update crashes

Author: lcnr

tests/crashes/129444.rs

@@ -0,0 +1,20 @@
+// A regression test for #129444. This previously ICE'd as
+// computing the best obligation for one ambiguous obligation
+// added spurious inference constraints which causes another
+// candidate to pass.
+trait Trait {
+    type Assoc;
+}
+
+struct W<T: Trait>(*mut T);
+impl<T> Trait for W<W<W<T>>> {}
+//~^ ERROR the trait bound `W<W<T>>: Trait` is not satisfied
+//~| ERROR the trait bound `W<T>: Trait` is not satisfied
+//~| ERROR the trait bound `T: Trait` is not satisfied
+//~| ERROR not all trait items implemented, missing: `Assoc`
+
+trait NoOverlap {}
+impl<T: Trait> NoOverlap for T {}
+impl<T: Trait<Assoc = u32>> NoOverlap for W<T> {}
+//~^ ERROR conflicting implementations of trait `NoOverlap` for type `W<W<W<W<_>>>>`
+fn main() {}

tests/ui/coherence/fuzzing/best-obligation-ICE.rs

@@ -0,0 +1,69 @@
+error[E0277]: the trait bound `W<W<T>>: Trait` is not satisfied
+  --> $DIR/best-obligation-ICE.rs:10:19
+   |
+LL | impl<T> Trait for W<W<W<T>>> {}
+   |                   ^^^^^^^^^^ the trait `Trait` is not implemented for `W<W<T>>`
+   |
+note: required by a bound in `W`
+  --> $DIR/best-obligation-ICE.rs:9:13
+   |
+LL | struct W<T: Trait>(*mut T);
+   |             ^^^^^ required by this bound in `W`
+help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
+   |
+LL | impl<T> Trait for W<W<W<T>>> where W<W<T>>: Trait {}
+   |                              ++++++++++++++++++++
+
+error[E0277]: the trait bound `W<T>: Trait` is not satisfied
+  --> $DIR/best-obligation-ICE.rs:10:19
+   |
+LL | impl<T> Trait for W<W<W<T>>> {}
+   |                   ^^^^^^^^^^ the trait `Trait` is not implemented for `W<T>`
+   |
+note: required by a bound in `W`
+  --> $DIR/best-obligation-ICE.rs:9:13
+   |
+LL | struct W<T: Trait>(*mut T);
+   |             ^^^^^ required by this bound in `W`
+help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
+   |
+LL | impl<T> Trait for W<W<W<T>>> where W<T>: Trait {}
+   |                              +++++++++++++++++
+
+error[E0277]: the trait bound `T: Trait` is not satisfied
+  --> $DIR/best-obligation-ICE.rs:10:19
+   |
+LL | impl<T> Trait for W<W<W<T>>> {}
+   |                   ^^^^^^^^^^ the trait `Trait` is not implemented for `T`
+   |
+note: required by a bound in `W`
+  --> $DIR/best-obligation-ICE.rs:9:13
+   |
+LL | struct W<T: Trait>(*mut T);
+   |             ^^^^^ required by this bound in `W`
+help: consider restricting type parameter `T`
+   |
+LL | impl<T: Trait> Trait for W<W<W<T>>> {}
+   |       +++++++
+
+error[E0046]: not all trait items implemented, missing: `Assoc`
+  --> $DIR/best-obligation-ICE.rs:10:1
+   |
+LL |     type Assoc;
+   |     ---------- `Assoc` from trait
+...
+LL | impl<T> Trait for W<W<W<T>>> {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `Assoc` in implementation
+
+error[E0119]: conflicting implementations of trait `NoOverlap` for type `W<W<W<W<_>>>>`
+  --> $DIR/best-obligation-ICE.rs:18:1
+   |
+LL | impl<T: Trait> NoOverlap for T {}
+   | ------------------------------ first implementation here
+LL | impl<T: Trait<Assoc = u32>> NoOverlap for W<T> {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `W<W<W<W<_>>>>`
+
+error: aborting due to 5 previous errors
+
+Some errors have detailed explanations: E0046, E0119, E0277.
+For more information about an error, try `rustc --explain E0046`.