auto merge of #7363 : bblum/rust/soundness, r=nikomatsakis

The commit f9a5453 is meant to be a temporary hold-over. Whether or not there is added a way for the compiler to "implicitly borrow" stack closures in this way, there should be a codegen optimization that prevents having to traverse possibly-very-many function pointers to find the function you ultimately wanted to call. I tried to separate out the changes so this particular commit could be straight-up reverted if auto-borrowing happens in the future.

r? @nikomatsakis

Author: bors

src/libextra/fun_treemap.rs

@@ -66,9 +66,9 @@ pub fn traverse<K, V: Copy>(m: Treemap<K, V>, f: &fn(&K, &V)) {
         // matches to me, so I changed it. but that may be a
         // de-optimization -- tjc
         Node(@ref k, @ref v, left, right) => {
-            traverse(left, f);
+            traverse(left, |k,v| f(k,v));
             f(k, v);
-            traverse(right, f);
+            traverse(right, |k,v| f(k,v));
         }
     }
 }

src/libextra/rope.rs

@@ -1078,7 +1078,7 @@ pub mod node {
 
     pub fn loop_chars(node: @Node, it: &fn(c: char) -> bool) -> bool {
         return loop_leaves(node,|leaf| {
-            leaf.content.slice(leaf.byte_offset, leaf.byte_len).iter().all(it)
+            leaf.content.slice(leaf.byte_offset, leaf.byte_len).iter().all(|c| it(c))
         });
     }
 
@@ -1101,7 +1101,7 @@ pub mod node {
         loop {
             match (*current) {
               Leaf(x) => return it(x),
-              Concat(ref x) => if loop_leaves(x.left, it) { //non tail call
+              Concat(ref x) => if loop_leaves(x.left, |l| it(l)) { //non tail call
                 current = x.right;       //tail call
               } else {
                 return false;

src/libextra/sort.rs

@@ -42,7 +42,8 @@ pub fn merge_sort<T:Copy>(v: &[T], le: Le<T>) -> ~[T] {
         let mid = v_len / 2 + begin;
         let a = (begin, mid);
         let b = (mid, end);
-        return merge(le, merge_sort_(v, a, le), merge_sort_(v, b, le));
+        return merge(|x,y| le(x,y), merge_sort_(v, a, |x,y| le(x,y)),
+                                    merge_sort_(v, b, |x,y| le(x,y)));
     }
 
     fn merge<T:Copy>(le: Le<T>, a: &[T], b: &[T]) -> ~[T] {
@@ -83,10 +84,10 @@ fn qsort<T>(arr: &mut [T], left: uint,
             right: uint, compare_func: Le<T>) {
     if right > left {
         let pivot = (left + right) / 2u;
-        let new_pivot = part::<T>(arr, left, right, pivot, compare_func);
+        let new_pivot = part::<T>(arr, left, right, pivot, |x,y| compare_func(x,y));
         if new_pivot != 0u {
             // Need to do this check before recursing due to overflow
-            qsort::<T>(arr, left, new_pivot - 1u, compare_func);
+            qsort::<T>(arr, left, new_pivot - 1u, |x,y| compare_func(x,y));
         }
         qsort::<T>(arr, new_pivot + 1u, right, compare_func);
     }
@@ -1202,7 +1203,7 @@ mod big_tests {
 
     struct LVal<'self> {
         val: uint,
-        key: &'self fn(@uint),
+        key: &'self fn:Copy(@uint),
     }
 
     #[unsafe_destructor]

src/libextra/sync.rs

@@ -563,7 +563,9 @@ impl RWlock {
                 (&self.order_lock).acquire();
                 do (&self.access_lock).access_waitqueue {
                     (&self.order_lock).release();
-                    task::rekillable(blk)
+                    do task::rekillable {
+                        blk()
+                    }
                 }
             }
         }
@@ -1182,12 +1184,12 @@ mod tests {
             Write => x.write(blk),
             Downgrade =>
                 do x.write_downgrade |mode| {
-                    (&mode).write(blk);
+                    do mode.write { blk() };
                 },
             DowngradeRead =>
                 do x.write_downgrade |mode| {
                     let mode = x.downgrade(mode);
-                    (&mode).read(blk);
+                    do mode.read { blk() };
                 },
         }
     }
@@ -1340,10 +1342,10 @@ mod tests {
         fn lock_cond(x: &RWlock, downgrade: bool, blk: &fn(c: &Condvar)) {
             if downgrade {
                 do x.write_downgrade |mode| {
-                    (&mode).write_cond(blk)
+                    do mode.write_cond |c| { blk(c) }
                 }
             } else {
-                x.write_cond(blk)
+                do x.write_cond |c| { blk(c) }
             }
         }
         let x = ~RWlock();

src/libextra/test.rs

@@ -678,7 +678,7 @@ impl BenchHarness {
 
         // Initial bench run to get ballpark figure.
         let mut n = 1_u64;
-        self.bench_n(n, f);
+        self.bench_n(n, |x| f(x));
 
         while n < 1_000_000_000 &&
             self.ns_elapsed() < 1_000_000_000 {
@@ -694,7 +694,7 @@ impl BenchHarness {
 
             n = u64::max(u64::min(n+n/2, 100*last), last+1);
             n = round_up(n);
-            self.bench_n(n, f);
+            self.bench_n(n, |x| f(x));
         }
     }
 
@@ -714,7 +714,7 @@ impl BenchHarness {
                                             magnitude * 2);
 
             let samples = do vec::from_fn(n_samples) |_| {
-                self.bench_n(n_iter as u64, f);
+                self.bench_n(n_iter as u64, |x| f(x));
                 self.ns_per_iter() as f64
             };
 

src/libextra/treemap.rs

@@ -511,14 +511,14 @@ impl<K: TotalOrd, V> TreeNode<K, V> {
 
 fn each<'r, K: TotalOrd, V>(node: &'r Option<~TreeNode<K, V>>,
                             f: &fn(&'r K, &'r V) -> bool) -> bool {
-    node.iter().advance(|x| each(&x.left, f) && f(&x.key, &x.value) &&
-                            each(&x.right, f))
+    node.iter().advance(|x| each(&x.left,  |k,v| f(k,v)) && f(&x.key, &x.value) &&
+                            each(&x.right, |k,v| f(k,v)))
 }
 
 fn each_reverse<'r, K: TotalOrd, V>(node: &'r Option<~TreeNode<K, V>>,
                                     f: &fn(&'r K, &'r V) -> bool) -> bool {
-    node.iter().advance(|x| each_reverse(&x.right, f) && f(&x.key, &x.value) &&
-                            each_reverse(&x.left, f))
+    node.iter().advance(|x| each_reverse(&x.right, |k,v| f(k,v)) && f(&x.key, &x.value) &&
+                            each_reverse(&x.left,  |k,v| f(k,v)))
 }
 
 fn mutate_values<'r, K: TotalOrd, V>(node: &'r mut Option<~TreeNode<K, V>>,
@@ -527,9 +527,9 @@ fn mutate_values<'r, K: TotalOrd, V>(node: &'r mut Option<~TreeNode<K, V>>,
     match *node {
       Some(~TreeNode{key: ref key, value: ref mut value, left: ref mut left,
                      right: ref mut right, _}) => {
-        if !mutate_values(left, f) { return false }
+        if !mutate_values(left,  |k,v| f(k,v)) { return false }
         if !f(key, value) { return false }
-        if !mutate_values(right, f) { return false }
+        if !mutate_values(right, |k,v| f(k,v)) { return false }
       }
       None => return false
     }

src/libextra/workcache.rs

@@ -107,7 +107,7 @@ struct WorkKey {
 impl to_bytes::IterBytes for WorkKey {
     #[inline]
     fn iter_bytes(&self, lsb0: bool, f: to_bytes::Cb) -> bool {
-        self.kind.iter_bytes(lsb0, f) && self.name.iter_bytes(lsb0, f)
+        self.kind.iter_bytes(lsb0, |b| f(b)) && self.name.iter_bytes(lsb0, |b| f(b))
     }
 }
 

src/librust/rust.rs

@@ -57,13 +57,13 @@ impl ValidUsage {
 }
 
 enum Action<'self> {
-    Call(&'self fn(args: &[~str]) -> ValidUsage),
-    CallMain(&'static str, &'self fn()),
+    Call(&'self fn:Copy(args: &[~str]) -> ValidUsage),
+    CallMain(&'static str, &'self fn:Copy()),
 }
 
 enum UsageSource<'self> {
     UsgStr(&'self str),
-    UsgCall(&'self fn()),
+    UsgCall(&'self fn:Copy()),
 }
 
 struct Command<'self> {

src/librustc/metadata/filesearch.rs

@@ -48,7 +48,7 @@ pub fn mk_filesearch(maybe_sysroot: &Option<@Path>,
             debug!("filesearch: searching additional lib search paths [%?]",
                    self.addl_lib_search_paths.len());
             // a little weird
-            self.addl_lib_search_paths.iter().advance(f);
+            self.addl_lib_search_paths.iter().advance(|path| f(path));
 
             debug!("filesearch: searching target lib path");
             if !f(&make_target_lib_path(self.sysroot,

src/librustc/metadata/tydecode.rs

@@ -189,11 +189,11 @@ fn parse_trait_store(st: &mut PState) -> ty::TraitStore {
 fn parse_substs(st: &mut PState, conv: conv_did) -> ty::substs {
     let self_r = parse_opt(st, |st| parse_region(st) );
 
-    let self_ty = parse_opt(st, |st| parse_ty(st, conv) );
+    let self_ty = parse_opt(st, |st| parse_ty(st, |x,y| conv(x,y)) );
 
     assert_eq!(next(st), '[');
     let mut params: ~[ty::t] = ~[];
-    while peek(st) != ']' { params.push(parse_ty(st, conv)); }
+    while peek(st) != ']' { params.push(parse_ty(st, |x,y| conv(x,y))); }
     st.pos = st.pos + 1u;
 
     return ty::substs {
@@ -270,8 +270,8 @@ fn parse_str(st: &mut PState, term: char) -> ~str {
 }
 
 fn parse_trait_ref(st: &mut PState, conv: conv_did) -> ty::TraitRef {
-    let def = parse_def(st, NominalType, conv);
-    let substs = parse_substs(st, conv);
+    let def = parse_def(st, NominalType, |x,y| conv(x,y));
+    let substs = parse_substs(st, |x,y| conv(x,y));
     ty::TraitRef {def_id: def, substs: substs}
 }
 
@@ -301,18 +301,18 @@ fn parse_ty(st: &mut PState, conv: conv_did) -> ty::t {
       'c' => return ty::mk_char(),
       't' => {
         assert_eq!(next(st), '[');
-        let def = parse_def(st, NominalType, conv);
-        let substs = parse_substs(st, conv);
+        let def = parse_def(st, NominalType, |x,y| conv(x,y));
+        let substs = parse_substs(st, |x,y| conv(x,y));
         assert_eq!(next(st), ']');
         return ty::mk_enum(st.tcx, def, substs);
       }
       'x' => {
         assert_eq!(next(st), '[');
-        let def = parse_def(st, NominalType, conv);
-        let substs = parse_substs(st, conv);
+        let def = parse_def(st, NominalType, |x,y| conv(x,y));
+        let substs = parse_substs(st, |x,y| conv(x,y));
         let store = parse_trait_store(st);
         let mt = parse_mutability(st);
-        let bounds = parse_bounds(st, conv);
+        let bounds = parse_bounds(st, |x,y| conv(x,y));
         assert_eq!(next(st), ']');
         return ty::mk_trait(st.tcx, def, substs, store, mt, bounds.builtin_bounds);
       }
@@ -346,7 +346,7 @@ fn parse_ty(st: &mut PState, conv: conv_did) -> ty::t {
       'T' => {
         assert_eq!(next(st), '[');
         let mut params = ~[];
-        while peek(st) != ']' { params.push(parse_ty(st, conv)); }
+        while peek(st) != ']' { params.push(parse_ty(st, |x,y| conv(x,y))); }
         st.pos = st.pos + 1u;
         return ty::mk_tup(st.tcx, params);
       }
@@ -380,15 +380,15 @@ fn parse_ty(st: &mut PState, conv: conv_did) -> ty::t {
         }
       }
       '"' => {
-        let _ = parse_def(st, TypeWithId, conv);
-        let inner = parse_ty(st, conv);
+        let _ = parse_def(st, TypeWithId, |x,y| conv(x,y));
+        let inner = parse_ty(st, |x,y| conv(x,y));
         inner
       }
       'B' => ty::mk_opaque_box(st.tcx),
       'a' => {
           assert_eq!(next(st), '[');
-          let did = parse_def(st, NominalType, conv);
-          let substs = parse_substs(st, conv);
+          let did = parse_def(st, NominalType, |x,y| conv(x,y));
+          let substs = parse_substs(st, |x,y| conv(x,y));
           assert_eq!(next(st), ']');
           return ty::mk_struct(st.tcx, did, substs);
       }
@@ -473,8 +473,8 @@ fn parse_closure_ty(st: &mut PState, conv: conv_did) -> ty::ClosureTy {
     let purity = parse_purity(next(st));
     let onceness = parse_onceness(next(st));
     let region = parse_region(st);
-    let bounds = parse_bounds(st, conv);
-    let sig = parse_sig(st, conv);
+    let bounds = parse_bounds(st, |x,y| conv(x,y));
+    let sig = parse_sig(st, |x,y| conv(x,y));
     ty::ClosureTy {
         purity: purity,
         sigil: sigil,
@@ -500,7 +500,7 @@ fn parse_sig(st: &mut PState, conv: conv_did) -> ty::FnSig {
     assert_eq!(next(st), '[');
     let mut inputs = ~[];
     while peek(st) != ']' {
-        inputs.push(parse_ty(st, conv));
+        inputs.push(parse_ty(st, |x,y| conv(x,y)));
     }
     st.pos += 1u; // eat the ']'
     let ret_ty = parse_ty(st, conv);
@@ -544,8 +544,8 @@ pub fn parse_type_param_def_data(data: &[u8], start: uint,
 }
 
 fn parse_type_param_def(st: &mut PState, conv: conv_did) -> ty::TypeParameterDef {
-    ty::TypeParameterDef {def_id: parse_def(st, NominalType, conv),
-                          bounds: @parse_bounds(st, conv)}
+    ty::TypeParameterDef {def_id: parse_def(st, NominalType, |x,y| conv(x,y)),
+                          bounds: @parse_bounds(st, |x,y| conv(x,y))}
 }
 
 fn parse_bounds(st: &mut PState, conv: conv_did) -> ty::ParamBounds {
@@ -571,7 +571,7 @@ fn parse_bounds(st: &mut PState, conv: conv_did) -> ty::ParamBounds {
                 param_bounds.builtin_bounds.add(ty::BoundSized);
             }
             'I' => {
-                param_bounds.trait_bounds.push(@parse_trait_ref(st, conv));
+                param_bounds.trait_bounds.push(@parse_trait_ref(st, |x,y| conv(x,y)));
             }
             '.' => {
                 return param_bounds;

src/librustc/middle/borrowck/move_data.rs

@@ -411,7 +411,7 @@ impl MoveData {
 
         let mut p = self.path(index).first_child;
         while p != InvalidMovePathIndex {
-            if !self.each_extending_path(p, f) {
+            if !self.each_extending_path(p, |x| f(x)) {
                 return false;
             }
             p = self.path(p).next_sibling;

src/librustc/middle/kind.rs

@@ -171,7 +171,7 @@ fn with_appropriate_checker(cx: Context, id: node_id,
         // check that only immutable variables are implicitly copied in
         check_imm_free_var(cx, fv.def, fv.span);
 
-        check_freevar_bounds(cx, fv.span, var_t, bounds);
+        check_freevar_bounds(cx, fv.span, var_t, bounds, None);
     }
 
     fn check_for_box(cx: Context, fv: &freevar_entry, bounds: ty::BuiltinBounds) {
@@ -182,13 +182,18 @@ fn with_appropriate_checker(cx: Context, id: node_id,
         // check that only immutable variables are implicitly copied in
         check_imm_free_var(cx, fv.def, fv.span);
 
-        check_freevar_bounds(cx, fv.span, var_t, bounds);
+        check_freevar_bounds(cx, fv.span, var_t, bounds, None);
     }
 
-    fn check_for_block(cx: Context, fv: &freevar_entry, bounds: ty::BuiltinBounds) {
+    fn check_for_block(cx: Context, fv: &freevar_entry,
+                       bounds: ty::BuiltinBounds, region: ty::Region) {
         let id = ast_util::def_id_of_def(fv.def).node;
         let var_t = ty::node_id_to_type(cx.tcx, id);
-        check_freevar_bounds(cx, fv.span, var_t, bounds);
+        // FIXME(#3569): Figure out whether the implicit borrow is actually
+        // mutable. Currently we assume all upvars are referenced mutably.
+        let implicit_borrowed_type = ty::mk_mut_rptr(cx.tcx, region, var_t);
+        check_freevar_bounds(cx, fv.span, implicit_borrowed_type,
+                             bounds, Some(var_t));
     }
 
     fn check_for_bare(cx: Context, fv: @freevar_entry) {
@@ -205,8 +210,9 @@ fn with_appropriate_checker(cx: Context, id: node_id,
         ty::ty_closure(ty::ClosureTy {sigil: ManagedSigil, bounds: bounds, _}) => {
             b(|cx, fv| check_for_box(cx, fv, bounds))
         }
-        ty::ty_closure(ty::ClosureTy {sigil: BorrowedSigil, bounds: bounds, _}) => {
-            b(|cx, fv| check_for_block(cx, fv, bounds))
+        ty::ty_closure(ty::ClosureTy {sigil: BorrowedSigil, bounds: bounds,
+                                      region: region, _}) => {
+            b(|cx, fv| check_for_block(cx, fv, bounds, region))
         }
         ty::ty_bare_fn(_) => {
             b(check_for_bare)
@@ -366,14 +372,21 @@ pub fn check_typaram_bounds(cx: Context,
 }
 
 pub fn check_freevar_bounds(cx: Context, sp: span, ty: ty::t,
-                            bounds: ty::BuiltinBounds)
+                            bounds: ty::BuiltinBounds, referenced_ty: Option<ty::t>)
 {
     do check_builtin_bounds(cx, ty, bounds) |missing| {
-        cx.tcx.sess.span_err(
-            sp,
-            fmt!("cannot capture variable of type `%s`, which does not fulfill \
-                  `%s`, in a bounded closure",
-                 ty_to_str(cx.tcx, ty), missing.user_string(cx.tcx)));
+        // Will be Some if the freevar is implicitly borrowed (stack closure).
+        // Emit a less mysterious error message in this case.
+        match referenced_ty {
+            Some(rty) => cx.tcx.sess.span_err(sp,
+                fmt!("cannot implicitly borrow variable of type `%s` in a bounded \
+                      stack closure (implicit reference does not fulfill `%s`)",
+                     ty_to_str(cx.tcx, rty), missing.user_string(cx.tcx))),
+            None => cx.tcx.sess.span_err(sp,
+                fmt!("cannot capture variable of type `%s`, which does \
+                      not fulfill `%s`, in a bounded closure",
+                     ty_to_str(cx.tcx, ty), missing.user_string(cx.tcx))),
+        }
         cx.tcx.sess.span_note(
             sp,
             fmt!("this closure's environment must satisfy `%s`",