///
/// For more information, see documentation for `std`'s macros.
mod builtin {
+
+ /// Unconditionally causes compilation to fail with the given error message when encountered.
+ ///
+ /// For more information, see the [RFC].
+ ///
+ /// [RFC]: https://github.com/rust-lang/rfcs/blob/master/text/1695-add-error-macro.md
+ #[unstable(feature = "compile_error_macro", issue = "40872")]
+ #[macro_export]
+ #[cfg(dox)]
+ macro_rules! compile_error { ($msg:expr) => ({ /* compiler built-in */ }) }
+
/// The core macro for formatted string creation & output.
///
/// For more information, see the documentation for [`std::format_args!`].
/// into libsyntax itself.
#[cfg(dox)]
pub mod builtin {
+
+ /// Unconditionally causes compilation to fail with the given error message when encountered.
+ ///
+ /// For more information, see the [RFC].
+ ///
+ /// [RFC]: https://github.com/rust-lang/rfcs/blob/master/text/1695-add-error-macro.md
+ #[unstable(feature = "compile_error_macro", issue = "40872")]
+ #[macro_export]
+ macro_rules! compile_error { ($msg:expr) => ({ /* compiler built-in */ }) }
+
/// The core macro for formatted string creation & output.
///
/// This macro produces a value of type [`fmt::Arguments`]. This value can be
fn enable_allow_internal_unstable = allow_internal_unstable,
fn enable_custom_derive = custom_derive,
fn proc_macro_enabled = proc_macro,
+ fn enable_compile_error = compile_error,
}
}
declare_features! (
(active, asm, "1.0.0", Some(29722)),
+ (active, compile_error, "1.20.0", Some(40872)),
(active, concat_idents, "1.0.0", Some(29599)),
(active, link_args, "1.0.0", Some(29596)),
(active, log_syntax, "1.0.0", Some(29598)),
pub const EXPLAIN_CONCAT_IDENTS: &'static str =
"`concat_idents` is not stable enough for use and is subject to change";
+pub const EXPLAIN_COMPILE_ERROR: &'static str =
+ "`compile_error` is not stable enough for use and is subject to change";
+
pub const EXPLAIN_TRACE_MACROS: &'static str =
"`trace_macros` is not stable enough for use and is subject to change";
pub const EXPLAIN_ALLOW_INTERNAL_UNSTABLE: &'static str =
--- /dev/null
+// Copyright 2012-2017 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.
+
+// The compiler code necessary to support the compile_error! extension.
+
+use syntax::ext::base::*;
+use syntax::ext::base;
+use syntax::feature_gate;
+use syntax_pos::Span;
+use syntax::tokenstream;
+
+pub fn expand_compile_error<'cx>(cx: &'cx mut ExtCtxt,
+ sp: Span,
+ tts: &[tokenstream::TokenTree])
+ -> Box<base::MacResult + 'cx> {
+ if !cx.ecfg.enable_compile_error() {
+ feature_gate::emit_feature_err(&cx.parse_sess,
+ "compile_error",
+ sp,
+ feature_gate::GateIssue::Language,
+ feature_gate::EXPLAIN_COMPILE_ERROR);
+ return DummyResult::expr(sp);
+ }
+
+ let var = match get_single_str_from_tts(cx, sp, tts, "compile_error!") {
+ None => return DummyResult::expr(sp),
+ Some(v) => v,
+ };
+
+ cx.span_err(sp, &var);
+
+ DummyResult::any(sp)
+}
mod asm;
mod cfg;
+mod compile_error;
mod concat;
mod concat_idents;
mod env;
option_env: env::expand_option_env,
log_syntax: log_syntax::expand_syntax_ext,
trace_macros: trace_macros::expand_trace_macros,
+ compile_error: compile_error::expand_compile_error,
}
// format_args uses `unstable` things internally.
--- /dev/null
+// Copyright 2017 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(compile_error)]
+
+fn main() {
+ compile_error!("a very descriptive error message"); //~ ERROR: a very descriptive error message
+}
--- /dev/null
+// Copyright 2017 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() {
+ compile_error!("test"); //~ ERROR: `compile_error` is not stable enough
+}