Use better error message for hard errors in CTFE

Currently the same message is used for hard errors and soft errors. This
makes hard errors use a message that indicates the reality of the
situation correctly, since usage of the constant is never allowed when
there was a hard error evaluating it.

2 files changed, 4 insertions, 9 deletions

diff --git a/compiler/rustc_mir/src/const_eval/error.rs b/compiler/rustc_mir/src/const_eval/error.rs
index fc21047ab72..17e8ab2a4da 100644
--- a/compiler/rustc_mir/src/const_eval/error.rs
+++ b/compiler/rustc_mir/src/const_eval/error.rs
@@ -157,7 +157,7 @@ impl<'tcx> ConstEvalErr<'tcx> {
         tcx: TyCtxtAt<'tcx>,
         message: &str,
         emit: impl FnOnce(DiagnosticBuilder<'_>),
-        mut lint_root: Option<hir::HirId>,
+        lint_root: Option<hir::HirId>,
     ) -> ErrorHandled {
         let finish = |mut err: DiagnosticBuilder<'_>, span_msg: Option<String>| {
             trace!("reporting const eval failure at {:?}", self.span);
@@ -194,12 +194,6 @@ impl<'tcx> ConstEvalErr<'tcx> {
             _ => {}
         };
 
-        // If we have a 'hard error', then set `lint_root` to `None` so that we don't
-        // emit a lint.
-        if matches!(&self.error, InterpError::MachineStop(err) if err.is_hard_err()) {
-            lint_root = None;
-        }
-
         let err_msg = self.error.to_string();
 
         // Regular case - emit a lint.
diff --git a/compiler/rustc_mir/src/const_eval/eval_queries.rs b/compiler/rustc_mir/src/const_eval/eval_queries.rs
index 460fea37461..6adb6e34958 100644
--- a/compiler/rustc_mir/src/const_eval/eval_queries.rs
+++ b/compiler/rustc_mir/src/const_eval/eval_queries.rs
@@ -2,8 +2,8 @@ use super::{CompileTimeEvalContext, CompileTimeInterpreter, ConstEvalErr, Memory
 use crate::interpret::eval_nullary_intrinsic;
 use crate::interpret::{
     intern_const_alloc_recursive, Allocation, ConstAlloc, ConstValue, CtfeValidationMode, GlobalId,
-    Immediate, InternKind, InterpCx, InterpResult, MPlaceTy, MemoryKind, OpTy, RefTracking, Scalar,
-    ScalarMaybeUninit, StackPopCleanup,
+    Immediate, InternKind, InterpCx, InterpError, InterpResult, MPlaceTy, MemoryKind, OpTy,
+    RefTracking, Scalar, ScalarMaybeUninit, StackPopCleanup,
 };
 use crate::util::pretty::display_allocation;
 
@@ -315,6 +315,7 @@ pub fn eval_to_allocation_raw_provider<'tcx>(
             let emit_as_lint = if let Some(def) = def.as_local() {
                 // (Associated) consts only emit a lint, since they might be unused.
                 matches!(tcx.def_kind(def.did.to_def_id()), DefKind::Const | DefKind::AssocConst)
+                    && !matches!(&err.error, InterpError::MachineStop(err) if err.is_hard_err())
             } else {
                 // use of broken constant from other crate: always an error
                 false