Rollup merge of rust-lang#136890 - saethlin:swap_nonoverlapping, r=RalfJung

GuillaumeGomez · gitbot · commit bf0be1b4f5c2 · 2025-03-11T09:46:29.000Z
Change swap_nonoverlapping from lang to library UB The implementation of ptr::swap_nonoverlapping does not always escalate its safety contract to language UB, so it should be `check_library_ub`. Fixes rust-lang/miri#4188
diff --git a/core/src/ptr/mod.rs b/core/src/ptr/mod.rs
@@ -1070,7 +1070,7 @@ pub const unsafe fn swap<T>(x: *mut T, y: *mut T) {
 #[rustc_diagnostic_item = "ptr_swap_nonoverlapping"]
 pub const unsafe fn swap_nonoverlapping<T>(x: *mut T, y: *mut T, count: usize) {
     ub_checks::assert_unsafe_precondition!(
-        check_language_ub,
+        check_library_ub,
         "ptr::swap_nonoverlapping requires that both pointer arguments are aligned and non-null \
         and the specified memory ranges do not overlap",
         (

Original file line number	Diff line number	Diff line change
`@@ -1070,7 +1070,7 @@ pub const unsafe fn swap<T>(x: mut T, y: mut T) {`
`1070`	`1070`	`#[rustc_diagnostic_item = "ptr_swap_nonoverlapping"]`
`1071`	`1071`	`pub const unsafe fn swap_nonoverlapping<T>(x: mut T, y: mut T, count: usize) {`
`1072`	`1072`	`ub_checks::assert_unsafe_precondition!(`
`1073`		`- check_language_ub,`
	`1073`	`+ check_library_ub,`
`1074`	`1074`	`"ptr::swap_nonoverlapping requires that both pointer arguments are aligned and non-null \`
`1075`	`1075`	`and the specified memory ranges do not overlap",`
`1076`	`1076`	`(`