From b2b8002fd325aa5a6f79d0306f508b4c17cd90af Mon Sep 17 00:00:00 2001
From: Marijn Haverbeke <marijnh@gmail.com>
Date: Wed, 15 Jun 2011 21:38:43 +0200
Subject: [PATCH] Fix unsafe uses of aliases in tail calls

---
 src/comp/middle/trans.rs  |  8 +++---
 src/comp/middle/typeck.rs | 10 ++++----
 src/lib/list.rs           | 53 ++++++++++++++++++++++++++-------------
 3 files changed, 44 insertions(+), 27 deletions(-)

diff --git a/src/comp/middle/trans.rs b/src/comp/middle/trans.rs
index 3b27c8597ed77..9605f4d6e63d1 100644
--- a/src/comp/middle/trans.rs
+++ b/src/comp/middle/trans.rs
@@ -1115,7 +1115,7 @@ fn trans_non_gc_free(&@block_ctxt cx, ValueRef v) -> result {
 fn find_scope_cx(&@block_ctxt cx) -> @block_ctxt {
     if (cx.kind != NON_SCOPE_BLOCK) { ret cx; }
     alt (cx.parent) {
-        case (parent_some(?b)) { be find_scope_cx(b); }
+        case (parent_some(?b)) { ret find_scope_cx(b); }
         case (parent_none) {
             cx.fcx.lcx.ccx.sess.bug("trans::find_scope_cx() " +
                                         "called on parentless block_ctxt");
@@ -2455,7 +2455,7 @@ fn iter_structural_ty(&@block_ctxt cx, ValueRef v, &ty::t t, val_and_ty_fn f)
                   ty::t t) -> result {
         ret f(cx, av, t);
     }
-    be iter_structural_ty_full(cx, v, v, t, bind adaptor_fn(f, _, _, _, _));
+    ret iter_structural_ty_full(cx, v, v, t, bind adaptor_fn(f, _, _, _, _));
 }
 
 fn iter_structural_ty_full(&@block_ctxt cx, ValueRef av, ValueRef bv,
@@ -2693,8 +2693,8 @@ fn iter_sequence_inner(&@block_ctxt cx, ValueRef src,
         ret f(cx, load_if_immediate(cx, p, elt_ty), elt_ty);
     }
     auto elt_sz = size_of(cx, elt_ty);
-    be iter_sequence_raw(elt_sz.bcx, src, src, src_lim, elt_sz.val,
-                         bind adaptor_fn(f, elt_ty, _, _, _));
+    ret iter_sequence_raw(elt_sz.bcx, src, src, src_lim, elt_sz.val,
+                          bind adaptor_fn(f, elt_ty, _, _, _));
 }
 
 
diff --git a/src/comp/middle/typeck.rs b/src/comp/middle/typeck.rs
index d86aa74c1bd4f..48ca4d8a8bc84 100644
--- a/src/comp/middle/typeck.rs
+++ b/src/comp/middle/typeck.rs
@@ -388,7 +388,7 @@ mod write {
     // Writes a type parameter count and type pair into the node type table.
     fn ty(&ty::ctxt tcx, uint node_id, &ty_param_substs_opt_and_ty tpot) {
         assert (!ty::type_contains_vars(tcx, tpot._1));
-        be inner(tcx.node_types, node_id, tpot);
+        ret inner(tcx.node_types, node_id, tpot);
     }
 
     // Writes a type parameter count and type pair into the node type table.
@@ -404,23 +404,23 @@ mod write {
 
     // Writes a type with no type parameters into the node type table.
     fn ty_only(&ty::ctxt tcx, uint node_id, ty::t typ) {
-        be ty(tcx, node_id, tup(none[vec[ty::t]], typ));
+        ret ty(tcx, node_id, tup(none[vec[ty::t]], typ));
     }
 
     // Writes a type with no type parameters into the node type table. This
     // function allows for the possibility of type variables.
     fn ty_only_fixup(@fn_ctxt fcx, uint node_id, ty::t typ) {
-        be ty_fixup(fcx, node_id, tup(none[vec[ty::t]], typ));
+        ret ty_fixup(fcx, node_id, tup(none[vec[ty::t]], typ));
     }
 
     // Writes a nil type into the node type table.
     fn nil_ty(&ty::ctxt tcx, uint node_id) {
-        be ty(tcx, node_id, tup(none[vec[ty::t]], ty::mk_nil(tcx)));
+        ret ty(tcx, node_id, tup(none[vec[ty::t]], ty::mk_nil(tcx)));
     }
 
     // Writes the bottom type into the node type table.
     fn bot_ty(&ty::ctxt tcx, uint node_id) {
-        be ty(tcx, node_id, tup(none[vec[ty::t]], ty::mk_bot(tcx)));
+        ret ty(tcx, node_id, tup(none[vec[ty::t]], ty::mk_bot(tcx)));
     }
 }
 
diff --git a/src/lib/list.rs b/src/lib/list.rs
index edd14a30133b0..a752e005b5e30 100644
--- a/src/lib/list.rs
+++ b/src/lib/list.rs
@@ -18,35 +18,52 @@ fn from_vec[T](vec[T] v) -> list[T] {
     ret l;
 }
 
-fn foldl[T, U](&list[T] ls, &U u, fn(&T, &U) -> U  f) -> U {
-    alt (ls) {
-        case (cons(?hd, ?tl)) {
-            auto u_ = f(hd, u);
-            be foldl[T, U](*tl, u_, f);
+fn foldl[T, U](&list[T] ls_, &U u, fn(&T, &U) -> U  f) -> U {
+    let U accum = u;
+    auto ls = ls_;
+    while (true) {
+        alt (ls) {
+            case (cons(?hd, ?tl)) {
+                accum = f(hd, accum);
+                ls = *tl;
+            }
+            case (nil) { break; }
         }
-        case (nil) { ret u; }
     }
+    ret accum;
 }
 
-fn find[T, U](&list[T] ls, fn(&T) -> option::t[U]  f) -> option::t[U] {
-    alt (ls) {
-        case (cons(?hd, ?tl)) {
-            alt (f(hd)) {
-                case (none) { be find[T, U](*tl, f); }
-                case (some(?res)) { ret some[U](res); }
+fn find[T, U](&list[T] ls_, fn(&T) -> option::t[U]  f) -> option::t[U] {
+    auto ls = ls_;
+    while (true) {
+        alt (ls) {
+            case (cons(?hd, ?tl)) {
+                alt (f(hd)) {
+                    case (none) { ls = *tl; }
+                    case (some(?res)) { ret some(res); }
+                }
             }
+            case (nil) { break; }
         }
-        case (nil) { ret none[U]; }
     }
+    ret none;
 }
 
-fn has[T](&list[T] ls, &T elt) -> bool {
-    alt (ls) {
-        case (cons(?hd, ?tl)) {
-            if (elt == hd) { ret true; } else { be has(*tl, elt); }
+fn has[T](&list[T] ls_, &T elt) -> bool {
+    auto ls = ls_;
+    while (true) {
+        alt (ls) {
+            case (cons(?hd, ?tl)) {
+                if (elt == hd) {
+                    ret true;
+                } else {
+                    ls = *tl;
+                }
+            }
+            case (nil) { ret false; }
         }
-        case (nil) { ret false; }
     }
+    ret false; // Typestate checker doesn't understand infinite loops
 }
 
 fn length[T](&list[T] ls) -> uint {