diff --git a/compiler/rustc_mir_transform/src/check_packed_ref.rs b/compiler/rustc_mir_transform/src/check_packed_ref.rs index c6661e9c74e9b..23d59c8007135 100644 --- a/compiler/rustc_mir_transform/src/check_packed_ref.rs +++ b/compiler/rustc_mir_transform/src/check_packed_ref.rs @@ -105,6 +105,11 @@ impl<'tcx> Visitor<'tcx> for PackedRefChecker<'_, 'tcx> { a misaligned reference is undefined behavior (even if that \ reference is never dereferenced)", ) + .help( + "copy the field contents to a local variable, or replace the \ + reference with a raw pointer and use `read_unaligned`/`write_unaligned` \ + (loads and stores via `*p` must be properly aligned even when using raw pointers)" + ) .emit() }, ); diff --git a/src/test/ui/binding/issue-53114-safety-checks.stderr b/src/test/ui/binding/issue-53114-safety-checks.stderr index 9e7deea4524cb..84cdb1453f82d 100644 --- a/src/test/ui/binding/issue-53114-safety-checks.stderr +++ b/src/test/ui/binding/issue-53114-safety-checks.stderr @@ -8,6 +8,7 @@ LL | let _ = &p.b; = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) warning: reference to packed field is unaligned --> $DIR/issue-53114-safety-checks.rs:29:17 @@ -18,6 +19,7 @@ LL | let (_,) = (&p.b,); = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) warning: reference to packed field is unaligned --> $DIR/issue-53114-safety-checks.rs:39:11 @@ -28,6 +30,7 @@ LL | match &p.b { _ => { } } = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) warning: reference to packed field is unaligned --> $DIR/issue-53114-safety-checks.rs:45:12 @@ -38,6 +41,7 @@ LL | match (&p.b,) { (_,) => { } } = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error[E0133]: access to union field is unsafe and requires unsafe function or block --> $DIR/issue-53114-safety-checks.rs:26:13 diff --git a/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.stderr b/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.stderr index 5acf3797ab53f..fc0179d2cb4ca 100644 --- a/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.stderr +++ b/src/test/ui/closures/2229_closure_analysis/diagnostics/repr_packed.stderr @@ -8,6 +8,7 @@ LL | println!("{}", foo.x); = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release! = note: for more information, see issue #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) = note: this warning originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info) warning: 1 warning emitted diff --git a/src/test/ui/lint/unaligned_references.stderr b/src/test/ui/lint/unaligned_references.stderr index 6a5cc91963da0..53c9380fb7efb 100644 --- a/src/test/ui/lint/unaligned_references.stderr +++ b/src/test/ui/lint/unaligned_references.stderr @@ -12,6 +12,7 @@ LL | #![deny(unaligned_references)] = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: reference to packed field is unaligned --> $DIR/unaligned_references.rs:24:17 @@ -22,6 +23,7 @@ LL | let _ = &good.data; = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: reference to packed field is unaligned --> $DIR/unaligned_references.rs:27:17 @@ -32,6 +34,7 @@ LL | let _ = &good.data 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: reference to packed field is unaligned --> $DIR/unaligned_references.rs:29:27 @@ -42,6 +45,7 @@ LL | let _: *const _ = &good.data; = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: reference to packed field is unaligned --> $DIR/unaligned_references.rs:32:17 @@ -52,6 +56,7 @@ LL | let _ = good.data.clone(); = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: reference to packed field is unaligned --> $DIR/unaligned_references.rs:35:17 @@ -62,6 +67,7 @@ LL | let _ = &good.data2[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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: reference to packed field is unaligned --> $DIR/unaligned_references.rs:45:17 @@ -72,6 +78,7 @@ LL | let _ = &packed2.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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: aborting due to 7 previous errors diff --git a/src/test/ui/lint/unaligned_references_external_macro.stderr b/src/test/ui/lint/unaligned_references_external_macro.stderr index 5e84fdca1d3ce..01e2395049df4 100644 --- a/src/test/ui/lint/unaligned_references_external_macro.stderr +++ b/src/test/ui/lint/unaligned_references_external_macro.stderr @@ -24,6 +24,7 @@ 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) = note: this error originates in the macro `unaligned_references_external_crate::mac` (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to previous error diff --git a/src/test/ui/packed/issue-27060.stderr b/src/test/ui/packed/issue-27060.stderr index 09297884ed377..bba056d59f831 100644 --- a/src/test/ui/packed/issue-27060.stderr +++ b/src/test/ui/packed/issue-27060.stderr @@ -12,6 +12,7 @@ LL | #[deny(unaligned_references)] = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: reference to packed field is unaligned --> $DIR/issue-27060.rs:18:13 @@ -22,6 +23,7 @@ LL | let _ = &good.data2[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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: reference to packed field is unaligned --> $DIR/issue-27060.rs:21:13 @@ -32,6 +34,7 @@ LL | let _ = &good.data; = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: reference to packed field is unaligned --> $DIR/issue-27060.rs:23:13 @@ -42,6 +45,7 @@ LL | let _ = &good.data2[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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) error: aborting due to 4 previous errors diff --git a/src/test/ui/packed/packed-struct-borrow-element-64bit.stderr b/src/test/ui/packed/packed-struct-borrow-element-64bit.stderr index 766d8a72c349e..04585b499862b 100644 --- a/src/test/ui/packed/packed-struct-borrow-element-64bit.stderr +++ b/src/test/ui/packed/packed-struct-borrow-element-64bit.stderr @@ -8,6 +8,7 @@ LL | let brw = &foo.baz; = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) warning: 1 warning emitted diff --git a/src/test/ui/packed/packed-struct-borrow-element.stderr b/src/test/ui/packed/packed-struct-borrow-element.stderr index 5764e951a4600..a50b130200151 100644 --- a/src/test/ui/packed/packed-struct-borrow-element.stderr +++ b/src/test/ui/packed/packed-struct-borrow-element.stderr @@ -8,6 +8,7 @@ LL | let brw = &foo.baz; = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) warning: reference to packed field is unaligned --> $DIR/packed-struct-borrow-element.rs:30:15 @@ -18,6 +19,7 @@ LL | let brw = &foo.baz; = 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 #82523 = note: fields of packed structs are not properly aligned, and creating a misaligned reference is undefined behavior (even if that reference is never dereferenced) + = help: copy the field contents to a local variable, or replace the reference with a raw pointer and use `read_unaligned`/`write_unaligned` (loads and stores via `*p` must be properly aligned even when using raw pointers) warning: 2 warnings emitted