auto merge of #6302 : nikomatsakis/rust/issue-6141-leaking-owned-fn, r=brson

When autoborrowing a fn in trans, adjust the type of the datum to be `&fn`.

Fixes #6141.

r? @brson

6 files changed, 71 insertions, 54 deletions

diff --git a/src/librustc/middle/trans/datum.rs b/src/librustc/middle/trans/datum.rs
index c19650e3b68..3b885ae9b94 100644
--- a/src/librustc/middle/trans/datum.rs
+++ b/src/librustc/middle/trans/datum.rs
@@ -548,11 +548,9 @@ pub impl Datum {
     }
 
     fn to_rptr(&self, bcx: block) -> Datum {
-        //!
-        //
-        // Returns a new datum of region-pointer type containing the
-        // the same ptr as this datum (after converting to by-ref
-        // using `to_ref_llval()`).
+        //! Returns a new datum of region-pointer type containing the
+        //! the same ptr as this datum (after converting to by-ref
+        //! using `to_ref_llval()`).
 
         // Convert to ref, yielding lltype *T.  Then create a Rust
         // type &'static T (which translates to *T).  Construct new
diff --git a/src/librustc/middle/trans/expr.rs b/src/librustc/middle/trans/expr.rs
index 0e8b2e04746..2c59d5c6bd6 100644
--- a/src/librustc/middle/trans/expr.rs
+++ b/src/librustc/middle/trans/expr.rs
@@ -183,30 +183,25 @@ fn drop_and_cancel_clean(bcx: block, dat: Datum) -> block {
 
 pub fn trans_to_datum(bcx: block, expr: @ast::expr) -> DatumBlock {
     debug!("trans_to_datum(expr=%s)", bcx.expr_to_str(expr));
-    return match bcx.tcx().adjustments.find(&expr.id) {
-        None => {
-            trans_to_datum_unadjusted(bcx, expr)
-        }
-        Some(&@AutoAddEnv(*)) => {
-            let mut bcx = bcx;
-            let datum = unpack_datum!(bcx, {
-                trans_to_datum_unadjusted(bcx, expr)
-            });
-            add_env(bcx, expr, datum)
-        }
-        Some(&@AutoDerefRef(ref adj)) => {
-            let mut bcx = bcx;
-            let mut datum = unpack_datum!(bcx, {
-                trans_to_datum_unadjusted(bcx, expr)
-            });
-
-            debug!("unadjusted datum: %s", datum.to_str(bcx.ccx()));
 
+    let mut bcx = bcx;
+    let mut datum = unpack_datum!(bcx, trans_to_datum_unadjusted(bcx, expr));
+    let adjustment = match bcx.tcx().adjustments.find_copy(&expr.id) {
+        None => { return DatumBlock {bcx: bcx, datum: datum}; }
+        Some(adj) => { adj }
+    };
+    debug!("unadjusted datum: %s", datum.to_str(bcx.ccx()));
+    match *adjustment {
+        AutoAddEnv(*) => {
+            datum = unpack_datum!(bcx, add_env(bcx, expr, datum));
+        }
+        AutoDerefRef(ref adj) => {
             if adj.autoderefs > 0 {
-                let DatumBlock { bcx: new_bcx, datum: new_datum } =
-                    datum.autoderef(bcx, expr.span, expr.id, adj.autoderefs);
-                datum = new_datum;
-                bcx = new_bcx;
+                datum =
+                    unpack_datum!(
+                        bcx,
+                        datum.autoderef(bcx, expr.span,
+                                        expr.id, adj.autoderefs));
             }
 
             datum = match adj.autoref {
@@ -224,23 +219,31 @@ pub fn trans_to_datum(bcx: block, expr: @ast::expr) -> DatumBlock {
                     unpack_datum!(bcx, auto_slice_and_ref(bcx, expr, datum))
                 }
                 Some(AutoBorrowFn(*)) => {
-                    // currently, all closure types are
-                    // represented precisely the same, so no
-                    // runtime adjustment is required:
-                    datum
+                    let adjusted_ty = ty::adjust_ty(bcx.tcx(), expr.span,
+                                                    datum.ty, Some(adjustment));
+                    unpack_datum!(bcx, auto_borrow_fn(bcx, adjusted_ty, datum))
                 }
             };
-
-            debug!("after adjustments, datum=%s", datum.to_str(bcx.ccx()));
-
-            return DatumBlock {bcx: bcx, datum: datum};
         }
-    };
+    }
+    debug!("after adjustments, datum=%s", datum.to_str(bcx.ccx()));
+    return DatumBlock {bcx: bcx, datum: datum};
 
     fn auto_ref(bcx: block, datum: Datum) -> DatumBlock {
         DatumBlock {bcx: bcx, datum: datum.to_rptr(bcx)}
     }
 
+    fn auto_borrow_fn(bcx: block,
+                      adjusted_ty: ty::t,
+                      datum: Datum) -> DatumBlock {
+        // Currently, all closure types are represented precisely the
+        // same, so no runtime adjustment is required, but we still
+        // must patchup the type.
+        DatumBlock {bcx: bcx,
+                    datum: Datum {val: datum.val, ty: adjusted_ty,
+                                  mode: datum.mode, source: datum.source}}
+    }
+
     fn auto_slice(bcx: block, expr: @ast::expr, datum: Datum) -> DatumBlock {
         // This is not the most efficient thing possible; since slices
         // are two words it'd be better if this were compiled in
diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs
index 892635416c2..b6e024b011e 100644
--- a/src/librustc/middle/ty.rs
+++ b/src/librustc/middle/ty.rs
@@ -2893,20 +2893,20 @@ pub fn expr_ty_adjusted(cx: ctxt, expr: @ast::expr) -> t {
      */
 
     let unadjusted_ty = expr_ty(cx, expr);
-    adjust_ty(cx, expr.span, unadjusted_ty, cx.adjustments.find(&expr.id))
+    adjust_ty(cx, expr.span, unadjusted_ty, cx.adjustments.find_copy(&expr.id))
 }
 
 pub fn adjust_ty(cx: ctxt,
                  span: span,
                  unadjusted_ty: ty::t,
-                 adjustment: Option<&@AutoAdjustment>) -> ty::t
+                 adjustment: Option<@AutoAdjustment>) -> ty::t
 {
     /*! See `expr_ty_adjusted` */
 
     return match adjustment {
         None => unadjusted_ty,
 
-        Some(&@AutoAddEnv(r, s)) => {
+        Some(@AutoAddEnv(r, s)) => {
             match ty::get(unadjusted_ty).sty {
                 ty::ty_bare_fn(ref b) => {
                     ty::mk_closure(
@@ -2924,7 +2924,7 @@ pub fn adjust_ty(cx: ctxt,
             }
         }
 
-        Some(&@AutoDerefRef(ref adj)) => {
+        Some(@AutoDerefRef(ref adj)) => {
             let mut adjusted_ty = unadjusted_ty;
 
             for uint::range(0, adj.autoderefs) |i| {
diff --git a/src/librustc/middle/typeck/check/regionck.rs b/src/librustc/middle/typeck/check/regionck.rs
index 6db6b7556ae..2274259f18c 100644
--- a/src/librustc/middle/typeck/check/regionck.rs
+++ b/src/librustc/middle/typeck/check/regionck.rs
@@ -118,6 +118,7 @@ pub impl Rcx {
     }
 
     /// Try to resolve the type for the given node.
+    #[config(stage0)]
     fn resolve_expr_type_adjusted(@mut self, expr: @ast::expr) -> ty::t {
         let ty_unadjusted = self.resolve_node_type(expr.id);
         if ty::type_is_error(ty_unadjusted) || ty::type_is_bot(ty_unadjusted) {
@@ -125,15 +126,29 @@ pub impl Rcx {
         } else {
             let tcx = self.fcx.tcx();
             let adjustments = self.fcx.inh.adjustments;
-            match adjustments.find(&expr.id) {
+            match adjustments.find_copy(&expr.id) {
                 None => ty_unadjusted,
-                Some(&adjustment) => {
-                    // FIXME(#3850) --- avoid region scoping errors
-                    ty::adjust_ty(tcx, expr.span, ty_unadjusted, Some(&adjustment))
+                Some(adjustment) => {
+                    ty::adjust_ty(tcx, expr.span, ty_unadjusted,
+                                  Some(adjustment))
                 }
             }
         }
     }
+
+    /// Try to resolve the type for the given node.
+    #[config(not(stage0))]
+    fn resolve_expr_type_adjusted(@mut self, expr: @ast::expr) -> ty::t {
+        let ty_unadjusted = self.resolve_node_type(expr.id);
+        if ty::type_is_error(ty_unadjusted) || ty::type_is_bot(ty_unadjusted) {
+            ty_unadjusted
+        } else {
+            let tcx = self.fcx.tcx();
+            let adjustments = self.fcx.inh.adjustments;
+            ty::adjust_ty(tcx, expr.span, ty_unadjusted,
+                          adjustments.find_copy(&expr.id))
+        }
+    }
 }
 
 pub fn regionck_expr(fcx: @mut FnCtxt, e: @ast::expr) {
@@ -650,7 +665,7 @@ fn constrain_regions_in_type_of_node(
     // is going to fail anyway, so just stop here and let typeck
     // report errors later on in the writeback phase.
     let ty0 = rcx.resolve_node_type(id);
-    let adjustment = rcx.fcx.inh.adjustments.find(&id);
+    let adjustment = rcx.fcx.inh.adjustments.find_copy(&id);
     let ty = ty::adjust_ty(tcx, span, ty0, adjustment);
     debug!("constrain_regions_in_type_of_node(\
             ty=%s, ty0=%s, id=%d, minimum_lifetime=%?, adjustment=%?)",
diff --git a/src/rt/rust_task.cpp b/src/rt/rust_task.cpp
index 23e70535768..266c0652c6e 100644
--- a/src/rt/rust_task.cpp
+++ b/src/rt/rust_task.cpp
@@ -76,15 +76,8 @@ rust_task::delete_this()
     assert(ref_count == 0); // ||
     //   (ref_count == 1 && this == sched->root_task));
 
-    if (borrow_list) {
-        // NOTE should free borrow_list from within rust code!
-        // If there is a pointer in there, it is a ~[BorrowRecord] pointer,
-        // which are currently allocated with LIBC malloc/free. But this is
-        // not really the right way to do this, we should be freeing this
-        // pointer from Rust code.
-        free(borrow_list);
-        borrow_list = NULL;
-    }
+    // The borrow list should be freed in the task annihilator
+    assert(!borrow_list);
 
     sched_loop->release_task(this);
 }
diff --git a/src/test/run-pass/issue-6141-leaking-owned-fn.rs b/src/test/run-pass/issue-6141-leaking-owned-fn.rs
new file mode 100644
index 00000000000..fe11bb0a972
--- /dev/null
+++ b/src/test/run-pass/issue-6141-leaking-owned-fn.rs
@@ -0,0 +1,8 @@
+fn run(f: &fn()) {
+    f()
+}
+
+fn main() {
+    let f: ~fn() = || ();
+    run(f);
+}
\ No newline at end of file