diff --git a/src/librustc_trait_selection/traits/select/mod.rs b/src/librustc_trait_selection/traits/select/mod.rs
index def99a7b5b52..7ebf30f61c09 100644
--- a/src/librustc_trait_selection/traits/select/mod.rs
+++ b/src/librustc_trait_selection/traits/select/mod.rs
@@ -1104,6 +1104,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // who might care about this case, like coherence, should use
         // that function).
         if candidates.is_empty() {
+            // If there's an error type, 'downgrade' our result from
+            // `Err(Unimplemented)` to `Ok(None)`. This helps us avoid
+            // emitting additional spurious errors, since we're guaranteed
+            // to have emitted at least one.
+            if stack.obligation.references_error() {
+                debug!("no results for error type, treating as ambiguous");
+                return Ok(None);
+            }
             return Err(Unimplemented);
         }
 
diff --git a/src/test/ui/impl-trait/auto-trait-leak.rs b/src/test/ui/impl-trait/auto-trait-leak.rs
index a6012835f441..087f4582b21c 100644
--- a/src/test/ui/impl-trait/auto-trait-leak.rs
+++ b/src/test/ui/impl-trait/auto-trait-leak.rs
@@ -11,8 +11,6 @@ fn main() {
 // return type, which can't depend on the obligation.
 fn cycle1() -> impl Clone {
     //~^ ERROR cycle detected
-    //~| ERROR cycle detected
-    //~| ERROR cycle detected
     send(cycle2().clone());
     //~^ ERROR cannot be sent between threads safely
 
diff --git a/src/test/ui/impl-trait/auto-trait-leak.stderr b/src/test/ui/impl-trait/auto-trait-leak.stderr
index 64d02f07048e..679b26efe593 100644
--- a/src/test/ui/impl-trait/auto-trait-leak.stderr
+++ b/src/test/ui/impl-trait/auto-trait-leak.stderr
@@ -36,37 +36,37 @@ LL | fn cycle1() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`...
 note: ...which requires computing type of `cycle2::{{opaque}}#0`...
-  --> $DIR/auto-trait-leak.rs:22:16
+  --> $DIR/auto-trait-leak.rs:20:16
    |
 LL | fn cycle2() -> impl Clone {
    |                ^^^^^^^^^^
 note: ...which requires borrow-checking `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
+  --> $DIR/auto-trait-leak.rs:20:1
    |
 LL | fn cycle2() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires processing `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
+  --> $DIR/auto-trait-leak.rs:20:1
    |
 LL | fn cycle2() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires processing MIR for `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
+  --> $DIR/auto-trait-leak.rs:20:1
    |
 LL | fn cycle2() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires unsafety-checking `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
+  --> $DIR/auto-trait-leak.rs:20:1
    |
 LL | fn cycle2() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires building MIR for `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
+  --> $DIR/auto-trait-leak.rs:20:1
    |
 LL | fn cycle2() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
 note: ...which requires type-checking `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
+  --> $DIR/auto-trait-leak.rs:20:1
    |
 LL | fn cycle2() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -84,178 +84,8 @@ LL | |     Rc::new(String::from("foo"))
 LL | | }
    | |_^
 
-error[E0391]: cycle detected when computing type of `cycle1::{{opaque}}#0`
-  --> $DIR/auto-trait-leak.rs:12:16
-   |
-LL | fn cycle1() -> impl Clone {
-   |                ^^^^^^^^^^
-   |
-note: ...which requires borrow-checking `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires processing `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires processing MIR for `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires unsafety-checking `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires building MIR for `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires type-checking `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`...
-note: ...which requires computing type of `cycle2::{{opaque}}#0`...
-  --> $DIR/auto-trait-leak.rs:22:16
-   |
-LL | fn cycle2() -> impl Clone {
-   |                ^^^^^^^^^^
-note: ...which requires borrow-checking `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires processing `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires processing MIR for `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires unsafety-checking `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires building MIR for `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires type-checking `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: ...which again requires computing type of `cycle1::{{opaque}}#0`, completing the cycle
-note: cycle used when checking item types in top-level module
-  --> $DIR/auto-trait-leak.rs:1:1
-   |
-LL | / use std::cell::Cell;
-LL | | use std::rc::Rc;
-LL | |
-LL | | fn send<T: Send>(_: T) {}
-...  |
-LL | |     Rc::new(String::from("foo"))
-LL | | }
-   | |_^
-
-error[E0391]: cycle detected when computing type of `cycle1::{{opaque}}#0`
-  --> $DIR/auto-trait-leak.rs:12:16
-   |
-LL | fn cycle1() -> impl Clone {
-   |                ^^^^^^^^^^
-   |
-note: ...which requires borrow-checking `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires processing `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires processing MIR for `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires unsafety-checking `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires building MIR for `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires type-checking `cycle1`...
-  --> $DIR/auto-trait-leak.rs:12:1
-   |
-LL | fn cycle1() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`...
-note: ...which requires computing type of `cycle2::{{opaque}}#0`...
-  --> $DIR/auto-trait-leak.rs:22:16
-   |
-LL | fn cycle2() -> impl Clone {
-   |                ^^^^^^^^^^
-note: ...which requires borrow-checking `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires processing `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires processing MIR for `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires unsafety-checking `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires building MIR for `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires type-checking `cycle2`...
-  --> $DIR/auto-trait-leak.rs:22:1
-   |
-LL | fn cycle2() -> impl Clone {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: ...which again requires computing type of `cycle1::{{opaque}}#0`, completing the cycle
-note: cycle used when checking item types in top-level module
-  --> $DIR/auto-trait-leak.rs:1:1
-   |
-LL | / use std::cell::Cell;
-LL | | use std::rc::Rc;
-LL | |
-LL | | fn send<T: Send>(_: T) {}
-...  |
-LL | |     Rc::new(String::from("foo"))
-LL | | }
-   | |_^
-
 error[E0277]: `std::rc::Rc<std::string::String>` cannot be sent between threads safely
-  --> $DIR/auto-trait-leak.rs:16:5
+  --> $DIR/auto-trait-leak.rs:14:5
    |
 LL | fn send<T: Send>(_: T) {}
    |            ---- required by this bound in `send`
@@ -269,7 +99,7 @@ LL | fn cycle2() -> impl Clone {
    = help: within `impl std::clone::Clone`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<std::string::String>`
    = note: required because it appears within the type `impl std::clone::Clone`
 
-error: aborting due to 4 previous errors
+error: aborting due to 2 previous errors
 
 Some errors have detailed explanations: E0277, E0391.
 For more information about an error, try `rustc --explain E0277`.