diff --git a/src/librustc_incremental/calculate_svh/svh_visitor.rs b/src/librustc_incremental/calculate_svh/svh_visitor.rs
index 393f99b3eb83..603a7fc40eb4 100644
--- a/src/librustc_incremental/calculate_svh/svh_visitor.rs
+++ b/src/librustc_incremental/calculate_svh/svh_visitor.rs
@@ -15,6 +15,11 @@
 
 use self::SawExprComponent::*;
 use self::SawAbiComponent::*;
+use self::SawItemComponent::*;
+use self::SawPatComponent::*;
+use self::SawTyComponent::*;
+use self::SawTraitOrImplItemComponent::*;
+use syntax::abi::Abi;
 use syntax::ast::{self, Name, NodeId};
 use syntax::parse::token;
 use syntax_pos::{Span, NO_EXPANSION, COMMAND_LINE_EXPN, BytePos};
@@ -155,11 +160,11 @@ enum SawAbiComponent<'a> {
 
     SawMod,
     SawForeignItem,
-    SawItem,
-    SawTy,
+    SawItem(SawItemComponent),
+    SawTy(SawTyComponent),
     SawGenerics,
-    SawTraitItem,
-    SawImplItem,
+    SawTraitItem(SawTraitOrImplItemComponent),
+    SawImplItem(SawTraitOrImplItemComponent),
     SawStructField,
     SawVariant,
     SawPath(bool),
@@ -167,7 +172,7 @@ enum SawAbiComponent<'a> {
     SawPathParameters,
     SawPathListItem,
     SawBlock,
-    SawPat,
+    SawPat(SawPatComponent),
     SawLocal,
     SawArm,
     SawExpr(SawExprComponent<'a>),
@@ -198,6 +203,9 @@ enum SawAbiComponent<'a> {
 /// because the SVH is just a developer convenience; there is no
 /// guarantee of collision-freedom, hash collisions are just
 /// (hopefully) unlikely.)
+///
+/// The xxxComponent enums and saw_xxx functions for Item, Pat,
+/// Ty, TraitItem and ImplItem follow the same methodology.
 #[derive(Hash)]
 enum SawExprComponent<'a> {
 
@@ -267,6 +275,134 @@ fn saw_expr<'a>(node: &'a Expr_) -> SawExprComponent<'a> {
     }
 }
 
+#[derive(Hash)]
+enum SawItemComponent {
+    SawItemExternCrate,
+    SawItemUse,
+    SawItemStatic(Mutability),
+    SawItemConst,
+    SawItemFn(Unsafety, Constness, Abi),
+    SawItemMod,
+    SawItemForeignMod,
+    SawItemTy,
+    SawItemEnum,
+    SawItemStruct,
+    SawItemUnion,
+    SawItemTrait(Unsafety),
+    SawItemDefaultImpl(Unsafety),
+    SawItemImpl(Unsafety, ImplPolarity)
+}
+
+fn saw_item(node: &Item_) -> SawItemComponent {
+    match *node {
+        ItemExternCrate(..) => SawItemExternCrate,
+        ItemUse(..) => SawItemUse,
+        ItemStatic(_, mutability, _) => SawItemStatic(mutability),
+        ItemConst(..) =>SawItemConst,
+        ItemFn(_, unsafety, constness, abi, _, _) => SawItemFn(unsafety, constness, abi),
+        ItemMod(..) => SawItemMod,
+        ItemForeignMod(..) => SawItemForeignMod,
+        ItemTy(..) => SawItemTy,
+        ItemEnum(..) => SawItemEnum,
+        ItemStruct(..) => SawItemStruct,
+        ItemUnion(..) => SawItemUnion,
+        ItemTrait(unsafety, ..) => SawItemTrait(unsafety),
+        ItemDefaultImpl(unsafety, _) => SawItemDefaultImpl(unsafety),
+        ItemImpl(unsafety, implpolarity, ..) => SawItemImpl(unsafety, implpolarity)
+    }
+}
+
+#[derive(Hash)]
+enum SawPatComponent {
+    SawPatWild,
+    SawPatBinding(BindingMode),
+    SawPatStruct,
+    SawPatTupleStruct,
+    SawPatPath,
+    SawPatTuple,
+    SawPatBox,
+    SawPatRef(Mutability),
+    SawPatLit,
+    SawPatRange,
+    SawPathVec
+}
+
+fn saw_pat(node: &PatKind) -> SawPatComponent {
+    match *node {
+        PatKind::Wild => SawPatWild,
+        PatKind::Binding(bindingmode, ..) => SawPatBinding(bindingmode),
+        PatKind::Struct(..) => SawPatStruct,
+        PatKind::TupleStruct(..) => SawPatTupleStruct,
+        PatKind::Path(..) => SawPatPath,
+        PatKind::Tuple(..) => SawPatTuple,
+        PatKind::Box(..) => SawPatBox,
+        PatKind::Ref(_, mutability) => SawPatRef(mutability),
+        PatKind::Lit(..) => SawPatLit,
+        PatKind::Range(..) => SawPatRange,
+        PatKind::Vec(..) => SawPathVec
+    }
+}
+
+#[derive(Hash)]
+enum SawTyComponent {
+    SawTyVec,
+    SawTyFixedLengthVec,
+    SawTyPtr(Mutability),
+    SawTyRptr(Mutability),
+    SawTyBareFn,
+    SawTyNever,
+    SawTyTup,
+    SawTyPath,
+    SawTyObjectSum,
+    SawTyPolyTraitRef,
+    SawTyImplTrait,
+    SawTyTypeof,
+    SawTyInfer
+}
+
+fn saw_ty(node: &Ty_) -> SawTyComponent {
+    match *node {
+      TyVec(..) => SawTyVec,
+      TyFixedLengthVec(..) => SawTyFixedLengthVec,
+      TyPtr(ref mty) => SawTyPtr(mty.mutbl),
+      TyRptr(_, ref mty) => SawTyRptr(mty.mutbl),
+      TyBareFn(..) => SawTyBareFn,
+      TyNever => SawTyNever,
+      TyTup(..) => SawTyTup,
+      TyPath(..) => SawTyPath,
+      TyObjectSum(..) => SawTyObjectSum,
+      TyPolyTraitRef(..) => SawTyPolyTraitRef,
+      TyImplTrait(..) => SawTyImplTrait,
+      TyTypeof(..) => SawTyTypeof,
+      TyInfer => SawTyInfer
+    }
+}
+
+#[derive(Hash)]
+enum SawTraitOrImplItemComponent {
+    SawTraitOrImplItemConst,
+    SawTraitOrImplItemMethod(Unsafety, Constness, Abi),
+    SawTraitOrImplItemType
+}
+
+fn saw_trait_item(ti: &TraitItem_) -> SawTraitOrImplItemComponent {
+    match *ti {
+        ConstTraitItem(..) => SawTraitOrImplItemConst,
+        MethodTraitItem(ref sig, _) =>
+            SawTraitOrImplItemMethod(sig.unsafety, sig.constness, sig.abi),
+        TypeTraitItem(..) => SawTraitOrImplItemType
+    }
+}
+
+fn saw_impl_item(ii: &ImplItemKind) -> SawTraitOrImplItemComponent {
+    match *ii {
+        ImplItemKind::Const(..) => SawTraitOrImplItemConst,
+        ImplItemKind::Method(ref sig, _) =>
+            SawTraitOrImplItemMethod(sig.unsafety, sig.constness, sig.abi),
+        ImplItemKind::Type(..) => SawTraitOrImplItemType
+    }
+}
+
 #[derive(Clone, Copy, Hash, Eq, PartialEq)]
 enum SawSpanExpnKind {
     NoExpansion,
@@ -383,10 +519,7 @@ impl<'a, 'hash, 'tcx> visit::Visitor<'tcx> for StrictVersionHashVisitor<'a, 'has
 
     fn visit_item(&mut self, i: &'tcx Item) {
         debug!("visit_item: {:?} st={:?}", i, self.st);
-
-        SawItem.hash(self.st);
-        // Hash the value of the discriminant of the Item variant.
-        self.hash_discriminant(&i.node);
+        SawItem(saw_item(&i.node)).hash(self.st);
         hash_span!(self, i.span);
         hash_attrs!(self, &i.attrs);
         visit::walk_item(self, i)
@@ -399,7 +532,7 @@ impl<'a, 'hash, 'tcx> visit::Visitor<'tcx> for StrictVersionHashVisitor<'a, 'has
 
     fn visit_ty(&mut self, t: &'tcx Ty) {
         debug!("visit_ty: st={:?}", self.st);
-        SawTy.hash(self.st);
+        SawTy(saw_ty(&t.node)).hash(self.st);
         hash_span!(self, t.span);
         visit::walk_ty(self, t)
     }
@@ -412,8 +545,7 @@ impl<'a, 'hash, 'tcx> visit::Visitor<'tcx> for StrictVersionHashVisitor<'a, 'has
 
     fn visit_trait_item(&mut self, ti: &'tcx TraitItem) {
         debug!("visit_trait_item: st={:?}", self.st);
-        SawTraitItem.hash(self.st);
-        self.hash_discriminant(&ti.node);
+        SawTraitItem(saw_trait_item(&ti.node)).hash(self.st);
         hash_span!(self, ti.span);
         hash_attrs!(self, &ti.attrs);
         visit::walk_trait_item(self, ti)
@@ -421,8 +553,7 @@ impl<'a, 'hash, 'tcx> visit::Visitor<'tcx> for StrictVersionHashVisitor<'a, 'has
 
     fn visit_impl_item(&mut self, ii: &'tcx ImplItem) {
         debug!("visit_impl_item: st={:?}", self.st);
-        SawImplItem.hash(self.st);
-        self.hash_discriminant(&ii.node);
+        SawImplItem(saw_impl_item(&ii.node)).hash(self.st);
         hash_span!(self, ii.span);
         hash_attrs!(self, &ii.attrs);
         visit::walk_impl_item(self, ii)
@@ -452,8 +583,7 @@ impl<'a, 'hash, 'tcx> visit::Visitor<'tcx> for StrictVersionHashVisitor<'a, 'has
 
     fn visit_pat(&mut self, p: &'tcx Pat) {
         debug!("visit_pat: st={:?}", self.st);
-        SawPat.hash(self.st);
-        self.hash_discriminant(&p.node);
+        SawPat(saw_pat(&p.node)).hash(self.st);
         hash_span!(self, p.span);
         visit::walk_pat(self, p)
     }