From 0e14b9ff268b6987f935847d7857969a69b7ee7d Mon Sep 17 00:00:00 2001
From: Oliver Scherer <github35764891676564198441@oli-obk.de>
Date: Wed, 15 Jan 2020 10:30:26 +0100
Subject: [PATCH] Add tests

---
 src/test/ui/consts/huge-values.rs             |  6 +++++
 src/test/ui/consts/validate_never_arrays.rs   |  6 ++++-
 .../ui/consts/validate_never_arrays.stderr    | 22 ++++++++++++++++---
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/src/test/ui/consts/huge-values.rs b/src/test/ui/consts/huge-values.rs
index ab09922d7614a..70a5b10e9be99 100644
--- a/src/test/ui/consts/huge-values.rs
+++ b/src/test/ui/consts/huge-values.rs
@@ -1,6 +1,10 @@
 // build-pass
 // ignore-32bit
 
+// This test is a canary test that will essentially not compile in a reasonable time frame
+// (so it'll take hours) if any of the optimizations regress. With the optimizations, these compile
+// in milliseconds just as if the length were set to `1`.
+
 #[derive(Clone, Copy)]
 struct Foo;
 
@@ -8,4 +12,6 @@ fn main() {
     let _ = [(); 4_000_000_000];
     let _ = [0u8; 4_000_000_000];
     let _ = [Foo; 4_000_000_000];
+    let _ = [(Foo, (), Foo, ((), Foo, [0; 0])); 4_000_000_000];
+    let _ = [[0; 0]; 4_000_000_000];
 }
diff --git a/src/test/ui/consts/validate_never_arrays.rs b/src/test/ui/consts/validate_never_arrays.rs
index 9610b7b22f161..c7144f05ec7a4 100644
--- a/src/test/ui/consts/validate_never_arrays.rs
+++ b/src/test/ui/consts/validate_never_arrays.rs
@@ -1,5 +1,9 @@
 #![feature(const_raw_ptr_deref, never_type)]
 
-const FOO: &[!; 1] = unsafe { &*(1_usize as *const [!; 1]) }; //~ ERROR undefined behavior
+const _: &[!; 1] = unsafe { &*(1_usize as *const [!; 1]) }; //~ ERROR undefined behavior
+const _: &[!; 0] = unsafe { &*(1_usize as *const [!; 0]) }; // ok
+const _: &[!] = unsafe { &*(1_usize as *const [!; 0]) }; // ok
+const _: &[!] = unsafe { &*(1_usize as *const [!; 1]) }; //~ ERROR undefined behavior
+const _: &[!] = unsafe { &*(1_usize as *const [!; 42]) }; //~ ERROR undefined behavior
 
 fn main() {}
diff --git a/src/test/ui/consts/validate_never_arrays.stderr b/src/test/ui/consts/validate_never_arrays.stderr
index c4c7a33718279..cb995b8216f4e 100644
--- a/src/test/ui/consts/validate_never_arrays.stderr
+++ b/src/test/ui/consts/validate_never_arrays.stderr
@@ -1,11 +1,27 @@
 error[E0080]: it is undefined behavior to use this value
   --> $DIR/validate_never_arrays.rs:3:1
    |
-LL | const FOO: &[!; 1] = unsafe { &*(1_usize as *const [!; 1]) };
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a value of an uninhabited type at .<deref>
+LL | const _: &[!; 1] = unsafe { &*(1_usize as *const [!; 1]) };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a value of an uninhabited type at .<deref>
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
 
-error: aborting due to previous error
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/validate_never_arrays.rs:6:1
+   |
+LL | const _: &[!] = unsafe { &*(1_usize as *const [!; 1]) };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a value of an uninhabited type at .<deref>[0]
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/validate_never_arrays.rs:7:1
+   |
+LL | const _: &[!] = unsafe { &*(1_usize as *const [!; 42]) };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered a value of an uninhabited type at .<deref>[0]
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
+
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0080`.