Treat trailing semicolon as a statement in macro call

See https://github.com/rust-lang/rust/issues/61733#issuecomment-716188981

We now preserve the trailing semicolon in a macro invocation, even if
the macro expands to nothing. As a result, the following code no longer
compiles:

```rust
macro_rules! empty {
    () => { }
}

fn foo() -> bool { //~ ERROR mismatched
    { true } //~ ERROR mismatched
    empty!();
}
```

Previously, `{ true }` would be considered the trailing expression, even
though there's a semicolon in `empty!();`

This makes macro expansion more token-based.

3 files changed, 28 insertions, 1 deletions

diff --git a/src/test/ui/macros/empty-trailing-stmt.rs b/src/test/ui/macros/empty-trailing-stmt.rs
new file mode 100644
index 00000000000..3d78ed4a475
--- /dev/null
+++ b/src/test/ui/macros/empty-trailing-stmt.rs
@@ -0,0 +1,10 @@
+macro_rules! empty {
+    () => { }
+}
+
+fn foo() -> bool { //~ ERROR mismatched
+    { true } //~ ERROR mismatched
+    empty!();
+}
+
+fn main() {}
diff --git a/src/test/ui/macros/empty-trailing-stmt.stderr b/src/test/ui/macros/empty-trailing-stmt.stderr
new file mode 100644
index 00000000000..e88b12712fb
--- /dev/null
+++ b/src/test/ui/macros/empty-trailing-stmt.stderr
@@ -0,0 +1,17 @@
+error[E0308]: mismatched types
+  --> $DIR/empty-trailing-stmt.rs:6:7
+   |
+LL |     { true }
+   |       ^^^^ expected `()`, found `bool`
+
+error[E0308]: mismatched types
+  --> $DIR/empty-trailing-stmt.rs:5:13
+   |
+LL | fn foo() -> bool {
+   |    ---      ^^^^ expected `bool`, found `()`
+   |    |
+   |    implicitly returns `()` as its body has no tail or `return` expression
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/proc-macro/meta-macro-hygiene.stdout b/src/test/ui/proc-macro/meta-macro-hygiene.stdout
index 81cebae17ae..a067b7b5411 100644
--- a/src/test/ui/proc-macro/meta-macro-hygiene.stdout
+++ b/src/test/ui/proc-macro/meta-macro-hygiene.stdout
@@ -40,7 +40,7 @@ macro_rules! produce_it
     }
 }
 
-fn main /* 0#0 */() { }
+fn main /* 0#0 */() { ; }
 
 /*
 Expansions: