From a0e057540eb996ea43ba5e0dce2b69fa972f718f Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 9 Aug 2020 17:47:29 +0200
Subject: [PATCH] evaluate required_consts when pushing stack frame in Miri
 engine

---
 src/librustc_mir/interpret/eval_context.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index fc192cd9b3c..7c2f749c156 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -652,6 +652,13 @@ pub fn push_stack_frame(
         let frame = M::init_frame_extra(self, pre_frame)?;
         self.stack_mut().push(frame);
 
+        // Make sure all the constants required by this frame evaluate successfully (post-monomorphization check).
+        for const_ in &body.required_consts {
+            let const_ =
+                self.subst_from_current_frame_and_normalize_erasing_regions(const_.literal);
+            self.const_to_op(const_, None)?;
+        }
+
         // Locals are initially uninitialized.
         let dummy = LocalState { value: LocalValue::Uninitialized, layout: Cell::new(None) };
         let mut locals = IndexVec::from_elem(dummy, &body.local_decls);