diff --git a/Cargo.lock b/Cargo.lock
index a30a644e371..f3c139c32cb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -435,7 +435,7 @@ dependencies = [
 [[package]]
 name = "chalk-base"
 version = "0.10.1-dev"
-source = "git+https://github.com/jackh726/chalk.git?rev=58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b#58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b"
+source = "git+https://github.com/jackh726/chalk.git?rev=c8f342bf5e48051333d0b2c7fab81347fc21c474#c8f342bf5e48051333d0b2c7fab81347fc21c474"
 dependencies = [
  "lazy_static",
 ]
@@ -443,7 +443,7 @@ dependencies = [
 [[package]]
 name = "chalk-derive"
 version = "0.10.1-dev"
-source = "git+https://github.com/jackh726/chalk.git?rev=58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b#58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b"
+source = "git+https://github.com/jackh726/chalk.git?rev=c8f342bf5e48051333d0b2c7fab81347fc21c474#c8f342bf5e48051333d0b2c7fab81347fc21c474"
 dependencies = [
  "proc-macro2 1.0.3",
  "quote 1.0.2",
@@ -454,7 +454,7 @@ dependencies = [
 [[package]]
 name = "chalk-engine"
 version = "0.10.1-dev"
-source = "git+https://github.com/jackh726/chalk.git?rev=58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b#58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b"
+source = "git+https://github.com/jackh726/chalk.git?rev=c8f342bf5e48051333d0b2c7fab81347fc21c474#c8f342bf5e48051333d0b2c7fab81347fc21c474"
 dependencies = [
  "chalk-base",
  "chalk-derive",
@@ -465,7 +465,7 @@ dependencies = [
 [[package]]
 name = "chalk-ir"
 version = "0.10.1-dev"
-source = "git+https://github.com/jackh726/chalk.git?rev=58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b#58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b"
+source = "git+https://github.com/jackh726/chalk.git?rev=c8f342bf5e48051333d0b2c7fab81347fc21c474#c8f342bf5e48051333d0b2c7fab81347fc21c474"
 dependencies = [
  "chalk-base",
  "chalk-derive",
@@ -474,7 +474,7 @@ dependencies = [
 [[package]]
 name = "chalk-solve"
 version = "0.10.1-dev"
-source = "git+https://github.com/jackh726/chalk.git?rev=58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b#58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b"
+source = "git+https://github.com/jackh726/chalk.git?rev=c8f342bf5e48051333d0b2c7fab81347fc21c474#c8f342bf5e48051333d0b2c7fab81347fc21c474"
 dependencies = [
  "chalk-base",
  "chalk-derive",
diff --git a/src/librustc_middle/Cargo.toml b/src/librustc_middle/Cargo.toml
index 34dece1a2ad..121491c8cc4 100644
--- a/src/librustc_middle/Cargo.toml
+++ b/src/librustc_middle/Cargo.toml
@@ -30,7 +30,7 @@ rustc_serialize = { path = "../librustc_serialize" }
 rustc_ast = { path = "../librustc_ast" }
 rustc_span = { path = "../librustc_span" }
 byteorder = { version = "1.3" }
-chalk-ir =      { git = "https://github.com/jackh726/chalk.git", rev = "58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b" }
+chalk-ir =      { git = "https://github.com/jackh726/chalk.git", rev = "c8f342bf5e48051333d0b2c7fab81347fc21c474" }
 #chalk-ir = "0.10.0"
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 measureme = "0.7.1"
diff --git a/src/librustc_traits/Cargo.toml b/src/librustc_traits/Cargo.toml
index cb056dba9ea..6bfebecf04c 100644
--- a/src/librustc_traits/Cargo.toml
+++ b/src/librustc_traits/Cargo.toml
@@ -19,8 +19,8 @@ rustc_span = { path = "../librustc_span" }
 #chalk-ir = "0.10.0"
 #chalk-rust-ir = "0.10.0"
 #chalk-solve = "0.10.0"
-chalk-solve =   { git = "https://github.com/jackh726/chalk.git", rev = "58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b" }
-chalk-ir =      { git = "https://github.com/jackh726/chalk.git", rev = "58e5a31f48ddd4b940c682e7079d3e79e6ffaa1b" }
+chalk-solve =   { git = "https://github.com/jackh726/chalk.git", rev = "c8f342bf5e48051333d0b2c7fab81347fc21c474" }
+chalk-ir =      { git = "https://github.com/jackh726/chalk.git", rev = "c8f342bf5e48051333d0b2c7fab81347fc21c474" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 rustc_infer = { path = "../librustc_infer" }
 rustc_trait_selection = { path = "../librustc_trait_selection" }
diff --git a/src/librustc_traits/chalk/db.rs b/src/librustc_traits/chalk/db.rs
index 818839e2e3b..5b00d322768 100644
--- a/src/librustc_traits/chalk/db.rs
+++ b/src/librustc_traits/chalk/db.rs
@@ -321,10 +321,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
         opaque_ty_id: chalk_ir::OpaqueTyId<RustInterner<'tcx>>,
     ) -> Arc<chalk_solve::rust_ir::OpaqueTyDatum<RustInterner<'tcx>>> {
         // FIXME(chalk): actually lower opaque ty
-        let hidden_ty =
-            self.tcx.mk_ty(ty::Tuple(self.tcx.intern_substs(&[]))).lower_into(&self.interner);
         let value = chalk_solve::rust_ir::OpaqueTyDatumBound {
-            hidden_ty,
             bounds: chalk_ir::Binders::new(chalk_ir::VariableKinds::new(&self.interner), vec![]),
         };
         Arc::new(chalk_solve::rust_ir::OpaqueTyDatum {
@@ -418,6 +415,14 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
     fn is_object_safe(&self, trait_id: chalk_ir::TraitId<RustInterner<'tcx>>) -> bool {
         self.tcx.is_object_safe(trait_id.0)
     }
+
+    fn hidden_opaque_type(
+        &self,
+        _id: chalk_ir::OpaqueTyId<RustInterner<'tcx>>,
+    ) -> chalk_ir::Ty<RustInterner<'tcx>> {
+        // FIXME(chalk): actually get hidden ty
+        self.tcx.mk_ty(ty::Tuple(self.tcx.intern_substs(&[]))).lower_into(&self.interner)
+    }
 }
 
 /// Creates a `InternalSubsts` that maps each generic parameter to a higher-ranked