Rollup merge of #117159 - oli-obk:error_shenanigans, r=estebank

Work around the fact that `check_mod_type_wf` may spuriously return `ErrorGuaranteed`

Even if that error is only emitted by `check_mod_item_types`.

fixes rust-lang/rust#117153

A cleaner refactoring would merge/chain these queries in ways that ensure we only actually get an `ErrorGuaranteed` if there was an error emitted.

Author: matthiaskrgr

tests/ui/crashes/ice-6252.stderr

@@ -24,6 +24,16 @@ help: you might be missing a type parameter
 LL | impl<N, M, VAL> TypeVal<usize> for Multiply<N, M> where N: TypeVal<VAL> {}
    |          +++++
 
-error: aborting due to 2 previous errors
+error[E0046]: not all trait items implemented, missing: `VAL`
+  --> $DIR/ice-6252.rs:11:1
+   |
+LL |     const VAL: T;
+   |     ------------ `VAL` from trait
+...
+LL | impl<N, M> TypeVal<usize> for Multiply<N, M> where N: TypeVal<VAL> {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `VAL` in implementation
+
+error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0412`.
+Some errors have detailed explanations: E0046, E0412.
+For more information about an error, try `rustc --explain E0046`.