Allow panicking with string literal messages inside constants

src/test/ui/const-eval/const_panic.rs

@@ -0,0 +1,22 @@
+// 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.
+
+#![feature(const_panic)]
+
+fn main() {}
+
+const Z: () = panic!("cheese");
+//~^ ERROR this constant cannot be used
+
+const Y: () = unreachable!();
+//~^ ERROR this constant cannot be used
+
+const X: () = unimplemented!();
+//~^ ERROR this constant cannot be used

src/test/ui/const-eval/const_panic.stderr

@@ -0,0 +1,33 @@
+error: this constant cannot be used
+  --> $DIR/const_panic.rs:15:1
+   |
+LL | const Z: () = panic!("cheese");
+   | ^^^^^^^^^^^^^^----------------^
+   |               |
+   |               the evaluated program panicked at 'cheese', $DIR/const_panic.rs:15:15
+   |
+   = note: #[deny(const_err)] on by default
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: this constant cannot be used
+  --> $DIR/const_panic.rs:18:1
+   |
+LL | const Y: () = unreachable!();
+   | ^^^^^^^^^^^^^^--------------^
+   |               |
+   |               the evaluated program panicked at 'internal error: entered unreachable code', $DIR/const_panic.rs:18:15
+   |
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: this constant cannot be used
+  --> $DIR/const_panic.rs:21:1
+   |
+LL | const X: () = unimplemented!();
+   | ^^^^^^^^^^^^^^----------------^
+   |               |
+   |               the evaluated program panicked at 'not yet implemented', $DIR/const_panic.rs:21:15
+   |
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to 3 previous errors
+

src/test/ui/const-eval/const_panic_libcore.rs

@@ -0,0 +1,22 @@
+// 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.
+
+#![no_std]
+#![crate_type = "lib"]
+#![feature(const_panic)]
+
+const Z: () = panic!("cheese");
+//~^ ERROR this constant cannot be used
+
+const Y: () = unreachable!();
+//~^ ERROR this constant cannot be used
+
+const X: () = unimplemented!();
+//~^ ERROR this constant cannot be used

src/test/ui/const-eval/const_panic_libcore.stderr

@@ -0,0 +1,33 @@
+error: this constant cannot be used
+  --> $DIR/const_panic_libcore.rs:15:1
+   |
+LL | const Z: () = panic!("cheese");
+   | ^^^^^^^^^^^^^^----------------^
+   |               |
+   |               the evaluated program panicked at 'cheese', $DIR/const_panic_libcore.rs:15:15
+   |
+   = note: #[deny(const_err)] on by default
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: this constant cannot be used
+  --> $DIR/const_panic_libcore.rs:18:1
+   |
+LL | const Y: () = unreachable!();
+   | ^^^^^^^^^^^^^^--------------^
+   |               |
+   |               the evaluated program panicked at 'internal error: entered unreachable code', $DIR/const_panic_libcore.rs:18:15
+   |
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: this constant cannot be used
+  --> $DIR/const_panic_libcore.rs:21:1
+   |
+LL | const X: () = unimplemented!();
+   | ^^^^^^^^^^^^^^----------------^
+   |               |
+   |               the evaluated program panicked at 'not yet implemented', $DIR/const_panic_libcore.rs:21:15
+   |
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to 3 previous errors
+

src/test/ui/const-eval/const_panic_libcore_main.rs

@@ -0,0 +1,35 @@
+// 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.
+
+#![crate_type = "bin"]
+#![feature(lang_items)]
+#![feature(panic_implementation)]
+#![feature(const_panic)]
+#![no_main]
+#![no_std]
+
+use core::panic::PanicInfo;
+
+const Z: () = panic!("cheese");
+//~^ ERROR this constant cannot be used
+
+const Y: () = unreachable!();
+//~^ ERROR this constant cannot be used
+
+const X: () = unimplemented!();
+//~^ ERROR this constant cannot be used
+
+#[lang = "eh_personality"]
+fn eh() {}
+
+#[panic_implementation]
+fn panic(_info: &PanicInfo) -> ! {
+    loop {}
+}

src/test/ui/const-eval/const_panic_libcore_main.stderr

@@ -0,0 +1,33 @@
+error: this constant cannot be used
+  --> $DIR/const_panic_libcore_main.rs:20:1
+   |
+LL | const Z: () = panic!("cheese");
+   | ^^^^^^^^^^^^^^----------------^
+   |               |
+   |               the evaluated program panicked at 'cheese', $DIR/const_panic_libcore_main.rs:20:15
+   |
+   = note: #[deny(const_err)] on by default
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: this constant cannot be used
+  --> $DIR/const_panic_libcore_main.rs:23:1
+   |
+LL | const Y: () = unreachable!();
+   | ^^^^^^^^^^^^^^--------------^
+   |               |
+   |               the evaluated program panicked at 'internal error: entered unreachable code', $DIR/const_panic_libcore_main.rs:23:15
+   |
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: this constant cannot be used
+  --> $DIR/const_panic_libcore_main.rs:26:1
+   |
+LL | const X: () = unimplemented!();
+   | ^^^^^^^^^^^^^^----------------^
+   |               |
+   |               the evaluated program panicked at 'not yet implemented', $DIR/const_panic_libcore_main.rs:26:15
+   |
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to 3 previous errors
+

src/test/ui/const-eval/feature-gate-const_panic.rs

@@ -0,0 +1,20 @@
+// 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 main() {}
+
+const Z: () = panic!("cheese");
+//~^ ERROR panicking in constants is unstable
+
+const Y: () = unreachable!();
+//~^ ERROR panicking in constants is unstable
+
+const X: () = unimplemented!();
+//~^ ERROR panicking in constants is unstable

src/test/ui/const-eval/feature-gate-const_panic.stderr

@@ -0,0 +1,30 @@
+error[E0658]: panicking in constants is unstable (see issue #51999)
+  --> $DIR/feature-gate-const_panic.rs:13:15
+   |
+LL | const Z: () = panic!("cheese");
+   |               ^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_panic)] to the crate attributes to enable
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error[E0658]: panicking in constants is unstable (see issue #51999)
+  --> $DIR/feature-gate-const_panic.rs:19:15
+   |
+LL | const X: () = unimplemented!();
+   |               ^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_panic)] to the crate attributes to enable
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error[E0658]: panicking in constants is unstable (see issue #51999)
+  --> $DIR/feature-gate-const_panic.rs:16:15
+   |
+LL | const Y: () = unreachable!();
+   |               ^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_panic)] to the crate attributes to enable
+   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0658`.

src/test/ui/issues/issue-32829.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 static S : u64 = { { panic!("foo"); 0 } };
-//~^ ERROR calls in statics are limited
+//~^ ERROR panicking in statics is unstable
 
 fn main() {
     println!("{:?}", S);

src/test/ui/issues/issue-32829.stderr

@@ -1,11 +1,12 @@
-error[E0015]: calls in statics are limited to constant functions, tuple structs and tuple variants
+error[E0658]: panicking in statics is unstable (see issue #51999)
   --> $DIR/issue-32829.rs:11:22
    |
 LL | static S : u64 = { { panic!("foo"); 0 } };
    |                      ^^^^^^^^^^^^^^
    |
+   = help: add #![feature(const_panic)] to the crate attributes to enable
    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0658`.