+
+/// Does this expression require a semicolon to be treated
+/// as a statement? The negation of this: 'can this expression
+/// be used as a statement without a semicolon' -- is used
+/// as an early-bail-out in the parser so that, for instance,
+/// if true {...} else {...}
+/// |x| 5
+/// isn't parsed as (if true {...} else {...} | x) | 5
+// From https://github.com/rust-lang/rust/blob/master/src/libsyntax/parse/classify.rs.
+fn expr_requires_semi_to_be_stmt(e: &ast::Expr) -> bool {
+ match e.kind {
+ ast::ExprKind::If(..)
+ | ast::ExprKind::Match(..)
+ | ast::ExprKind::Block(..)
+ | ast::ExprKind::While(..)
+ | ast::ExprKind::Loop(..)
+ | ast::ExprKind::ForLoop(..)
+ | ast::ExprKind::TryBlock(..) => false,
+ _ => true,
+ }
+}