Added deny(const_eval_mutable_ptr_in_final_value) attribute to all tests that were expecting the hard error for it.

I attempted to do this in a manner that preserved the line numbers to reduce the
review effort on the resulting diff, but we still have to deal with the
ramifications of how a future-incompat lint behaves compared to a hard-error (in
terms of its impact on the diagnostic output).

(cherry picked from commit 1c3424b)

Author: pnkfelix

tests/ui/consts/const-eval/heap/alloc_intrinsic_untyped.rs

@@ -1,9 +1,11 @@
 #![feature(core_intrinsics)]
 #![feature(const_heap)]
 #![feature(const_mut_refs)]
+#![deny(const_eval_mutable_ptr_in_final_value)]
 use std::intrinsics;
 
 const BAR: *mut i32 = unsafe { intrinsics::const_allocate(4, 4) as *mut i32 };
 //~^ error: mutable pointer in final value of constant
+//~| WARNING this was previously accepted by the compiler
 
 fn main() {}

tests/ui/consts/const-eval/heap/alloc_intrinsic_untyped.stderr

@@ -1,8 +1,31 @@
 error: encountered mutable pointer in final value of constant
-  --> $DIR/alloc_intrinsic_untyped.rs:6:1
+  --> $DIR/alloc_intrinsic_untyped.rs:7:1
    |
 LL | const BAR: *mut i32 = unsafe { intrinsics::const_allocate(4, 4) as *mut i32 };
    | ^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/alloc_intrinsic_untyped.rs:4:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error
 
+Future incompatibility report: Future breakage diagnostic:
+error: encountered mutable pointer in final value of constant
+  --> $DIR/alloc_intrinsic_untyped.rs:7:1
+   |
+LL | const BAR: *mut i32 = unsafe { intrinsics::const_allocate(4, 4) as *mut i32 };
+   | ^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/alloc_intrinsic_untyped.rs:4:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+

tests/ui/consts/miri_unleashed/mutable_references_err.32bit.stderr

@@ -1,7 +1,7 @@
 // stderr-per-bitwidth
 // compile-flags: -Zunleash-the-miri-inside-of-you
 #![allow(invalid_reference_casting, static_mut_refs)]
-
+#![deny(const_eval_mutable_ptr_in_final_value)]
 use std::cell::UnsafeCell;
 use std::sync::atomic::*;
 
@@ -16,6 +16,8 @@ unsafe impl Sync for Meh {}
 // all allocs interned here will be marked immutable.
 const MUH: Meh = Meh {
     //~^ ERROR encountered mutable pointer in final value of constant
+    //~| WARNING this was previously accepted by the compiler
+    //~| ERROR: it is undefined behavior to use this value
     x: &UnsafeCell::new(42),
 };
 
@@ -27,14 +29,19 @@ unsafe impl Sync for Synced {}
 // Make sure we also catch this behind a type-erased `dyn Trait` reference.
 const SNEAKY: &dyn Sync = &Synced { x: UnsafeCell::new(42) };
 //~^ ERROR: mutable pointer in final value
+//~| WARNING this was previously accepted by the compiler
+//~| ERROR it is undefined behavior to use this value
 
 // Make sure we also catch mutable references in values that shouldn't have them.
 static mut FOO: i32 = 0;
 const SUBTLE: &mut i32 = unsafe { &mut FOO };
 //~^ ERROR: it is undefined behavior to use this value
 //~| static
+
 const BLUNT: &mut i32 = &mut 42;
 //~^ ERROR: mutable pointer in final value
+//~| WARNING this was previously accepted by the compiler
+//~| ERROR it is undefined behavior to use this value
 
 // Check for mutable references to read-only memory.
 static READONLY: i32 = 0;
@@ -55,10 +62,15 @@ const POINTS_TO_MUTABLE2: &i32 = unsafe { &*MUTABLE_REF };
 
 const POINTS_TO_MUTABLE_INNER: *const i32 = &mut 42 as *mut _ as *const _;
 //~^ ERROR: mutable pointer in final value
+//~| WARNING this was previously accepted by the compiler
+
 const POINTS_TO_MUTABLE_INNER2: *const i32 = &mut 42 as *const _;
 //~^ ERROR: mutable pointer in final value
+//~| WARNING this was previously accepted by the compiler
+
 const INTERIOR_MUTABLE_BEHIND_RAW: *mut i32 = &UnsafeCell::new(42) as *const _ as *mut _;
 //~^ ERROR: mutable pointer in final value
+//~| WARNING this was previously accepted by the compiler
 
 struct SyncPtr<T> {
     x: *const T,
@@ -71,10 +83,15 @@ unsafe impl<T> Sync for SyncPtr<T> {}
 // (Also see `static-no-inner-mut` for similar tests on `static`.)
 const RAW_SYNC: SyncPtr<AtomicI32> = SyncPtr { x: &AtomicI32::new(42) };
 //~^ ERROR mutable pointer in final value
+//~| WARNING this was previously accepted by the compiler
+
 const RAW_MUT_CAST: SyncPtr<i32> = SyncPtr { x: &mut 42 as *mut _ as *const _ };
 //~^ ERROR mutable pointer in final value
+//~| WARNING this was previously accepted by the compiler
+
 const RAW_MUT_COERCE: SyncPtr<i32> = SyncPtr { x: &mut 0 };
 //~^ ERROR mutable pointer in final value
+//~| WARNING this was previously accepted by the compiler
 
 fn main() {
     unsafe {

tests/ui/consts/miri_unleashed/mutable_references_err.64bit.stderr

@@ -3,42 +3,112 @@ error: encountered mutable pointer in final value of static
    |
 LL | static REF: &AtomicI32 = &AtomicI32::new(42);
    | ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/static-no-inner-mut.rs:6:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/static-no-inner-mut.rs:9:1
+   |
+LL | static REF: &AtomicI32 = &AtomicI32::new(42);
+   | ^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>.v: encountered `UnsafeCell` in read-only memory
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 4, align: 4) {
+               ╾ALLOC0╼                                     │ ╾──╼
+           }
 
 error: encountered mutable pointer in final value of static
-  --> $DIR/static-no-inner-mut.rs:10:1
+  --> $DIR/static-no-inner-mut.rs:14:1
    |
 LL | static REFMUT: &mut i32 = &mut 0;
    | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/static-no-inner-mut.rs:14:1
+   |
+LL | static REFMUT: &mut i32 = &mut 0;
+   | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered mutable reference in a `const` or `static`
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 4, align: 4) {
+               ╾ALLOC1╼                                     │ ╾──╼
+           }
 
 error: encountered mutable pointer in final value of static
-  --> $DIR/static-no-inner-mut.rs:13:1
+  --> $DIR/static-no-inner-mut.rs:20:1
    |
 LL | static REF2: &AtomicI32 = {let x = AtomicI32::new(42); &{x}};
    | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/static-no-inner-mut.rs:20:1
+   |
+LL | static REF2: &AtomicI32 = {let x = AtomicI32::new(42); &{x}};
+   | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<deref>.v: encountered `UnsafeCell` in read-only memory
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 4, align: 4) {
+               ╾ALLOC2╼                                     │ ╾──╼
+           }
 
 error: encountered mutable pointer in final value of static
-  --> $DIR/static-no-inner-mut.rs:14:1
+  --> $DIR/static-no-inner-mut.rs:25:1
    |
 LL | static REFMUT2: &mut i32 = {let mut x = 0; &mut {x}};
    | ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/static-no-inner-mut.rs:25:1
+   |
+LL | static REFMUT2: &mut i32 = {let mut x = 0; &mut {x}};
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered mutable reference in a `const` or `static`
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+   = note: the raw bytes of the constant (size: 4, align: 4) {
+               ╾ALLOC3╼                                     │ ╾──╼
+           }
 
 error: encountered mutable pointer in final value of static
-  --> $DIR/static-no-inner-mut.rs:29:1
+  --> $DIR/static-no-inner-mut.rs:43:1
    |
 LL | static RAW_SYNC: SyncPtr<AtomicI32> = SyncPtr { x: &AtomicI32::new(42) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
 
 error: encountered mutable pointer in final value of static
-  --> $DIR/static-no-inner-mut.rs:31:1
+  --> $DIR/static-no-inner-mut.rs:47:1
    |
 LL | static RAW_MUT_CAST: SyncPtr<i32> = SyncPtr { x : &mut 42 as *mut _ as *const _ };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
 
 error: encountered mutable pointer in final value of static
-  --> $DIR/static-no-inner-mut.rs:33:1
+  --> $DIR/static-no-inner-mut.rs:51:1
    |
 LL | static RAW_MUT_COERCE: SyncPtr<i32> = SyncPtr { x: &mut 0 };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
 
 warning: skipping const checks
    |
@@ -48,35 +118,141 @@ help: skipping check that does not even have a feature gate
 LL | static REF: &AtomicI32 = &AtomicI32::new(42);
    |                          ^^^^^^^^^^^^^^^^^^^
 help: skipping check that does not even have a feature gate
-  --> $DIR/static-no-inner-mut.rs:10:27
+  --> $DIR/static-no-inner-mut.rs:14:27
    |
 LL | static REFMUT: &mut i32 = &mut 0;
    |                           ^^^^^^
 help: skipping check that does not even have a feature gate
-  --> $DIR/static-no-inner-mut.rs:13:56
+  --> $DIR/static-no-inner-mut.rs:20:56
    |
 LL | static REF2: &AtomicI32 = {let x = AtomicI32::new(42); &{x}};
    |                                                        ^^^^
 help: skipping check that does not even have a feature gate
-  --> $DIR/static-no-inner-mut.rs:14:44
+  --> $DIR/static-no-inner-mut.rs:25:44
    |
 LL | static REFMUT2: &mut i32 = {let mut x = 0; &mut {x}};
    |                                            ^^^^^^^^
 help: skipping check that does not even have a feature gate
-  --> $DIR/static-no-inner-mut.rs:29:52
+  --> $DIR/static-no-inner-mut.rs:43:52
    |
 LL | static RAW_SYNC: SyncPtr<AtomicI32> = SyncPtr { x: &AtomicI32::new(42) };
    |                                                    ^^^^^^^^^^^^^^^^^^^
 help: skipping check that does not even have a feature gate
-  --> $DIR/static-no-inner-mut.rs:31:51
+  --> $DIR/static-no-inner-mut.rs:47:51
    |
 LL | static RAW_MUT_CAST: SyncPtr<i32> = SyncPtr { x : &mut 42 as *mut _ as *const _ };
    |                                                   ^^^^^^^
 help: skipping check that does not even have a feature gate
-  --> $DIR/static-no-inner-mut.rs:33:52
+  --> $DIR/static-no-inner-mut.rs:51:52
    |
 LL | static RAW_MUT_COERCE: SyncPtr<i32> = SyncPtr { x: &mut 0 };
    |                                                    ^^^^^^
 
-error: aborting due to 7 previous errors; 1 warning emitted
+error: aborting due to 11 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0080`.
+Future incompatibility report: Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/static-no-inner-mut.rs:9:1
+   |
+LL | static REF: &AtomicI32 = &AtomicI32::new(42);
+   | ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/static-no-inner-mut.rs:6:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/static-no-inner-mut.rs:14:1
+   |
+LL | static REFMUT: &mut i32 = &mut 0;
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/static-no-inner-mut.rs:6:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/static-no-inner-mut.rs:20:1
+   |
+LL | static REF2: &AtomicI32 = {let x = AtomicI32::new(42); &{x}};
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/static-no-inner-mut.rs:6:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/static-no-inner-mut.rs:25:1
+   |
+LL | static REFMUT2: &mut i32 = {let mut x = 0; &mut {x}};
+   | ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/static-no-inner-mut.rs:6:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/static-no-inner-mut.rs:43:1
+   |
+LL | static RAW_SYNC: SyncPtr<AtomicI32> = SyncPtr { x: &AtomicI32::new(42) };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/static-no-inner-mut.rs:6:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/static-no-inner-mut.rs:47:1
+   |
+LL | static RAW_MUT_CAST: SyncPtr<i32> = SyncPtr { x : &mut 42 as *mut _ as *const _ };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/static-no-inner-mut.rs:6:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Future breakage diagnostic:
+error: encountered mutable pointer in final value of static
+  --> $DIR/static-no-inner-mut.rs:51:1
+   |
+LL | static RAW_MUT_COERCE: SyncPtr<i32> = SyncPtr { x: &mut 0 };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #122153 <https://github.com/rust-lang/rust/issues/122153>
+note: the lint level is defined here
+  --> $DIR/static-no-inner-mut.rs:6:9
+   |
+LL | #![deny(const_eval_mutable_ptr_in_final_value)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^