auto merge of #15585 : bgamari/rust/subst-bug, r=pnkfelix

This branch has a fix for #15557 (a2bcef9) as well as a variety of patches I found useful while debugging this issue. These include adding `Show` impls to a variety of types, including the majority of `syntax::ast` and some of `middle::ty`.

src/librustc/middle/def.rs

@@ -14,7 +14,7 @@ use syntax::ast_util::local_def;
 
 use std::gc::Gc;
 
-#[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash)]
+#[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash, Show)]
 pub enum Def {
     DefFn(ast::DefId, ast::FnStyle),
     DefStaticMethod(/* method */ ast::DefId, MethodProvenance, ast::FnStyle),
@@ -51,7 +51,7 @@ pub enum Def {
     DefMethod(ast::DefId /* method */, Option<ast::DefId> /* trait */),
 }
 
-#[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash)]
+#[deriving(Clone, PartialEq, Eq, Encodable, Decodable, Hash, Show)]
 pub enum MethodProvenance {
     FromTrait(ast::DefId),
     FromImpl(ast::DefId),

src/librustc/middle/kind.rs

@@ -87,7 +87,8 @@ fn check_struct_safe_for_destructor(cx: &mut Context,
                                     span: Span,
                                     struct_did: DefId) {
     let struct_tpt = ty::lookup_item_type(cx.tcx, struct_did);
-    if !struct_tpt.generics.has_type_params(subst::TypeSpace) {
+    if !struct_tpt.generics.has_type_params(subst::TypeSpace)
+      && !struct_tpt.generics.has_region_params(subst::TypeSpace) {
         let struct_ty = ty::mk_struct(cx.tcx, struct_did,
                                       subst::Substs::empty());
         if !ty::type_is_sendable(cx.tcx, struct_ty) {
@@ -121,7 +122,7 @@ fn check_impl_of_trait(cx: &mut Context, it: &Item, trait_ref: &TraitRef, self_t
 
     // If this trait has builtin-kind supertraits, meet them.
     let self_ty: ty::t = ty::node_id_to_type(cx.tcx, it.id);
-    debug!("checking impl with self type {:?}", ty::get(self_ty).sty);
+    debug!("checking impl with self type {}", ty::get(self_ty).sty);
     check_builtin_bounds(cx, self_ty, trait_def.bounds, |missing| {
         cx.tcx.sess.span_err(self_type.span,
             format!("the type `{}', which does not fulfill `{}`, cannot implement this \

src/librustc/middle/subst.rs

@@ -15,6 +15,7 @@ use middle::ty_fold;
 use middle::ty_fold::{TypeFoldable, TypeFolder};
 use util::ppaux::Repr;
 
+use std::fmt;
 use std::mem;
 use std::raw;
 use std::slice::{Items, MutItems};
@@ -83,7 +84,7 @@ impl<T> HomogeneousTuple3<T> for (T, T, T) {
  * space* (which indices where the parameter is defined; see
  * `ParamSpace`).
  */
-#[deriving(Clone, PartialEq, Eq, Hash)]
+#[deriving(Clone, PartialEq, Eq, Hash, Show)]
 pub struct Substs {
     pub types: VecPerParamSpace<ty::t>,
     pub regions: RegionSubsts,
@@ -93,7 +94,7 @@ pub struct Substs {
  * Represents the values to use when substituting lifetime parameters.
  * If the value is `ErasedRegions`, then this subst is occurring during
  * trans, and all region parameters will be replaced with `ty::ReStatic`. */
-#[deriving(Clone, PartialEq, Eq, Hash)]
+#[deriving(Clone, PartialEq, Eq, Hash, Show)]
 pub enum RegionSubsts {
     ErasedRegions,
     NonerasedRegions(VecPerParamSpace<ty::Region>)
@@ -275,6 +276,17 @@ pub struct VecPerParamSpace<T> {
     content: Vec<T>,
 }
 
+impl<T:fmt::Show> fmt::Show for VecPerParamSpace<T> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        try!(write!(fmt, "VecPerParamSpace {{"));
+        for space in ParamSpace::all().iter() {
+            try!(write!(fmt, "{}: {}, ", *space, self.get_slice(*space)));
+        }
+        try!(write!(fmt, "}}"));
+        Ok(())
+    }
+}
+
 impl<T:Clone> VecPerParamSpace<T> {
     pub fn push_all(&mut self, space: ParamSpace, values: &[T]) {
         // FIXME (#15435): slow; O(n^2); could enhance vec to make it O(n).
@@ -558,10 +570,22 @@ impl<'a> TypeFolder for SubstFolder<'a> {
         // the specialized routine
         // `middle::typeck::check::regionmanip::replace_late_regions_in_fn_sig()`.
         match r {
-            ty::ReEarlyBound(_, space, i, _) => {
+            ty::ReEarlyBound(_, space, i, region_name) => {
                 match self.substs.regions {
                     ErasedRegions => ty::ReStatic,
-                    NonerasedRegions(ref regions) => *regions.get(space, i),
+                    NonerasedRegions(ref regions) =>
+                        match regions.opt_get(space, i) {
+                            Some(t) => *t,
+                            None => {
+                                let span = self.span.unwrap_or(DUMMY_SP);
+                                self.tcx().sess.span_bug(
+                                    span,
+                                    format!("Type parameter out of range \
+                                     when substituting in region {} (root type={})",
+                                    region_name.as_str(),
+                                    self.root_ty.repr(self.tcx())).as_slice());
+                            }
+                        }
                 }
             }
             _ => r

src/librustc/middle/ty.rs

@@ -124,7 +124,7 @@ impl Method {
     }
 }
 
-#[deriving(Clone, PartialEq, Eq, Hash)]
+#[deriving(Clone, PartialEq, Eq, Hash, Show)]
 pub struct mt {
     pub ty: t,
     pub mutbl: ast::Mutability,
@@ -138,7 +138,7 @@ pub enum TraitStore {
     RegionTraitStore(Region, ast::Mutability),
 }
 
-#[deriving(Clone)]
+#[deriving(Clone, Show)]
 pub struct field_ty {
     pub name: Name,
     pub id: DefId,
@@ -394,6 +394,7 @@ pub enum tbox_flag {
 
 pub type t_box = &'static t_box_;
 
+#[deriving(Show)]
 pub struct t_box_ {
     pub sty: sty,
     pub id: uint,
@@ -436,14 +437,14 @@ pub fn type_needs_infer(t: t) -> bool {
 }
 pub fn type_id(t: t) -> uint { get(t).id }
 
-#[deriving(Clone, PartialEq, Eq, Hash)]
+#[deriving(Clone, PartialEq, Eq, Hash, Show)]
 pub struct BareFnTy {
     pub fn_style: ast::FnStyle,
     pub abi: abi::Abi,
     pub sig: FnSig,
 }
 
-#[deriving(Clone, PartialEq, Eq, Hash)]
+#[deriving(Clone, PartialEq, Eq, Hash, Show)]
 pub struct ClosureTy {
     pub fn_style: ast::FnStyle,
     pub onceness: ast::Onceness,
@@ -472,7 +473,7 @@ pub struct FnSig {
     pub variadic: bool
 }
 
-#[deriving(Clone, PartialEq, Eq, Hash)]
+#[deriving(Clone, PartialEq, Eq, Hash, Show)]
 pub struct ParamTy {
     pub space: subst::ParamSpace,
     pub idx: uint,
@@ -712,7 +713,7 @@ mod primitives {
 
 // NB: If you change this, you'll probably want to change the corresponding
 // AST structure in libsyntax/ast.rs as well.
-#[deriving(Clone, PartialEq, Eq, Hash)]
+#[deriving(Clone, PartialEq, Eq, Hash, Show)]
 pub enum sty {
     ty_nil,
     ty_bot,
@@ -741,14 +742,14 @@ pub enum sty {
             // on non-useful type error messages)
 }
 
-#[deriving(Clone, PartialEq, Eq, Hash)]
+#[deriving(Clone, PartialEq, Eq, Hash, Show)]
 pub struct TyTrait {
     pub def_id: DefId,
     pub substs: Substs,
     pub bounds: BuiltinBounds
 }
 
-#[deriving(PartialEq, Eq, Hash)]
+#[deriving(PartialEq, Eq, Hash, Show)]
 pub struct TraitRef {
     pub def_id: DefId,
     pub substs: Substs,
@@ -808,7 +809,7 @@ pub enum type_err {
     terr_variadic_mismatch(expected_found<bool>)
 }
 
-#[deriving(PartialEq, Eq, Hash)]
+#[deriving(PartialEq, Eq, Hash, Show)]
 pub struct ParamBounds {
     pub builtin_bounds: BuiltinBounds,
     pub trait_bounds: Vec<Rc<TraitRef>>
@@ -948,7 +949,7 @@ impl fmt::Show for IntVarValue {
     }
 }
 
-#[deriving(Clone)]
+#[deriving(Clone, Show)]
 pub struct TypeParameterDef {
     pub ident: ast::Ident,
     pub def_id: ast::DefId,
@@ -958,7 +959,7 @@ pub struct TypeParameterDef {
     pub default: Option<ty::t>
 }
 
-#[deriving(Encodable, Decodable, Clone)]
+#[deriving(Encodable, Decodable, Clone, Show)]
 pub struct RegionParameterDef {
     pub name: ast::Name,
     pub def_id: ast::DefId,
@@ -968,7 +969,7 @@ pub struct RegionParameterDef {
 
 /// Information about the type/lifetime parameters associated with an
 /// item or method. Analogous to ast::Generics.
-#[deriving(Clone)]
+#[deriving(Clone, Show)]
 pub struct Generics {
     pub types: VecPerParamSpace<TypeParameterDef>,
     pub regions: VecPerParamSpace<RegionParameterDef>,
@@ -983,6 +984,10 @@ impl Generics {
     pub fn has_type_params(&self, space: subst::ParamSpace) -> bool {
         !self.types.is_empty_in(space)
     }
+
+    pub fn has_region_params(&self, space: subst::ParamSpace) -> bool {
+        !self.regions.is_empty_in(space)
+    }
 }
 
 /// When type checking, we use the `ParameterEnvironment` to track
@@ -1014,7 +1019,7 @@ pub struct ParameterEnvironment {
 /// - `generics`: the set of type parameters and their bounds
 /// - `ty`: the base types, which may reference the parameters defined
 ///   in `generics`
-#[deriving(Clone)]
+#[deriving(Clone, Show)]
 pub struct Polytype {
     pub generics: Generics,
     pub ty: t

src/librustc/middle/typeck/astconv.rs

@@ -141,7 +141,7 @@ pub fn opt_ast_region_to_region<AC:AstConv,RS:RegionScope>(
         }
     };
 
-    debug!("opt_ast_region_to_region(opt_lifetime={:?}) yields {}",
+    debug!("opt_ast_region_to_region(opt_lifetime={}) yields {}",
             opt_lifetime.as_ref().map(|e| lifetime_to_string(e)),
             r.repr(this.tcx()));
 
@@ -504,6 +504,7 @@ pub fn ast_ty_to_builtin_ty<AC:AstConv,
     }
 }
 
+#[deriving(Show)]
 enum PointerTy {
     Box,
     RPtr(ty::Region),
@@ -565,7 +566,7 @@ fn mk_pointer<AC:AstConv,
               constr: |ty::t| -> ty::t)
               -> ty::t {
     let tcx = this.tcx();
-    debug!("mk_pointer(ptr_ty={:?})", ptr_ty);
+    debug!("mk_pointer(ptr_ty={})", ptr_ty);
 
     match a_seq_ty.ty.node {
         ast::TyVec(ref ty) => {

src/librustc/middle/typeck/check/_match.rs

@@ -507,14 +507,20 @@ pub fn check_pat(pcx: &pat_ctxt, pat: &ast::Pat, expected: ty::t) {
             ty::ty_struct(cid, ref substs) => {
                 // Verify that the pattern named the right structure.
                 let item_did = tcx.def_map.borrow().get(&pat.id).def_id();
-                let struct_did =
-                    ty::ty_to_def_id(
-                        ty::lookup_item_type(tcx, item_did).ty).unwrap();
-                if struct_did != cid {
-                    span_err!(tcx.sess, pat.span, E0032,
-                        "`{}` does not name the structure `{}`",
-                        pprust::path_to_string(path),
-                        fcx.infcx().ty_to_string(expected));
+                match ty::ty_to_def_id(ty::lookup_item_type(tcx, item_did).ty) {
+                    Some(struct_did) if struct_did != cid => {
+                        span_err!(tcx.sess, path.span, E0032,
+                                  "`{}` does not name the structure `{}`",
+                                  pprust::path_to_string(path),
+                                  fcx.infcx().ty_to_string(expected));
+                    },
+                    Some(_) => {},
+                    None => {
+                        tcx.sess.span_bug(
+                            path.span,
+                            format!("This shouldn't happen: failed to lookup structure. \
+                                item_did = {}", item_did).as_slice())
+                    },
                 }
 
                 check_struct_pat(pcx, pat.id, pat.span, expected, path,

src/librustc/middle/typeck/collect.rs

@@ -1018,16 +1018,17 @@ fn ty_generics(ccx: &CrateCtxt,
     let mut result = base_generics;
 
     for (i, l) in lifetimes.iter().enumerate() {
-        result.regions.push(space,
-                            ty::RegionParameterDef { name: l.name,
-                                                     space: space,
-                                                     index: i,
-                                                     def_id: local_def(l.id) });
+        let def = ty::RegionParameterDef { name: l.name,
+                                           space: space,
+                                           index: i,
+                                           def_id: local_def(l.id) };
+        debug!("ty_generics: def for region param: {}", def);
+        result.regions.push(space, def);
     }
 
     for (i, param) in types.iter().enumerate() {
         let def = get_or_create_type_parameter_def(ccx, space, param, i);
-        debug!("def for param: {}", def.repr(ccx.tcx));
+        debug!("ty_generics: def for type param: {}", def.repr(ccx.tcx));
         result.types.push(space, def);
     }
 

src/librustc/middle/typeck/infer/region_inference/mod.rs

@@ -246,7 +246,7 @@ impl<'a> RegionVarBindings<'a> {
         if self.in_snapshot() {
             self.undo_log.borrow_mut().push(AddVar(vid));
         }
-        debug!("created new region variable {:?} with origin {:?}",
+        debug!("created new region variable {} with origin {}",
                vid, origin.repr(self.tcx));
         return vid;
     }