From 92d1b390438e1aefef6532463ddccc27ec3b2dda Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Mon, 4 Jan 2021 17:15:57 +0100
Subject: [PATCH] make sure that promoteds which fail to evaluate in dead const
 code behave correctly

---
 src/test/ui/consts/promotion.rs | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/test/ui/consts/promotion.rs b/src/test/ui/consts/promotion.rs
index e6f5c3d27ca99..b6e7127a9b779 100644
--- a/src/test/ui/consts/promotion.rs
+++ b/src/test/ui/consts/promotion.rs
@@ -4,12 +4,23 @@
 
 fn foo(_: &'static [&'static str]) {}
 fn bar(_: &'static [&'static str; 3]) {}
-fn baz_i32(_: &'static i32) {}
-fn baz_u32(_: &'static u32) {}
+const fn baz_i32(_: &'static i32) {}
+const fn baz_u32(_: &'static u32) {}
+
+const fn fail() -> i32 { 1/0 }
+const C: i32 = {
+    // Promoted that fails to evaluate in dead code -- this must work
+    // (for backwards compatibility reasons).
+    if false {
+        baz_i32(&fail());
+    }
+    42
+};
 
 fn main() {
     foo(&["a", "b", "c"]);
     bar(&["d", "e", "f"]);
+    assert_eq!(C, 42);
 
     // make sure that these do not cause trouble despite overflowing
     baz_u32(&(0-1));