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/librustc_borrowck/borrowck/mod.rs b/src/librustc_borrowck/borrowck/mod.rs
index a3fb91aced0..7f469db3186 100644
--- a/src/librustc_borrowck/borrowck/mod.rs
+++ b/src/librustc_borrowck/borrowck/mod.rs
@@ -39,14 +39,14 @@ use syntax::visit;
 use syntax::visit::{Visitor, FnKind};
 use syntax::ast::{FnDecl, Block, NodeId};
 
-macro_rules! if_ok(
+macro_rules! if_ok {
     ($inp: expr) => (
         match $inp {
             Ok(v) => { v }
             Err(e) => { return Err(e); }
         }
     )
-)
+}
 
 pub mod doc;