Rollup merge of #34436 - jseyfried:no_block_expr, r=eddyb

To allow these braced macro invocation, this PR removes the optional expression from `ast::Block` and instead uses a `StmtKind::Expr` at the end of the statement list.

Currently, braced macro invocations in blocks can expand into statements (and items) except when they are last in a block, in which case they can only expand into expressions.

For example,
```rust
macro_rules! make_stmt {
    () => { let x = 0; }
}

fn f() {
    make_stmt! {} //< This is OK...
    let x = 0; //< ... unless this line is commented out.
}
```

Fixes #34418.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libsyntax_ext/deriving/cmp/eq.rs b/src/libsyntax_ext/deriving/cmp/eq.rs
index 4258e152088..9c5072eeb3e 100644
--- a/src/libsyntax_ext/deriving/cmp/eq.rs
+++ b/src/libsyntax_ext/deriving/cmp/eq.rs
@@ -30,7 +30,7 @@ pub fn expand_deriving_eq(cx: &mut ExtCtxt,
                 // create `a.<method>(); b.<method>(); c.<method>(); ...`
                 // (where method is `assert_receiver_is_total_eq`)
                 let stmts = exprs.into_iter().map(|e| cx.stmt_expr(e)).collect();
-                let block = cx.block(span, stmts, None);
+                let block = cx.block(span, stmts);
                 cx.expr_block(block)
             },
             Box::new(|cx, sp, _, _| {