cd64446196
Update the bootstrap compiler This updates the bootstrap compiler, notably leaving out a change to enable semicolon in macro expressions lint, because stdarch still depends on the old behavior.
1380 lines
46 KiB
Rust
1380 lines
46 KiB
Rust
#[doc(include = "panic.md")]
|
|
#[macro_export]
|
|
#[rustc_builtin_macro = "core_panic"]
|
|
#[allow_internal_unstable(edition_panic)]
|
|
#[stable(feature = "core", since = "1.6.0")]
|
|
#[rustc_diagnostic_item = "core_panic_macro"]
|
|
macro_rules! panic {
|
|
// Expands to either `$crate::panic::panic_2015` or `$crate::panic::panic_2021`
|
|
// depending on the edition of the caller.
|
|
($($arg:tt)*) => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// Asserts that two expressions are equal to each other (using [`PartialEq`]).
|
|
///
|
|
/// On panic, this macro will print the values of the expressions with their
|
|
/// debug representations.
|
|
///
|
|
/// Like [`assert!`], this macro has a second form, where a custom
|
|
/// panic message can be provided.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let a = 3;
|
|
/// let b = 1 + 2;
|
|
/// assert_eq!(a, b);
|
|
///
|
|
/// assert_eq!(a, b, "we are testing addition with {} and {}", a, b);
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[allow_internal_unstable(core_panic)]
|
|
macro_rules! assert_eq {
|
|
($left:expr, $right:expr $(,)?) => ({
|
|
match (&$left, &$right) {
|
|
(left_val, right_val) => {
|
|
if !(*left_val == *right_val) {
|
|
let kind = $crate::panicking::AssertKind::Eq;
|
|
// The reborrows below are intentional. Without them, the stack slot for the
|
|
// borrow is initialized even before the values are compared, leading to a
|
|
// noticeable slow down.
|
|
$crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::None);
|
|
}
|
|
}
|
|
}
|
|
});
|
|
($left:expr, $right:expr, $($arg:tt)+) => ({
|
|
match (&$left, &$right) {
|
|
(left_val, right_val) => {
|
|
if !(*left_val == *right_val) {
|
|
let kind = $crate::panicking::AssertKind::Eq;
|
|
// The reborrows below are intentional. Without them, the stack slot for the
|
|
// borrow is initialized even before the values are compared, leading to a
|
|
// noticeable slow down.
|
|
$crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::Some($crate::format_args!($($arg)+)));
|
|
}
|
|
}
|
|
}
|
|
});
|
|
}
|
|
|
|
/// Asserts that two expressions are not equal to each other (using [`PartialEq`]).
|
|
///
|
|
/// On panic, this macro will print the values of the expressions with their
|
|
/// debug representations.
|
|
///
|
|
/// Like [`assert!`], this macro has a second form, where a custom
|
|
/// panic message can be provided.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let a = 3;
|
|
/// let b = 2;
|
|
/// assert_ne!(a, b);
|
|
///
|
|
/// assert_ne!(a, b, "we are testing that the values are not equal");
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "assert_ne", since = "1.13.0")]
|
|
#[allow_internal_unstable(core_panic)]
|
|
macro_rules! assert_ne {
|
|
($left:expr, $right:expr $(,)?) => ({
|
|
match (&$left, &$right) {
|
|
(left_val, right_val) => {
|
|
if *left_val == *right_val {
|
|
let kind = $crate::panicking::AssertKind::Ne;
|
|
// The reborrows below are intentional. Without them, the stack slot for the
|
|
// borrow is initialized even before the values are compared, leading to a
|
|
// noticeable slow down.
|
|
$crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::None);
|
|
}
|
|
}
|
|
}
|
|
});
|
|
($left:expr, $right:expr, $($arg:tt)+) => ({
|
|
match (&($left), &($right)) {
|
|
(left_val, right_val) => {
|
|
if *left_val == *right_val {
|
|
let kind = $crate::panicking::AssertKind::Ne;
|
|
// The reborrows below are intentional. Without them, the stack slot for the
|
|
// borrow is initialized even before the values are compared, leading to a
|
|
// noticeable slow down.
|
|
$crate::panicking::assert_failed(kind, &*left_val, &*right_val, $crate::option::Option::Some($crate::format_args!($($arg)+)));
|
|
}
|
|
}
|
|
}
|
|
});
|
|
}
|
|
|
|
/// Asserts that a boolean expression is `true` at runtime.
|
|
///
|
|
/// This will invoke the [`panic!`] macro if the provided expression cannot be
|
|
/// evaluated to `true` at runtime.
|
|
///
|
|
/// Like [`assert!`], this macro also has a second version, where a custom panic
|
|
/// message can be provided.
|
|
///
|
|
/// # Uses
|
|
///
|
|
/// Unlike [`assert!`], `debug_assert!` statements are only enabled in non
|
|
/// optimized builds by default. An optimized build will not execute
|
|
/// `debug_assert!` statements unless `-C debug-assertions` is passed to the
|
|
/// compiler. This makes `debug_assert!` useful for checks that are too
|
|
/// expensive to be present in a release build but may be helpful during
|
|
/// development. The result of expanding `debug_assert!` is always type checked.
|
|
///
|
|
/// An unchecked assertion allows a program in an inconsistent state to keep
|
|
/// running, which might have unexpected consequences but does not introduce
|
|
/// unsafety as long as this only happens in safe code. The performance cost
|
|
/// of assertions, however, is not measurable in general. Replacing [`assert!`]
|
|
/// with `debug_assert!` is thus only encouraged after thorough profiling, and
|
|
/// more importantly, only in safe code!
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// // the panic message for these assertions is the stringified value of the
|
|
/// // expression given.
|
|
/// debug_assert!(true);
|
|
///
|
|
/// fn some_expensive_computation() -> bool { true } // a very simple function
|
|
/// debug_assert!(some_expensive_computation());
|
|
///
|
|
/// // assert with a custom message
|
|
/// let x = true;
|
|
/// debug_assert!(x, "x wasn't true!");
|
|
///
|
|
/// let a = 3; let b = 27;
|
|
/// debug_assert!(a + b == 30, "a = {}, b = {}", a, b);
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_diagnostic_item = "debug_assert_macro"]
|
|
macro_rules! debug_assert {
|
|
($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert!($($arg)*); })
|
|
}
|
|
|
|
/// Asserts that two expressions are equal to each other.
|
|
///
|
|
/// On panic, this macro will print the values of the expressions with their
|
|
/// debug representations.
|
|
///
|
|
/// Unlike [`assert_eq!`], `debug_assert_eq!` statements are only enabled in non
|
|
/// optimized builds by default. An optimized build will not execute
|
|
/// `debug_assert_eq!` statements unless `-C debug-assertions` is passed to the
|
|
/// compiler. This makes `debug_assert_eq!` useful for checks that are too
|
|
/// expensive to be present in a release build but may be helpful during
|
|
/// development. The result of expanding `debug_assert_eq!` is always type checked.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let a = 3;
|
|
/// let b = 1 + 2;
|
|
/// debug_assert_eq!(a, b);
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
macro_rules! debug_assert_eq {
|
|
($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert_eq!($($arg)*); })
|
|
}
|
|
|
|
/// Asserts that two expressions are not equal to each other.
|
|
///
|
|
/// On panic, this macro will print the values of the expressions with their
|
|
/// debug representations.
|
|
///
|
|
/// Unlike [`assert_ne!`], `debug_assert_ne!` statements are only enabled in non
|
|
/// optimized builds by default. An optimized build will not execute
|
|
/// `debug_assert_ne!` statements unless `-C debug-assertions` is passed to the
|
|
/// compiler. This makes `debug_assert_ne!` useful for checks that are too
|
|
/// expensive to be present in a release build but may be helpful during
|
|
/// development. The result of expanding `debug_assert_ne!` is always type checked.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let a = 3;
|
|
/// let b = 2;
|
|
/// debug_assert_ne!(a, b);
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "assert_ne", since = "1.13.0")]
|
|
macro_rules! debug_assert_ne {
|
|
($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert_ne!($($arg)*); })
|
|
}
|
|
|
|
/// Returns whether the given expression matches any of the given patterns.
|
|
///
|
|
/// Like in a `match` expression, the pattern can be optionally followed by `if`
|
|
/// and a guard expression that has access to names bound by the pattern.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let foo = 'f';
|
|
/// assert!(matches!(foo, 'A'..='Z' | 'a'..='z'));
|
|
///
|
|
/// let bar = Some(4);
|
|
/// assert!(matches!(bar, Some(x) if x > 2));
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "matches_macro", since = "1.42.0")]
|
|
macro_rules! matches {
|
|
($expression:expr, $( $pattern:pat )|+ $( if $guard: expr )? $(,)?) => {
|
|
match $expression {
|
|
$( $pattern )|+ $( if $guard )? => true,
|
|
_ => false
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Unwraps a result or propagates its error.
|
|
///
|
|
/// The `?` operator was added to replace `try!` and should be used instead.
|
|
/// Furthermore, `try` is a reserved word in Rust 2018, so if you must use
|
|
/// it, you will need to use the [raw-identifier syntax][ris]: `r#try`.
|
|
///
|
|
/// [ris]: https://doc.rust-lang.org/nightly/rust-by-example/compatibility/raw_identifiers.html
|
|
///
|
|
/// `try!` matches the given [`Result`]. In case of the `Ok` variant, the
|
|
/// expression has the value of the wrapped value.
|
|
///
|
|
/// In case of the `Err` variant, it retrieves the inner error. `try!` then
|
|
/// performs conversion using `From`. This provides automatic conversion
|
|
/// between specialized errors and more general ones. The resulting
|
|
/// error is then immediately returned.
|
|
///
|
|
/// Because of the early return, `try!` can only be used in functions that
|
|
/// return [`Result`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::io;
|
|
/// use std::fs::File;
|
|
/// use std::io::prelude::*;
|
|
///
|
|
/// enum MyError {
|
|
/// FileWriteError
|
|
/// }
|
|
///
|
|
/// impl From<io::Error> for MyError {
|
|
/// fn from(e: io::Error) -> MyError {
|
|
/// MyError::FileWriteError
|
|
/// }
|
|
/// }
|
|
///
|
|
/// // The preferred method of quick returning Errors
|
|
/// fn write_to_file_question() -> Result<(), MyError> {
|
|
/// let mut file = File::create("my_best_friends.txt")?;
|
|
/// file.write_all(b"This is a list of my best friends.")?;
|
|
/// Ok(())
|
|
/// }
|
|
///
|
|
/// // The previous method of quick returning Errors
|
|
/// fn write_to_file_using_try() -> Result<(), MyError> {
|
|
/// let mut file = r#try!(File::create("my_best_friends.txt"));
|
|
/// r#try!(file.write_all(b"This is a list of my best friends."));
|
|
/// Ok(())
|
|
/// }
|
|
///
|
|
/// // This is equivalent to:
|
|
/// fn write_to_file_using_match() -> Result<(), MyError> {
|
|
/// let mut file = r#try!(File::create("my_best_friends.txt"));
|
|
/// match file.write_all(b"This is a list of my best friends.") {
|
|
/// Ok(v) => v,
|
|
/// Err(e) => return Err(From::from(e)),
|
|
/// }
|
|
/// Ok(())
|
|
/// }
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_deprecated(since = "1.39.0", reason = "use the `?` operator instead")]
|
|
#[doc(alias = "?")]
|
|
macro_rules! r#try {
|
|
($expr:expr $(,)?) => {
|
|
match $expr {
|
|
$crate::result::Result::Ok(val) => val,
|
|
$crate::result::Result::Err(err) => {
|
|
return $crate::result::Result::Err($crate::convert::From::from(err));
|
|
}
|
|
}
|
|
};
|
|
}
|
|
|
|
/// Writes formatted data into a buffer.
|
|
///
|
|
/// This macro accepts a 'writer', a format string, and a list of arguments. Arguments will be
|
|
/// formatted according to the specified format string and the result will be passed to the writer.
|
|
/// The writer may be any value with a `write_fmt` method; generally this comes from an
|
|
/// implementation of either the [`fmt::Write`] or the [`io::Write`] trait. The macro
|
|
/// returns whatever the `write_fmt` method returns; commonly a [`fmt::Result`], or an
|
|
/// [`io::Result`].
|
|
///
|
|
/// See [`std::fmt`] for more information on the format string syntax.
|
|
///
|
|
/// [`std::fmt`]: ../std/fmt/index.html
|
|
/// [`fmt::Write`]: crate::fmt::Write
|
|
/// [`io::Write`]: ../std/io/trait.Write.html
|
|
/// [`fmt::Result`]: crate::fmt::Result
|
|
/// [`io::Result`]: ../std/io/type.Result.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::io::Write;
|
|
///
|
|
/// fn main() -> std::io::Result<()> {
|
|
/// let mut w = Vec::new();
|
|
/// write!(&mut w, "test")?;
|
|
/// write!(&mut w, "formatted {}", "arguments")?;
|
|
///
|
|
/// assert_eq!(w, b"testformatted arguments");
|
|
/// Ok(())
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// A module can import both `std::fmt::Write` and `std::io::Write` and call `write!` on objects
|
|
/// implementing either, as objects do not typically implement both. However, the module must
|
|
/// import the traits qualified so their names do not conflict:
|
|
///
|
|
/// ```
|
|
/// use std::fmt::Write as FmtWrite;
|
|
/// use std::io::Write as IoWrite;
|
|
///
|
|
/// fn main() -> Result<(), Box<dyn std::error::Error>> {
|
|
/// let mut s = String::new();
|
|
/// let mut v = Vec::new();
|
|
///
|
|
/// write!(&mut s, "{} {}", "abc", 123)?; // uses fmt::Write::write_fmt
|
|
/// write!(&mut v, "s = {:?}", s)?; // uses io::Write::write_fmt
|
|
/// assert_eq!(v, b"s = \"abc 123\"");
|
|
/// Ok(())
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// Note: This macro can be used in `no_std` setups as well.
|
|
/// In a `no_std` setup you are responsible for the implementation details of the components.
|
|
///
|
|
/// ```no_run
|
|
/// # extern crate core;
|
|
/// use core::fmt::Write;
|
|
///
|
|
/// struct Example;
|
|
///
|
|
/// impl Write for Example {
|
|
/// fn write_str(&mut self, _s: &str) -> core::fmt::Result {
|
|
/// unimplemented!();
|
|
/// }
|
|
/// }
|
|
///
|
|
/// let mut m = Example{};
|
|
/// write!(&mut m, "Hello World").expect("Not written");
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
macro_rules! write {
|
|
($dst:expr, $($arg:tt)*) => ($dst.write_fmt($crate::format_args!($($arg)*)))
|
|
}
|
|
|
|
/// Write formatted data into a buffer, with a newline appended.
|
|
///
|
|
/// On all platforms, the newline is the LINE FEED character (`\n`/`U+000A`) alone
|
|
/// (no additional CARRIAGE RETURN (`\r`/`U+000D`).
|
|
///
|
|
/// For more information, see [`write!`]. For information on the format string syntax, see
|
|
/// [`std::fmt`].
|
|
///
|
|
/// [`std::fmt`]: ../std/fmt/index.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::io::{Write, Result};
|
|
///
|
|
/// fn main() -> Result<()> {
|
|
/// let mut w = Vec::new();
|
|
/// writeln!(&mut w)?;
|
|
/// writeln!(&mut w, "test")?;
|
|
/// writeln!(&mut w, "formatted {}", "arguments")?;
|
|
///
|
|
/// assert_eq!(&w[..], "\ntest\nformatted arguments\n".as_bytes());
|
|
/// Ok(())
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// A module can import both `std::fmt::Write` and `std::io::Write` and call `write!` on objects
|
|
/// implementing either, as objects do not typically implement both. However, the module must
|
|
/// import the traits qualified so their names do not conflict:
|
|
///
|
|
/// ```
|
|
/// use std::fmt::Write as FmtWrite;
|
|
/// use std::io::Write as IoWrite;
|
|
///
|
|
/// fn main() -> Result<(), Box<dyn std::error::Error>> {
|
|
/// let mut s = String::new();
|
|
/// let mut v = Vec::new();
|
|
///
|
|
/// writeln!(&mut s, "{} {}", "abc", 123)?; // uses fmt::Write::write_fmt
|
|
/// writeln!(&mut v, "s = {:?}", s)?; // uses io::Write::write_fmt
|
|
/// assert_eq!(v, b"s = \"abc 123\\n\"\n");
|
|
/// Ok(())
|
|
/// }
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[allow_internal_unstable(format_args_nl)]
|
|
macro_rules! writeln {
|
|
($dst:expr $(,)?) => (
|
|
$crate::write!($dst, "\n")
|
|
);
|
|
($dst:expr, $($arg:tt)*) => (
|
|
$dst.write_fmt($crate::format_args_nl!($($arg)*))
|
|
);
|
|
}
|
|
|
|
/// Indicates unreachable code.
|
|
///
|
|
/// This is useful any time that the compiler can't determine that some code is unreachable. For
|
|
/// example:
|
|
///
|
|
/// * Match arms with guard conditions.
|
|
/// * Loops that dynamically terminate.
|
|
/// * Iterators that dynamically terminate.
|
|
///
|
|
/// If the determination that the code is unreachable proves incorrect, the
|
|
/// program immediately terminates with a [`panic!`].
|
|
///
|
|
/// The unsafe counterpart of this macro is the [`unreachable_unchecked`] function, which
|
|
/// will cause undefined behavior if the code is reached.
|
|
///
|
|
/// [`unreachable_unchecked`]: crate::hint::unreachable_unchecked
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// This will always [`panic!`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Match arms:
|
|
///
|
|
/// ```
|
|
/// # #[allow(dead_code)]
|
|
/// fn foo(x: Option<i32>) {
|
|
/// match x {
|
|
/// Some(n) if n >= 0 => println!("Some(Non-negative)"),
|
|
/// Some(n) if n < 0 => println!("Some(Negative)"),
|
|
/// Some(_) => unreachable!(), // compile error if commented out
|
|
/// None => println!("None")
|
|
/// }
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// Iterators:
|
|
///
|
|
/// ```
|
|
/// # #[allow(dead_code)]
|
|
/// fn divide_by_three(x: u32) -> u32 { // one of the poorest implementations of x/3
|
|
/// for i in 0.. {
|
|
/// if 3*i < i { panic!("u32 overflow"); }
|
|
/// if x < 3*i { return i-1; }
|
|
/// }
|
|
/// unreachable!();
|
|
/// }
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
macro_rules! unreachable {
|
|
() => ({
|
|
$crate::panic!("internal error: entered unreachable code")
|
|
});
|
|
($msg:expr $(,)?) => ({
|
|
$crate::unreachable!("{}", $msg)
|
|
});
|
|
($fmt:expr, $($arg:tt)*) => ({
|
|
$crate::panic!($crate::concat!("internal error: entered unreachable code: ", $fmt), $($arg)*)
|
|
});
|
|
}
|
|
|
|
/// Indicates unimplemented code by panicking with a message of "not implemented".
|
|
///
|
|
/// This allows your code to type-check, which is useful if you are prototyping or
|
|
/// implementing a trait that requires multiple methods which you don't plan of using all of.
|
|
///
|
|
/// The difference between `unimplemented!` and [`todo!`] is that while `todo!`
|
|
/// conveys an intent of implementing the functionality later and the message is "not yet
|
|
/// implemented", `unimplemented!` makes no such claims. Its message is "not implemented".
|
|
/// Also some IDEs will mark `todo!`s.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// This will always [`panic!`] because `unimplemented!` is just a shorthand for `panic!` with a
|
|
/// fixed, specific message.
|
|
///
|
|
/// Like `panic!`, this macro has a second form for displaying custom values.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Say we have a trait `Foo`:
|
|
///
|
|
/// ```
|
|
/// trait Foo {
|
|
/// fn bar(&self) -> u8;
|
|
/// fn baz(&self);
|
|
/// fn qux(&self) -> Result<u64, ()>;
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// We want to implement `Foo` for 'MyStruct', but for some reason it only makes sense
|
|
/// to implement the `bar()` function. `baz()` and `qux()` will still need to be defined
|
|
/// in our implementation of `Foo`, but we can use `unimplemented!` in their definitions
|
|
/// to allow our code to compile.
|
|
///
|
|
/// We still want to have our program stop running if the unimplemented methods are
|
|
/// reached.
|
|
///
|
|
/// ```
|
|
/// # trait Foo {
|
|
/// # fn bar(&self) -> u8;
|
|
/// # fn baz(&self);
|
|
/// # fn qux(&self) -> Result<u64, ()>;
|
|
/// # }
|
|
/// struct MyStruct;
|
|
///
|
|
/// impl Foo for MyStruct {
|
|
/// fn bar(&self) -> u8 {
|
|
/// 1 + 1
|
|
/// }
|
|
///
|
|
/// fn baz(&self) {
|
|
/// // It makes no sense to `baz` a `MyStruct`, so we have no logic here
|
|
/// // at all.
|
|
/// // This will display "thread 'main' panicked at 'not implemented'".
|
|
/// unimplemented!();
|
|
/// }
|
|
///
|
|
/// fn qux(&self) -> Result<u64, ()> {
|
|
/// // We have some logic here,
|
|
/// // We can add a message to unimplemented! to display our omission.
|
|
/// // This will display:
|
|
/// // "thread 'main' panicked at 'not implemented: MyStruct isn't quxable'".
|
|
/// unimplemented!("MyStruct isn't quxable");
|
|
/// }
|
|
/// }
|
|
///
|
|
/// fn main() {
|
|
/// let s = MyStruct;
|
|
/// s.bar();
|
|
/// }
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
macro_rules! unimplemented {
|
|
() => ($crate::panic!("not implemented"));
|
|
($($arg:tt)+) => ($crate::panic!("not implemented: {}", $crate::format_args!($($arg)+)));
|
|
}
|
|
|
|
/// Indicates unfinished code.
|
|
///
|
|
/// This can be useful if you are prototyping and are just looking to have your
|
|
/// code typecheck.
|
|
///
|
|
/// The difference between [`unimplemented!`] and `todo!` is that while `todo!` conveys
|
|
/// an intent of implementing the functionality later and the message is "not yet
|
|
/// implemented", `unimplemented!` makes no such claims. Its message is "not implemented".
|
|
/// Also some IDEs will mark `todo!`s.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// This will always [`panic!`].
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Here's an example of some in-progress code. We have a trait `Foo`:
|
|
///
|
|
/// ```
|
|
/// trait Foo {
|
|
/// fn bar(&self);
|
|
/// fn baz(&self);
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// We want to implement `Foo` on one of our types, but we also want to work on
|
|
/// just `bar()` first. In order for our code to compile, we need to implement
|
|
/// `baz()`, so we can use `todo!`:
|
|
///
|
|
/// ```
|
|
/// # trait Foo {
|
|
/// # fn bar(&self);
|
|
/// # fn baz(&self);
|
|
/// # }
|
|
/// struct MyStruct;
|
|
///
|
|
/// impl Foo for MyStruct {
|
|
/// fn bar(&self) {
|
|
/// // implementation goes here
|
|
/// }
|
|
///
|
|
/// fn baz(&self) {
|
|
/// // let's not worry about implementing baz() for now
|
|
/// todo!();
|
|
/// }
|
|
/// }
|
|
///
|
|
/// fn main() {
|
|
/// let s = MyStruct;
|
|
/// s.bar();
|
|
///
|
|
/// // we aren't even using baz(), so this is fine.
|
|
/// }
|
|
/// ```
|
|
#[macro_export]
|
|
#[stable(feature = "todo_macro", since = "1.40.0")]
|
|
macro_rules! todo {
|
|
() => ($crate::panic!("not yet implemented"));
|
|
($($arg:tt)+) => ($crate::panic!("not yet implemented: {}", $crate::format_args!($($arg)+)));
|
|
}
|
|
|
|
/// Definitions of built-in macros.
|
|
///
|
|
/// Most of the macro properties (stability, visibility, etc.) are taken from the source code here,
|
|
/// with exception of expansion functions transforming macro inputs into outputs,
|
|
/// those functions are provided by the compiler.
|
|
pub(crate) mod builtin {
|
|
|
|
/// Causes compilation to fail with the given error message when encountered.
|
|
///
|
|
/// This macro should be used when a crate uses a conditional compilation strategy to provide
|
|
/// better error messages for erroneous conditions. It's the compiler-level form of [`panic!`],
|
|
/// but emits an error during *compilation* rather than at *runtime*.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Two such examples are macros and `#[cfg]` environments.
|
|
///
|
|
/// Emit better compiler error if a macro is passed invalid values. Without the final branch,
|
|
/// the compiler would still emit an error, but the error's message would not mention the two
|
|
/// valid values.
|
|
///
|
|
/// ```compile_fail
|
|
/// macro_rules! give_me_foo_or_bar {
|
|
/// (foo) => {};
|
|
/// (bar) => {};
|
|
/// ($x:ident) => {
|
|
/// compile_error!("This macro only accepts `foo` or `bar`");
|
|
/// }
|
|
/// }
|
|
///
|
|
/// give_me_foo_or_bar!(neither);
|
|
/// // ^ will fail at compile time with message "This macro only accepts `foo` or `bar`"
|
|
/// ```
|
|
///
|
|
/// Emit compiler error if one of a number of features isn't available.
|
|
///
|
|
/// ```compile_fail
|
|
/// #[cfg(not(any(feature = "foo", feature = "bar")))]
|
|
/// compile_error!("Either feature \"foo\" or \"bar\" must be enabled for this crate.");
|
|
/// ```
|
|
#[stable(feature = "compile_error_macro", since = "1.20.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! compile_error {
|
|
($msg:expr $(,)?) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Constructs parameters for the other string-formatting macros.
|
|
///
|
|
/// This macro functions by taking a formatting string literal containing
|
|
/// `{}` for each additional argument passed. `format_args!` prepares the
|
|
/// additional parameters to ensure the output can be interpreted as a string
|
|
/// and canonicalizes the arguments into a single type. Any value that implements
|
|
/// the [`Display`] trait can be passed to `format_args!`, as can any
|
|
/// [`Debug`] implementation be passed to a `{:?}` within the formatting string.
|
|
///
|
|
/// This macro produces a value of type [`fmt::Arguments`]. This value can be
|
|
/// passed to the macros within [`std::fmt`] for performing useful redirection.
|
|
/// All other formatting macros ([`format!`], [`write!`], [`println!`], etc) are
|
|
/// proxied through this one. `format_args!`, unlike its derived macros, avoids
|
|
/// heap allocations.
|
|
///
|
|
/// You can use the [`fmt::Arguments`] value that `format_args!` returns
|
|
/// in `Debug` and `Display` contexts as seen below. The example also shows
|
|
/// that `Debug` and `Display` format to the same thing: the interpolated
|
|
/// format string in `format_args!`.
|
|
///
|
|
/// ```rust
|
|
/// let debug = format!("{:?}", format_args!("{} foo {:?}", 1, 2));
|
|
/// let display = format!("{}", format_args!("{} foo {:?}", 1, 2));
|
|
/// assert_eq!("1 foo 2", display);
|
|
/// assert_eq!(display, debug);
|
|
/// ```
|
|
///
|
|
/// For more information, see the documentation in [`std::fmt`].
|
|
///
|
|
/// [`Display`]: crate::fmt::Display
|
|
/// [`Debug`]: crate::fmt::Debug
|
|
/// [`fmt::Arguments`]: crate::fmt::Arguments
|
|
/// [`std::fmt`]: ../std/fmt/index.html
|
|
/// [`format!`]: ../std/macro.format.html
|
|
/// [`println!`]: ../std/macro.println.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// use std::fmt;
|
|
///
|
|
/// let s = fmt::format(format_args!("hello {}", "world"));
|
|
/// assert_eq!(s, format!("hello {}", "world"));
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[allow_internal_unstable(fmt_internals)]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! format_args {
|
|
($fmt:expr) => {{ /* compiler built-in */ }};
|
|
($fmt:expr, $($args:tt)*) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Same as `format_args`, but adds a newline in the end.
|
|
#[unstable(
|
|
feature = "format_args_nl",
|
|
issue = "none",
|
|
reason = "`format_args_nl` is only for internal \
|
|
language use and is subject to change"
|
|
)]
|
|
#[allow_internal_unstable(fmt_internals)]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! format_args_nl {
|
|
($fmt:expr) => {{ /* compiler built-in */ }};
|
|
($fmt:expr, $($args:tt)*) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Inspects an environment variable at compile time.
|
|
///
|
|
/// This macro will expand to the value of the named environment variable at
|
|
/// compile time, yielding an expression of type `&'static str`.
|
|
///
|
|
/// If the environment variable is not defined, then a compilation error
|
|
/// will be emitted. To not emit a compile error, use the [`option_env!`]
|
|
/// macro instead.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let path: &'static str = env!("PATH");
|
|
/// println!("the $PATH variable at the time of compiling was: {}", path);
|
|
/// ```
|
|
///
|
|
/// You can customize the error message by passing a string as the second
|
|
/// parameter:
|
|
///
|
|
/// ```compile_fail
|
|
/// let doc: &'static str = env!("documentation", "what's that?!");
|
|
/// ```
|
|
///
|
|
/// If the `documentation` environment variable is not defined, you'll get
|
|
/// the following error:
|
|
///
|
|
/// ```text
|
|
/// error: what's that?!
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! env {
|
|
($name:expr $(,)?) => {{ /* compiler built-in */ }};
|
|
($name:expr, $error_msg:expr $(,)?) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Optionally inspects an environment variable at compile time.
|
|
///
|
|
/// If the named environment variable is present at compile time, this will
|
|
/// expand into an expression of type `Option<&'static str>` whose value is
|
|
/// `Some` of the value of the environment variable. If the environment
|
|
/// variable is not present, then this will expand to `None`. See
|
|
/// [`Option<T>`][Option] for more information on this type.
|
|
///
|
|
/// A compile time error is never emitted when using this macro regardless
|
|
/// of whether the environment variable is present or not.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let key: Option<&'static str> = option_env!("SECRET_KEY");
|
|
/// println!("the secret key might be: {:?}", key);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! option_env {
|
|
($name:expr $(,)?) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Concatenates identifiers into one identifier.
|
|
///
|
|
/// This macro takes any number of comma-separated identifiers, and
|
|
/// concatenates them all into one, yielding an expression which is a new
|
|
/// identifier. Note that hygiene makes it such that this macro cannot
|
|
/// capture local variables. Also, as a general rule, macros are only
|
|
/// allowed in item, statement or expression position. That means while
|
|
/// you may use this macro for referring to existing variables, functions or
|
|
/// modules etc, you cannot define a new one with it.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// #![feature(concat_idents)]
|
|
///
|
|
/// # fn main() {
|
|
/// fn foobar() -> u32 { 23 }
|
|
///
|
|
/// let f = concat_idents!(foo, bar);
|
|
/// println!("{}", f());
|
|
///
|
|
/// // fn concat_idents!(new, fun, name) { } // not usable in this way!
|
|
/// # }
|
|
/// ```
|
|
#[unstable(
|
|
feature = "concat_idents",
|
|
issue = "29599",
|
|
reason = "`concat_idents` is not stable enough for use and is subject to change"
|
|
)]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! concat_idents {
|
|
($($e:ident),+ $(,)?) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Concatenates literals into a static string slice.
|
|
///
|
|
/// This macro takes any number of comma-separated literals, yielding an
|
|
/// expression of type `&'static str` which represents all of the literals
|
|
/// concatenated left-to-right.
|
|
///
|
|
/// Integer and floating point literals are stringified in order to be
|
|
/// concatenated.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let s = concat!("test", 10, 'b', true);
|
|
/// assert_eq!(s, "test10btrue");
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! concat {
|
|
($($e:expr),* $(,)?) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Expands to the line number on which it was invoked.
|
|
///
|
|
/// With [`column!`] and [`file!`], these macros provide debugging information for
|
|
/// developers about the location within the source.
|
|
///
|
|
/// The expanded expression has type `u32` and is 1-based, so the first line
|
|
/// in each file evaluates to 1, the second to 2, etc. This is consistent
|
|
/// with error messages by common compilers or popular editors.
|
|
/// The returned line is *not necessarily* the line of the `line!` invocation itself,
|
|
/// but rather the first macro invocation leading up to the invocation
|
|
/// of the `line!` macro.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let current_line = line!();
|
|
/// println!("defined on line: {}", current_line);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! line {
|
|
() => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// Expands to the column number at which it was invoked.
|
|
///
|
|
/// With [`line!`] and [`file!`], these macros provide debugging information for
|
|
/// developers about the location within the source.
|
|
///
|
|
/// The expanded expression has type `u32` and is 1-based, so the first column
|
|
/// in each line evaluates to 1, the second to 2, etc. This is consistent
|
|
/// with error messages by common compilers or popular editors.
|
|
/// The returned column is *not necessarily* the line of the `column!` invocation itself,
|
|
/// but rather the first macro invocation leading up to the invocation
|
|
/// of the `column!` macro.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let current_col = column!();
|
|
/// println!("defined on column: {}", current_col);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! column {
|
|
() => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// Expands to the file name in which it was invoked.
|
|
///
|
|
/// With [`line!`] and [`column!`], these macros provide debugging information for
|
|
/// developers about the location within the source.
|
|
///
|
|
/// The expanded expression has type `&'static str`, and the returned file
|
|
/// is not the invocation of the `file!` macro itself, but rather the
|
|
/// first macro invocation leading up to the invocation of the `file!`
|
|
/// macro.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let this_file = file!();
|
|
/// println!("defined in file: {}", this_file);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! file {
|
|
() => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// Stringifies its arguments.
|
|
///
|
|
/// This macro will yield an expression of type `&'static str` which is the
|
|
/// stringification of all the tokens passed to the macro. No restrictions
|
|
/// are placed on the syntax of the macro invocation itself.
|
|
///
|
|
/// Note that the expanded results of the input tokens may change in the
|
|
/// future. You should be careful if you rely on the output.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let one_plus_one = stringify!(1 + 1);
|
|
/// assert_eq!(one_plus_one, "1 + 1");
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! stringify {
|
|
($($t:tt)*) => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// Includes a UTF-8 encoded file as a string.
|
|
///
|
|
/// The file is located relative to the current file (similarly to how
|
|
/// modules are found). The provided path is interpreted in a platform-specific
|
|
/// way at compile time. So, for instance, an invocation with a Windows path
|
|
/// containing backslashes `\` would not compile correctly on Unix.
|
|
///
|
|
/// This macro will yield an expression of type `&'static str` which is the
|
|
/// contents of the file.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Assume there are two files in the same directory with the following
|
|
/// contents:
|
|
///
|
|
/// File 'spanish.in':
|
|
///
|
|
/// ```text
|
|
/// adiós
|
|
/// ```
|
|
///
|
|
/// File 'main.rs':
|
|
///
|
|
/// ```ignore (cannot-doctest-external-file-dependency)
|
|
/// fn main() {
|
|
/// let my_str = include_str!("spanish.in");
|
|
/// assert_eq!(my_str, "adiós\n");
|
|
/// print!("{}", my_str);
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// Compiling 'main.rs' and running the resulting binary will print "adiós".
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! include_str {
|
|
($file:expr $(,)?) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Includes a file as a reference to a byte array.
|
|
///
|
|
/// The file is located relative to the current file (similarly to how
|
|
/// modules are found). The provided path is interpreted in a platform-specific
|
|
/// way at compile time. So, for instance, an invocation with a Windows path
|
|
/// containing backslashes `\` would not compile correctly on Unix.
|
|
///
|
|
/// This macro will yield an expression of type `&'static [u8; N]` which is
|
|
/// the contents of the file.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Assume there are two files in the same directory with the following
|
|
/// contents:
|
|
///
|
|
/// File 'spanish.in':
|
|
///
|
|
/// ```text
|
|
/// adiós
|
|
/// ```
|
|
///
|
|
/// File 'main.rs':
|
|
///
|
|
/// ```ignore (cannot-doctest-external-file-dependency)
|
|
/// fn main() {
|
|
/// let bytes = include_bytes!("spanish.in");
|
|
/// assert_eq!(bytes, b"adi\xc3\xb3s\n");
|
|
/// print!("{}", String::from_utf8_lossy(bytes));
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// Compiling 'main.rs' and running the resulting binary will print "adiós".
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! include_bytes {
|
|
($file:expr $(,)?) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Expands to a string that represents the current module path.
|
|
///
|
|
/// The current module path can be thought of as the hierarchy of modules
|
|
/// leading back up to the crate root. The first component of the path
|
|
/// returned is the name of the crate currently being compiled.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// mod test {
|
|
/// pub fn foo() {
|
|
/// assert!(module_path!().ends_with("test"));
|
|
/// }
|
|
/// }
|
|
///
|
|
/// test::foo();
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! module_path {
|
|
() => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// Evaluates boolean combinations of configuration flags at compile-time.
|
|
///
|
|
/// In addition to the `#[cfg]` attribute, this macro is provided to allow
|
|
/// boolean expression evaluation of configuration flags. This frequently
|
|
/// leads to less duplicated code.
|
|
///
|
|
/// The syntax given to this macro is the same syntax as the [`cfg`]
|
|
/// attribute.
|
|
///
|
|
/// `cfg!`, unlike `#[cfg]`, does not remove any code and only evaluates to true or false. For
|
|
/// example, all blocks in an if/else expression need to be valid when `cfg!` is used for
|
|
/// the condition, regardless of what `cfg!` is evaluating.
|
|
///
|
|
/// [`cfg`]: ../reference/conditional-compilation.html#the-cfg-attribute
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let my_directory = if cfg!(windows) {
|
|
/// "windows-specific-directory"
|
|
/// } else {
|
|
/// "unix-directory"
|
|
/// };
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! cfg {
|
|
($($cfg:tt)*) => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// Parses a file as an expression or an item according to the context.
|
|
///
|
|
/// The file is located relative to the current file (similarly to how
|
|
/// modules are found). The provided path is interpreted in a platform-specific
|
|
/// way at compile time. So, for instance, an invocation with a Windows path
|
|
/// containing backslashes `\` would not compile correctly on Unix.
|
|
///
|
|
/// Using this macro is often a bad idea, because if the file is
|
|
/// parsed as an expression, it is going to be placed in the
|
|
/// surrounding code unhygienically. This could result in variables
|
|
/// or functions being different from what the file expected if
|
|
/// there are variables or functions that have the same name in
|
|
/// the current file.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// Assume there are two files in the same directory with the following
|
|
/// contents:
|
|
///
|
|
/// File 'monkeys.in':
|
|
///
|
|
/// ```ignore (only-for-syntax-highlight)
|
|
/// ['🙈', '🙊', '🙉']
|
|
/// .iter()
|
|
/// .cycle()
|
|
/// .take(6)
|
|
/// .collect::<String>()
|
|
/// ```
|
|
///
|
|
/// File 'main.rs':
|
|
///
|
|
/// ```ignore (cannot-doctest-external-file-dependency)
|
|
/// fn main() {
|
|
/// let my_string = include!("monkeys.in");
|
|
/// assert_eq!("🙈🙊🙉🙈🙊🙉", my_string);
|
|
/// println!("{}", my_string);
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// Compiling 'main.rs' and running the resulting binary will print
|
|
/// "🙈🙊🙉🙈🙊🙉".
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! include {
|
|
($file:expr $(,)?) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Asserts that a boolean expression is `true` at runtime.
|
|
///
|
|
/// This will invoke the [`panic!`] macro if the provided expression cannot be
|
|
/// evaluated to `true` at runtime.
|
|
///
|
|
/// # Uses
|
|
///
|
|
/// Assertions are always checked in both debug and release builds, and cannot
|
|
/// be disabled. See [`debug_assert!`] for assertions that are not enabled in
|
|
/// release builds by default.
|
|
///
|
|
/// Unsafe code may rely on `assert!` to enforce run-time invariants that, if
|
|
/// violated could lead to unsafety.
|
|
///
|
|
/// Other use-cases of `assert!` include testing and enforcing run-time
|
|
/// invariants in safe code (whose violation cannot result in unsafety).
|
|
///
|
|
/// # Custom Messages
|
|
///
|
|
/// This macro has a second form, where a custom panic message can
|
|
/// be provided with or without arguments for formatting. See [`std::fmt`]
|
|
/// for syntax for this form. Expressions used as format arguments will only
|
|
/// be evaluated if the assertion fails.
|
|
///
|
|
/// [`std::fmt`]: ../std/fmt/index.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// // the panic message for these assertions is the stringified value of the
|
|
/// // expression given.
|
|
/// assert!(true);
|
|
///
|
|
/// fn some_computation() -> bool { true } // a very simple function
|
|
///
|
|
/// assert!(some_computation());
|
|
///
|
|
/// // assert with a custom message
|
|
/// let x = true;
|
|
/// assert!(x, "x wasn't true!");
|
|
///
|
|
/// let a = 3; let b = 27;
|
|
/// assert!(a + b == 30, "a = {}, b = {}", a, b);
|
|
/// ```
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
#[rustc_diagnostic_item = "assert_macro"]
|
|
#[allow_internal_unstable(core_panic, edition_panic)]
|
|
macro_rules! assert {
|
|
($cond:expr $(,)?) => {{ /* compiler built-in */ }};
|
|
($cond:expr, $($arg:tt)+) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Inline assembly.
|
|
///
|
|
/// Read the [unstable book] for the usage.
|
|
///
|
|
/// [unstable book]: ../unstable-book/library-features/asm.html
|
|
#[unstable(
|
|
feature = "asm",
|
|
issue = "72016",
|
|
reason = "inline assembly is not stable enough for use and is subject to change"
|
|
)]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! asm {
|
|
("assembly template",
|
|
$(operands,)*
|
|
$(options($(option),*))?
|
|
) => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// LLVM-style inline assembly.
|
|
///
|
|
/// Read the [unstable book] for the usage.
|
|
///
|
|
/// [unstable book]: ../unstable-book/library-features/llvm-asm.html
|
|
#[unstable(
|
|
feature = "llvm_asm",
|
|
issue = "70173",
|
|
reason = "prefer using the new asm! syntax instead"
|
|
)]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! llvm_asm {
|
|
("assembly template"
|
|
: $("output"(operand),)*
|
|
: $("input"(operand),)*
|
|
: $("clobbers",)*
|
|
: $("options",)*) => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// Module-level inline assembly.
|
|
#[unstable(
|
|
feature = "global_asm",
|
|
issue = "35119",
|
|
reason = "`global_asm!` is not stable enough for use and is subject to change"
|
|
)]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! global_asm {
|
|
("assembly") => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// Prints passed tokens into the standard output.
|
|
#[unstable(
|
|
feature = "log_syntax",
|
|
issue = "29598",
|
|
reason = "`log_syntax!` is not stable enough for use and is subject to change"
|
|
)]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! log_syntax {
|
|
($($arg:tt)*) => {
|
|
/* compiler built-in */
|
|
};
|
|
}
|
|
|
|
/// Enables or disables tracing functionality used for debugging other macros.
|
|
#[unstable(
|
|
feature = "trace_macros",
|
|
issue = "29598",
|
|
reason = "`trace_macros` is not stable enough for use and is subject to change"
|
|
)]
|
|
#[rustc_builtin_macro]
|
|
#[macro_export]
|
|
macro_rules! trace_macros {
|
|
(true) => {{ /* compiler built-in */ }};
|
|
(false) => {{ /* compiler built-in */ }};
|
|
}
|
|
|
|
/// Attribute macro used to apply derive macros.
|
|
#[cfg(not(bootstrap))]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[rustc_builtin_macro]
|
|
pub macro derive($item:item) {
|
|
/* compiler built-in */
|
|
}
|
|
|
|
/// Attribute macro applied to a function to turn it into a unit test.
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[allow_internal_unstable(test, rustc_attrs)]
|
|
#[rustc_builtin_macro]
|
|
pub macro test($item:item) {
|
|
/* compiler built-in */
|
|
}
|
|
|
|
/// Attribute macro applied to a function to turn it into a benchmark test.
|
|
#[unstable(
|
|
feature = "test",
|
|
issue = "50297",
|
|
soft,
|
|
reason = "`bench` is a part of custom test frameworks which are unstable"
|
|
)]
|
|
#[allow_internal_unstable(test, rustc_attrs)]
|
|
#[rustc_builtin_macro]
|
|
pub macro bench($item:item) {
|
|
/* compiler built-in */
|
|
}
|
|
|
|
/// An implementation detail of the `#[test]` and `#[bench]` macros.
|
|
#[unstable(
|
|
feature = "custom_test_frameworks",
|
|
issue = "50297",
|
|
reason = "custom test frameworks are an unstable feature"
|
|
)]
|
|
#[allow_internal_unstable(test, rustc_attrs)]
|
|
#[rustc_builtin_macro]
|
|
pub macro test_case($item:item) {
|
|
/* compiler built-in */
|
|
}
|
|
|
|
/// Attribute macro applied to a static to register it as a global allocator.
|
|
///
|
|
/// See also [`std::alloc::GlobalAlloc`](../std/alloc/trait.GlobalAlloc.html).
|
|
#[stable(feature = "global_allocator", since = "1.28.0")]
|
|
#[allow_internal_unstable(rustc_attrs)]
|
|
#[rustc_builtin_macro]
|
|
pub macro global_allocator($item:item) {
|
|
/* compiler built-in */
|
|
}
|
|
|
|
/// Keeps the item it's applied to if the passed path is accessible, and removes it otherwise.
|
|
#[unstable(
|
|
feature = "cfg_accessible",
|
|
issue = "64797",
|
|
reason = "`cfg_accessible` is not fully implemented"
|
|
)]
|
|
#[rustc_builtin_macro]
|
|
pub macro cfg_accessible($item:item) {
|
|
/* compiler built-in */
|
|
}
|
|
|
|
/// Unstable implementation detail of the `rustc` compiler, do not use.
|
|
#[rustc_builtin_macro]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[allow_internal_unstable(core_intrinsics, libstd_sys_internals)]
|
|
pub macro RustcDecodable($item:item) {
|
|
/* compiler built-in */
|
|
}
|
|
|
|
/// Unstable implementation detail of the `rustc` compiler, do not use.
|
|
#[rustc_builtin_macro]
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
#[allow_internal_unstable(core_intrinsics)]
|
|
pub macro RustcEncodable($item:item) {
|
|
/* compiler built-in */
|
|
}
|
|
}
|