Hygienize macros in the standard library

Author: petrochenkov

src/liballoc/macros.rs

@@ -42,7 +42,7 @@ macro_rules! vec {
     ($($x:expr),*) => (
         <[_]>::into_vec(box [$($x),*])
     );
-    ($($x:expr,)*) => (vec![$($x),*])
+    ($($x:expr,)*) => ($crate::vec![$($x),*])
 }
 
 // HACK(japaric): with cfg(test) the inherent `[T]::into_vec` method, which is

src/libcore/macros.rs

@@ -6,13 +6,13 @@
 #[stable(feature = "core", since = "1.6.0")]
 macro_rules! panic {
     () => (
-        panic!("explicit panic")
+        $crate::panic!("explicit panic")
     );
     ($msg:expr) => ({
         $crate::panicking::panic(&($msg, file!(), line!(), __rust_unstable_column!()))
     });
     ($msg:expr,) => (
-        panic!($msg)
+        $crate::panic!($msg)
     );
     ($fmt:expr, $($arg:tt)+) => ({
         $crate::panicking::panic_fmt(format_args!($fmt, $($arg)*),
@@ -58,7 +58,7 @@ macro_rules! assert_eq {
         }
     });
     ($left:expr, $right:expr,) => ({
-        assert_eq!($left, $right)
+        $crate::assert_eq!($left, $right)
     });
     ($left:expr, $right:expr, $($arg:tt)+) => ({
         match (&($left), &($right)) {
@@ -115,7 +115,7 @@ macro_rules! assert_ne {
         }
     });
     ($left:expr, $right:expr,) => {
-        assert_ne!($left, $right)
+        $crate::assert_ne!($left, $right)
     };
     ($left:expr, $right:expr, $($arg:tt)+) => ({
         match (&($left), &($right)) {
@@ -208,7 +208,7 @@ macro_rules! debug_assert {
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 macro_rules! debug_assert_eq {
-    ($($arg:tt)*) => (if cfg!(debug_assertions) { assert_eq!($($arg)*); })
+    ($($arg:tt)*) => (if cfg!(debug_assertions) { $crate::assert_eq!($($arg)*); })
 }
 
 /// Asserts that two expressions are not equal to each other.
@@ -235,7 +235,7 @@ macro_rules! debug_assert_eq {
 #[macro_export]
 #[stable(feature = "assert_ne", since = "1.13.0")]
 macro_rules! debug_assert_ne {
-    ($($arg:tt)*) => (if cfg!(debug_assertions) { assert_ne!($($arg)*); })
+    ($($arg:tt)*) => (if cfg!(debug_assertions) { $crate::assert_ne!($($arg)*); })
 }
 
 /// Unwraps a result or propagates its error.
@@ -310,7 +310,7 @@ macro_rules! r#try {
             return $crate::result::Result::Err($crate::convert::From::from(err))
         }
     });
-    ($expr:expr,) => (r#try!($expr));
+    ($expr:expr,) => ($crate::r#try!($expr));
 }
 
 /// Writes formatted data into a buffer.
@@ -425,10 +425,10 @@ macro_rules! write {
 #[allow_internal_unstable(format_args_nl)]
 macro_rules! writeln {
     ($dst:expr) => (
-        write!($dst, "\n")
+        $crate::write!($dst, "\n")
     );
     ($dst:expr,) => (
-        writeln!($dst)
+        $crate::writeln!($dst)
     );
     ($dst:expr, $($arg:tt)*) => (
         $dst.write_fmt(format_args_nl!($($arg)*))
@@ -494,10 +494,10 @@ macro_rules! unreachable {
         panic!("internal error: entered unreachable code")
     });
     ($msg:expr) => ({
-        unreachable!("{}", $msg)
+        $crate::unreachable!("{}", $msg)
     });
     ($msg:expr,) => ({
-        unreachable!($msg)
+        $crate::unreachable!($msg)
     });
     ($fmt:expr, $($arg:tt)*) => ({
         panic!(concat!("internal error: entered unreachable code: ", $fmt), $($arg)*)

src/libstd/macros.rs

@@ -56,13 +56,13 @@
 #[allow_internal_unstable(__rust_unstable_column, libstd_sys_internals)]
 macro_rules! panic {
     () => ({
-        panic!("explicit panic")
+        $crate::panic!("explicit panic")
     });
     ($msg:expr) => ({
         $crate::rt::begin_panic($msg, &(file!(), line!(), __rust_unstable_column!()))
     });
     ($msg:expr,) => ({
-        panic!($msg)
+        $crate::panic!($msg)
     });
     ($fmt:expr, $($arg:tt)+) => ({
         $crate::rt::begin_panic_fmt(&format_args!($fmt, $($arg)+),
@@ -145,7 +145,7 @@ macro_rules! print {
 #[stable(feature = "rust1", since = "1.0.0")]
 #[allow_internal_unstable(print_internals, format_args_nl)]
 macro_rules! println {
-    () => (print!("\n"));
+    () => ($crate::print!("\n"));
     ($($arg:tt)*) => ({
         $crate::io::_print(format_args_nl!($($arg)*));
     })
@@ -204,7 +204,7 @@ macro_rules! eprint {
 #[stable(feature = "eprint", since = "1.19.0")]
 #[allow_internal_unstable(print_internals, format_args_nl)]
 macro_rules! eprintln {
-    () => (eprint!("\n"));
+    () => ($crate::eprint!("\n"));
     ($($arg:tt)*) => ({
         $crate::io::_eprint(format_args_nl!($($arg)*));
     })
@@ -337,23 +337,23 @@ macro_rules! eprintln {
 #[stable(feature = "dbg_macro", since = "1.32.0")]
 macro_rules! dbg {
     () => {
-        eprintln!("[{}:{}]", file!(), line!());
+        $crate::eprintln!("[{}:{}]", file!(), line!());
     };
     ($val:expr) => {
         // Use of `match` here is intentional because it affects the lifetimes
         // of temporaries - https://stackoverflow.com/a/48732525/1063961
         match $val {
             tmp => {
-                eprintln!("[{}:{}] {} = {:#?}",
+                $crate::eprintln!("[{}:{}] {} = {:#?}",
                     file!(), line!(), stringify!($val), &tmp);
                 tmp
             }
         }
     };
     // Trailing comma with single argument is ignored
-    ($val:expr,) => { dbg!($val) };
+    ($val:expr,) => { $crate::dbg!($val) };
     ($($val:expr),+ $(,)?) => {
-        ($(dbg!($val)),+,)
+        ($($crate::dbg!($val)),+,)
     };
 }
 

src/test/ui/hygiene/no_implicit_prelude.rs

@@ -13,7 +13,7 @@ mod bar {
     }
     fn f() {
         ::foo::m!();
-        println!(); //~ ERROR cannot find macro `print!` in this scope
+        assert_eq!(0, 0); //~ ERROR cannot find macro `panic!` in this scope
     }
 }
 

src/test/ui/hygiene/no_implicit_prelude.stderr

@@ -7,11 +7,11 @@ LL |     fn f() { ::bar::m!(); }
 LL |         Vec::new();
    |         ^^^ use of undeclared type or module `Vec`
 
-error: cannot find macro `print!` in this scope
+error: cannot find macro `panic!` in this scope
   --> $DIR/no_implicit_prelude.rs:16:9
    |
-LL |         println!();
-   |         ^^^^^^^^^^^
+LL |         assert_eq!(0, 0);
+   |         ^^^^^^^^^^^^^^^^^
    |
    = help: have you added the `#[macro_use]` on the module/import?
    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

src/test/ui/imports/local-modularized-tricky-fail-1.rs

@@ -33,7 +33,6 @@ mod inner2 {
 
 fn main() {
     panic!(); //~ ERROR `panic` is ambiguous
-              //~| ERROR `panic` is ambiguous
 }
 
 mod inner3 {

src/test/ui/imports/local-modularized-tricky-fail-1.stderr

@@ -22,7 +22,7 @@ LL | use inner1::*;
    = help: consider adding an explicit import of `exported` to disambiguate
 
 error[E0659]: `include` is ambiguous (macro-expanded name vs less macro-expanded name from outer scope during import/macro resolution)
-  --> $DIR/local-modularized-tricky-fail-1.rs:47:1
+  --> $DIR/local-modularized-tricky-fail-1.rs:46:1
    |
 LL | include!();
    | ^^^^^^^ ambiguous name
@@ -59,26 +59,6 @@ LL |       define_panic!();
    |       ---------------- in this macro invocation
    = help: use `crate::panic` to refer to this macro unambiguously
 
-error[E0659]: `panic` is ambiguous (macro-expanded name vs less macro-expanded name from outer scope during import/macro resolution)
-  --> $DIR/local-modularized-tricky-fail-1.rs:35:5
-   |
-LL |     panic!();
-   |     ^^^^^^^^^ ambiguous name
-   |
-   = note: `panic` could refer to a macro from prelude
-note: `panic` could also refer to the macro defined here
-  --> $DIR/local-modularized-tricky-fail-1.rs:11:5
-   |
-LL | /     macro_rules! panic {
-LL | |         () => ()
-LL | |     }
-   | |_____^
-...
-LL |       define_panic!();
-   |       ---------------- in this macro invocation
-   = help: use `crate::panic` to refer to this macro unambiguously
-   = 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 4 previous errors
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0659`.