Auto merge of #45822 - kennytm:rollup, r=kennytm

Rollup of 9 pull requests

- Successful merges: #45470, #45588, #45682, #45714, #45751, #45764, #45778, #45782, #45784
- Failed merges:

1 files changed, 9 insertions, 0 deletions

diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 227db93cf65..5cb8e8694cf 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1987,6 +1987,15 @@ impl<'a> State<'a> {
             Fixity::None => (prec + 1, prec + 1),
         };
 
+        let left_prec = match (&lhs.node, op.node) {
+            // These cases need parens: `x as i32 < y` has the parser thinking that `i32 < y` is
+            // the beginning of a path type. It starts trying to parse `x as (i32 < y ...` instead
+            // of `(x as i32) < ...`. We need to convince it _not_ to do that.
+            (&ast::ExprKind::Cast { .. }, ast::BinOpKind::Lt) |
+            (&ast::ExprKind::Cast { .. }, ast::BinOpKind::Shl) => parser::PREC_FORCE_PAREN,
+            _ => left_prec,
+        };
+
         self.print_expr_maybe_paren(lhs, left_prec)?;
         self.s.space()?;
         self.word_space(op.node.to_string())?;