3 files changed, 12 insertions, 7 deletions
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index f6b45eb4466..3d1007a4673 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -115,9 +115,9 @@ fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     let (source, target) =
         cx.tcx().struct_lockstep_tails_for_codegen(source, target, bx.param_env());
     match (source.kind(), target.kind()) {
-        (&ty::Array(_, len), &ty::Slice(_)) => {
-            cx.const_usize(len.eval_target_usize(cx.tcx(), ty::ParamEnv::reveal_all()))
-        }
+        (&ty::Array(_, len), &ty::Slice(_)) => cx.const_usize(
+            len.try_to_target_usize(cx.tcx()).expect("expected monomorphic const in codegen"),
+        ),
         (&ty::Dynamic(data_a, _, src_dyn_kind), &ty::Dynamic(data_b, _, target_dyn_kind))
             if src_dyn_kind == target_dyn_kind =>
         {
diff --git a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
index 55a71db9bae..369ab387bea 100644
--- a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
+++ b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
@@ -188,7 +188,8 @@ fn push_debuginfo_type_name<'tcx>(
                     _ => write!(
                         output,
                         ",{}>",
-                        len.eval_target_usize(tcx, ty::ParamEnv::reveal_all())
+                        len.try_to_target_usize(tcx)
+                            .expect("expected monomorphic const in codegen")
                     )
                     .unwrap(),
                 }
@@ -200,7 +201,8 @@ fn push_debuginfo_type_name<'tcx>(
                     _ => write!(
                         output,
                         "; {}]",
-                        len.eval_target_usize(tcx, ty::ParamEnv::reveal_all())
+                        len.try_to_target_usize(tcx)
+                            .expect("expected monomorphic const in codegen")
                     )
                     .unwrap(),
                 }
diff --git a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
index 37474d85b11..6bf75293fce 100644
--- a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs
@@ -114,7 +114,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
                 let count = self
                     .monomorphize(count)
-                    .eval_target_usize(bx.cx().tcx(), ty::ParamEnv::reveal_all());
+                    .try_to_target_usize(bx.tcx())
+                    .expect("expected monomorphic const in codegen");
 
                 bx.write_operand_repeatedly(cg_elem, count, dest);
             }
@@ -803,7 +804,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         if let Some(index) = place.as_local() {
             if let LocalRef::Operand(op) = self.locals[index] {
                 if let ty::Array(_, n) = op.layout.ty.kind() {
-                    let n = n.eval_target_usize(bx.cx().tcx(), ty::ParamEnv::reveal_all());
+                    let n = n
+                        .try_to_target_usize(bx.tcx())
+                        .expect("expected monomorphic const in codegen");
                     return bx.cx().const_usize(n);
                 }
             }