diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
index 4e78d79ef87..4f365a97f4c 100644
--- a/src/librustc/ich/impls_ty.rs
+++ b/src/librustc/ich/impls_ty.rs
@@ -524,10 +524,9 @@ for ty::TypeVariants<'tcx>
                 region.hash_stable(hcx, hasher);
                 pointee_ty.hash_stable(hcx, hasher);
             }
-            TyFnDef(def_id, substs, ref sig) => {
+            TyFnDef(def_id, substs) => {
                 def_id.hash_stable(hcx, hasher);
                 substs.hash_stable(hcx, hasher);
-                sig.hash_stable(hcx, hasher);
             }
             TyFnPtr(ref sig) => {
                 sig.hash_stable(hcx, hasher);
diff --git a/src/librustc/middle/effect.rs b/src/librustc/middle/effect.rs
index 74e1225f394..eab5a8f9103 100644
--- a/src/librustc/middle/effect.rs
+++ b/src/librustc/middle/effect.rs
@@ -12,7 +12,7 @@
 //! `unsafe`.
 use self::RootUnsafeContext::*;
 
-use ty::{self, Ty, TyCtxt};
+use ty::{self, TyCtxt};
 use lint;
 
 use syntax::ast;
@@ -40,14 +40,6 @@ enum RootUnsafeContext {
     UnsafeBlock(ast::NodeId),
 }
 
-fn type_is_unsafe_function(ty: Ty) -> bool {
-    match ty.sty {
-        ty::TyFnDef(.., f) |
-        ty::TyFnPtr(f) => f.unsafety() == hir::Unsafety::Unsafe,
-        _ => false,
-    }
-}
-
 struct EffectCheckVisitor<'a, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     tables: &'a ty::TypeckTables<'tcx>,
@@ -174,10 +166,11 @@ impl<'a, 'tcx> Visitor<'tcx> for EffectCheckVisitor<'a, 'tcx> {
         match expr.node {
             hir::ExprMethodCall(..) => {
                 let def_id = self.tables.type_dependent_defs[&expr.id].def_id();
-                let base_type = self.tcx.type_of(def_id);
-                debug!("effect: method call case, base type is {:?}",
-                        base_type);
-                if type_is_unsafe_function(base_type) {
+                let sig = self.tcx.fn_sig(def_id);
+                debug!("effect: method call case, signature is {:?}",
+                        sig);
+
+                if sig.0.unsafety == hir::Unsafety::Unsafe {
                     self.require_unsafe(expr.span,
                                         "invocation of unsafe method")
                 }
@@ -186,8 +179,13 @@ impl<'a, 'tcx> Visitor<'tcx> for EffectCheckVisitor<'a, 'tcx> {
                 let base_type = self.tables.expr_ty_adjusted(base);
                 debug!("effect: call case, base type is {:?}",
                         base_type);
-                if type_is_unsafe_function(base_type) {
-                    self.require_unsafe(expr.span, "call to unsafe function")
+                match base_type.sty {
+                    ty::TyFnDef(..) | ty::TyFnPtr(_) => {
+                        if base_type.fn_sig(self.tcx).unsafety() == hir::Unsafety::Unsafe {
+                            self.require_unsafe(expr.span, "call to unsafe function")
+                        }
+                    }
+                    _ => {}
                 }
             }
             hir::ExprUnary(hir::UnDeref, ref base) => {
diff --git a/src/librustc/middle/intrinsicck.rs b/src/librustc/middle/intrinsicck.rs
index f180ae53b8a..fde207e4b2f 100644
--- a/src/librustc/middle/intrinsicck.rs
+++ b/src/librustc/middle/intrinsicck.rs
@@ -66,11 +66,8 @@ fn unpack_option_like<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
 impl<'a, 'tcx> ExprVisitor<'a, 'tcx> {
     fn def_id_is_transmute(&self, def_id: DefId) -> bool {
-        let intrinsic = match self.tcx.type_of(def_id).sty {
-            ty::TyFnDef(.., bfty) => bfty.abi() == RustIntrinsic,
-            _ => return false
-        };
-        intrinsic && self.tcx.item_name(def_id) == "transmute"
+        self.tcx.fn_sig(def_id).abi() == RustIntrinsic &&
+        self.tcx.item_name(def_id) == "transmute"
     }
 
     fn check_transmute(&self, span: Span, from: Ty<'tcx>, to: Ty<'tcx>) {
@@ -153,22 +150,14 @@ impl<'a, 'tcx> Visitor<'tcx> for ExprVisitor<'a, 'tcx> {
         } else {
             Def::Err
         };
-        match def {
-            Def::Fn(did) if self.def_id_is_transmute(did) => {
+        if let Def::Fn(did) = def {
+            if self.def_id_is_transmute(did) {
                 let typ = self.tables.node_id_to_type(expr.id);
-                let typ = self.tcx.lift_to_global(&typ).unwrap();
-                match typ.sty {
-                    ty::TyFnDef(.., sig) if sig.abi() == RustIntrinsic => {
-                        let from = sig.inputs().skip_binder()[0];
-                        let to = *sig.output().skip_binder();
-                        self.check_transmute(expr.span, from, to);
-                    }
-                    _ => {
-                        span_bug!(expr.span, "transmute wasn't a bare fn?!");
-                    }
-                }
+                let sig = typ.fn_sig(self.tcx);
+                let from = sig.inputs().skip_binder()[0];
+                let to = *sig.output().skip_binder();
+                self.check_transmute(expr.span, from, to);
             }
-            _ => {}
         }
 
         intravisit::walk_expr(self, expr);
diff --git a/src/librustc/traits/object_safety.rs b/src/librustc/traits/object_safety.rs
index 0e3a53129d1..c6c052fa4b1 100644
--- a/src/librustc/traits/object_safety.rs
+++ b/src/librustc/traits/object_safety.rs
@@ -260,7 +260,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
         // The `Self` type is erased, so it should not appear in list of
         // arguments or return type apart from the receiver.
-        let ref sig = self.type_of(method.def_id).fn_sig();
+        let ref sig = self.fn_sig(method.def_id);
         for input_ty in &sig.skip_binder().inputs()[1..] {
             if self.contains_illegal_self_type_reference(trait_def_id, input_ty) {
                 return Some(MethodViolationCode::ReferencesSelf);
diff --git a/src/librustc/traits/project.rs b/src/librustc/traits/project.rs
index f71f75dbaa8..c356e53234d 100644
--- a/src/librustc/traits/project.rs
+++ b/src/librustc/traits/project.rs
@@ -1137,9 +1137,19 @@ fn confirm_fn_pointer_candidate<'cx, 'gcx, 'tcx>(
     -> Progress<'tcx>
 {
     let fn_type = selcx.infcx().shallow_resolve(fn_pointer_vtable.fn_ty);
-    let sig = fn_type.fn_sig();
+    let sig = fn_type.fn_sig(selcx.tcx());
+    let Normalized {
+        value: sig,
+        obligations
+    } = normalize_with_depth(selcx,
+                             obligation.param_env,
+                             obligation.cause.clone(),
+                             obligation.recursion_depth+1,
+                             &sig);
+
     confirm_callable_candidate(selcx, obligation, sig, util::TupleArgumentsFlag::Yes)
         .with_addl_obligations(fn_pointer_vtable.nested)
+        .with_addl_obligations(obligations)
 }
 
 fn confirm_closure_candidate<'cx, 'gcx, 'tcx>(
diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs
index c68b8ee14b8..a66b6b86354 100644
--- a/src/librustc/traits/select.rs
+++ b/src/librustc/traits/select.rs
@@ -1404,19 +1404,15 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             }
 
             // provide an impl, but only for suitable `fn` pointers
-            ty::TyFnDef(.., ty::Binder(ty::FnSig {
-                unsafety: hir::Unsafety::Normal,
-                abi: Abi::Rust,
-                variadic: false,
-                ..
-            })) |
-            ty::TyFnPtr(ty::Binder(ty::FnSig {
-                unsafety: hir::Unsafety::Normal,
-                abi: Abi::Rust,
-                variadic: false,
-                ..
-            })) => {
-                candidates.vec.push(FnPointerCandidate);
+            ty::TyFnDef(..) | ty::TyFnPtr(_) => {
+                if let ty::Binder(ty::FnSig {
+                    unsafety: hir::Unsafety::Normal,
+                    abi: Abi::Rust,
+                    variadic: false,
+                    ..
+                }) = self_ty.fn_sig(self.tcx()) {
+                    candidates.vec.push(FnPointerCandidate);
+                }
             }
 
             _ => { }
@@ -2348,7 +2344,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
 
         // ok to skip binder; it is reintroduced below
         let self_ty = self.infcx.shallow_resolve(*obligation.self_ty().skip_binder());
-        let sig = self_ty.fn_sig();
+        let sig = self_ty.fn_sig(self.tcx());
         let trait_ref =
             self.tcx().closure_trait_ref_and_return_type(obligation.predicate.def_id(),
                                                          self_ty,
@@ -2356,11 +2352,18 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                                                          util::TupleArgumentsFlag::Yes)
             .map_bound(|(trait_ref, _)| trait_ref);
 
+        let Normalized { value: trait_ref, obligations } =
+            project::normalize_with_depth(self,
+                                          obligation.param_env,
+                                          obligation.cause.clone(),
+                                          obligation.recursion_depth + 1,
+                                          &trait_ref);
+
         self.confirm_poly_trait_refs(obligation.cause.clone(),
                                      obligation.param_env,
                                      obligation.predicate.to_poly_trait_ref(),
                                      trait_ref)?;
-        Ok(VtableFnPointerData { fn_ty: self_ty, nested: vec![] })
+        Ok(VtableFnPointerData { fn_ty: self_ty, nested: obligations })
     }
 
     fn confirm_closure_candidate(&mut self,
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 2d81606329e..5f869fc5567 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -1378,9 +1378,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     }
 
     pub fn mk_fn_def(self, def_id: DefId,
-                     substs: &'tcx Substs<'tcx>,
-                     fty: PolyFnSig<'tcx>) -> Ty<'tcx> {
-        self.mk_ty(TyFnDef(def_id, substs, fty))
+                     substs: &'tcx Substs<'tcx>) -> Ty<'tcx> {
+        self.mk_ty(TyFnDef(def_id, substs))
     }
 
     pub fn mk_fn_ptr(self, fty: PolyFnSig<'tcx>) -> Ty<'tcx> {
diff --git a/src/librustc/ty/fast_reject.rs b/src/librustc/ty/fast_reject.rs
index 3d2cc4c598a..68f85ba7d33 100644
--- a/src/librustc/ty/fast_reject.rs
+++ b/src/librustc/ty/fast_reject.rs
@@ -68,6 +68,7 @@ pub fn simplify_type<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
             // view of possibly unifying
             simplify_type(tcx, mt.ty, can_simplify_params)
         }
+        ty::TyFnDef(def_id, _) |
         ty::TyClosure(def_id, _) => {
             Some(ClosureSimplifiedType(def_id))
         }
@@ -75,7 +76,7 @@ pub fn simplify_type<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
         ty::TyTuple(ref tys, _) => {
             Some(TupleSimplifiedType(tys.len()))
         }
-        ty::TyFnDef(.., ref f) | ty::TyFnPtr(ref f) => {
+        ty::TyFnPtr(ref f) => {
             Some(FunctionSimplifiedType(f.skip_binder().inputs().len()))
         }
         ty::TyProjection(_) | ty::TyParam(_) => {
diff --git a/src/librustc/ty/flags.rs b/src/librustc/ty/flags.rs
index 46afa6ee7d0..d5aa9f55ff0 100644
--- a/src/librustc/ty/flags.rs
+++ b/src/librustc/ty/flags.rs
@@ -155,9 +155,8 @@ impl FlagComputation {
                 self.add_tys(&ts[..]);
             }
 
-            &ty::TyFnDef(_, substs, f) => {
+            &ty::TyFnDef(_, substs) => {
                 self.add_substs(substs);
-                self.add_fn_sig(f);
             }
 
             &ty::TyFnPtr(f) => {
diff --git a/src/librustc/ty/item_path.rs b/src/librustc/ty/item_path.rs
index 09a3bcd0613..b9896e0cecf 100644
--- a/src/librustc/ty/item_path.rs
+++ b/src/librustc/ty/item_path.rs
@@ -348,7 +348,7 @@ pub fn characteristic_def_id_of_type(ty: Ty) -> Option<DefId> {
                                       .filter_map(|ty| characteristic_def_id_of_type(ty))
                                       .next(),
 
-        ty::TyFnDef(def_id, ..) |
+        ty::TyFnDef(def_id, _) |
         ty::TyClosure(def_id, _) => Some(def_id),
 
         ty::TyBool |
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 13e46a265c6..f4d0867d130 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -206,7 +206,7 @@ impl AssociatedItem {
                 // late-bound regions, and we don't want method signatures to show up
                 // `as for<'r> fn(&'r MyType)`.  Pretty-printing handles late-bound
                 // regions just fine, showing `fn(&MyType)`.
-                format!("{}", tcx.type_of(self.def_id).fn_sig().skip_binder())
+                format!("{}", tcx.fn_sig(self.def_id).skip_binder())
             }
             ty::AssociatedKind::Type => format!("type {};", self.name.to_string()),
             ty::AssociatedKind::Const => {
diff --git a/src/librustc/ty/relate.rs b/src/librustc/ty/relate.rs
index d4f06a902ee..9345e504701 100644
--- a/src/librustc/ty/relate.rs
+++ b/src/librustc/ty/relate.rs
@@ -440,13 +440,11 @@ pub fn super_relate_tys<'a, 'gcx, 'tcx, R>(relation: &mut R,
             }
         }
 
-        (&ty::TyFnDef(a_def_id, a_substs, a_fty),
-         &ty::TyFnDef(b_def_id, b_substs, b_fty))
+        (&ty::TyFnDef(a_def_id, a_substs), &ty::TyFnDef(b_def_id, b_substs))
             if a_def_id == b_def_id =>
         {
             let substs = relate_substs(relation, None, a_substs, b_substs)?;
-            let fty = relation.relate(&a_fty, &b_fty)?;
-            Ok(tcx.mk_fn_def(a_def_id, substs, fty))
+            Ok(tcx.mk_fn_def(a_def_id, substs))
         }
 
         (&ty::TyFnPtr(a_fty), &ty::TyFnPtr(b_fty)) =>
diff --git a/src/librustc/ty/structural_impls.rs b/src/librustc/ty/structural_impls.rs
index 1e268924390..d05262965d7 100644
--- a/src/librustc/ty/structural_impls.rs
+++ b/src/librustc/ty/structural_impls.rs
@@ -531,10 +531,8 @@ impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
             ty::TyDynamic(ref trait_ty, ref region) =>
                 ty::TyDynamic(trait_ty.fold_with(folder), region.fold_with(folder)),
             ty::TyTuple(ts, defaulted) => ty::TyTuple(ts.fold_with(folder), defaulted),
-            ty::TyFnDef(def_id, substs, f) => {
-                ty::TyFnDef(def_id,
-                            substs.fold_with(folder),
-                            f.fold_with(folder))
+            ty::TyFnDef(def_id, substs) => {
+                ty::TyFnDef(def_id, substs.fold_with(folder))
             }
             ty::TyFnPtr(f) => ty::TyFnPtr(f.fold_with(folder)),
             ty::TyRef(ref r, tm) => {
@@ -568,9 +566,7 @@ impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
             ty::TyDynamic(ref trait_ty, ref reg) =>
                 trait_ty.visit_with(visitor) || reg.visit_with(visitor),
             ty::TyTuple(ts, _) => ts.visit_with(visitor),
-            ty::TyFnDef(_, substs, ref f) => {
-                substs.visit_with(visitor) || f.visit_with(visitor)
-            }
+            ty::TyFnDef(_, substs) => substs.visit_with(visitor),
             ty::TyFnPtr(ref f) => f.visit_with(visitor),
             ty::TyRef(r, ref tm) => r.visit_with(visitor) || tm.visit_with(visitor),
             ty::TyClosure(_did, ref substs) => substs.visit_with(visitor),
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index 6923a6d21d6..ed3312d88a3 100644
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -14,7 +14,7 @@ use hir::def_id::DefId;
 use hir::map::DefPathHash;
 
 use middle::region;
-use ty::subst::Substs;
+use ty::subst::{Substs, Subst};
 use ty::{self, AdtDef, TypeFlags, Ty, TyCtxt, TypeFoldable};
 use ty::{Slice, TyS};
 use ty::subst::Kind;
@@ -138,7 +138,7 @@ pub enum TypeVariants<'tcx> {
 
     /// The anonymous type of a function declaration/definition. Each
     /// function has a unique type.
-    TyFnDef(DefId, &'tcx Substs<'tcx>, PolyFnSig<'tcx>),
+    TyFnDef(DefId, &'tcx Substs<'tcx>),
 
     /// A pointer to a function.  Written as `fn() -> i32`.
     TyFnPtr(PolyFnSig<'tcx>),
@@ -1329,9 +1329,12 @@ impl<'a, 'gcx, 'tcx> TyS<'tcx> {
         }
     }
 
-    pub fn fn_sig(&self) -> PolyFnSig<'tcx> {
+    pub fn fn_sig(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> PolyFnSig<'tcx> {
         match self.sty {
-            TyFnDef(.., f) | TyFnPtr(f) => f,
+            TyFnDef(def_id, substs) => {
+                tcx.fn_sig(def_id).subst(tcx, substs)
+            }
+            TyFnPtr(f) => f,
             _ => bug!("Ty::fn_sig() called on non-fn type: {:?}", self)
         }
     }
diff --git a/src/librustc/ty/util.rs b/src/librustc/ty/util.rs
index 1bbc7673485..98ef7918fef 100644
--- a/src/librustc/ty/util.rs
+++ b/src/librustc/ty/util.rs
@@ -679,7 +679,7 @@ impl<'a, 'gcx, 'tcx, W> TypeVisitor<'tcx> for TypeIdHasher<'a, 'gcx, 'tcx, W>
             TyRef(_, m) => self.hash(m.mutbl),
             TyClosure(def_id, _) |
             TyAnon(def_id, _) |
-            TyFnDef(def_id, ..) => self.def_id(def_id),
+            TyFnDef(def_id, _) => self.def_id(def_id),
             TyAdt(d, _) => self.def_id(d.did),
             TyFnPtr(f) => {
                 self.hash(f.unsafety());
diff --git a/src/librustc/ty/walk.rs b/src/librustc/ty/walk.rs
index d7954953aba..71844abfe53 100644
--- a/src/librustc/ty/walk.rs
+++ b/src/librustc/ty/walk.rs
@@ -115,9 +115,8 @@ fn push_subtypes<'tcx>(stack: &mut TypeWalkerStack<'tcx>, parent_ty: Ty<'tcx>) {
         ty::TyTuple(ts, _) => {
             stack.extend(ts.iter().cloned().rev());
         }
-        ty::TyFnDef(_, substs, ft) => {
+        ty::TyFnDef(_, substs) => {
             stack.extend(substs.types().rev());
-            push_sig_subtypes(stack, ft);
         }
         ty::TyFnPtr(ft) => {
             push_sig_subtypes(stack, ft);
diff --git a/src/librustc/util/ppaux.rs b/src/librustc/util/ppaux.rs
index 1fa63577196..eb6bffc29c5 100644
--- a/src/librustc/util/ppaux.rs
+++ b/src/librustc/util/ppaux.rs
@@ -753,8 +753,14 @@ impl<'tcx> fmt::Display for ty::TypeVariants<'tcx> {
                 }
                 write!(f, ")")
             }
-            TyFnDef(def_id, substs, ref bare_fn) => {
-                write!(f, "{} {{", bare_fn.0)?;
+            TyFnDef(def_id, substs) => {
+                ty::tls::with(|tcx| {
+                    let mut sig = tcx.fn_sig(def_id);
+                    if let Some(substs) = tcx.lift(&substs) {
+                        sig = sig.subst(tcx, substs);
+                    }
+                    write!(f, "{} {{", sig.0)
+                })?;
                 parameterized(f, substs, def_id, &[])?;
                 write!(f, "}}")
             }
diff --git a/src/librustc_borrowck/borrowck/mir/dataflow/sanity_check.rs b/src/librustc_borrowck/borrowck/mir/dataflow/sanity_check.rs
index 2c55460fb30..4bef191b113 100644
--- a/src/librustc_borrowck/borrowck/mir/dataflow/sanity_check.rs
+++ b/src/librustc_borrowck/borrowck/mir/dataflow/sanity_check.rs
@@ -161,18 +161,13 @@ fn is_rustc_peek<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                            terminator: &'a Option<mir::Terminator<'tcx>>)
                            -> Option<(&'a [mir::Operand<'tcx>], Span)> {
     if let Some(mir::Terminator { ref kind, source_info, .. }) = *terminator {
-        if let mir::TerminatorKind::Call { func: ref oper, ref args, .. } = *kind
-        {
-            if let mir::Operand::Constant(ref func) = *oper
-            {
-                if let ty::TyFnDef(def_id, _, sig) = func.ty.sty
-                {
-                    let abi = sig.abi();
+        if let mir::TerminatorKind::Call { func: ref oper, ref args, .. } = *kind {
+            if let mir::Operand::Constant(ref func) = *oper {
+                if let ty::TyFnDef(def_id, _) = func.ty.sty {
+                    let abi = tcx.fn_sig(def_id).abi();
                     let name = tcx.item_name(def_id);
-                    if abi == Abi::RustIntrinsic || abi == Abi::PlatformIntrinsic {
-                        if name == "rustc_peek" {
-                            return Some((args, source_info.span));
-                        }
+                    if abi == Abi::RustIntrinsic &&  name == "rustc_peek" {
+                        return Some((args, source_info.span));
                     }
                 }
             }
diff --git a/src/librustc_const_eval/pattern.rs b/src/librustc_const_eval/pattern.rs
index d175920e8a6..0a966b0c170 100644
--- a/src/librustc_const_eval/pattern.rs
+++ b/src/librustc_const_eval/pattern.rs
@@ -12,7 +12,7 @@ use eval;
 
 use rustc::middle::const_val::{ConstEvalErr, ConstVal};
 use rustc::mir::{Field, BorrowKind, Mutability};
-use rustc::ty::{self, TyCtxt, AdtDef, Ty, TypeVariants, Region};
+use rustc::ty::{self, TyCtxt, AdtDef, Ty, Region};
 use rustc::ty::subst::{Substs, Kind};
 use rustc::hir::{self, PatKind, RangeEnd};
 use rustc::hir::def::{Def, CtorKind};
@@ -549,8 +549,8 @@ impl<'a, 'gcx, 'tcx> PatternContext<'a, 'gcx, 'tcx> {
                 let adt_def = self.tcx.adt_def(enum_id);
                 if adt_def.variants.len() > 1 {
                     let substs = match ty.sty {
-                        TypeVariants::TyAdt(_, substs) => substs,
-                        TypeVariants::TyFnDef(_, substs, _) => substs,
+                        ty::TyAdt(_, substs) |
+                        ty::TyFnDef(_, substs) => substs,
                         _ => bug!("inappropriate type for def: {:?}", ty.sty),
                     };
                     PatternKind::Variant {
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index 9800012917c..ad154f9b815 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -1154,24 +1154,16 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MutableTransmutes {
                 if !def_id_is_transmute(cx, did) {
                     return None;
                 }
-                let typ = cx.tables.node_id_to_type(expr.id);
-                match typ.sty {
-                    ty::TyFnDef(.., bare_fn) if bare_fn.abi() == RustIntrinsic => {
-                        let from = bare_fn.inputs().skip_binder()[0];
-                        let to = *bare_fn.output().skip_binder();
-                        return Some((&from.sty, &to.sty));
-                    }
-                    _ => (),
-                }
+                let sig = cx.tables.node_id_to_type(expr.id).fn_sig(cx.tcx);
+                let from = sig.inputs().skip_binder()[0];
+                let to = *sig.output().skip_binder();
+                return Some((&from.sty, &to.sty));
             }
             None
         }
 
         fn def_id_is_transmute(cx: &LateContext, def_id: DefId) -> bool {
-            match cx.tcx.type_of(def_id).sty {
-                ty::TyFnDef(.., bfty) if bfty.abi() == RustIntrinsic => (),
-                _ => return false,
-            }
+            cx.tcx.fn_sig(def_id).abi() == RustIntrinsic &&
             cx.tcx.item_name(def_id) == "transmute"
         }
     }
diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs
index 32bde42b526..ac3977bd216 100644
--- a/src/librustc_lint/types.rs
+++ b/src/librustc_lint/types.rs
@@ -659,7 +659,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
 
     fn check_foreign_fn(&mut self, id: ast::NodeId, decl: &hir::FnDecl) {
         let def_id = self.cx.tcx.hir.local_def_id(id);
-        let sig = self.cx.tcx.type_of(def_id).fn_sig();
+        let sig = self.cx.tcx.fn_sig(def_id);
         let sig = self.cx.tcx.erase_late_bound_regions(&sig);
 
         for (input_ty, input_hir) in sig.inputs().iter().zip(&decl.inputs) {
diff --git a/src/librustc_metadata/decoder.rs b/src/librustc_metadata/decoder.rs
index 77f01d5c28c..3e6d06ec86f 100644
--- a/src/librustc_metadata/decoder.rs
+++ b/src/librustc_metadata/decoder.rs
@@ -1085,13 +1085,19 @@ impl<'a, 'tcx> CrateMetadata {
     }
 
     pub fn fn_sig(&self,
-                  closure_id: DefIndex,
+                  id: DefIndex,
                   tcx: TyCtxt<'a, 'tcx, 'tcx>)
                   -> ty::PolyFnSig<'tcx> {
-        match self.entry(closure_id).kind {
-            EntryKind::Closure(data) => data.decode(self).sig.decode((self, tcx)),
+        let sig = match self.entry(id).kind {
+            EntryKind::Fn(data) |
+            EntryKind::ForeignFn(data) => data.decode(self).sig,
+            EntryKind::Method(data) => data.decode(self).fn_data.sig,
+            EntryKind::Variant(data) |
+            EntryKind::Struct(data, _) => data.decode(self).ctor_sig.unwrap(),
+            EntryKind::Closure(data) => data.decode(self).sig,
             _ => bug!(),
-        }
+        };
+        sig.decode((self, tcx))
     }
 
     #[inline]
diff --git a/src/librustc_metadata/encoder.rs b/src/librustc_metadata/encoder.rs
index 860b553959f..34b25a4b7e4 100644
--- a/src/librustc_metadata/encoder.rs
+++ b/src/librustc_metadata/encoder.rs
@@ -16,6 +16,7 @@ use schema::*;
 use rustc::middle::cstore::{LinkMeta, LinkagePreference, NativeLibrary,
                             EncodedMetadata, EncodedMetadataHashes,
                             EncodedMetadataHash};
+use rustc::hir::def::CtorKind;
 use rustc::hir::def_id::{CrateNum, CRATE_DEF_INDEX, DefIndex, DefId, LOCAL_CRATE};
 use rustc::hir::map::definitions::{DefPathTable, GlobalMetaDataKind};
 use rustc::ich::Fingerprint;
@@ -499,6 +500,11 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
             ctor_kind: variant.ctor_kind,
             discr: variant.discr,
             struct_ctor: None,
+            ctor_sig: if variant.ctor_kind == CtorKind::Fn {
+                Some(self.lazy(&tcx.fn_sig(def_id)))
+            } else {
+                None
+            }
         };
 
         let enum_id = tcx.hir.as_local_node_id(enum_did).unwrap();
@@ -617,6 +623,11 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
             ctor_kind: variant.ctor_kind,
             discr: variant.discr,
             struct_ctor: Some(def_id.index),
+            ctor_sig: if variant.ctor_kind == CtorKind::Fn {
+                Some(self.lazy(&tcx.fn_sig(def_id)))
+            } else {
+                None
+            }
         };
 
         let struct_id = tcx.hir.as_local_node_id(adt_def_id).unwrap();
@@ -695,7 +706,8 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
                     };
                     FnData {
                         constness: hir::Constness::NotConst,
-                        arg_names: arg_names
+                        arg_names: arg_names,
+                        sig: self.lazy(&tcx.fn_sig(def_id)),
                     }
                 } else {
                     bug!()
@@ -747,6 +759,8 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
 
     fn encode_info_for_impl_item(&mut self, def_id: DefId) -> Entry<'tcx> {
         debug!("IsolatedEncoder::encode_info_for_impl_item({:?})", def_id);
+        let tcx = self.tcx;
+
         let node_id = self.tcx.hir.as_local_node_id(def_id).unwrap();
         let ast_item = self.tcx.hir.expect_impl_item(node_id);
         let impl_item = self.tcx.associated_item(def_id);
@@ -768,6 +782,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
                     FnData {
                         constness: sig.constness,
                         arg_names: self.encode_fn_arg_names_for_body(body),
+                        sig: self.lazy(&tcx.fn_sig(def_id)),
                     }
                 } else {
                     bug!()
@@ -881,6 +896,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
                 let data = FnData {
                     constness: constness,
                     arg_names: self.encode_fn_arg_names_for_body(body),
+                    sig: self.lazy(&tcx.fn_sig(def_id)),
                 };
 
                 EntryKind::Fn(self.lazy(&data))
@@ -910,6 +926,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
                     ctor_kind: variant.ctor_kind,
                     discr: variant.discr,
                     struct_ctor: struct_ctor,
+                    ctor_sig: None,
                 }), repr_options)
             }
             hir::ItemUnion(..) => {
@@ -920,6 +937,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
                     ctor_kind: variant.ctor_kind,
                     discr: variant.discr,
                     struct_ctor: None,
+                    ctor_sig: None,
                 }), repr_options)
             }
             hir::ItemDefaultImpl(..) => {
@@ -1363,6 +1381,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
                 let data = FnData {
                     constness: hir::Constness::NotConst,
                     arg_names: self.encode_fn_arg_names(names),
+                    sig: self.lazy(&tcx.fn_sig(def_id)),
                 };
                 EntryKind::ForeignFn(self.lazy(&data))
             }
diff --git a/src/librustc_metadata/schema.rs b/src/librustc_metadata/schema.rs
index 36977cb5db2..9ef5b940830 100644
--- a/src/librustc_metadata/schema.rs
+++ b/src/librustc_metadata/schema.rs
@@ -343,18 +343,18 @@ pub enum EntryKind<'tcx> {
     Type,
     Enum(ReprOptions),
     Field,
-    Variant(Lazy<VariantData>),
-    Struct(Lazy<VariantData>, ReprOptions),
-    Union(Lazy<VariantData>, ReprOptions),
-    Fn(Lazy<FnData>),
-    ForeignFn(Lazy<FnData>),
+    Variant(Lazy<VariantData<'tcx>>),
+    Struct(Lazy<VariantData<'tcx>>, ReprOptions),
+    Union(Lazy<VariantData<'tcx>>, ReprOptions),
+    Fn(Lazy<FnData<'tcx>>),
+    ForeignFn(Lazy<FnData<'tcx>>),
     Mod(Lazy<ModData>),
     MacroDef(Lazy<MacroDef>),
     Closure(Lazy<ClosureData<'tcx>>),
     Trait(Lazy<TraitData<'tcx>>),
     Impl(Lazy<ImplData<'tcx>>),
     DefaultImpl(Lazy<ImplData<'tcx>>),
-    Method(Lazy<MethodData>),
+    Method(Lazy<MethodData<'tcx>>),
     AssociatedType(AssociatedContainer),
     AssociatedConst(AssociatedContainer, u8),
 }
@@ -439,27 +439,33 @@ pub struct MacroDef {
 impl_stable_hash_for!(struct MacroDef { body, legacy });
 
 #[derive(RustcEncodable, RustcDecodable)]
-pub struct FnData {
+pub struct FnData<'tcx> {
     pub constness: hir::Constness,
     pub arg_names: LazySeq<ast::Name>,
+    pub sig: Lazy<ty::PolyFnSig<'tcx>>,
 }
 
-impl_stable_hash_for!(struct FnData { constness, arg_names });
+impl_stable_hash_for!(struct FnData<'tcx> { constness, arg_names, sig });
 
 #[derive(RustcEncodable, RustcDecodable)]
-pub struct VariantData {
+pub struct VariantData<'tcx> {
     pub ctor_kind: CtorKind,
     pub discr: ty::VariantDiscr,
 
     /// If this is a struct's only variant, this
     /// is the index of the "struct ctor" item.
     pub struct_ctor: Option<DefIndex>,
+
+    /// If this is a tuple struct or variant
+    /// ctor, this is its "function" signature.
+    pub ctor_sig: Option<Lazy<ty::PolyFnSig<'tcx>>>,
 }
 
-impl_stable_hash_for!(struct VariantData {
+impl_stable_hash_for!(struct VariantData<'tcx> {
     ctor_kind,
     discr,
-    struct_ctor
+    struct_ctor,
+    ctor_sig
 });
 
 #[derive(RustcEncodable, RustcDecodable)]
@@ -543,12 +549,12 @@ impl AssociatedContainer {
 }
 
 #[derive(RustcEncodable, RustcDecodable)]
-pub struct MethodData {
-    pub fn_data: FnData,
+pub struct MethodData<'tcx> {
+    pub fn_data: FnData<'tcx>,
     pub container: AssociatedContainer,
     pub has_self: bool,
 }
-impl_stable_hash_for!(struct MethodData { fn_data, container, has_self });
+impl_stable_hash_for!(struct MethodData<'tcx> { fn_data, container, has_self });
 
 #[derive(RustcEncodable, RustcDecodable)]
 pub struct ClosureData<'tcx> {
diff --git a/src/librustc_mir/build/expr/into.rs b/src/librustc_mir/build/expr/into.rs
index b7abc707a38..326c1df69eb 100644
--- a/src/librustc_mir/build/expr/into.rs
+++ b/src/librustc_mir/build/expr/into.rs
@@ -205,11 +205,14 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 // FIXME(canndrew): This is_never should probably be an is_uninhabited
                 let diverges = expr.ty.is_never();
                 let intrinsic = match ty.sty {
-                    ty::TyFnDef(def_id, _, ref f) if
-                        f.abi() == Abi::RustIntrinsic ||
-                        f.abi() == Abi::PlatformIntrinsic =>
-                    {
-                        Some(this.hir.tcx().item_name(def_id).as_str())
+                    ty::TyFnDef(def_id, _)  => {
+                        let f = ty.fn_sig(this.hir.tcx());
+                        if f.abi() == Abi::RustIntrinsic ||
+                           f.abi() == Abi::PlatformIntrinsic {
+                            Some(this.hir.tcx().item_name(def_id).as_str())
+                        } else {
+                            None
+                        }
                     }
                     _ => None
                 };
diff --git a/src/librustc_mir/hair/cx/expr.rs b/src/librustc_mir/hair/cx/expr.rs
index 474feefabbb..0010f312ef9 100644
--- a/src/librustc_mir/hair/cx/expr.rs
+++ b/src/librustc_mir/hair/cx/expr.rs
@@ -19,7 +19,6 @@ use rustc::middle::const_val::ConstVal;
 use rustc::ty::{self, AdtKind, VariantDef, Ty};
 use rustc::ty::adjustment::{Adjustment, Adjust, AutoBorrow};
 use rustc::ty::cast::CastKind as TyCastKind;
-use rustc::ty::subst::Subst;
 use rustc::hir;
 
 impl<'tcx> Mirror<'tcx> for &'tcx hir::Expr {
@@ -586,7 +585,7 @@ fn method_callee<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
     });
     Expr {
         temp_lifetime: temp_lifetime,
-        ty: cx.tcx.type_of(def_id).subst(cx.tcx, substs),
+        ty: cx.tcx().mk_fn_def(def_id, substs),
         span: expr.span,
         kind: ExprKind::Literal {
             literal: Literal::Value {
diff --git a/src/librustc_mir/shim.rs b/src/librustc_mir/shim.rs
index 54779cbe301..11ad5d1509d 100644
--- a/src/librustc_mir/shim.rs
+++ b/src/librustc_mir/shim.rs
@@ -58,7 +58,7 @@ fn make_shim<'a, 'tcx>(tcx: ty::TyCtxt<'a, 'tcx, 'tcx>,
             // types in the MIR. They will be substituted again with
             // the param-substs, but because they are concrete, this
             // will not do any harm.
-            let sig = tcx.erase_late_bound_regions(&ty.fn_sig());
+            let sig = tcx.erase_late_bound_regions(&ty.fn_sig(tcx));
             let arg_tys = sig.inputs();
 
             build_call_shim(
@@ -153,8 +153,8 @@ fn build_drop_shim<'a, 'tcx>(tcx: ty::TyCtxt<'a, 'tcx, 'tcx>,
     } else {
         Substs::identity_for_item(tcx, def_id)
     };
-    let fn_ty = tcx.type_of(def_id).subst(tcx, substs);
-    let sig = tcx.erase_late_bound_regions(&fn_ty.fn_sig());
+    let sig = tcx.fn_sig(def_id).subst(tcx, substs);
+    let sig = tcx.erase_late_bound_regions(&sig);
     let span = tcx.def_span(def_id);
 
     let source_info = SourceInfo { span, scope: ARGUMENT_VISIBILITY_SCOPE };
@@ -276,8 +276,8 @@ fn build_call_shim<'a, 'tcx>(tcx: ty::TyCtxt<'a, 'tcx, 'tcx>,
             call_kind={:?}, untuple_args={:?})",
            def_id, rcvr_adjustment, call_kind, untuple_args);
 
-    let fn_ty = tcx.type_of(def_id);
-    let sig = tcx.erase_late_bound_regions(&fn_ty.fn_sig());
+    let sig = tcx.fn_sig(def_id);
+    let sig = tcx.erase_late_bound_regions(&sig);
     let span = tcx.def_span(def_id);
 
     debug!("build_call_shim: sig={:?}", sig);
@@ -409,11 +409,8 @@ pub fn build_adt_ctor<'a, 'gcx, 'tcx>(infcx: &infer::InferCtxt<'a, 'gcx, 'tcx>,
 {
     let tcx = infcx.tcx;
     let def_id = tcx.hir.local_def_id(ctor_id);
-    let sig = match tcx.type_of(def_id).sty {
-        ty::TyFnDef(_, _, fty) => tcx.no_late_bound_regions(&fty)
-            .expect("LBR in ADT constructor signature"),
-        _ => bug!("unexpected type for ctor {:?}", def_id)
-    };
+    let sig = tcx.no_late_bound_regions(&tcx.fn_sig(def_id))
+        .expect("LBR in ADT constructor signature");
     let sig = tcx.erase_regions(&sig);
 
     let (adt_def, substs) = match sig.output().sty {
diff --git a/src/librustc_mir/transform/inline.rs b/src/librustc_mir/transform/inline.rs
index 0ac35a5fdd4..5f80c7bee14 100644
--- a/src/librustc_mir/transform/inline.rs
+++ b/src/librustc_mir/transform/inline.rs
@@ -87,7 +87,7 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> {
                 let terminator = bb_data.terminator();
                 if let TerminatorKind::Call {
                     func: Operand::Constant(ref f), .. } = terminator.kind {
-                    if let ty::TyFnDef(callee_def_id, substs, _) = f.ty.sty {
+                    if let ty::TyFnDef(callee_def_id, substs) = f.ty.sty {
                         callsites.push_back(CallSite {
                             callee: callee_def_id,
                             substs: substs,
@@ -131,7 +131,7 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> {
                     let terminator = bb_data.terminator();
                     if let TerminatorKind::Call {
                         func: Operand::Constant(ref f), .. } = terminator.kind {
-                        if let ty::TyFnDef(callee_def_id, substs, _) = f.ty.sty {
+                        if let ty::TyFnDef(callee_def_id, substs) = f.ty.sty {
                             // Don't inline the same function multiple times.
                             if callsite.callee != callee_def_id {
                                 callsites.push_back(CallSite {
@@ -270,8 +270,9 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> {
                 }
 
                 TerminatorKind::Call {func: Operand::Constant(ref f), .. } => {
-                    if let ty::TyFnDef(.., f) = f.ty.sty {
+                    if let ty::TyFnDef(def_id, _) = f.ty.sty {
                         // Don't give intrinsics the extra penalty for calls
+                        let f = tcx.fn_sig(def_id);
                         if f.abi() == Abi::RustIntrinsic || f.abi() == Abi::PlatformIntrinsic {
                             cost += INSTR_COST;
                         } else {
diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index 05a6cdd57ff..91d6ce60b39 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -750,8 +750,8 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
 
             let fn_ty = func.ty(self.mir, self.tcx);
             let (is_shuffle, is_const_fn) = match fn_ty.sty {
-                ty::TyFnDef(def_id, _, f) => {
-                    (f.abi() == Abi::PlatformIntrinsic &&
+                ty::TyFnDef(def_id, _) => {
+                    (self.tcx.fn_sig(def_id).abi() == Abi::PlatformIntrinsic &&
                      self.tcx.item_name(def_id).as_str().starts_with("simd_shuffle"),
                      self.tcx.is_const_fn(def_id))
                 }
diff --git a/src/librustc_mir/transform/type_check.rs b/src/librustc_mir/transform/type_check.rs
index efde39ad6a4..7e6fccf3019 100644
--- a/src/librustc_mir/transform/type_check.rs
+++ b/src/librustc_mir/transform/type_check.rs
@@ -462,7 +462,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
                 let func_ty = func.ty(mir, tcx);
                 debug!("check_terminator: call, func_ty={:?}", func_ty);
                 let sig = match func_ty.sty {
-                    ty::TyFnDef(.., sig) | ty::TyFnPtr(sig) => sig,
+                    ty::TyFnDef(..) | ty::TyFnPtr(_) => func_ty.fn_sig(tcx),
                     _ => {
                         span_mirbug!(self, term, "call to non-function {:?}", func_ty);
                         return;
diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
index fb7258d4266..9eb96fea527 100644
--- a/src/librustc_privacy/lib.rs
+++ b/src/librustc_privacy/lib.rs
@@ -400,7 +400,13 @@ impl<'b, 'a, 'tcx> ReachEverythingInTheInterfaceVisitor<'b, 'a, 'tcx> {
     }
 
     fn ty(&mut self) -> &mut Self {
-        self.ev.tcx.type_of(self.item_def_id).visit_with(self);
+        let ty = self.ev.tcx.type_of(self.item_def_id);
+        ty.visit_with(self);
+        if let ty::TyFnDef(def_id, _) = ty.sty {
+            if def_id == self.item_def_id {
+                self.ev.tcx.fn_sig(def_id).visit_with(self);
+            }
+        }
         self
     }
 
@@ -910,7 +916,13 @@ impl<'a, 'tcx: 'a> SearchInterfaceForPrivateItemsVisitor<'a, 'tcx> {
     }
 
     fn ty(&mut self) -> &mut Self {
-        self.tcx.type_of(self.item_def_id).visit_with(self);
+        let ty = self.tcx.type_of(self.item_def_id);
+        ty.visit_with(self);
+        if let ty::TyFnDef(def_id, _) = ty.sty {
+            if def_id == self.item_def_id {
+                self.tcx.fn_sig(def_id).visit_with(self);
+            }
+        }
         self
     }
 
diff --git a/src/librustc_trans/back/symbol_names.rs b/src/librustc_trans/back/symbol_names.rs
index 8e14335ceac..10b66fb1991 100644
--- a/src/librustc_trans/back/symbol_names.rs
+++ b/src/librustc_trans/back/symbol_names.rs
@@ -154,6 +154,13 @@ fn get_symbol_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         assert!(!item_type.has_erasable_regions());
         hasher.visit_ty(item_type);
 
+        // If this is a function, we hash the signature as well.
+        // This is not *strictly* needed, but it may help in some
+        // situations, see the `run-make/a-b-a-linker-guard` test.
+        if let ty::TyFnDef(..) = item_type.sty {
+            item_type.fn_sig(tcx).visit_with(&mut hasher);
+        }
+
         // also include any type parameters (for generic items)
         if let Some(substs) = substs {
             assert!(!substs.has_erasable_regions());
diff --git a/src/librustc_trans/collector.rs b/src/librustc_trans/collector.rs
index d723cf32571..3c502eec549 100644
--- a/src/librustc_trans/collector.rs
+++ b/src/librustc_trans/collector.rs
@@ -587,7 +587,7 @@ fn visit_fn_use<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
                           is_direct_call: bool,
                           output: &mut Vec<TransItem<'tcx>>)
 {
-    if let ty::TyFnDef(def_id, substs, _) = ty.sty {
+    if let ty::TyFnDef(def_id, substs) = ty.sty {
         let instance = monomorphize::resolve(scx, def_id, substs);
         visit_instance_use(scx, instance, is_direct_call, output);
     }
diff --git a/src/librustc_trans/common.rs b/src/librustc_trans/common.rs
index 0db74c9454a..9b0803908b1 100644
--- a/src/librustc_trans/common.rs
+++ b/src/librustc_trans/common.rs
@@ -495,9 +495,9 @@ pub fn ty_fn_sig<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
                            -> ty::PolyFnSig<'tcx>
 {
     match ty.sty {
-        ty::TyFnDef(_, _, sig) => sig,
+        ty::TyFnDef(..) |
         // Shims currently have type TyFnPtr. Not sure this should remain.
-        ty::TyFnPtr(sig) => sig,
+        ty::TyFnPtr(_) => ty.fn_sig(ccx.tcx()),
         ty::TyClosure(def_id, substs) => {
             let tcx = ccx.tcx();
             let sig = tcx.fn_sig(def_id).subst(tcx, substs.substs);
diff --git a/src/librustc_trans/debuginfo/metadata.rs b/src/librustc_trans/debuginfo/metadata.rs
index 95ceec610ea..0cc19936011 100644
--- a/src/librustc_trans/debuginfo/metadata.rs
+++ b/src/librustc_trans/debuginfo/metadata.rs
@@ -488,7 +488,6 @@ pub fn type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 
     debug!("type_metadata: {:?}", t);
 
-    let sty = &t.sty;
     let ptr_metadata = |ty: Ty<'tcx>| {
         match ty.sty {
             ty::TySlice(typ) => {
@@ -518,7 +517,7 @@ pub fn type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
         }
     };
 
-    let MetadataCreationResult { metadata, already_stored_in_typemap } = match *sty {
+    let MetadataCreationResult { metadata, already_stored_in_typemap } = match t.sty {
         ty::TyNever    |
         ty::TyBool     |
         ty::TyChar     |
@@ -557,10 +556,10 @@ pub fn type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
                 Err(metadata) => return metadata,
             }
         }
-        ty::TyFnDef(.., sig) | ty::TyFnPtr(sig) => {
+        ty::TyFnDef(..) | ty::TyFnPtr(_) => {
             let fn_metadata = subroutine_type_metadata(cx,
                                                        unique_type_id,
-                                                       sig,
+                                                       t.fn_sig(cx.tcx()),
                                                        usage_site_span).metadata;
             match debug_context(cx).type_map
                                    .borrow()
@@ -610,7 +609,7 @@ pub fn type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
                                    usage_site_span).finalize(cx)
         }
         _ => {
-            bug!("debuginfo: unexpected type in type_metadata: {:?}", sty)
+            bug!("debuginfo: unexpected type in type_metadata: {:?}", t)
         }
     };
 
diff --git a/src/librustc_trans/debuginfo/type_names.rs b/src/librustc_trans/debuginfo/type_names.rs
index 13ff6646e66..bfca4fec706 100644
--- a/src/librustc_trans/debuginfo/type_names.rs
+++ b/src/librustc_trans/debuginfo/type_names.rs
@@ -96,8 +96,8 @@ pub fn push_debuginfo_type_name<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
                 push_type_params(cx, principal.substs, output);
             }
         },
-        ty::TyFnDef(.., sig) |
-        ty::TyFnPtr(sig) => {
+        ty::TyFnDef(..) | ty::TyFnPtr(_) => {
+            let sig = t.fn_sig(cx.tcx());
             if sig.unsafety() == hir::Unsafety::Unsafe {
                 output.push_str("unsafe ");
             }
diff --git a/src/librustc_trans/intrinsic.rs b/src/librustc_trans/intrinsic.rs
index de908bb24a7..9956c28e641 100644
--- a/src/librustc_trans/intrinsic.rs
+++ b/src/librustc_trans/intrinsic.rs
@@ -95,11 +95,12 @@ pub fn trans_intrinsic_call<'a, 'tcx>(bcx: &Builder<'a, 'tcx>,
     let ccx = bcx.ccx;
     let tcx = ccx.tcx();
 
-    let (def_id, substs, sig) = match callee_ty.sty {
-        ty::TyFnDef(def_id, substs, sig) => (def_id, substs, sig),
+    let (def_id, substs) = match callee_ty.sty {
+        ty::TyFnDef(def_id, substs) => (def_id, substs),
         _ => bug!("expected fn item type, found {}", callee_ty)
     };
 
+    let sig = callee_ty.fn_sig(tcx);
     let sig = tcx.erase_late_bound_regions_and_normalize(&sig);
     let arg_tys = sig.inputs();
     let ret_ty = sig.output();
@@ -986,7 +987,7 @@ fn generic_simd_intrinsic<'a, 'tcx>(
 
 
     let tcx = bcx.tcx();
-    let sig = tcx.erase_late_bound_regions_and_normalize(&callee_ty.fn_sig());
+    let sig = tcx.erase_late_bound_regions_and_normalize(&callee_ty.fn_sig(tcx));
     let arg_tys = sig.inputs();
 
     // every intrinsic takes a SIMD vector as its first argument
diff --git a/src/librustc_trans/mir/block.rs b/src/librustc_trans/mir/block.rs
index 8863c7ffae6..16972a1b1ae 100644
--- a/src/librustc_trans/mir/block.rs
+++ b/src/librustc_trans/mir/block.rs
@@ -404,20 +404,18 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
                 // Create the callee. This is a fn ptr or zero-sized and hence a kind of scalar.
                 let callee = self.trans_operand(&bcx, func);
 
-                let (instance, mut llfn, sig) = match callee.ty.sty {
-                    ty::TyFnDef(def_id, substs, sig) => {
+                let (instance, mut llfn) = match callee.ty.sty {
+                    ty::TyFnDef(def_id, substs) => {
                         (Some(monomorphize::resolve(bcx.ccx.shared(), def_id, substs)),
-                         None,
-                         sig)
+                         None)
                     }
-                    ty::TyFnPtr(sig) => {
-                        (None,
-                         Some(callee.immediate()),
-                         sig)
+                    ty::TyFnPtr(_) => {
+                        (None, Some(callee.immediate()))
                     }
                     _ => bug!("{} is not callable", callee.ty)
                 };
                 let def = instance.map(|i| i.def);
+                let sig = callee.ty.fn_sig(bcx.tcx());
                 let sig = bcx.tcx().erase_late_bound_regions_and_normalize(&sig);
                 let abi = sig.abi;
 
diff --git a/src/librustc_trans/mir/constant.rs b/src/librustc_trans/mir/constant.rs
index 60886b2b35f..fcb4b25e6fe 100644
--- a/src/librustc_trans/mir/constant.rs
+++ b/src/librustc_trans/mir/constant.rs
@@ -334,7 +334,7 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
                     let fn_ty = func.ty(self.mir, tcx);
                     let fn_ty = self.monomorphize(&fn_ty);
                     let (def_id, substs) = match fn_ty.sty {
-                        ty::TyFnDef(def_id, substs, _) => (def_id, substs),
+                        ty::TyFnDef(def_id, substs) => (def_id, substs),
                         _ => span_bug!(span, "calling {:?} (of type {}) in constant",
                                        func, fn_ty)
                     };
@@ -560,7 +560,7 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
                 let val = match *kind {
                     mir::CastKind::ReifyFnPointer => {
                         match operand.ty.sty {
-                            ty::TyFnDef(def_id, substs, _) => {
+                            ty::TyFnDef(def_id, substs) => {
                                 callee::resolve_and_get_fn(self.ccx, def_id, substs)
                             }
                             _ => {
diff --git a/src/librustc_trans/mir/rvalue.rs b/src/librustc_trans/mir/rvalue.rs
index 61e537c9cc0..4bd5091a4f3 100644
--- a/src/librustc_trans/mir/rvalue.rs
+++ b/src/librustc_trans/mir/rvalue.rs
@@ -180,7 +180,7 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
                 let val = match *kind {
                     mir::CastKind::ReifyFnPointer => {
                         match operand.ty.sty {
-                            ty::TyFnDef(def_id, substs, _) => {
+                            ty::TyFnDef(def_id, substs) => {
                                 OperandValue::Immediate(
                                     callee::resolve_and_get_fn(bcx.ccx, def_id, substs))
                             }
diff --git a/src/librustc_trans/monomorphize.rs b/src/librustc_trans/monomorphize.rs
index a5fe70a2fd7..1f6a262162d 100644
--- a/src/librustc_trans/monomorphize.rs
+++ b/src/librustc_trans/monomorphize.rs
@@ -165,9 +165,11 @@ pub fn resolve<'a, 'tcx>(
     } else {
         let item_type = def_ty(scx, def_id, substs);
         let def = match item_type.sty {
-            ty::TyFnDef(_, _, f) if
-                f.abi() == Abi::RustIntrinsic ||
-                f.abi() == Abi::PlatformIntrinsic =>
+            ty::TyFnDef(..) if {
+                    let f = item_type.fn_sig(scx.tcx());
+                    f.abi() == Abi::RustIntrinsic ||
+                    f.abi() == Abi::PlatformIntrinsic
+                } =>
             {
                 debug!(" => intrinsic");
                 ty::InstanceDef::Intrinsic(def_id)
diff --git a/src/librustc_trans/trans_item.rs b/src/librustc_trans/trans_item.rs
index 0dc2bc85e30..f59f6850da1 100644
--- a/src/librustc_trans/trans_item.rs
+++ b/src/librustc_trans/trans_item.rs
@@ -401,8 +401,9 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
                         output);
                 }
             },
-            ty::TyFnDef(.., sig) |
-            ty::TyFnPtr(sig) => {
+            ty::TyFnDef(..) |
+            ty::TyFnPtr(_) => {
+                let sig = t.fn_sig(self.tcx);
                 if sig.unsafety() == hir::Unsafety::Unsafe {
                     output.push_str("unsafe ");
                 }
diff --git a/src/librustc_typeck/check/_match.rs b/src/librustc_typeck/check/_match.rs
index bdd8169b84f..68726a7b1c4 100644
--- a/src/librustc_typeck/check/_match.rs
+++ b/src/librustc_typeck/check/_match.rs
@@ -619,7 +619,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         // Type check the path.
         let pat_ty = self.instantiate_value_path(segments, opt_ty, def, pat.span, pat.id);
         // Replace constructor type with constructed type for tuple struct patterns.
-        let pat_ty = pat_ty.fn_sig().output();
+        let pat_ty = pat_ty.fn_sig(tcx).output();
         let pat_ty = tcx.no_late_bound_regions(&pat_ty).expect("expected fn type");
         self.demand_eqtype(pat.span, expected, pat_ty);
 
diff --git a/src/librustc_typeck/check/callee.rs b/src/librustc_typeck/check/callee.rs
index 7cd372f3f00..a0801a74866 100644
--- a/src/librustc_typeck/check/callee.rs
+++ b/src/librustc_typeck/check/callee.rs
@@ -196,8 +196,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                             expected: Expectation<'tcx>)
                             -> Ty<'tcx> {
         let (fn_sig, def_span) = match callee_ty.sty {
-            ty::TyFnDef(def_id, .., sig) => {
-                (sig, self.tcx.hir.span_if_local(def_id))
+            ty::TyFnDef(def_id, _) => {
+                (callee_ty.fn_sig(self.tcx), self.tcx.hir.span_if_local(def_id))
             }
             ty::TyFnPtr(sig) => (sig, None),
             ref t => {
diff --git a/src/librustc_typeck/check/cast.rs b/src/librustc_typeck/check/cast.rs
index ea08f1f624e..46d304976dc 100644
--- a/src/librustc_typeck/check/cast.rs
+++ b/src/librustc_typeck/check/cast.rs
@@ -356,8 +356,9 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> {
             (Some(t_from), Some(t_cast)) => (t_from, t_cast),
             // Function item types may need to be reified before casts.
             (None, Some(t_cast)) => {
-                if let ty::TyFnDef(.., f) = self.expr_ty.sty {
+                if let ty::TyFnDef(..) = self.expr_ty.sty {
                     // Attempt a coercion to a fn pointer type.
+                    let f = self.expr_ty.fn_sig(fcx.tcx);
                     let res = fcx.try_coerce(self.expr,
                                              self.expr_ty,
                                              self.expr_diverges,
diff --git a/src/librustc_typeck/check/coercion.rs b/src/librustc_typeck/check/coercion.rs
index c5fd1f56320..17d02223716 100644
--- a/src/librustc_typeck/check/coercion.rs
+++ b/src/librustc_typeck/check/coercion.rs
@@ -210,13 +210,13 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
         }
 
         match a.sty {
-            ty::TyFnDef(.., a_f) => {
+            ty::TyFnDef(..) => {
                 // Function items are coercible to any closure
                 // type; function pointers are not (that would
                 // require double indirection).
                 // Additionally, we permit coercion of function
                 // items to drop the unsafe qualifier.
-                self.coerce_from_fn_item(a, a_f, b)
+                self.coerce_from_fn_item(a, b)
             }
             ty::TyFnPtr(a_f) => {
                 // We permit coercion of fn pointers to drop the
@@ -600,7 +600,6 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
 
     fn coerce_from_fn_item(&self,
                            a: Ty<'tcx>,
-                           fn_ty_a: ty::PolyFnSig<'tcx>,
                            b: Ty<'tcx>)
                            -> CoerceResult<'tcx> {
         //! Attempts to coerce from the type of a Rust function item
@@ -612,9 +611,17 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
 
         match b.sty {
             ty::TyFnPtr(_) => {
-                let a_fn_pointer = self.tcx.mk_fn_ptr(fn_ty_a);
-                self.coerce_from_safe_fn(a_fn_pointer, fn_ty_a, b,
-                    simple(Adjust::ReifyFnPointer), simple(Adjust::ReifyFnPointer))
+                let a_sig = a.fn_sig(self.tcx);
+                let InferOk { value: a_sig, mut obligations } =
+                    self.normalize_associated_types_in_as_infer_ok(self.cause.span, &a_sig);
+
+                let a_fn_pointer = self.tcx.mk_fn_ptr(a_sig);
+                let InferOk { value, obligations: o2 } =
+                    self.coerce_from_safe_fn(a_fn_pointer, a_sig, b,
+                        simple(Adjust::ReifyFnPointer), simple(Adjust::ReifyFnPointer))?;
+
+                obligations.extend(o2);
+                Ok(InferOk { value, obligations })
             }
             _ => self.unify_and(a, b, identity),
         }
@@ -775,42 +782,41 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
         // Special-case that coercion alone cannot handle:
         // Two function item types of differing IDs or Substs.
-        match (&prev_ty.sty, &new_ty.sty) {
-            (&ty::TyFnDef(a_def_id, a_substs, a_fty), &ty::TyFnDef(b_def_id, b_substs, b_fty)) => {
-                // The signature must always match.
-                let fty = self.at(cause, self.param_env)
-                              .trace(prev_ty, new_ty)
-                              .lub(&a_fty, &b_fty)
-                              .map(|ok| self.register_infer_ok_obligations(ok))?;
+        if let (&ty::TyFnDef(..), &ty::TyFnDef(..)) = (&prev_ty.sty, &new_ty.sty) {
+            // Don't reify if the function types have a LUB, i.e. they
+            // are the same function and their parameters have a LUB.
+            let lub_ty = self.commit_if_ok(|_| {
+                self.at(cause, self.param_env)
+                    .lub(prev_ty, new_ty)
+                    .map(|ok| self.register_infer_ok_obligations(ok))
+            });
 
-                if a_def_id == b_def_id {
-                    // Same function, maybe the parameters match.
-                    let substs = self.commit_if_ok(|_| {
-                        self.at(cause, self.param_env)
-                            .trace(prev_ty, new_ty)
-                            .lub(&a_substs, &b_substs)
-                            .map(|ok| self.register_infer_ok_obligations(ok))
-                    });
-
-                    if let Ok(substs) = substs {
-                        // We have a LUB of prev_ty and new_ty, just return it.
-                        return Ok(self.tcx.mk_fn_def(a_def_id, substs, fty));
-                    }
-                }
-
-                // Reify both sides and return the reified fn pointer type.
-                let fn_ptr = self.tcx.mk_fn_ptr(fty);
-                for expr in exprs.iter().map(|e| e.as_coercion_site()).chain(Some(new)) {
-                    // The only adjustment that can produce an fn item is
-                    // `NeverToAny`, so this should always be valid.
-                    self.apply_adjustments(expr, vec![Adjustment {
-                        kind: Adjust::ReifyFnPointer,
-                        target: fn_ptr
-                    }]);
-                }
-                return Ok(fn_ptr);
+            if lub_ty.is_ok() {
+                // We have a LUB of prev_ty and new_ty, just return it.
+                return lub_ty;
             }
-            _ => {}
+
+            // The signature must match.
+            let a_sig = prev_ty.fn_sig(self.tcx);
+            let a_sig = self.normalize_associated_types_in(new.span, &a_sig);
+            let b_sig = new_ty.fn_sig(self.tcx);
+            let b_sig = self.normalize_associated_types_in(new.span, &b_sig);
+            let sig = self.at(cause, self.param_env)
+                          .trace(prev_ty, new_ty)
+                          .lub(&a_sig, &b_sig)
+                          .map(|ok| self.register_infer_ok_obligations(ok))?;
+
+            // Reify both sides and return the reified fn pointer type.
+            let fn_ptr = self.tcx.mk_fn_ptr(sig);
+            for expr in exprs.iter().map(|e| e.as_coercion_site()).chain(Some(new)) {
+                // The only adjustment that can produce an fn item is
+                // `NeverToAny`, so this should always be valid.
+                self.apply_adjustments(expr, vec![Adjustment {
+                    kind: Adjust::ReifyFnPointer,
+                    target: fn_ptr
+                }]);
+            }
+            return Ok(fn_ptr);
         }
 
         let mut coerce = Coerce::new(self, cause.clone());
diff --git a/src/librustc_typeck/check/compare_method.rs b/src/librustc_typeck/check/compare_method.rs
index 29742469f84..fd5147d76e8 100644
--- a/src/librustc_typeck/check/compare_method.rs
+++ b/src/librustc_typeck/check/compare_method.rs
@@ -256,17 +256,10 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         // Compute skolemized form of impl and trait method tys.
         let tcx = infcx.tcx;
 
-        let m_sig = |method: &ty::AssociatedItem| {
-            match tcx.type_of(method.def_id).sty {
-                ty::TyFnDef(_, _, f) => f,
-                _ => bug!()
-            }
-        };
-
         let (impl_sig, _) =
             infcx.replace_late_bound_regions_with_fresh_var(impl_m_span,
                                                             infer::HigherRankedType,
-                                                            &m_sig(impl_m));
+                                                            &tcx.fn_sig(impl_m.def_id));
         let impl_sig =
             inh.normalize_associated_types_in(impl_m_span,
                                               impl_m_node_id,
@@ -277,7 +270,7 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
         let trait_sig = inh.liberate_late_bound_regions(
             impl_m.def_id,
-            &m_sig(trait_m));
+            &tcx.fn_sig(trait_m.def_id));
         let trait_sig =
             trait_sig.subst(tcx, trait_to_skol_substs);
         let trait_sig =
@@ -507,8 +500,7 @@ fn compare_self_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             ty::ImplContainer(_) => impl_trait_ref.self_ty(),
             ty::TraitContainer(_) => tcx.mk_self_type()
         };
-        let method_ty = tcx.type_of(method.def_id);
-        let self_arg_ty = *method_ty.fn_sig().input(0).skip_binder();
+        let self_arg_ty = *tcx.fn_sig(method.def_id).input(0).skip_binder();
         match ExplicitSelf::determine(untransformed_self_ty, self_arg_ty) {
             ExplicitSelf::ByValue => "self".to_string(),
             ExplicitSelf::ByReference(_, hir::MutImmutable) => "&self".to_string(),
@@ -637,14 +629,8 @@ fn compare_number_of_method_arguments<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                                 trait_m: &ty::AssociatedItem,
                                                 trait_item_span: Option<Span>)
                                                 -> Result<(), ErrorReported> {
-    let m_fty = |method: &ty::AssociatedItem| {
-        match tcx.type_of(method.def_id).sty {
-            ty::TyFnDef(_, _, f) => f,
-            _ => bug!()
-        }
-    };
-    let impl_m_fty = m_fty(impl_m);
-    let trait_m_fty = m_fty(trait_m);
+    let impl_m_fty = tcx.fn_sig(impl_m.def_id);
+    let trait_m_fty = tcx.fn_sig(trait_m.def_id);
     let trait_number_args = trait_m_fty.inputs().skip_binder().len();
     let impl_number_args = impl_m_fty.inputs().skip_binder().len();
     if trait_number_args != impl_number_args {
diff --git a/src/librustc_typeck/check/demand.rs b/src/librustc_typeck/check/demand.rs
index 1b6f96cf651..287c591c118 100644
--- a/src/librustc_typeck/check/demand.rs
+++ b/src/librustc_typeck/check/demand.rs
@@ -143,12 +143,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     fn has_no_input_arg(&self, method: &AssociatedItem) -> bool {
         match method.def() {
             Def::Method(def_id) => {
-                match self.tcx.type_of(def_id).sty {
-                    ty::TypeVariants::TyFnDef(_, _, sig) => {
-                        sig.inputs().skip_binder().len() == 1
-                    }
-                    _ => false,
-                }
+                self.tcx.fn_sig(def_id).inputs().skip_binder().len() == 1
             }
             _ => false,
         }
diff --git a/src/librustc_typeck/check/intrinsic.rs b/src/librustc_typeck/check/intrinsic.rs
index 4d9f50b0fc0..3acfbd1d844 100644
--- a/src/librustc_typeck/check/intrinsic.rs
+++ b/src/librustc_typeck/check/intrinsic.rs
@@ -13,7 +13,6 @@
 
 use intrinsics;
 use rustc::traits::{ObligationCause, ObligationCauseCode};
-use rustc::ty::subst::Substs;
 use rustc::ty::{self, TyCtxt, Ty};
 use rustc::util::nodemap::FxHashMap;
 use require_same_types;
@@ -35,22 +34,22 @@ fn equate_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                    output: Ty<'tcx>) {
     let def_id = tcx.hir.local_def_id(it.id);
 
-    let substs = Substs::for_item(tcx, def_id,
-                                  |_, _| tcx.types.re_erased,
-                                  |def, _| tcx.mk_param_from_def(def));
+    match it.node {
+        hir::ForeignItemFn(..) => {}
+        _ => {
+            struct_span_err!(tcx.sess, it.span, E0619,
+                             "intrinsic must be a function")
+                .span_label(it.span, "expected a function")
+                .emit();
+            return;
+        }
+    }
 
-    let fty = tcx.mk_fn_def(def_id, substs, ty::Binder(tcx.mk_fn_sig(
-        inputs.into_iter(),
-        output,
-        false,
-        hir::Unsafety::Unsafe,
-        abi
-    )));
     let i_n_tps = tcx.generics_of(def_id).types.len();
     if i_n_tps != n_tps {
         let span = match it.node {
             hir::ForeignItemFn(_, _, ref generics) => generics.span,
-            hir::ForeignItemStatic(..) => it.span
+            _ => bug!()
         };
 
         struct_span_err!(tcx.sess, span, E0094,
@@ -59,14 +58,18 @@ fn equate_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                         i_n_tps, n_tps)
             .span_label(span, format!("expected {} type parameter", n_tps))
             .emit();
-    } else {
-        require_same_types(tcx,
-                           &ObligationCause::new(it.span,
-                                                 it.id,
-                                                 ObligationCauseCode::IntrinsicType),
-                           tcx.type_of(def_id),
-                           fty);
+        return;
     }
+
+    let fty = tcx.mk_fn_ptr(ty::Binder(tcx.mk_fn_sig(
+        inputs.into_iter(),
+        output,
+        false,
+        hir::Unsafety::Unsafe,
+        abi
+    )));
+    let cause = ObligationCause::new(it.span, it.id, ObligationCauseCode::IntrinsicType);
+    require_same_types(tcx, &cause, tcx.mk_fn_ptr(tcx.fn_sig(def_id)), fty);
 }
 
 /// Remember to add all intrinsics here, in librustc_trans/trans/intrinsic.rs,
@@ -376,7 +379,7 @@ pub fn check_platform_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
                     let mut structural_to_nomimal = FxHashMap();
 
-                    let sig = tcx.type_of(def_id).fn_sig();
+                    let sig = tcx.fn_sig(def_id);
                     let sig = tcx.no_late_bound_regions(&sig).unwrap();
                     if intr.inputs.len() != sig.inputs().len() {
                         span_err!(tcx.sess, it.span, E0444,
diff --git a/src/librustc_typeck/check/method/confirm.rs b/src/librustc_typeck/check/method/confirm.rs
index 36bd6657389..209245187b1 100644
--- a/src/librustc_typeck/check/method/confirm.rs
+++ b/src/librustc_typeck/check/method/confirm.rs
@@ -375,7 +375,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
 
         debug!("method_predicates after subst = {:?}", method_predicates);
 
-        let sig = self.tcx.type_of(def_id).fn_sig();
+        let sig = self.tcx.fn_sig(def_id);
 
         // Instantiate late-bound regions and substitute the trait
         // parameters into the method type to get the actual method type.
diff --git a/src/librustc_typeck/check/method/mod.rs b/src/librustc_typeck/check/method/mod.rs
index 73c1215f275..4f4169ac93d 100644
--- a/src/librustc_typeck/check/method/mod.rs
+++ b/src/librustc_typeck/check/method/mod.rs
@@ -235,7 +235,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         // NB: Instantiate late-bound regions first so that
         // `instantiate_type_scheme` can normalize associated types that
         // may reference those regions.
-        let fn_sig = tcx.type_of(def_id).fn_sig();
+        let fn_sig = tcx.fn_sig(def_id);
         let fn_sig = self.replace_late_bound_regions_with_fresh_var(span,
                                                                     infer::FnCall,
                                                                     &fn_sig).0;
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 2518a1739f7..ee9a347ae95 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -673,7 +673,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
                                expected: ty::Ty<'tcx>) -> bool {
         match method.def() {
             Def::Method(def_id) => {
-                let fty = self.tcx.type_of(def_id).fn_sig();
+                let fty = self.tcx.fn_sig(def_id);
                 self.probe(|_| {
                     let substs = self.fresh_substs_for_item(self.span, method.def_id);
                     let output = fty.output().subst(self.tcx, substs);
@@ -1288,7 +1288,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
                             impl_ty: Ty<'tcx>,
                             substs: &Substs<'tcx>)
                             -> Ty<'tcx> {
-        let self_ty = self.tcx.type_of(method).fn_sig().input(0);
+        let self_ty = self.tcx.fn_sig(method).input(0);
         debug!("xform_self_ty(impl_ty={:?}, self_ty={:?}, substs={:?})",
                impl_ty,
                self_ty,
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index b92a78987a3..701de029b2b 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -718,20 +718,12 @@ pub fn provide(providers: &mut Providers) {
         typeck_item_bodies,
         typeck_tables_of,
         has_typeck_tables,
-        fn_sig,
         closure_kind,
         adt_destructor,
         ..*providers
     };
 }
 
-fn fn_sig<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                    def_id: DefId)
-                    -> ty::PolyFnSig<'tcx> {
-    let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
-    tcx.typeck_tables_of(def_id).closure_tys[&node_id]
-}
-
 fn closure_kind<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                           def_id: DefId)
                           -> ty::ClosureKind {
@@ -844,7 +836,7 @@ fn typeck_tables_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     Inherited::build(tcx, def_id).enter(|inh| {
         let param_env = tcx.param_env(def_id);
         let fcx = if let Some(decl) = fn_decl {
-            let fn_sig = tcx.type_of(def_id).fn_sig();
+            let fn_sig = tcx.fn_sig(def_id);
 
             check_abi(tcx, span, fn_sig.abi());
 
@@ -2173,7 +2165,6 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                           -> ty::TypeAndMut<'tcx>
     {
         // extract method return type, which will be &T;
-        // all LB regions should have been instantiated during method lookup
         let ret_ty = method.sig.output();
 
         // method returns &T, but the type as visible to user is T, so deref
@@ -2580,8 +2571,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     ty::TyUint(ast::UintTy::U8) | ty::TyUint(ast::UintTy::U16) => {
                         variadic_error(tcx.sess, arg.span, arg_ty, "c_uint");
                     }
-                    ty::TyFnDef(.., f) => {
-                        let ptr_ty = self.tcx.mk_fn_ptr(f);
+                    ty::TyFnDef(..) => {
+                        let ptr_ty = self.tcx.mk_fn_ptr(arg_ty.fn_sig(self.tcx));
                         let ptr_ty = self.resolve_type_vars_if_possible(&ptr_ty);
                         variadic_error(tcx.sess, arg.span, arg_ty, &format!("{}", ptr_ty));
                     }
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index 26f708e9345..cbda1227742 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -177,12 +177,11 @@ impl<'a, 'gcx> CheckTypeWellFormedVisitor<'a, 'gcx> {
                 }
                 ty::AssociatedKind::Method => {
                     reject_shadowing_type_parameters(fcx.tcx, item.def_id);
-                    let method_ty = fcx.tcx.type_of(item.def_id);
-                    let method_ty = fcx.normalize_associated_types_in(span, &method_ty);
+                    let sig = fcx.tcx.fn_sig(item.def_id);
+                    let sig = fcx.normalize_associated_types_in(span, &sig);
                     let predicates = fcx.tcx.predicates_of(item.def_id)
                         .instantiate_identity(fcx.tcx);
                     let predicates = fcx.normalize_associated_types_in(span, &predicates);
-                    let sig = method_ty.fn_sig();
                     this.check_fn_or_method(fcx, span, sig, &predicates,
                                             item.def_id, &mut implied_bounds);
                     let sig_if_method = sig_if_method.expect("bad signature for method");
@@ -331,9 +330,8 @@ impl<'a, 'gcx> CheckTypeWellFormedVisitor<'a, 'gcx> {
     fn check_item_fn(&mut self, item: &hir::Item) {
         self.for_item(item).with_fcx(|fcx, this| {
             let def_id = fcx.tcx.hir.local_def_id(item.id);
-            let ty = fcx.tcx.type_of(def_id);
-            let item_ty = fcx.normalize_associated_types_in(item.span, &ty);
-            let sig = item_ty.fn_sig();
+            let sig = fcx.tcx.fn_sig(def_id);
+            let sig = fcx.normalize_associated_types_in(item.span, &sig);
 
             let predicates = fcx.tcx.predicates_of(def_id).instantiate_identity(fcx.tcx);
             let predicates = fcx.normalize_associated_types_in(item.span, &predicates);
@@ -461,9 +459,9 @@ impl<'a, 'gcx> CheckTypeWellFormedVisitor<'a, 'gcx> {
 
         let span = method_sig.decl.inputs[0].span;
 
-        let method_ty = fcx.tcx.type_of(method.def_id);
-        let fty = fcx.normalize_associated_types_in(span, &method_ty);
-        let sig = fcx.liberate_late_bound_regions(method.def_id, &fty.fn_sig());
+        let sig = fcx.tcx.fn_sig(method.def_id);
+        let sig = fcx.normalize_associated_types_in(span, &sig);
+        let sig = fcx.liberate_late_bound_regions(method.def_id, &sig);
 
         debug!("check_method_receiver: sig={:?}", sig);
 
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index fb3bcd31e21..fd6dda5ccf4 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -97,6 +97,7 @@ pub fn provide(providers: &mut Providers) {
         type_param_predicates,
         trait_def,
         adt_def,
+        fn_sig,
         impl_trait_ref,
         impl_polarity,
         is_foreign_item,
@@ -447,6 +448,9 @@ fn convert_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_id: ast::NodeId) {
                 tcx.generics_of(def_id);
                 tcx.type_of(def_id);
                 tcx.predicates_of(def_id);
+                if let hir::ForeignItemFn(..) = item.node {
+                    tcx.fn_sig(def_id);
+                }
             }
         }
         hir::ItemEnum(ref enum_definition, _) => {
@@ -497,6 +501,9 @@ fn convert_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_id: ast::NodeId) {
             tcx.generics_of(def_id);
             tcx.type_of(def_id);
             tcx.predicates_of(def_id);
+            if let hir::ItemFn(..) = it.node {
+                tcx.fn_sig(def_id);
+            }
         }
     }
 }
@@ -511,6 +518,9 @@ fn convert_trait_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, trait_item_id: ast:
         hir::TraitItemKind::Type(_, Some(_)) |
         hir::TraitItemKind::Method(..) => {
             tcx.type_of(def_id);
+            if let hir::TraitItemKind::Method(..) = trait_item.node {
+                tcx.fn_sig(def_id);
+            }
         }
 
         hir::TraitItemKind::Type(_, None) => {}
@@ -524,6 +534,9 @@ fn convert_impl_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, impl_item_id: ast::N
     tcx.generics_of(def_id);
     tcx.type_of(def_id);
     tcx.predicates_of(def_id);
+    if let hir::ImplItemKind::Method(..) = tcx.hir.expect_impl_item(impl_item_id).node {
+        tcx.fn_sig(def_id);
+    }
 }
 
 fn convert_variant_ctor<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -963,10 +976,9 @@ fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     match tcx.hir.get(node_id) {
         NodeTraitItem(item) => {
             match item.node {
-                TraitItemKind::Method(ref sig, _) => {
-                    let fty = AstConv::ty_of_fn(&icx, sig.unsafety, sig.abi, &sig.decl);
+                TraitItemKind::Method(..) => {
                     let substs = Substs::identity_for_item(tcx, def_id);
-                    tcx.mk_fn_def(def_id, substs, fty)
+                    tcx.mk_fn_def(def_id, substs)
                 }
                 TraitItemKind::Const(ref ty, _) |
                 TraitItemKind::Type(_, Some(ref ty)) => icx.to_ty(ty),
@@ -978,10 +990,9 @@ fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
         NodeImplItem(item) => {
             match item.node {
-                ImplItemKind::Method(ref sig, _) => {
-                    let fty = AstConv::ty_of_fn(&icx, sig.unsafety, sig.abi, &sig.decl);
+                ImplItemKind::Method(..) => {
                     let substs = Substs::identity_for_item(tcx, def_id);
-                    tcx.mk_fn_def(def_id, substs, fty)
+                    tcx.mk_fn_def(def_id, substs)
                 }
                 ImplItemKind::Const(ref ty, _) => icx.to_ty(ty),
                 ImplItemKind::Type(ref ty) => {
@@ -1001,10 +1012,9 @@ fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 ItemTy(ref t, _) | ItemImpl(.., ref t, _) => {
                     icx.to_ty(t)
                 }
-                ItemFn(ref decl, unsafety, _, abi, _, _) => {
-                    let tofd = AstConv::ty_of_fn(&icx, unsafety, abi, &decl);
+                ItemFn(..) => {
                     let substs = Substs::identity_for_item(tcx, def_id);
-                    tcx.mk_fn_def(def_id, substs, tofd)
+                    tcx.mk_fn_def(def_id, substs)
                 }
                 ItemEnum(..) |
                 ItemStruct(..) |
@@ -1029,11 +1039,10 @@ fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         }
 
         NodeForeignItem(foreign_item) => {
-            let abi = tcx.hir.get_foreign_abi(node_id);
-
             match foreign_item.node {
-                ForeignItemFn(ref fn_decl, _, _) => {
-                    compute_type_of_foreign_fn_decl(tcx, def_id, fn_decl, abi)
+                ForeignItemFn(..) => {
+                    let substs = Substs::identity_for_item(tcx, def_id);
+                    tcx.mk_fn_def(def_id, substs)
                 }
                 ForeignItemStatic(ref t, _) => icx.to_ty(t)
             }
@@ -1041,21 +1050,13 @@ fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
         NodeStructCtor(&ref def) |
         NodeVariant(&Spanned { node: hir::Variant_ { data: ref def, .. }, .. }) => {
-            let ty = tcx.type_of(tcx.hir.get_parent_did(node_id));
             match *def {
-                VariantData::Unit(..) | VariantData::Struct(..) => ty,
-                VariantData::Tuple(ref fields, _) => {
-                    let inputs = fields.iter().map(|f| {
-                        tcx.type_of(tcx.hir.local_def_id(f.id))
-                    });
+                VariantData::Unit(..) | VariantData::Struct(..) => {
+                    tcx.type_of(tcx.hir.get_parent_did(node_id))
+                }
+                VariantData::Tuple(..) => {
                     let substs = Substs::identity_for_item(tcx, def_id);
-                    tcx.mk_fn_def(def_id, substs, ty::Binder(tcx.mk_fn_sig(
-                        inputs,
-                        ty,
-                        false,
-                        hir::Unsafety::Normal,
-                        abi::Abi::Rust
-                    )))
+                    tcx.mk_fn_def(def_id, substs)
                 }
             }
         }
@@ -1105,6 +1106,58 @@ fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     }
 }
 
+fn fn_sig<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
+                    def_id: DefId)
+                    -> ty::PolyFnSig<'tcx> {
+    use rustc::hir::map::*;
+    use rustc::hir::*;
+
+    let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
+
+    let icx = ItemCtxt::new(tcx, def_id);
+
+    match tcx.hir.get(node_id) {
+        NodeTraitItem(&hir::TraitItem { node: TraitItemKind::Method(ref sig, _), .. }) |
+        NodeImplItem(&hir::ImplItem { node: ImplItemKind::Method(ref sig, _), .. }) => {
+            AstConv::ty_of_fn(&icx, sig.unsafety, sig.abi, &sig.decl)
+        }
+
+        NodeItem(&hir::Item { node: ItemFn(ref decl, unsafety, _, abi, _, _), .. }) => {
+            AstConv::ty_of_fn(&icx, unsafety, abi, decl)
+        }
+
+        NodeForeignItem(&hir::ForeignItem { node: ForeignItemFn(ref fn_decl, _, _), .. }) => {
+            let abi = tcx.hir.get_foreign_abi(node_id);
+            compute_sig_of_foreign_fn_decl(tcx, def_id, fn_decl, abi)
+        }
+
+        NodeStructCtor(&VariantData::Tuple(ref fields, _)) |
+        NodeVariant(&Spanned { node: hir::Variant_ {
+            data: VariantData::Tuple(ref fields, _), ..
+        }, .. }) => {
+            let ty = tcx.type_of(tcx.hir.get_parent_did(node_id));
+            let inputs = fields.iter().map(|f| {
+                tcx.type_of(tcx.hir.local_def_id(f.id))
+            });
+            ty::Binder(tcx.mk_fn_sig(
+                inputs,
+                ty,
+                false,
+                hir::Unsafety::Normal,
+                abi::Abi::Rust
+            ))
+        }
+
+        NodeExpr(&hir::Expr { node: hir::ExprClosure(..), .. }) => {
+            tcx.typeck_tables_of(def_id).closure_tys[&node_id]
+        }
+
+        x => {
+            bug!("unexpected sort of node in fn_sig(): {:?}", x);
+        }
+    }
+}
+
 fn impl_trait_ref<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                             def_id: DefId)
                             -> Option<ty::TraitRef<'tcx>> {
@@ -1502,12 +1555,12 @@ fn predicates_from_bound<'tcx>(astconv: &AstConv<'tcx, 'tcx>,
     }
 }
 
-fn compute_type_of_foreign_fn_decl<'a, 'tcx>(
+fn compute_sig_of_foreign_fn_decl<'a, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     def_id: DefId,
     decl: &hir::FnDecl,
     abi: abi::Abi)
-    -> Ty<'tcx>
+    -> ty::PolyFnSig<'tcx>
 {
     let fty = AstConv::ty_of_fn(&ItemCtxt::new(tcx, def_id), hir::Unsafety::Unsafe, abi, decl);
 
@@ -1533,8 +1586,7 @@ fn compute_type_of_foreign_fn_decl<'a, 'tcx>(
         }
     }
 
-    let substs = Substs::identity_for_item(tcx, def_id);
-    tcx.mk_fn_def(def_id, substs, fty)
+    fty
 }
 
 fn is_foreign_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
diff --git a/src/librustc_typeck/diagnostics.rs b/src/librustc_typeck/diagnostics.rs
index b2fa2cc7c61..bf5adc8644d 100644
--- a/src/librustc_typeck/diagnostics.rs
+++ b/src/librustc_typeck/diagnostics.rs
@@ -4736,4 +4736,5 @@ register_diagnostics! {
     E0568, // auto-traits can not have predicates,
     E0588, // packed struct cannot transitively contain a `[repr(align)]` struct
     E0592, // duplicate definitions with name `{}`
+    E0619, // intrinsic must be a function
 }
diff --git a/src/librustc_typeck/lib.rs b/src/librustc_typeck/lib.rs
index 9e99af633d5..519e1ca6e5a 100644
--- a/src/librustc_typeck/lib.rs
+++ b/src/librustc_typeck/lib.rs
@@ -198,22 +198,21 @@ fn check_main_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 }
                 _ => ()
             }
-            let substs = tcx.intern_substs(&[]);
-            let se_ty = tcx.mk_fn_def(main_def_id, substs,
-                ty::Binder(tcx.mk_fn_sig(
+            let se_ty = tcx.mk_fn_ptr(ty::Binder(
+                tcx.mk_fn_sig(
                     iter::empty(),
                     tcx.mk_nil(),
                     false,
                     hir::Unsafety::Normal,
                     Abi::Rust
-                ))
-            );
+                )
+            ));
 
             require_same_types(
                 tcx,
                 &ObligationCause::new(main_span, main_id, ObligationCauseCode::MainFunctionType),
                 se_ty,
-                main_t);
+                tcx.mk_fn_ptr(tcx.fn_sig(main_def_id)));
         }
         _ => {
             span_bug!(main_span,
@@ -248,9 +247,8 @@ fn check_start_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 _ => ()
             }
 
-            let substs = tcx.intern_substs(&[]);
-            let se_ty = tcx.mk_fn_def(start_def_id, substs,
-                ty::Binder(tcx.mk_fn_sig(
+            let se_ty = tcx.mk_fn_ptr(ty::Binder(
+                tcx.mk_fn_sig(
                     [
                         tcx.types.isize,
                         tcx.mk_imm_ptr(tcx.mk_imm_ptr(tcx.types.u8))
@@ -259,14 +257,14 @@ fn check_start_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                     false,
                     hir::Unsafety::Normal,
                     Abi::Rust
-                ))
-            );
+                )
+            ));
 
             require_same_types(
                 tcx,
                 &ObligationCause::new(start_span, start_id, ObligationCauseCode::StartFunctionType),
                 se_ty,
-                start_t);
+                tcx.mk_fn_ptr(tcx.fn_sig(start_def_id)));
         }
         _ => {
             span_bug!(start_span,
diff --git a/src/librustc_typeck/variance/constraints.rs b/src/librustc_typeck/variance/constraints.rs
index c434edb1c31..4c09d90f853 100644
--- a/src/librustc_typeck/variance/constraints.rs
+++ b/src/librustc_typeck/variance/constraints.rs
@@ -382,6 +382,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 // leaf type -- noop
             }
 
+            ty::TyFnDef(..) |
             ty::TyClosure(..) |
             ty::TyAnon(..) => {
                 bug!("Unexpected closure type in variance computation");
@@ -466,7 +467,6 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 }
             }
 
-            ty::TyFnDef(.., sig) |
             ty::TyFnPtr(sig) => {
                 self.add_constraints_from_sig(current, sig, variance);
             }
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index aeade470482..fa5a999adf1 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -149,7 +149,7 @@ pub fn build_external_trait(cx: &DocContext, did: DefId) -> clean::Trait {
 }
 
 fn build_external_function(cx: &DocContext, did: DefId) -> clean::Function {
-    let sig = cx.tcx.type_of(did).fn_sig();
+    let sig = cx.tcx.fn_sig(did);
 
     let constness = if cx.tcx.is_const_fn(did) {
         hir::Constness::Const
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 8fc8ccd0cfd..478e2fc5085 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1367,7 +1367,7 @@ impl<'tcx> Clean<Item> for ty::AssociatedItem {
             ty::AssociatedKind::Method => {
                 let generics = (cx.tcx.generics_of(self.def_id),
                                 &cx.tcx.predicates_of(self.def_id)).clean(cx);
-                let sig = cx.tcx.type_of(self.def_id).fn_sig();
+                let sig = cx.tcx.fn_sig(self.def_id);
                 let mut decl = (self.def_id, sig).clean(cx);
 
                 if self.method_has_self_argument {
@@ -1842,17 +1842,21 @@ impl<'tcx> Clean<Type> for ty::Ty<'tcx> {
                 mutability: mt.mutbl.clean(cx),
                 type_: box mt.ty.clean(cx),
             },
-            ty::TyFnDef(.., sig) |
-            ty::TyFnPtr(sig) => BareFunction(box BareFunctionDecl {
-                unsafety: sig.unsafety(),
-                generics: Generics {
-                    lifetimes: Vec::new(),
-                    type_params: Vec::new(),
-                    where_predicates: Vec::new()
-                },
-                decl: (cx.tcx.hir.local_def_id(ast::CRATE_NODE_ID), sig).clean(cx),
-                abi: sig.abi(),
-            }),
+            ty::TyFnDef(..) |
+            ty::TyFnPtr(_) => {
+                let ty = cx.tcx.lift(self).unwrap();
+                let sig = ty.fn_sig(cx.tcx);
+                BareFunction(box BareFunctionDecl {
+                    unsafety: sig.unsafety(),
+                    generics: Generics {
+                        lifetimes: Vec::new(),
+                        type_params: Vec::new(),
+                        where_predicates: Vec::new()
+                    },
+                    decl: (cx.tcx.hir.local_def_id(ast::CRATE_NODE_ID), sig).clean(cx),
+                    abi: sig.abi(),
+                })
+            }
             ty::TyAdt(def, substs) => {
                 let did = def.did;
                 let kind = match def.adt_kind() {
diff --git a/src/test/compile-fail/invalid-intrinsic.rs b/src/test/compile-fail/invalid-intrinsic.rs
index 2aa2546cb9f..c42d78c323e 100644
--- a/src/test/compile-fail/invalid-intrinsic.rs
+++ b/src/test/compile-fail/invalid-intrinsic.rs
@@ -11,6 +11,6 @@
 #![feature(intrinsics)]
 extern "rust-intrinsic" {
     pub static breakpoint : unsafe extern "rust-intrinsic" fn();
-    //~^ ERROR intrinsic has wrong type
+    //~^ ERROR intrinsic must be a function
 }
-fn main() { unsafe { breakpoint(); } }
\ No newline at end of file
+fn main() { unsafe { breakpoint(); } }