Auto merge of #86003 - pnkfelix:issue-84297-revert-81238, r=Mark-Simulacrum

Make copy/copy_nonoverlapping fn's again

Make copy/copy_nonoverlapping fn's again, rather than intrinsics.

This a short-term change to address issue #84297.

It effectively reverts PRs #81167 #81238 (and part of #82967), #83091, and parts of #79684.

9 files changed, 25 insertions, 198 deletions

diff --git a/src/test/ui/const-ptr/out_of_bounds_read.rs b/src/test/ui/const-ptr/out_of_bounds_read.rs
deleted file mode 100644
index 183aa9e5122..00000000000
--- a/src/test/ui/const-ptr/out_of_bounds_read.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-// error-pattern: any use of this value will cause an error
-
-#![feature(const_ptr_read)]
-#![feature(const_ptr_offset)]
-
-fn main() {
-    use std::ptr;
-
-    const DATA: [u32; 1] = [42];
-
-    const PAST_END_PTR: *const u32 = unsafe { DATA.as_ptr().add(1) };
-
-    const _READ: u32 = unsafe { ptr::read(PAST_END_PTR) };
-    const _CONST_READ: u32 = unsafe { PAST_END_PTR.read() };
-    const _MUT_READ: u32 = unsafe { (PAST_END_PTR as *mut u32).read() };
-}
diff --git a/src/test/ui/const-ptr/out_of_bounds_read.stderr b/src/test/ui/const-ptr/out_of_bounds_read.stderr
deleted file mode 100644
index 6c4092e3e5c..00000000000
--- a/src/test/ui/const-ptr/out_of_bounds_read.stderr
+++ /dev/null
@@ -1,59 +0,0 @@
-error: any use of this value will cause an error
-  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-   |
-LL |         copy_nonoverlapping(src, tmp.as_mut_ptr(), 1);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |         |
-   |         memory access failed: pointer must be in-bounds at offset 8, but is outside bounds of alloc6 which has size 4
-   |         inside `std::ptr::read::<u32>` at $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-   |         inside `_READ` at $DIR/out_of_bounds_read.rs:13:33
-   | 
-  ::: $DIR/out_of_bounds_read.rs:13:5
-   |
-LL |     const _READ: u32 = unsafe { ptr::read(PAST_END_PTR) };
-   |     ------------------------------------------------------
-   |
-   = note: `#[deny(const_err)]` on by default
-   = 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 #71800 <https://github.com/rust-lang/rust/issues/71800>
-
-error: any use of this value will cause an error
-  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-   |
-LL |         copy_nonoverlapping(src, tmp.as_mut_ptr(), 1);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |         |
-   |         memory access failed: pointer must be in-bounds at offset 8, but is outside bounds of alloc6 which has size 4
-   |         inside `std::ptr::read::<u32>` at $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-   |         inside `ptr::const_ptr::<impl *const u32>::read` at $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
-   |         inside `_CONST_READ` at $DIR/out_of_bounds_read.rs:14:39
-   | 
-  ::: $DIR/out_of_bounds_read.rs:14:5
-   |
-LL |     const _CONST_READ: u32 = unsafe { PAST_END_PTR.read() };
-   |     --------------------------------------------------------
-   |
-   = 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 #71800 <https://github.com/rust-lang/rust/issues/71800>
-
-error: any use of this value will cause an error
-  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-   |
-LL |         copy_nonoverlapping(src, tmp.as_mut_ptr(), 1);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |         |
-   |         memory access failed: pointer must be in-bounds at offset 8, but is outside bounds of alloc6 which has size 4
-   |         inside `std::ptr::read::<u32>` at $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-   |         inside `ptr::mut_ptr::<impl *mut u32>::read` at $SRC_DIR/core/src/ptr/mut_ptr.rs:LL:COL
-   |         inside `_MUT_READ` at $DIR/out_of_bounds_read.rs:15:37
-   | 
-  ::: $DIR/out_of_bounds_read.rs:15:5
-   |
-LL |     const _MUT_READ: u32 = unsafe { (PAST_END_PTR as *mut u32).read() };
-   |     --------------------------------------------------------------------
-   |
-   = 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 #71800 <https://github.com/rust-lang/rust/issues/71800>
-
-error: aborting due to 3 previous errors
-
diff --git a/src/test/ui/consts/copy-intrinsic.rs b/src/test/ui/consts/copy-intrinsic.rs
deleted file mode 100644
index 9dc595f37fa..00000000000
--- a/src/test/ui/consts/copy-intrinsic.rs
+++ /dev/null
@@ -1,45 +0,0 @@
-// ignore-tidy-linelength
-#![feature(const_mut_refs, const_intrinsic_copy, const_ptr_offset)]
-use std::{ptr, mem};
-
-const COPY_ZERO: () = unsafe {
-    // Since we are not copying anything, this should be allowed.
-    let src = ();
-    let mut dst = ();
-    ptr::copy_nonoverlapping(&src as *const _ as *const i32, &mut dst as *mut _ as *mut i32, 0);
-};
-
-const COPY_OOB_1: () = unsafe {
-    let mut x = 0i32;
-    let dangle = (&mut x as *mut i32).wrapping_add(10);
-    // Even if the first ptr is an int ptr and this is a ZST copy, we should detect dangling 2nd ptrs.
-    ptr::copy_nonoverlapping(0x100 as *const i32, dangle, 0); //~ ERROR any use of this value will cause an error
-    //~| memory access failed: pointer must be in-bounds
-    //~| previously accepted
-};
-const COPY_OOB_2: () = unsafe {
-    let x = 0i32;
-    let dangle = (&x as *const i32).wrapping_add(10);
-    // Even if the second ptr is an int ptr and this is a ZST copy, we should detect dangling 1st ptrs.
-    ptr::copy_nonoverlapping(dangle, 0x100 as *mut i32, 0); //~ ERROR any use of this value will cause an error
-    //~| memory access failed: pointer must be in-bounds
-    //~| previously accepted
-};
-
-const COPY_SIZE_OVERFLOW: () = unsafe {
-    let x = 0;
-    let mut y = 0;
-    ptr::copy(&x, &mut y, 1usize << (mem::size_of::<usize>() * 8 - 1)); //~ ERROR any use of this value will cause an error
-    //~| overflow computing total size of `copy`
-    //~| previously accepted
-};
-const COPY_NONOVERLAPPING_SIZE_OVERFLOW: () = unsafe {
-    let x = 0;
-    let mut y = 0;
-    ptr::copy_nonoverlapping(&x, &mut y, 1usize << (mem::size_of::<usize>() * 8 - 1)); //~ ERROR any use of this value will cause an error
-    //~| overflow computing total size of `copy_nonoverlapping`
-    //~| previously accepted
-};
-
-fn main() {
-}
diff --git a/src/test/ui/consts/copy-intrinsic.stderr b/src/test/ui/consts/copy-intrinsic.stderr
deleted file mode 100644
index 2736cdeac69..00000000000
--- a/src/test/ui/consts/copy-intrinsic.stderr
+++ /dev/null
@@ -1,69 +0,0 @@
-error: any use of this value will cause an error
-  --> $DIR/copy-intrinsic.rs:16:5
-   |
-LL | / const COPY_OOB_1: () = unsafe {
-LL | |     let mut x = 0i32;
-LL | |     let dangle = (&mut x as *mut i32).wrapping_add(10);
-LL | |     // Even if the first ptr is an int ptr and this is a ZST copy, we should detect dangling 2nd ptrs.
-LL | |     ptr::copy_nonoverlapping(0x100 as *const i32, dangle, 0);
-   | |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: pointer must be in-bounds at offset 40, but is outside bounds of alloc4 which has size 4
-LL | |
-LL | |
-LL | | };
-   | |__-
-   |
-   = note: `#[deny(const_err)]` on by default
-   = 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 #71800 <https://github.com/rust-lang/rust/issues/71800>
-
-error: any use of this value will cause an error
-  --> $DIR/copy-intrinsic.rs:24:5
-   |
-LL | / const COPY_OOB_2: () = unsafe {
-LL | |     let x = 0i32;
-LL | |     let dangle = (&x as *const i32).wrapping_add(10);
-LL | |     // Even if the second ptr is an int ptr and this is a ZST copy, we should detect dangling 1st ptrs.
-LL | |     ptr::copy_nonoverlapping(dangle, 0x100 as *mut i32, 0);
-   | |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: pointer must be in-bounds at offset 40, but is outside bounds of alloc6 which has size 4
-LL | |
-LL | |
-LL | | };
-   | |__-
-   |
-   = 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 #71800 <https://github.com/rust-lang/rust/issues/71800>
-
-error: any use of this value will cause an error
-  --> $DIR/copy-intrinsic.rs:32:5
-   |
-LL | / const COPY_SIZE_OVERFLOW: () = unsafe {
-LL | |     let x = 0;
-LL | |     let mut y = 0;
-LL | |     ptr::copy(&x, &mut y, 1usize << (mem::size_of::<usize>() * 8 - 1));
-   | |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow computing total size of `copy`
-LL | |
-LL | |
-LL | | };
-   | |__-
-   |
-   = 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 #71800 <https://github.com/rust-lang/rust/issues/71800>
-
-error: any use of this value will cause an error
-  --> $DIR/copy-intrinsic.rs:39:5
-   |
-LL | / const COPY_NONOVERLAPPING_SIZE_OVERFLOW: () = unsafe {
-LL | |     let x = 0;
-LL | |     let mut y = 0;
-LL | |     ptr::copy_nonoverlapping(&x, &mut y, 1usize << (mem::size_of::<usize>() * 8 - 1));
-   | |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ overflow computing total size of `copy_nonoverlapping`
-LL | |
-LL | |
-LL | | };
-   | |__-
-   |
-   = 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 #71800 <https://github.com/rust-lang/rust/issues/71800>
-
-error: aborting due to 4 previous errors
-
diff --git a/src/test/ui/intrinsics/issue-84297-reifying-copy.rs b/src/test/ui/intrinsics/issue-84297-reifying-copy.rs
new file mode 100644
index 00000000000..08ba9ce7ecb
--- /dev/null
+++ b/src/test/ui/intrinsics/issue-84297-reifying-copy.rs
@@ -0,0 +1,9 @@
+// check-pass
+
+fn main() {
+    let _unused = if true {
+        core::ptr::copy::<i32>
+    } else {
+        core::ptr::copy_nonoverlapping::<i32>
+    };
+}
diff --git a/src/test/ui/reify-intrinsic.rs b/src/test/ui/reify-intrinsic.rs
index 05535b92cca..9eb2f724017 100644
--- a/src/test/ui/reify-intrinsic.rs
+++ b/src/test/ui/reify-intrinsic.rs
@@ -1,6 +1,6 @@
 // check-fail
 
-#![feature(intrinsics)]
+#![feature(core_intrinsics, intrinsics)]
 
 fn a() {
     let _: unsafe extern "rust-intrinsic" fn(isize) -> usize = std::mem::transmute;
@@ -14,8 +14,8 @@ fn b() {
 
 fn c() {
     let _ = [
-        std::intrinsics::copy_nonoverlapping::<i32>,
-        std::intrinsics::copy::<i32>,
+        std::intrinsics::likely,
+        std::intrinsics::unlikely,
         //~^ ERROR cannot coerce
     ];
 }
diff --git a/src/test/ui/reify-intrinsic.stderr b/src/test/ui/reify-intrinsic.stderr
index 5d82fdbd311..69c11b5c56f 100644
--- a/src/test/ui/reify-intrinsic.stderr
+++ b/src/test/ui/reify-intrinsic.stderr
@@ -22,11 +22,11 @@ LL |     let _ = std::mem::transmute as unsafe extern "rust-intrinsic" fn(isize)
 error[E0308]: cannot coerce intrinsics to function pointers
   --> $DIR/reify-intrinsic.rs:18:9
    |
-LL |         std::intrinsics::copy::<i32>,
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot coerce intrinsics to function pointers
+LL |         std::intrinsics::unlikely,
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^ cannot coerce intrinsics to function pointers
    |
-   = note: expected type `unsafe extern "rust-intrinsic" fn(_, _, _) {copy_nonoverlapping::<i32>}`
-           found fn item `unsafe extern "rust-intrinsic" fn(_, _, _) {std::intrinsics::copy::<i32>}`
+   = note: expected type `extern "rust-intrinsic" fn(_) -> _ {likely}`
+           found fn item `extern "rust-intrinsic" fn(_) -> _ {unlikely}`
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/thread-local-static.rs b/src/test/ui/thread-local-static.rs
index c7fee9e6b4c..dc542fe2db9 100644
--- a/src/test/ui/thread-local-static.rs
+++ b/src/test/ui/thread-local-static.rs
@@ -11,6 +11,7 @@ const fn g(x: &mut [u32; 8]) {
     //~| ERROR mutable references are not allowed
     //~| ERROR use of mutable static is unsafe
     //~| constant functions cannot refer to statics
+    //~| ERROR calls in constant functions are limited to constant functions
 }
 
 fn main() {}
diff --git a/src/test/ui/thread-local-static.stderr b/src/test/ui/thread-local-static.stderr
index 08bf593a5a7..a213282eb85 100644
--- a/src/test/ui/thread-local-static.stderr
+++ b/src/test/ui/thread-local-static.stderr
@@ -30,6 +30,12 @@ LL |     std::mem::swap(x, &mut STATIC_VAR_2)
    = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
 
+error[E0015]: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+  --> $DIR/thread-local-static.rs:9:5
+   |
+LL |     std::mem::swap(x, &mut STATIC_VAR_2)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 error[E0133]: use of mutable static is unsafe and requires unsafe function or block
   --> $DIR/thread-local-static.rs:9:23
    |
@@ -38,7 +44,7 @@ LL |     std::mem::swap(x, &mut STATIC_VAR_2)
    |
    = note: mutable statics can be mutated by multiple threads: aliasing violations or data races will cause undefined behavior
 
-error: aborting due to 5 previous errors
+error: aborting due to 6 previous errors
 
-Some errors have detailed explanations: E0013, E0133, E0658.
+Some errors have detailed explanations: E0013, E0015, E0133, E0658.
 For more information about an error, try `rustc --explain E0013`.