kill custom type inference defaults (these don't really work anyway)

Author: nikomatsakis

src/librustc/infer/mod.rs

@@ -22,7 +22,7 @@ use middle::free_region::RegionRelations;
 use middle::region;
 use middle::lang_items;
 use mir::tcx::PlaceTy;
-use ty::subst::{Kind, Subst, Substs};
+use ty::subst::Substs;
 use ty::{TyVid, IntVid, FloatVid};
 use ty::{self, Ty, TyCtxt};
 use ty::error::{ExpectedFound, TypeError, UnconstrainedNumeric};
@@ -1093,26 +1093,13 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     /// as the substitutions for the default, `(T, U)`.
     pub fn type_var_for_def(&self,
                             span: Span,
-                            def: &ty::TypeParameterDef,
-                            substs: &[Kind<'tcx>])
+                            def: &ty::TypeParameterDef)
                             -> Ty<'tcx> {
-        let default = if def.has_default {
-            let default = self.tcx.type_of(def.def_id);
-            Some(type_variable::Default {
-                ty: default.subst_spanned(self.tcx, substs, Some(span)),
-                origin_span: span,
-                def_id: def.def_id
-            })
-        } else {
-            None
-        };
-
-
         let ty_var_id = self.type_variables
                             .borrow_mut()
                             .new_var(false,
                                      TypeVariableOrigin::TypeParameterDefinition(span, def.name),
-                                     default);
+                                     None);
 
         self.tcx.mk_var(ty_var_id)
     }
@@ -1125,8 +1112,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                                  -> &'tcx Substs<'tcx> {
         Substs::for_item(self.tcx, def_id, |def, _| {
             self.region_var_for_def(span, def)
-        }, |def, substs| {
-            self.type_var_for_def(span, def, substs)
+        }, |def, _| {
+            self.type_var_for_def(span, def)
         })
     }
 

src/librustc_typeck/astconv.rs

@@ -19,7 +19,7 @@ use hir::def::Def;
 use hir::def_id::DefId;
 use middle::resolve_lifetime as rl;
 use namespace::Namespace;
-use rustc::ty::subst::{Kind, Subst, Substs};
+use rustc::ty::subst::{Subst, Substs};
 use rustc::traits;
 use rustc::ty::{self, RegionKind, Ty, TyCtxt, ToPredicate, TypeFoldable};
 use rustc::ty::wf::object_region_bounds;
@@ -51,7 +51,6 @@ pub trait AstConv<'gcx, 'tcx> {
     /// Same as ty_infer, but with a known type parameter definition.
     fn ty_infer_for_def(&self,
                         _def: &ty::TypeParameterDef,
-                        _substs: &[Kind<'tcx>],
                         span: Span) -> Ty<'tcx> {
         self.ty_infer(span)
     }
@@ -261,7 +260,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
             } else if infer_types {
                 // No type parameters were provided, we can infer all.
                 let ty_var = if !default_needs_object_self(def) {
-                    self.ty_infer_for_def(def, substs, span)
+                    self.ty_infer_for_def(def, span)
                 } else {
                     self.ty_infer(span)
                 };

src/librustc_typeck/check/method/confirm.rs

@@ -317,7 +317,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
             } else {
                 self.region_var_for_def(self.span, def)
             }
-        }, |def, cur_substs| {
+        }, |def, _cur_substs| {
             let i = def.index as usize;
             if i < parent_substs.len() {
                 parent_substs.type_at(i)
@@ -328,7 +328,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
             {
                 self.to_ty(ast_ty)
             } else {
-                self.type_var_for_def(self.span, def, cur_substs)
+                self.type_var_for_def(self.span, def)
             }
         })
     }

src/librustc_typeck/check/method/mod.rs

@@ -249,13 +249,13 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         let substs = Substs::for_item(self.tcx,
                                       trait_def_id,
                                       |def, _| self.region_var_for_def(span, def),
-                                      |def, substs| {
+                                      |def, _substs| {
             if def.index == 0 {
                 self_ty
             } else if let Some(ref input_types) = opt_input_types {
                 input_types[def.index as usize - 1]
             } else {
-                self.type_var_for_def(span, def, substs)
+                self.type_var_for_def(span, def)
             }
         });
 

src/librustc_typeck/check/method/probe.rs

@@ -1298,12 +1298,12 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
                     // `impl_self_ty()` for an explanation.
                     self.tcx.types.re_erased
                 }
-            }, |def, cur_substs| {
+            }, |def, _cur_substs| {
                 let i = def.index as usize;
                 if i < substs.len() {
                     substs.type_at(i)
                 } else {
-                    self.type_var_for_def(self.span, def, cur_substs)
+                    self.type_var_for_def(self.span, def)
                 }
             });
             xform_fn_sig.subst(self.tcx, substs)

src/librustc_typeck/check/mod.rs

@@ -93,7 +93,7 @@ use rustc::infer::{self, InferCtxt, InferOk, RegionVariableOrigin};
 use rustc::infer::anon_types::AnonTypeDecl;
 use rustc::infer::type_variable::{TypeVariableOrigin};
 use rustc::middle::region;
-use rustc::ty::subst::{Kind, Subst, Substs};
+use rustc::ty::subst::{Subst, Substs};
 use rustc::traits::{self, FulfillmentContext, ObligationCause, ObligationCauseCode};
 use rustc::ty::{ParamTy, LvaluePreference, NoPreference, PreferMutLvalue};
 use rustc::ty::{self, Ty, TyCtxt, Visibility, ToPredicate};
@@ -1666,9 +1666,8 @@ impl<'a, 'gcx, 'tcx> AstConv<'gcx, 'tcx> for FnCtxt<'a, 'gcx, 'tcx> {
 
     fn ty_infer_for_def(&self,
                         ty_param_def: &ty::TypeParameterDef,
-                        substs: &[Kind<'tcx>],
                         span: Span) -> Ty<'tcx> {
-        self.type_var_for_def(span, ty_param_def, substs)
+        self.type_var_for_def(span, ty_param_def)
     }
 
     fn projected_ty_from_poly_trait_ref(&self,
@@ -4736,7 +4735,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 // Handle Self first, so we can adjust the index to match the AST.
                 if has_self && i == 0 {
                     return opt_self_ty.unwrap_or_else(|| {
-                        self.type_var_for_def(span, def, substs)
+                        self.type_var_for_def(span, def)
                     });
                 }
                 i -= has_self as usize;
@@ -4769,7 +4768,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 // This can also be reached in some error cases:
                 // We prefer to use inference variables instead of
                 // TyError to let type inference recover somewhat.
-                self.type_var_for_def(span, def, substs)
+                self.type_var_for_def(span, def)
             }
         });