Rollup merge of #138173 - compiler-errors:incoherent-negative-impl, r=oli-obk

Delay bug for negative auto trait rather than ICEing

Fixes #138149

r? oli-obk

compiler/rustc_hir_analysis/src/check/always_applicable.rs

@@ -124,7 +124,10 @@ pub(crate) fn check_negative_auto_trait_impl<'tcx>(
                 // be implemented here to handle non-ADT rigid types.
                 Ok(())
             } else {
-                span_bug!(tcx.def_span(impl_def_id), "incoherent impl of negative auto trait");
+                Err(tcx.dcx().span_delayed_bug(
+                    tcx.def_span(impl_def_id),
+                    "incoherent impl of negative auto trait",
+                ))
             }
         }
     }

tests/ui/auto-traits/ungated-impl.rs

@@ -0,0 +1,7 @@
+auto trait MyTrait {}
+//~^ ERROR auto traits are experimental and possibly buggy
+
+impl<T> !MyTrait for *mut T {}
+//~^ ERROR negative trait bounds are not fully implemented
+
+fn main() {}

tests/ui/auto-traits/ungated-impl.stderr

@@ -0,0 +1,23 @@
+error[E0658]: auto traits are experimental and possibly buggy
+  --> $DIR/ungated-impl.rs:1:1
+   |
+LL | auto trait MyTrait {}
+   | ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #13231 <https://github.com/rust-lang/rust/issues/13231> for more information
+   = help: add `#![feature(auto_traits)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: negative trait bounds are not fully implemented; use marker types for now
+  --> $DIR/ungated-impl.rs:4:9
+   |
+LL | impl<T> !MyTrait for *mut T {}
+   |         ^^^^^^^^
+   |
+   = note: see issue #68318 <https://github.com/rust-lang/rust/issues/68318> for more information
+   = help: add `#![feature(negative_impls)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.