From 629722893cd39bcf9929b56b50ef5476f1d22a55 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 21 Jun 2020 18:24:51 +0200
Subject: [PATCH] MIR validation: check switch_ty

---
 src/librustc_mir/transform/validate.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/librustc_mir/transform/validate.rs b/src/librustc_mir/transform/validate.rs
index 625f40cd792..18744ef3d72 100644
--- a/src/librustc_mir/transform/validate.rs
+++ b/src/librustc_mir/transform/validate.rs
@@ -121,7 +121,18 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
             TerminatorKind::Goto { target } => {
                 self.check_edge(location, *target, EdgeKind::Normal);
             }
-            TerminatorKind::SwitchInt { targets, values, .. } => {
+            TerminatorKind::SwitchInt { targets, values, switch_ty, discr } => {
+                let ty = discr.ty(&self.body.local_decls, self.tcx);
+                if ty != *switch_ty {
+                    self.fail(
+                        location,
+                        format!(
+                            "encountered `SwitchInt` terminator with type mismatch: {:?} != {:?}",
+                            ty,
+                            switch_ty,
+                        ),
+                    );
+                }
                 if targets.len() != values.len() + 1 {
                     self.fail(
                         location,