librustc: Always parse `macro!()`/`macro![]` as expressions if not

followed by a semicolon.

This allows code like `vec![1i, 2, 3].len();` to work.

This breaks code that uses macros as statements without putting
semicolons after them, such as:

    fn main() {
        ...
        assert!(a == b)
        assert!(c == d)
        println(...);
    }

It also breaks code that uses macros as items without semicolons:

    local_data_key!(foo)

    fn main() {
        println("hello world")
    }

Add semicolons to fix this code. Those two examples can be fixed as
follows:

    fn main() {
        ...
        assert!(a == b);
        assert!(c == d);
        println(...);
    }

    local_data_key!(foo);

    fn main() {
        println("hello world")
    }

RFC #378.

Closes #18635.

[breaking-change]

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libstd/io/extensions.rs b/src/libstd/io/extensions.rs
index 24a000adef2..c1f1a5b7869 100644
--- a/src/libstd/io/extensions.rs
+++ b/src/libstd/io/extensions.rs
@@ -511,7 +511,7 @@ mod bench {
     use self::test::Bencher;
 
     // why is this a macro? wouldn't an inlined function work just as well?
-    macro_rules! u64_from_be_bytes_bench_impl(
+    macro_rules! u64_from_be_bytes_bench_impl {
         ($b:expr, $size:expr, $stride:expr, $start_index:expr) =>
         ({
             use super::u64_from_be_bytes;
@@ -526,7 +526,7 @@ mod bench {
                 }
             });
         })
-    )
+    }
 
     #[bench]
     fn u64_from_be_bytes_4_aligned(b: &mut Bencher) {