macro_legacy_warnings -> error

src/test/ui/parser/missing-semicolon.rs

@@ -0,0 +1,8 @@
+macro_rules! m {
+    ($($e1:expr),*; $($e2:expr),*) => {
+        $( let x = $e1 )*; //~ ERROR expected one of `.`, `;`, `?`, or
+        $( println!("{}", $e2) )*;
+    }
+}
+
+fn main() { m!(0, 0; 0, 0); }

src/test/ui/parser/missing-semicolon.stderr

@@ -0,0 +1,13 @@
+error: expected one of `.`, `;`, `?`, or an operator, found keyword `let`
+  --> $DIR/missing-semicolon.rs:3:12
+   |
+LL |         $( let x = $e1 )*;
+   |            ^^^ expected one of `.`, `;`, `?`, or an operator
+...
+LL | fn main() { m!(0, 0; 0, 0); }
+   |             --------------- in this macro invocation
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+