From 142134d54fb20b0669754f439cf0001869c406b5 Mon Sep 17 00:00:00 2001
From: Seiichi Uchida <seuchida@gmail.com>
Date: Fri, 12 Jan 2018 19:54:52 +0900
Subject: [PATCH] Ignore CTFE errors while lowering patterns

Closes #43105.
---
 src/librustc_const_eval/pattern.rs   |  2 +-
 src/test/compile-fail/issue-43105.rs | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 src/test/compile-fail/issue-43105.rs

diff --git a/src/librustc_const_eval/pattern.rs b/src/librustc_const_eval/pattern.rs
index cfbb9623f7d..0f8efa030ea 100644
--- a/src/librustc_const_eval/pattern.rs
+++ b/src/librustc_const_eval/pattern.rs
@@ -280,7 +280,7 @@ impl<'a, 'tcx> Pattern<'tcx> {
         let mut pcx = PatternContext::new(tcx, param_env_and_substs, tables);
         let result = pcx.lower_pattern(pat);
         if !pcx.errors.is_empty() {
-            span_bug!(pat.span, "encountered errors lowering pattern: {:?}", pcx.errors)
+            debug!("encountered errors lowering pattern: {:?}", pcx.errors)
         }
         debug!("Pattern::from_hir({:?}) = {:?}", pat, result);
         result
diff --git a/src/test/compile-fail/issue-43105.rs b/src/test/compile-fail/issue-43105.rs
new file mode 100644
index 00000000000..fb419d751b4
--- /dev/null
+++ b/src/test/compile-fail/issue-43105.rs
@@ -0,0 +1,21 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn xyz() -> u8 { 42 }
+
+const NUM: u8 = xyz();
+//~^ ERROR calls in constants are limited to constant functions, struct and enum constructors
+
+fn main() {
+    match 1 {
+        NUM => unimplemented!(),
+        _ => unimplemented!(),
+    }
+}