Reuse the ctfe error emitting logic for the future incompat lint

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -1,7 +1,7 @@
 use rustc_hir::def::DefKind;
 use rustc_hir::{LangItem, CRATE_HIR_ID};
 use rustc_middle::mir;
-use rustc_middle::mir::interpret::{PointerArithmetic, UndefinedBehaviorInfo};
+use rustc_middle::mir::interpret::{InterpError, PointerArithmetic, UndefinedBehaviorInfo};
 use rustc_middle::ty::layout::FnAbiOf;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_session::lint::builtin::INVALID_ALIGNMENT;
@@ -353,22 +353,27 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
                 ecx.cur_span(),
                 "`alignment_check_failed` called when no alignment check requested"
             ),
-            CheckAlignment::FutureIncompat => ecx.tcx.struct_span_lint_hir(
+            CheckAlignment::FutureIncompat => {
-                INVALID_ALIGNMENT,
+                let err = ConstEvalErr::new(
-                ecx.stack().iter().find_map(|frame| frame.lint_root()).unwrap_or(CRATE_HIR_ID),
+                    ecx,
-                ecx.cur_span(),
+                    InterpError::UndefinedBehavior(UndefinedBehaviorInfo::AlignmentCheckFailed {
-                UndefinedBehaviorInfo::AlignmentCheckFailed { has, required }.to_string(),
+                        has,
-                |db| {
+                        required,
-                    let mut stacktrace = ecx.generate_stacktrace();
+                    })
-                    // Filter out `requires_caller_location` frames.
+                    .into(),
-                    stacktrace
+                    None,
-                        .retain(|frame| !frame.instance.def.requires_caller_location(*ecx.tcx));
+                );
-                    for frame in stacktrace {
+                ecx.tcx.struct_span_lint_hir(
-                        db.span_label(frame.span, format!("inside `{}`", frame.instance));
+                    INVALID_ALIGNMENT,
-                    }
+                    ecx.stack().iter().find_map(|frame| frame.lint_root()).unwrap_or(CRATE_HIR_ID),
-                    db
+                    err.span,
-                },
+                    err.error.to_string(),
-            ),
+                    |db| {
+                        err.decorate(db, |_| {});
+                        db
+                    },
+                );
+            }
         }
         Ok(())
     }

src/test/ui/consts/const-eval/ub-ref-ptr.32bit.stderr

@@ -150,19 +150,18 @@ LL | const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
 
 error: accessing memory with alignment 1, but alignment 4 is required
   --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-   |
-   = note: inside `std::ptr::read::<u32>`
-  --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
-   |
-   = note: inside `ptr::const_ptr::<impl *const u32>::read`
-   |
-  ::: $DIR/ub-ref-ptr.rs:65:5
-   |
-LL |     ptr.read();
-   |     ---------- inside `UNALIGNED_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 #68585 <https://github.com/rust-lang/rust/issues/104616>
+note: inside `std::ptr::read::<u32>`
+  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
+note: inside `ptr::const_ptr::<impl *const u32>::read`
+  --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
+note: inside `UNALIGNED_READ`
+  --> $DIR/ub-ref-ptr.rs:65:5
+   |
+LL |     ptr.read();
+   |     ^^^^^^^^^^
    = note: `#[deny(invalid_alignment)]` on by default
 
 error: aborting due to 15 previous errors
@@ -171,18 +170,17 @@ For more information about this error, try `rustc --explain E0080`.
 Future incompatibility report: Future breakage diagnostic:
 error: accessing memory with alignment 1, but alignment 4 is required
   --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-   |
-   = note: inside `std::ptr::read::<u32>`
-  --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
-   |
-   = note: inside `ptr::const_ptr::<impl *const u32>::read`
-   |
-  ::: $DIR/ub-ref-ptr.rs:65:5
-   |
-LL |     ptr.read();
-   |     ---------- inside `UNALIGNED_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 #68585 <https://github.com/rust-lang/rust/issues/104616>
+note: inside `std::ptr::read::<u32>`
+  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
+note: inside `ptr::const_ptr::<impl *const u32>::read`
+  --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
+note: inside `UNALIGNED_READ`
+  --> $DIR/ub-ref-ptr.rs:65:5
+   |
+LL |     ptr.read();
+   |     ^^^^^^^^^^
    = note: `#[deny(invalid_alignment)]` on by default
 

src/test/ui/consts/const-eval/ub-ref-ptr.64bit.stderr

@@ -150,19 +150,18 @@ LL | const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
 
 error: accessing memory with alignment 1, but alignment 4 is required
   --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-   |
-   = note: inside `std::ptr::read::<u32>`
-  --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
-   |
-   = note: inside `ptr::const_ptr::<impl *const u32>::read`
-   |
-  ::: $DIR/ub-ref-ptr.rs:65:5
-   |
-LL |     ptr.read();
-   |     ---------- inside `UNALIGNED_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 #68585 <https://github.com/rust-lang/rust/issues/104616>
+note: inside `std::ptr::read::<u32>`
+  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
+note: inside `ptr::const_ptr::<impl *const u32>::read`
+  --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
+note: inside `UNALIGNED_READ`
+  --> $DIR/ub-ref-ptr.rs:65:5
+   |
+LL |     ptr.read();
+   |     ^^^^^^^^^^
    = note: `#[deny(invalid_alignment)]` on by default
 
 error: aborting due to 15 previous errors
@@ -171,18 +170,17 @@ For more information about this error, try `rustc --explain E0080`.
 Future incompatibility report: Future breakage diagnostic:
 error: accessing memory with alignment 1, but alignment 4 is required
   --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
-   |
-   = note: inside `std::ptr::read::<u32>`
-  --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
-   |
-   = note: inside `ptr::const_ptr::<impl *const u32>::read`
-   |
-  ::: $DIR/ub-ref-ptr.rs:65:5
-   |
-LL |     ptr.read();
-   |     ---------- inside `UNALIGNED_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 #68585 <https://github.com/rust-lang/rust/issues/104616>
+note: inside `std::ptr::read::<u32>`
+  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
+note: inside `ptr::const_ptr::<impl *const u32>::read`
+  --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
+note: inside `UNALIGNED_READ`
+  --> $DIR/ub-ref-ptr.rs:65:5
+   |
+LL |     ptr.read();
+   |     ^^^^^^^^^^
    = note: `#[deny(invalid_alignment)]` on by default