From dcbe09e2b57d165f40f6ccebc915c09bbc1f6bd7 Mon Sep 17 00:00:00 2001
From: Oliver Schneider <github35764891676564198441@oli-obk.de>
Date: Thu, 24 May 2018 17:05:16 +0200
Subject: [PATCH 1/2] Don't ICE if crate has no valid crate types left

---
 src/librustc_codegen_llvm/base.rs |  2 +-
 src/test/ui/issue-50993.rs        | 18 ++++++++++++++++++
 src/test/ui/issue-50993.stderr    |  2 ++
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/issue-50993.rs
 create mode 100644 src/test/ui/issue-50993.stderr

diff --git a/src/librustc_codegen_llvm/base.rs b/src/librustc_codegen_llvm/base.rs
index 59d227557aeef..8660c0bcc6c3f 100644
--- a/src/librustc_codegen_llvm/base.rs
+++ b/src/librustc_codegen_llvm/base.rs
@@ -642,7 +642,7 @@ fn write_metadata<'a, 'gcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>,
             config::CrateTypeDylib |
             config::CrateTypeProcMacro => MetadataKind::Compressed,
         }
-    }).max().unwrap();
+    }).max().unwrap_or(MetadataKind::None);
 
     if kind == MetadataKind::None {
         return (metadata_llcx,
diff --git a/src/test/ui/issue-50993.rs b/src/test/ui/issue-50993.rs
new file mode 100644
index 0000000000000..a6e881b80340b
--- /dev/null
+++ b/src/test/ui/issue-50993.rs
@@ -0,0 +1,18 @@
+// 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.
+
+// compile-flags: --crate-type dylib --target thumbv7em-none-eabihf
+// compile-pass
+// error-pattern: dropping unsupported crate type `dylib` for target `thumbv7em-none-eabihf`
+
+#![feature(no_core)]
+
+#![no_std]
+#![no_core]
\ No newline at end of file
diff --git a/src/test/ui/issue-50993.stderr b/src/test/ui/issue-50993.stderr
new file mode 100644
index 0000000000000..d7b33a22e9c31
--- /dev/null
+++ b/src/test/ui/issue-50993.stderr
@@ -0,0 +1,2 @@
+warning: dropping unsupported crate type `dylib` for target `thumbv7em-none-eabihf`
+

From 0b1b26f17f783858ad746b49adb9681c88e81a46 Mon Sep 17 00:00:00 2001
From: Oliver Schneider <oli-obk@users.noreply.github.com>
Date: Thu, 24 May 2018 21:03:48 +0200
Subject: [PATCH 2/2] Update issue-50993.rs

---
 src/test/ui/issue-50993.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/ui/issue-50993.rs b/src/test/ui/issue-50993.rs
index a6e881b80340b..d6cdd7380010f 100644
--- a/src/test/ui/issue-50993.rs
+++ b/src/test/ui/issue-50993.rs
@@ -15,4 +15,4 @@
 #![feature(no_core)]
 
 #![no_std]
-#![no_core]
\ No newline at end of file
+#![no_core]