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/test/compile-fail/macro-incomplete-parse.rs b/src/test/compile-fail/macro-incomplete-parse.rs
index 94386858d29..71b656d0bbb 100644
--- a/src/test/compile-fail/macro-incomplete-parse.rs
+++ b/src/test/compile-fail/macro-incomplete-parse.rs
@@ -26,10 +26,10 @@ macro_rules! ignored_pat {
     () => ( 1, 2 ) //~ ERROR macro expansion ignores token `,`
 }
 
-ignored_item!()
+ignored_item!();
 
 fn main() {
-    ignored_expr!()
+    ignored_expr!();
     match 1 {
         ignored_pat!() => (),
         _ => (),