Rollup merge of rust-lang#94868 - dtolnay:noblock, r=Dylan-DPC

Format core and std macro rules, removing needless surrounding blocks

Many of the asserting and printing macros in `core` and `std` are written with prehistoric-looking formatting, like this:

https://github.com/rust-lang/rust/blob/335ffbfa547df94ac236f5c56130cecf99c8d82b/library/std/src/macros.rs#L96-L101

In modern Rust style this would conventionally be written as follows instead, always using braces and a trailing semicolon on the macro arms:

https://github.com/rust-lang/rust/blob/af53809c874e0afb7be966df4d3cfcaa05277c53/library/std/src/macros.rs#L98-L105

Getting rid of the unneeded braces inside the expansion reduces extraneous indentation in macro-expanded code. For example:

```rust
println!("repro {}", true);
```

```rust
// before:

{
    ::std::io::_print(
        ::core::fmt::Arguments::new_v1(
            &["repro ", "\n"],
            &[::core::fmt::ArgumentV1::new_display(&true)],
        ),
    );
};
```

```rust
// after:

::std::io::_print(
    ::core::fmt::Arguments::new_v1(
        &["repro ", "\n"],
        &[::core::fmt::ArgumentV1::new_display(&true)],
    ),
);
```

Author: matthiaskrgr

library/core/src/macros/mod.rs

@@ -34,7 +34,7 @@ macro_rules! panic {
 #[cfg_attr(not(test), rustc_diagnostic_item = "assert_eq_macro")]
 #[allow_internal_unstable(core_panic)]
 macro_rules! assert_eq {
-    ($left:expr, $right:expr $(,)?) => ({
+    ($left:expr, $right:expr $(,)?) => {
         match (&$left, &$right) {
             (left_val, right_val) => {
                 if !(*left_val == *right_val) {
@@ -46,8 +46,8 @@ macro_rules! assert_eq {
                 }
             }
         }
-    });
-    ($left:expr, $right:expr, $($arg:tt)+) => ({
+    };
+    ($left:expr, $right:expr, $($arg:tt)+) => {
         match (&$left, &$right) {
             (left_val, right_val) => {
                 if !(*left_val == *right_val) {
@@ -59,7 +59,7 @@ macro_rules! assert_eq {
                 }
             }
         }
-    });
+    };
 }
 
 /// Asserts that two expressions are not equal to each other (using [`PartialEq`]).
@@ -84,7 +84,7 @@ macro_rules! assert_eq {
 #[cfg_attr(not(test), rustc_diagnostic_item = "assert_ne_macro")]
 #[allow_internal_unstable(core_panic)]
 macro_rules! assert_ne {
-    ($left:expr, $right:expr $(,)?) => ({
+    ($left:expr, $right:expr $(,)?) => {
         match (&$left, &$right) {
             (left_val, right_val) => {
                 if *left_val == *right_val {
@@ -96,8 +96,8 @@ macro_rules! assert_ne {
                 }
             }
         }
-    });
-    ($left:expr, $right:expr, $($arg:tt)+) => ({
+    };
+    ($left:expr, $right:expr, $($arg:tt)+) => {
         match (&($left), &($right)) {
             (left_val, right_val) => {
                 if *left_val == *right_val {
@@ -109,7 +109,7 @@ macro_rules! assert_ne {
                 }
             }
         }
-    });
+    };
 }
 
 /// Asserts that an expression matches any of the given patterns.
@@ -142,7 +142,7 @@ macro_rules! assert_ne {
 #[allow_internal_unstable(core_panic)]
 #[rustc_macro_transparency = "semitransparent"]
 pub macro assert_matches {
-    ($left:expr, $(|)? $( $pattern:pat_param )|+ $( if $guard: expr )? $(,)?) => ({
+    ($left:expr, $(|)? $( $pattern:pat_param )|+ $( if $guard: expr )? $(,)?) => {
         match $left {
             $( $pattern )|+ $( if $guard )? => {}
             ref left_val => {
@@ -153,8 +153,8 @@ pub macro assert_matches {
                 );
             }
         }
-    }),
-    ($left:expr, $(|)? $( $pattern:pat_param )|+ $( if $guard: expr )?, $($arg:tt)+) => ({
+    },
+    ($left:expr, $(|)? $( $pattern:pat_param )|+ $( if $guard: expr )?, $($arg:tt)+) => {
         match $left {
             $( $pattern )|+ $( if $guard )? => {}
             ref left_val => {
@@ -165,7 +165,7 @@ pub macro assert_matches {
                 );
             }
         }
-    }),
+    },
 }
 
 /// Asserts that a boolean expression is `true` at runtime.
@@ -214,7 +214,11 @@ pub macro assert_matches {
 #[rustc_diagnostic_item = "debug_assert_macro"]
 #[allow_internal_unstable(edition_panic)]
 macro_rules! debug_assert {
-    ($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert!($($arg)*); })
+    ($($arg:tt)*) => {
+        if $crate::cfg!(debug_assertions) {
+            $crate::assert!($($arg)*);
+        }
+    };
 }
 
 /// Asserts that two expressions are equal to each other.
@@ -240,7 +244,11 @@ macro_rules! debug_assert {
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "debug_assert_eq_macro")]
 macro_rules! debug_assert_eq {
-    ($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert_eq!($($arg)*); })
+    ($($arg:tt)*) => {
+        if $crate::cfg!(debug_assertions) {
+            $crate::assert_eq!($($arg)*);
+        }
+    };
 }
 
 /// Asserts that two expressions are not equal to each other.
@@ -266,7 +274,11 @@ macro_rules! debug_assert_eq {
 #[stable(feature = "assert_ne", since = "1.13.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "debug_assert_ne_macro")]
 macro_rules! debug_assert_ne {
-    ($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert_ne!($($arg)*); })
+    ($($arg:tt)*) => {
+        if $crate::cfg!(debug_assertions) {
+            $crate::assert_ne!($($arg)*);
+        }
+    };
 }
 
 /// Asserts that an expression matches any of the given patterns.
@@ -305,7 +317,9 @@ macro_rules! debug_assert_ne {
 #[allow_internal_unstable(assert_matches)]
 #[rustc_macro_transparency = "semitransparent"]
 pub macro debug_assert_matches($($arg:tt)*) {
-    if $crate::cfg!(debug_assertions) { $crate::assert_matches::assert_matches!($($arg)*); }
+    if $crate::cfg!(debug_assertions) {
+        $crate::assert_matches::assert_matches!($($arg)*);
+    }
 }
 
 /// Returns whether the given expression matches any of the given patterns.
@@ -331,7 +345,7 @@ macro_rules! matches {
             $( $pattern )|+ $( if $guard )? => true,
             _ => false
         }
-    }
+    };
 }
 
 /// Unwraps a result or propagates its error.
@@ -482,7 +496,9 @@ macro_rules! r#try {
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "write_macro")]
 macro_rules! write {
-    ($dst:expr, $($arg:tt)*) => ($dst.write_fmt($crate::format_args!($($arg)*)))
+    ($dst:expr, $($arg:tt)*) => {
+        $dst.write_fmt($crate::format_args!($($arg)*))
+    };
 }
 
 /// Write formatted data into a buffer, with a newline appended.
@@ -534,12 +550,12 @@ macro_rules! write {
 #[cfg_attr(not(test), rustc_diagnostic_item = "writeln_macro")]
 #[allow_internal_unstable(format_args_nl)]
 macro_rules! writeln {
-    ($dst:expr $(,)?) => (
+    ($dst:expr $(,)?) => {
         $crate::write!($dst, "\n")
-    );
-    ($dst:expr, $($arg:tt)*) => (
+    };
+    ($dst:expr, $($arg:tt)*) => {
         $dst.write_fmt($crate::format_args_nl!($($arg)*))
-    );
+    };
 }
 
 /// Indicates unreachable code.
@@ -683,8 +699,12 @@ macro_rules! unreachable {
 #[cfg_attr(not(test), rustc_diagnostic_item = "unimplemented_macro")]
 #[allow_internal_unstable(core_panic)]
 macro_rules! unimplemented {
-    () => ($crate::panicking::panic("not implemented"));
-    ($($arg:tt)+) => ($crate::panic!("not implemented: {}", $crate::format_args!($($arg)+)));
+    () => {
+        $crate::panicking::panic("not implemented")
+    };
+    ($($arg:tt)+) => {
+        $crate::panic!("not implemented: {}", $crate::format_args!($($arg)+))
+    };
 }
 
 /// Indicates unfinished code.
@@ -746,8 +766,12 @@ macro_rules! unimplemented {
 #[cfg_attr(not(test), rustc_diagnostic_item = "todo_macro")]
 #[allow_internal_unstable(core_panic)]
 macro_rules! todo {
-    () => ($crate::panicking::panic("not yet implemented"));
-    ($($arg:tt)+) => ($crate::panic!("not yet implemented: {}", $crate::format_args!($($arg)+)));
+    () => {
+        $crate::panicking::panic("not yet implemented")
+    };
+    ($($arg:tt)+) => {
+        $crate::panic!("not yet implemented: {}", $crate::format_args!($($arg)+))
+    };
 }
 
 /// Definitions of built-in macros.

library/std/src/macros.rs

@@ -60,7 +60,9 @@ macro_rules! panic {
 #[cfg_attr(not(test), rustc_diagnostic_item = "print_macro")]
 #[allow_internal_unstable(print_internals)]
 macro_rules! print {
-    ($($arg:tt)*) => ($crate::io::_print($crate::format_args!($($arg)*)));
+    ($($arg:tt)*) => {
+        $crate::io::_print($crate::format_args!($($arg)*))
+    };
 }
 
 /// Prints to the standard output, with a newline.
@@ -94,10 +96,12 @@ macro_rules! print {
 #[cfg_attr(not(test), rustc_diagnostic_item = "println_macro")]
 #[allow_internal_unstable(print_internals, format_args_nl)]
 macro_rules! println {
-    () => ($crate::print!("\n"));
-    ($($arg:tt)*) => ({
-        $crate::io::_print($crate::format_args_nl!($($arg)*));
-    })
+    () => {
+        $crate::print!("\n")
+    };
+    ($($arg:tt)*) => {
+        $crate::io::_print($crate::format_args_nl!($($arg)*))
+    };
 }
 
 /// Prints to the standard error.
@@ -126,7 +130,9 @@ macro_rules! println {
 #[cfg_attr(not(test), rustc_diagnostic_item = "eprint_macro")]
 #[allow_internal_unstable(print_internals)]
 macro_rules! eprint {
-    ($($arg:tt)*) => ($crate::io::_eprint($crate::format_args!($($arg)*)));
+    ($($arg:tt)*) => {
+        $crate::io::_eprint($crate::format_args!($($arg)*))
+    };
 }
 
 /// Prints to the standard error, with a newline.
@@ -155,10 +161,12 @@ macro_rules! eprint {
 #[cfg_attr(not(test), rustc_diagnostic_item = "eprintln_macro")]
 #[allow_internal_unstable(print_internals, format_args_nl)]
 macro_rules! eprintln {
-    () => ($crate::eprint!("\n"));
-    ($($arg:tt)*) => ({
-        $crate::io::_eprint($crate::format_args_nl!($($arg)*));
-    })
+    () => {
+        $crate::eprint!("\n")
+    };
+    ($($arg:tt)*) => {
+        $crate::io::_eprint($crate::format_args_nl!($($arg)*))
+    };
 }
 
 /// Prints and returns the value of a given expression for quick and dirty

src/test/pretty/dollar-crate.pp

@@ -9,5 +9,5 @@
 // pp-exact:dollar-crate.pp
 
 fn main() {
-    { ::std::io::_print(::core::fmt::Arguments::new_v1(&["rust\n"], &[])); };
+    ::std::io::_print(::core::fmt::Arguments::new_v1(&["rust\n"], &[]));
 }

src/test/ui/macros/trace-macro.stderr

@@ -5,5 +5,5 @@ LL |     println!("Hello, World!");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: expanding `println! { "Hello, World!" }`
-   = note: to `{ $crate :: io :: _print($crate :: format_args_nl! ("Hello, World!")) ; }`
+   = note: to `$crate :: io :: _print($crate :: format_args_nl! ("Hello, World!"))`
 

src/test/ui/parser/issues/issue-62894.stderr

@@ -45,7 +45,7 @@ LL | fn main() {}
    |
   ::: $SRC_DIR/core/src/macros/mod.rs:LL:COL
    |
-LL |     ($left:expr, $right:expr $(,)?) => ({
+LL |     ($left:expr, $right:expr $(,)?) => {
    |      ---------- while parsing argument for this `expr` macro fragment
 
 error: aborting due to 4 previous errors

src/test/ui/pattern/usefulness/tuple-struct-nonexhaustive.stderr

@@ -12,7 +12,7 @@ LL | struct Foo(isize, isize);
    = note: the matched value is of type `Foo`
 help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
    |
-LL ~         Foo(2, b) => println!("{}", b)
+LL ~         Foo(2, b) => println!("{}", b),
 LL +         Foo(_, _) => todo!()
    |