---

yaml
---
r: 164608
b: refs/heads/auto
c: 3efc9d2
h: refs/heads/master
v: v3

Author: nikomatsakis

[refs]

@@ -10,7 +10,7 @@ refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503
 refs/tags/release-0.3.1: 495bae036dfe5ec6ceafd3312b4dca48741e845b
 refs/tags/release-0.4: e828ea2080499553b97dfe33b3f4d472b4562ad7
 refs/tags/release-0.5: 7e3bcfbf21278251ee936ad53e92e9b719702d73
-refs/heads/auto: 514dfdbf12b71758c7abc3219ae1a3936e4d59d9
+refs/heads/auto: 3efc9d2c55af6e58dd96c5814260bacc2b582ef3
 refs/heads/servo: af82457af293e2a842ba6b7759b70288da276167
 refs/tags/release-0.6: b4ebcfa1812664df5e142f0134a5faea3918544c
 refs/tags/0.1: b19db808c2793fe2976759b85a355c3ad8c8b336

branches/auto/src/librustc/middle/infer/coercion.rs

@@ -286,7 +286,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                             let ty = ty::mk_rptr(self.get_ref().infcx.tcx,
                                                  r_borrow,
                                                  ty::mt{ty: ty, mutbl: mt_b.mutbl});
-                            try!(self.get_ref().infcx.try(|| sub.tys(ty, b)));
+                            try!(self.get_ref().infcx.try(|_| sub.tys(ty, b)));
                             debug!("Success, coerced with AutoDerefRef(1, \
                                     AutoPtr(AutoUnsize({})))", kind);
                             Ok(Some(AdjustDerefRef(AutoDerefRef {
@@ -309,7 +309,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
 
                             let ty = ty::mk_ptr(self.get_ref().infcx.tcx,
                                                  ty::mt{ty: ty, mutbl: mt_b.mutbl});
-                            try!(self.get_ref().infcx.try(|| sub.tys(ty, b)));
+                            try!(self.get_ref().infcx.try(|_| sub.tys(ty, b)));
                             debug!("Success, coerced with AutoDerefRef(1, \
                                     AutoPtr(AutoUnsize({})))", kind);
                             Ok(Some(AdjustDerefRef(AutoDerefRef {
@@ -327,7 +327,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                     match self.unsize_ty(t_a, sty_a, t_b) {
                         Some((ty, kind)) => {
                             let ty = ty::mk_uniq(self.get_ref().infcx.tcx, ty);
-                            try!(self.get_ref().infcx.try(|| sub.tys(ty, b)));
+                            try!(self.get_ref().infcx.try(|_| sub.tys(ty, b)));
                             debug!("Success, coerced with AutoDerefRef(1, \
                                     AutoUnsizeUniq({}))", kind);
                             Ok(Some(AdjustDerefRef(AutoDerefRef {
@@ -384,7 +384,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                     let mut result = None;
                     let mut tps = ty_substs_a.iter().zip(ty_substs_b.iter()).enumerate();
                     for (i, (tp_a, tp_b)) in tps {
-                        if self.get_ref().infcx.try(|| sub.tys(*tp_a, *tp_b)).is_ok() {
+                        if self.get_ref().infcx.try(|_| sub.tys(*tp_a, *tp_b)).is_ok() {
                             continue;
                         }
                         match
@@ -397,7 +397,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                                 let mut new_substs = substs_a.clone();
                                 new_substs.types.get_mut_slice(subst::TypeSpace)[i] = new_tp;
                                 let ty = ty::mk_struct(tcx, did_a, new_substs);
-                                if self.get_ref().infcx.try(|| sub.tys(ty, ty_b)).is_err() {
+                                if self.get_ref().infcx.try(|_| sub.tys(ty, ty_b)).is_err() {
                                     debug!("Unsized type parameter '{}', but still \
                                             could not match types {} and {}",
                                            ppaux::ty_to_string(tcx, *tp_a),

branches/auto/src/librustc/middle/infer/combine.rs

@@ -706,14 +706,38 @@ impl<'cx, 'tcx> ty_fold::TypeFolder<'tcx> for Generalizer<'cx, 'tcx> {
 
     fn fold_region(&mut self, r: ty::Region) -> ty::Region {
         match r {
-            ty::ReLateBound(..) | ty::ReEarlyBound(..) => r,
-            _ if self.make_region_vars => {
-                // FIXME: This is non-ideal because we don't give a
-                // very descriptive origin for this region variable.
-                self.infcx.next_region_var(MiscVariable(self.span))
+            // Never make variables for regions bound within the type itself.
+            ty::ReLateBound(..) => { return r; }
+
+            // Early-bound regions should really have been substituted away before
+            // we get to this point.
+            ty::ReEarlyBound(..) => {
+                self.tcx().sess.span_bug(
+                    self.span,
+                    format!("Encountered early bound region when generalizing: {}",
+                            r.repr(self.tcx()))[]);
+            }
+
+            // Always make a fresh region variable for skolemized regions;
+            // the higher-ranked decision procedures rely on this.
+            ty::ReInfer(ty::ReSkolemized(..)) => { }
+
+            // For anything else, we make a region variable, unless we
+            // are *equating*, in which case it's just wasteful.
+            ty::ReEmpty |
+            ty::ReStatic |
+            ty::ReScope(..) |
+            ty::ReInfer(ty::ReVar(..)) |
+            ty::ReFree(..) => {
+                if !self.make_region_vars {
+                    return r;
+                }
             }
-            _ => r,
         }
+
+        // FIXME: This is non-ideal because we don't give a
+        // very descriptive origin for this region variable.
+        self.infcx.next_region_var(MiscVariable(self.span))
     }
 }
 

branches/auto/src/librustc/middle/infer/error_reporting.rs

@@ -1640,7 +1640,7 @@ pub trait Resolvable<'tcx> {
 
 impl<'tcx> Resolvable<'tcx> for Ty<'tcx> {
     fn resolve<'a>(&self, infcx: &InferCtxt<'a, 'tcx>) -> Ty<'tcx> {
-        infcx.resolve_type_vars_if_possible(*self)
+        infcx.resolve_type_vars_if_possible(self)
     }
     fn contains_error(&self) -> bool {
         ty::type_is_error(*self)
@@ -1650,7 +1650,7 @@ impl<'tcx> Resolvable<'tcx> for Ty<'tcx> {
 impl<'tcx> Resolvable<'tcx> for Rc<ty::TraitRef<'tcx>> {
     fn resolve<'a>(&self, infcx: &InferCtxt<'a, 'tcx>)
                    -> Rc<ty::TraitRef<'tcx>> {
-        Rc::new(infcx.resolve_type_vars_in_trait_ref_if_possible(&**self))
+        Rc::new(infcx.resolve_type_vars_if_possible(&**self))
     }
     fn contains_error(&self) -> bool {
         ty::trait_ref_contains_error(&**self)

branches/auto/src/librustc/middle/infer/higher_ranked/doc.rs

@@ -249,19 +249,21 @@
 //! in T and try to, in some cases, replace them with bound regions to
 //! yield the final result.
 //!
-//! To decide whether to replace a region `R` that appears in `T` with a
-//! bound region, the algorithms make use of two bits of information.
-//! First is a set `V` that contains all region variables created as part
-//! of the LUB/GLB computation. `V` will contain the region variables
-//! created to replace the bound regions in the input types, but it also
-//! contains 'intermediate' variables created to represent the LUB/GLB of
-//! individual regions.  Basically, when asked to compute the LUB/GLB of a
-//! region variable with another region, the inferencer cannot oblige
-//! immediately since the values of that variables are not known.
-//! Therefore, it creates a new variable that is related to the two
-//! regions.  For example, the LUB of two variables `$x` and `$y` is a
-//! fresh variable `$z` that is constrained such that `$x <= $z` and `$y
-//! <= $z`.  So `V` will contain these intermediate variables as well.
+//! To decide whether to replace a region `R` that appears in `T` with
+//! a bound region, the algorithms make use of two bits of
+//! information.  First is a set `V` that contains all region
+//! variables created as part of the LUB/GLB computation (roughly; see
+//! `region_vars_confined_to_snapshot()` for full details). `V` will
+//! contain the region variables created to replace the bound regions
+//! in the input types, but it also contains 'intermediate' variables
+//! created to represent the LUB/GLB of individual regions.
+//! Basically, when asked to compute the LUB/GLB of a region variable
+//! with another region, the inferencer cannot oblige immediately
+//! since the values of that variables are not known.  Therefore, it
+//! creates a new variable that is related to the two regions.  For
+//! example, the LUB of two variables `$x` and `$y` is a fresh
+//! variable `$z` that is constrained such that `$x <= $z` and `$y <=
+//! $z`.  So `V` will contain these intermediate variables as well.
 //!
 //! The other important factor in deciding how to replace a region in T is
 //! the function `Tainted($r)` which, for a region variable, identifies