Rollup merge of #122471 - RalfJung:const-eval-span, r=oli-obk

preserve span when evaluating mir::ConstOperand

This lets us show to the user where they were using the faulty const (which can be quite relevant when generics are involved).

I wonder if we should change "erroneous constant encountered" to something like "the above error was encountered while evaluating this constant" or so, to make this more similar to what the collector emits when showing a "backtrace" of where things get monomorphized? It seems a bit strange to rely on the order of emitted diagnostics for that but it seems the collector already [does that](https://github.com/rust-lang/rust/blob/da8a8c9223722e17cc0173ce9490076b4a6d263d/compiler/rustc_monomorphize/src/collector.rs#L472-L475).

21 files changed, 192 insertions, 7 deletions

diff --git a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
index c3e932fe187..f456196b282 100644
--- a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
+++ b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
@@ -393,7 +393,9 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
                 }
             }
             Operand::Constant(box constant) => {
-                if let Ok(constant) = self.ecx.eval_mir_constant(&constant.const_, None, None) {
+                if let Ok(constant) =
+                    self.ecx.eval_mir_constant(&constant.const_, Some(constant.span), None)
+                {
                     self.assign_constant(state, place, constant, &[]);
                 }
             }
diff --git a/compiler/rustc_mir_transform/src/jump_threading.rs b/compiler/rustc_mir_transform/src/jump_threading.rs
index ad8f21ffbda..6629face940 100644
--- a/compiler/rustc_mir_transform/src/jump_threading.rs
+++ b/compiler/rustc_mir_transform/src/jump_threading.rs
@@ -416,7 +416,8 @@ impl<'tcx, 'a> TOFinder<'tcx, 'a> {
         match rhs {
             // If we expect `lhs ?= A`, we have an opportunity if we assume `constant == A`.
             Operand::Constant(constant) => {
-                let constant = self.ecx.eval_mir_constant(&constant.const_, None, None).ok()?;
+                let constant =
+                    self.ecx.eval_mir_constant(&constant.const_, Some(constant.span), None).ok()?;
                 self.process_constant(bb, lhs, constant, state);
             }
             // Transfer the conditions on the copied rhs.
diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index 2465f9fbfa8..cd9eb4916ce 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -828,14 +828,17 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
         // a codegen-time error). rustc stops after collection if there was an error, so this
         // ensures codegen never has to worry about failing consts.
         // (codegen relies on this and ICEs will happen if this is violated.)
-        let val = match const_.eval(self.tcx, param_env, None) {
+        let val = match const_.eval(self.tcx, param_env, Some(constant.span)) {
             Ok(v) => v,
-            Err(ErrorHandled::Reported(..)) => return,
             Err(ErrorHandled::TooGeneric(..)) => span_bug!(
                 self.body.source_info(location).span,
                 "collection encountered polymorphic constant: {:?}",
                 const_
             ),
+            Err(err @ ErrorHandled::Reported(..)) => {
+                err.emit_note(self.tcx);
+                return;
+            }
         };
         collect_const_value(self.tcx, val, self.output);
         MirVisitor::visit_ty(self, const_.ty(), TyContext::Location(location));
diff --git a/compiler/rustc_smir/src/rustc_smir/builder.rs b/compiler/rustc_smir/src/rustc_smir/builder.rs
index 039bdec4c78..a13262cdcc4 100644
--- a/compiler/rustc_smir/src/rustc_smir/builder.rs
+++ b/compiler/rustc_smir/src/rustc_smir/builder.rs
@@ -56,7 +56,7 @@ impl<'tcx> MutVisitor<'tcx> for BodyBuilder<'tcx> {
 
     fn visit_constant(&mut self, constant: &mut mir::ConstOperand<'tcx>, location: mir::Location) {
         let const_ = self.monomorphize(constant.const_);
-        let val = match const_.eval(self.tcx, ty::ParamEnv::reveal_all(), None) {
+        let val = match const_.eval(self.tcx, ty::ParamEnv::reveal_all(), Some(constant.span)) {
             Ok(v) => v,
             Err(mir::interpret::ErrorHandled::Reported(..)) => return,
             Err(mir::interpret::ErrorHandled::TooGeneric(..)) => {
diff --git a/tests/ui/consts/assoc_const_generic_impl.stderr b/tests/ui/consts/assoc_const_generic_impl.stderr
index d826972ce9f..45219508396 100644
--- a/tests/ui/consts/assoc_const_generic_impl.stderr
+++ b/tests/ui/consts/assoc_const_generic_impl.stderr
@@ -4,6 +4,12 @@ error[E0080]: evaluation of `<u32 as ZeroSized>::I_AM_ZERO_SIZED` failed
 LL |     const I_AM_ZERO_SIZED: ()  = [()][std::mem::size_of::<Self>()];
    |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ index out of bounds: the length is 1 but the index is 4
 
+note: erroneous constant encountered
+  --> $DIR/assoc_const_generic_impl.rs:11:9
+   |
+LL |         Self::I_AM_ZERO_SIZED;
+   |         ^^^^^^^^^^^^^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn <u32 as ZeroSized>::requires_zero_size`
   --> $DIR/assoc_const_generic_impl.rs:18:5
    |
diff --git a/tests/ui/consts/const-eval/index-out-of-bounds-never-type.stderr b/tests/ui/consts/const-eval/index-out-of-bounds-never-type.stderr
index 4e7ef52f674..7facb2d1a5c 100644
--- a/tests/ui/consts/const-eval/index-out-of-bounds-never-type.stderr
+++ b/tests/ui/consts/const-eval/index-out-of-bounds-never-type.stderr
@@ -4,6 +4,12 @@ error[E0080]: evaluation of `PrintName::<()>::VOID` failed
 LL |     const VOID: ! = { let x = 0 * std::mem::size_of::<T>(); [][x] };
    |                                                             ^^^^^ index out of bounds: the length is 0 but the index is 0
 
+note: erroneous constant encountered
+  --> $DIR/index-out-of-bounds-never-type.rs:16:13
+   |
+LL |     let _ = PrintName::<T>::VOID;
+   |             ^^^^^^^^^^^^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn f::<()>`
   --> $DIR/index-out-of-bounds-never-type.rs:20:5
    |
diff --git a/tests/ui/consts/const-eval/issue-50814-2.mir-opt.stderr b/tests/ui/consts/const-eval/issue-50814-2.mir-opt.stderr
index 7e764ca7239..2de68d3fee9 100644
--- a/tests/ui/consts/const-eval/issue-50814-2.mir-opt.stderr
+++ b/tests/ui/consts/const-eval/issue-50814-2.mir-opt.stderr
@@ -10,6 +10,52 @@ note: erroneous constant encountered
 LL |     &<A<T> as Foo<T>>::BAR
    |      ^^^^^^^^^^^^^^^^^^^^^
 
+note: erroneous constant encountered
+  --> $DIR/issue-50814-2.rs:20:5
+   |
+LL |     &<A<T> as Foo<T>>::BAR
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+
+note: erroneous constant encountered
+  --> $DIR/issue-50814-2.rs:20:5
+   |
+LL |     &<A<T> as Foo<T>>::BAR
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+note: erroneous constant encountered
+  --> $DIR/issue-50814-2.rs:20:5
+   |
+LL |     &<A<T> as Foo<T>>::BAR
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+note: erroneous constant encountered
+  --> $DIR/issue-50814-2.rs:20:5
+   |
+LL |     &<A<T> as Foo<T>>::BAR
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+note: erroneous constant encountered
+  --> $DIR/issue-50814-2.rs:20:6
+   |
+LL |     &<A<T> as Foo<T>>::BAR
+   |      ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+note: erroneous constant encountered
+  --> $DIR/issue-50814-2.rs:20:6
+   |
+LL |     &<A<T> as Foo<T>>::BAR
+   |      ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/const-eval/issue-50814-2.normal.stderr b/tests/ui/consts/const-eval/issue-50814-2.normal.stderr
index f552c8fde5b..4a7dfb19304 100644
--- a/tests/ui/consts/const-eval/issue-50814-2.normal.stderr
+++ b/tests/ui/consts/const-eval/issue-50814-2.normal.stderr
@@ -10,6 +10,20 @@ note: erroneous constant encountered
 LL |     &<A<T> as Foo<T>>::BAR
    |      ^^^^^^^^^^^^^^^^^^^^^
 
+note: erroneous constant encountered
+  --> $DIR/issue-50814-2.rs:20:5
+   |
+LL |     &<A<T> as Foo<T>>::BAR
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+
+note: erroneous constant encountered
+  --> $DIR/issue-50814-2.rs:20:6
+   |
+LL |     &<A<T> as Foo<T>>::BAR
+   |      ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 note: the above error was encountered while instantiating `fn foo::<()>`
   --> $DIR/issue-50814-2.rs:32:22
    |
diff --git a/tests/ui/consts/const-eval/issue-50814.stderr b/tests/ui/consts/const-eval/issue-50814.stderr
index 8d018161401..fe0e25b820f 100644
--- a/tests/ui/consts/const-eval/issue-50814.stderr
+++ b/tests/ui/consts/const-eval/issue-50814.stderr
@@ -26,6 +26,20 @@ LL |     &Sum::<U8, U8>::MAX
    |
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
+note: erroneous constant encountered
+  --> $DIR/issue-50814.rs:21:5
+   |
+LL |     &Sum::<U8, U8>::MAX
+   |     ^^^^^^^^^^^^^^^^^^^
+
+note: erroneous constant encountered
+  --> $DIR/issue-50814.rs:21:6
+   |
+LL |     &Sum::<U8, U8>::MAX
+   |      ^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 note: the above error was encountered while instantiating `fn foo::<i32>`
   --> $DIR/issue-50814.rs:26:5
    |
diff --git a/tests/ui/consts/const-eval/issue-85155.stderr b/tests/ui/consts/const-eval/issue-85155.stderr
index a88e959a8a6..99836a3fac6 100644
--- a/tests/ui/consts/const-eval/issue-85155.stderr
+++ b/tests/ui/consts/const-eval/issue-85155.stderr
@@ -4,6 +4,14 @@ error[E0080]: evaluation of `post_monomorphization_error::ValidateConstImm::<2,
 LL |         let _ = 1 / ((IMM >= MIN && IMM <= MAX) as usize);
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ attempt to divide `1_usize` by zero
 
+note: erroneous constant encountered
+  --> $DIR/auxiliary/post_monomorphization_error.rs:19:5
+   |
+LL |     static_assert_imm1!(IMM1);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this note originates in the macro `static_assert_imm1` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 note: the above error was encountered while instantiating `fn post_monomorphization_error::stdarch_intrinsic::<2>`
   --> $DIR/issue-85155.rs:19:5
    |
diff --git a/tests/ui/consts/required-consts/collect-in-called-fn.noopt.stderr b/tests/ui/consts/required-consts/collect-in-called-fn.noopt.stderr
index c7ff1328917..14a4cb0217f 100644
--- a/tests/ui/consts/required-consts/collect-in-called-fn.noopt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-called-fn.noopt.stderr
@@ -6,6 +6,12 @@ LL |     const C: () = panic!();
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/collect-in-called-fn.rs:18:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn called::<i32>`
   --> $DIR/collect-in-called-fn.rs:23:5
    |
diff --git a/tests/ui/consts/required-consts/collect-in-called-fn.opt.stderr b/tests/ui/consts/required-consts/collect-in-called-fn.opt.stderr
index c7ff1328917..14a4cb0217f 100644
--- a/tests/ui/consts/required-consts/collect-in-called-fn.opt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-called-fn.opt.stderr
@@ -6,6 +6,12 @@ LL |     const C: () = panic!();
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/collect-in-called-fn.rs:18:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn called::<i32>`
   --> $DIR/collect-in-called-fn.rs:23:5
    |
diff --git a/tests/ui/consts/required-consts/collect-in-dead-drop.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-drop.noopt.stderr
index b7010e78763..0bf231d09f1 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-drop.noopt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-dead-drop.noopt.stderr
@@ -6,6 +6,12 @@ LL |     const C: () = panic!();
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-drop.rs:19:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn <Fail<i32> as std::ops::Drop>::drop`
   --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
 
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fn.noopt.stderr
index 2162c35c837..8bb99efe8e4 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-fn.noopt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn.noopt.stderr
@@ -6,6 +6,12 @@ LL |     const C: () = panic!();
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fn.rs:22:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn not_called::<i32>`
   --> $DIR/collect-in-dead-fn.rs:29:9
    |
diff --git a/tests/ui/consts/required-consts/collect-in-dead-move.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-move.noopt.stderr
index 8c853127e04..5b1df78b232 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-move.noopt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-dead-move.noopt.stderr
@@ -6,6 +6,12 @@ LL |     const C: () = panic!();
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-move.rs:19:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn <Fail<i32> as std::ops::Drop>::drop`
   --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
 
diff --git a/tests/ui/consts/required-consts/collect-in-dead-vtable.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-vtable.noopt.stderr
index 6fd82777bd3..56b6989b441 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-vtable.noopt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-dead-vtable.noopt.stderr
@@ -6,6 +6,12 @@ LL |     const C: () = panic!();
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-vtable.rs:26:21
+   |
+LL |             let _ = Fail::<T>::C;
+   |                     ^^^^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn <std::vec::Vec<i32> as MyTrait>::not_called`
   --> $DIR/collect-in-dead-vtable.rs:35:40
    |
diff --git a/tests/ui/generics/post_monomorphization_error_backtrace.rs b/tests/ui/generics/post_monomorphization_error_backtrace.rs
index 56155ae2bd5..2c18f2b233a 100644
--- a/tests/ui/generics/post_monomorphization_error_backtrace.rs
+++ b/tests/ui/generics/post_monomorphization_error_backtrace.rs
@@ -12,6 +12,9 @@ fn assert_zst<T>() {
         //~| NOTE: the evaluated program panicked
     }
     F::<T>::V;
+    //~^NOTE: erroneous constant
+    //~|NOTE: erroneous constant
+    //~|NOTE: duplicate
 }
 
 fn foo<U>() {
diff --git a/tests/ui/generics/post_monomorphization_error_backtrace.stderr b/tests/ui/generics/post_monomorphization_error_backtrace.stderr
index 0d707d83d26..8a57979bca7 100644
--- a/tests/ui/generics/post_monomorphization_error_backtrace.stderr
+++ b/tests/ui/generics/post_monomorphization_error_backtrace.stderr
@@ -6,8 +6,14 @@ LL |         const V: () = assert!(std::mem::size_of::<T>() == 0);
    |
    = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/post_monomorphization_error_backtrace.rs:14:5
+   |
+LL |     F::<T>::V;
+   |     ^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn assert_zst::<u32>`
-  --> $DIR/post_monomorphization_error_backtrace.rs:18:5
+  --> $DIR/post_monomorphization_error_backtrace.rs:21:5
    |
 LL |     assert_zst::<U>()
    |     ^^^^^^^^^^^^^^^^^
@@ -20,8 +26,16 @@ LL |         const V: () = assert!(std::mem::size_of::<T>() == 0);
    |
    = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/post_monomorphization_error_backtrace.rs:14:5
+   |
+LL |     F::<T>::V;
+   |     ^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 note: the above error was encountered while instantiating `fn assert_zst::<i32>`
-  --> $DIR/post_monomorphization_error_backtrace.rs:18:5
+  --> $DIR/post_monomorphization_error_backtrace.rs:21:5
    |
 LL |     assert_zst::<U>()
    |     ^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/inline-const/const-expr-generic-err.stderr b/tests/ui/inline-const/const-expr-generic-err.stderr
index fc0b6cc4451..7331c7f18e9 100644
--- a/tests/ui/inline-const/const-expr-generic-err.stderr
+++ b/tests/ui/inline-const/const-expr-generic-err.stderr
@@ -6,6 +6,12 @@ LL |     const { assert!(std::mem::size_of::<T>() == 0); }
    |
    = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/const-expr-generic-err.rs:5:5
+   |
+LL |     const { assert!(std::mem::size_of::<T>() == 0); }
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn foo::<i32>`
   --> $DIR/const-expr-generic-err.rs:13:5
    |
@@ -18,6 +24,20 @@ error[E0080]: evaluation of `bar::<0>::{constant#0}` failed
 LL |     const { N - 1 }
    |             ^^^^^ attempt to compute `0_usize - 1_usize`, which would overflow
 
+note: erroneous constant encountered
+  --> $DIR/const-expr-generic-err.rs:9:5
+   |
+LL |     const { N - 1 }
+   |     ^^^^^^^^^^^^^^^
+
+note: erroneous constant encountered
+  --> $DIR/const-expr-generic-err.rs:9:5
+   |
+LL |     const { N - 1 }
+   |     ^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 note: the above error was encountered while instantiating `fn bar::<0>`
   --> $DIR/const-expr-generic-err.rs:14:5
    |
diff --git a/tests/ui/inline-const/required-const.stderr b/tests/ui/inline-const/required-const.stderr
index cd86020184d..2a13d18547c 100644
--- a/tests/ui/inline-const/required-const.stderr
+++ b/tests/ui/inline-const/required-const.stderr
@@ -6,6 +6,12 @@ LL |         const { panic!() }
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/required-const.rs:7:9
+   |
+LL |         const { panic!() }
+   |         ^^^^^^^^^^^^^^^^^^
+
 error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/simd/const-err-trumps-simd-err.stderr b/tests/ui/simd/const-err-trumps-simd-err.stderr
index 6e6aba8b6f1..1e46667cf4e 100644
--- a/tests/ui/simd/const-err-trumps-simd-err.stderr
+++ b/tests/ui/simd/const-err-trumps-simd-err.stderr
@@ -6,6 +6,12 @@ LL |     const { assert!(LANE < 4); } // the error should be here...
    |
    = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+note: erroneous constant encountered
+  --> $DIR/const-err-trumps-simd-err.rs:16:5
+   |
+LL |     const { assert!(LANE < 4); } // the error should be here...
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 note: the above error was encountered while instantiating `fn get_elem::<4>`
   --> $DIR/const-err-trumps-simd-err.rs:23:5
    |