From 09e21fe2b93e926b77f105939f6d7f2fb6f7dcc9 Mon Sep 17 00:00:00 2001
From: Brian Anderson <banderson@mozilla.com>
Date: Thu, 18 Aug 2011 23:28:49 -0700
Subject: [PATCH] Pretty-print parens around more things that need
 disambiguation

Ridiculous stuff like (ret 0) == (log "error")
---
 src/comp/syntax/print/pprust.rs  | 22 ++++++++++++++++------
 src/test/run-pass/wierd-exprs.rs |  1 -
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/comp/syntax/print/pprust.rs b/src/comp/syntax/print/pprust.rs
index e9c1dee1f544..21d446c9c5c0 100644
--- a/src/comp/syntax/print/pprust.rs
+++ b/src/comp/syntax/print/pprust.rs
@@ -1377,18 +1377,28 @@ fn operator_prec(op: ast::binop) -> int {
 }
 
 fn need_parens(expr: &@ast::expr, outer_prec: int) -> bool {
-    let add_them;
     alt expr.node {
       ast::expr_binary(op, _, _) {
-        add_them = operator_prec(op) < outer_prec;
+        operator_prec(op) < outer_prec
       }
-      ast::expr_cast(_, _) { add_them = parse::parser::as_prec < outer_prec; }
+      ast::expr_cast(_, _) { parse::parser::as_prec < outer_prec }
       ast::expr_ternary(_, _, _) {
-        add_them = parse::parser::ternary_prec < outer_prec;
+        parse::parser::ternary_prec < outer_prec
       }
-      _ { add_them = false; }
+
+      // This may be too conservative in some cases
+      ast::expr_assign(_, _) { true }
+      ast::expr_move(_, _) { true }
+      ast::expr_swap(_, _) { true }
+      ast::expr_assign_op(_, _, _) { true }
+      ast::expr_ret(_) { true }
+      ast::expr_put(_) { true }
+      ast::expr_be(_) { true }
+      ast::expr_assert(_) { true }
+      ast::expr_check(_, _) { true }
+      ast::expr_log(_, _) { true }
+      _ { false }
     }
-    ret add_them;
 }
 
 fn print_maybe_parens(s: &ps, expr: &@ast::expr, outer_prec: int) {
diff --git a/src/test/run-pass/wierd-exprs.rs b/src/test/run-pass/wierd-exprs.rs
index 4496d6f15560..a8276c92bb6d 100644
--- a/src/test/run-pass/wierd-exprs.rs
+++ b/src/test/run-pass/wierd-exprs.rs
@@ -1,4 +1,3 @@
-// xfail-pretty
 // Just a grab bug of stuff that you wouldn't want to actualy write
 
 fn strange() -> bool {