-installer/combine-installers.sh
@@ -11,5 +11,9 @@ abs_path() {
     (unset CDPATH && cd "$path" > /dev/null && pwd)
 }
 
+# Running cargo will read the libstd Cargo.toml
+# which uses the unstable `public-dependency` feature.
+export RUSTC_BOOTSTRAP=1
+
 src_dir="$(abs_path $(dirname "$0"))"
 $CARGO run --manifest-path="$src_dir/Cargo.toml" -- combine "$@"
diff --git a/src/tools/rust-installer/gen-installer.sh b/src/tools/rust-installer/gen-installer.sh
index eabd8c95cd8..cc45b5e0803 100755
--- a/src/tools/rust-installer/gen-installer.sh
+++ b/src/tools/rust-installer/gen-installer.sh
@@ -11,5 +11,9 @@ abs_path() {
     (unset CDPATH && cd "$path" > /dev/null && pwd)
 }
 
+# Running cargo will read the libstd Cargo.toml
+# which uses the unstable `public-dependency` feature.
+export RUSTC_BOOTSTRAP=1
+
 src_dir="$(abs_path $(dirname "$0"))"
 $CARGO run --manifest-path="$src_dir/Cargo.toml" -- generate "$@"
diff --git a/src/tools/rust-installer/make-tarballs.sh b/src/tools/rust-installer/make-tarballs.sh
index e342007da37..374e103e89c 100755
--- a/src/tools/rust-installer/make-tarballs.sh
+++ b/src/tools/rust-installer/make-tarballs.sh
@@ -11,5 +11,9 @@ abs_path() {
     (unset CDPATH && cd "$path" > /dev/null && pwd)
 }
 
+# Running cargo will read the libstd Cargo.toml
+# which uses the unstable `public-dependency` feature.
+export RUSTC_BOOTSTRAP=1
+
 src_dir="$(abs_path $(dirname "$0"))"
 $CARGO run --manifest-path="$src_dir/Cargo.toml" -- tarball "$@"
diff --git a/src/tools/tidy/src/main.rs b/src/tools/tidy/src/main.rs
index 1c4d96c321c..e21068490b6 100644
--- a/src/tools/tidy/src/main.rs
+++ b/src/tools/tidy/src/main.rs
@@ -16,6 +16,12 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::thread::{self, scope, ScopedJoinHandle};
 
 fn main() {
+    // Running Cargo will read the libstd Cargo.toml
+    // which uses the unstable `public-dependency` feature.
+    //
+    // `setenv` might not be thread safe, so run it before using multiple threads.
+    env::set_var("RUSTC_BOOTSTRAP", "1");
+
     let root_path: PathBuf = env::args_os().nth(1).expect("need path to root of repo").into();
     let cargo: PathBuf = env::args_os().nth(2).expect("need path to cargo").into();
     let output_directory: PathBuf =