diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index 0b182d42287..54403275ba6 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -256,7 +256,7 @@ pub(super) fn mir_assign_valid_types<'tcx>(
 /// or compute the layout.
 #[cfg_attr(not(debug_assertions), inline(always))]
 pub(super) fn from_known_layout<'tcx>(
-    tcx: TyCtxt<'tcx>,
+    tcx: TyCtxtAt<'tcx>,
     known_layout: Option<TyAndLayout<'tcx>>,
     compute: impl FnOnce() -> InterpResult<'tcx, TyAndLayout<'tcx>>,
 ) -> InterpResult<'tcx, TyAndLayout<'tcx>> {
@@ -265,12 +265,14 @@ pub(super) fn from_known_layout<'tcx>(
         Some(known_layout) => {
             if cfg!(debug_assertions) {
                 let check_layout = compute()?;
-                assert!(
-                    mir_assign_valid_types(tcx, check_layout, known_layout),
-                    "expected type differs from actual type.\nexpected: {:?}\nactual: {:?}",
-                    known_layout.ty,
-                    check_layout.ty,
-                );
+                if !mir_assign_valid_types(tcx.tcx, check_layout, known_layout) {
+                    span_bug!(
+                        tcx.span,
+                        "expected type differs from actual type.\nexpected: {:?}\nactual: {:?}",
+                        known_layout.ty,
+                        check_layout.ty,
+                    );
+                }
             }
             Ok(known_layout)
         }
@@ -444,7 +446,7 @@ pub fn layout_of_local(
         // have to support that case (mostly by skipping all caching).
         match frame.locals.get(local).and_then(|state| state.layout.get()) {
             None => {
-                let layout = from_known_layout(self.tcx.tcx, layout, || {
+                let layout = from_known_layout(self.tcx, layout, || {
                     let local_ty = frame.body.local_decls[local].ty;
                     let local_ty =
                         self.subst_from_frame_and_normalize_erasing_regions(frame, local_ty);
diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs
index 03614b2803f..3741f31927e 100644
--- a/src/librustc_mir/interpret/operand.rs
+++ b/src/librustc_mir/interpret/operand.rs
@@ -529,7 +529,7 @@ pub(super) fn eval_operands(
             ty::ConstKind::Value(val_val) => val_val,
         };
         // Other cases need layout.
-        let layout = from_known_layout(self.tcx.tcx, layout, || self.layout_of(val.ty))?;
+        let layout = from_known_layout(self.tcx, layout, || self.layout_of(val.ty))?;
         let op = match val_val {
             ConstValue::ByRef { alloc, offset } => {
                 let id = self.tcx.alloc_map.lock().create_memory_alloc(alloc);
diff --git a/src/librustc_mir/interpret/place.rs b/src/librustc_mir/interpret/place.rs
index 716c7c7d933..828df9a0930 100644
--- a/src/librustc_mir/interpret/place.rs
+++ b/src/librustc_mir/interpret/place.rs
@@ -867,12 +867,14 @@ fn copy_op_no_validate(
     ) -> InterpResult<'tcx> {
         // We do NOT compare the types for equality, because well-typed code can
         // actually "transmute" `&mut T` to `&T` in an assignment without a cast.
-        assert!(
-            mir_assign_valid_types(self.tcx.tcx, src.layout, dest.layout),
-            "type mismatch when copying!\nsrc: {:?},\ndest: {:?}",
-            src.layout.ty,
-            dest.layout.ty,
-        );
+        if !mir_assign_valid_types(self.tcx.tcx, src.layout, dest.layout) {
+            span_bug!(
+                self.tcx.span,
+                "type mismatch when copying!\nsrc: {:?},\ndest: {:?}",
+                src.layout.ty,
+                dest.layout.ty,
+            );
+        }
 
         // Let us see if the layout is simple so we take a shortcut, avoid force_allocation.
         let src = match self.try_read_immediate(src)? {
diff --git a/src/librustc_mir/interpret/terminator.rs b/src/librustc_mir/interpret/terminator.rs
index 161fbdc9ed4..2d8551b2bbf 100644
--- a/src/librustc_mir/interpret/terminator.rs
+++ b/src/librustc_mir/interpret/terminator.rs
@@ -66,7 +66,11 @@ pub(super) fn eval_terminator(
                         let sig = func.layout.ty.fn_sig(*self.tcx);
                         (FnVal::Instance(self.resolve(def_id, substs)?), sig.abi())
                     }
-                    _ => bug!("invalid callee of type {:?}", func.layout.ty),
+                    _ => span_bug!(
+                        terminator.source_info.span,
+                        "invalid callee of type {:?}",
+                        func.layout.ty
+                    ),
                 };
                 let args = self.eval_operands(args)?;
                 let ret = match destination {
@@ -76,7 +80,9 @@ pub(super) fn eval_terminator(
                 self.eval_fn_call(fn_val, abi, &args[..], ret, *cleanup)?;
                 // Sanity-check that `eval_fn_call` either pushed a new frame or
                 // did a jump to another block.
-                assert!(self.cur_frame() != old_stack || self.frame().block != old_bb);
+                if self.cur_frame() == old_stack && self.frame().block == old_bb {
+                    span_bug!(terminator.source_info.span, "evaluating this call made no progress");
+                }
             }
 
             Drop { location, target, unwind } => {
@@ -121,9 +127,11 @@ pub(super) fn eval_terminator(
             | FalseEdges { .. }
             | FalseUnwind { .. }
             | Yield { .. }
-            | GeneratorDrop => {
-                bug!("{:#?} should have been eliminated by MIR pass", terminator.kind)
-            }
+            | GeneratorDrop => span_bug!(
+                terminator.source_info.span,
+                "{:#?} should have been eliminated by MIR pass",
+                terminator.kind
+            ),
         }
 
         Ok(())