Merge from rustc

Author: RalfJung

src/expr.rs

@@ -399,7 +399,9 @@ pub(crate) fn format_expr(
             }
         }
         ast::ExprKind::Underscore => Some("_".to_owned()),
-        ast::ExprKind::FormatArgs(..) | ast::ExprKind::IncludedBytes(..) => {
+        ast::ExprKind::FormatArgs(..)
+        | ast::ExprKind::IncludedBytes(..)
+        | ast::ExprKind::OffsetOf(..) => {
             // These do not occur in the AST because macros aren't expanded.
             unreachable!()
         }

src/utils.rs

@@ -499,6 +499,7 @@ pub(crate) fn is_block_expr(context: &RewriteContext<'_>, expr: &ast::Expr, repr
         | ast::ExprKind::Field(..)
         | ast::ExprKind::IncludedBytes(..)
         | ast::ExprKind::InlineAsm(..)
+        | ast::ExprKind::OffsetOf(..)
         | ast::ExprKind::Let(..)
         | ast::ExprKind::Path(..)
         | ast::ExprKind::Range(..)