Rollup merge of #111991 - BoxyUwU:change_error_term_display, r=compiler-errors

Change ty and const error's pretty printing to be in braces

`[const error]` and `[type error]` are slightly confusing since they look like either a slice with an error type for the element ty or a slice with a const argument as the type ???. This PR changes them to display as `{const error}` and `{type error}`  similar to `{integer}`.

This does not update the `Debug` impls for them which is done in #111988.

I updated some error logic to avoid printing the substs of trait refs when unable to resolve an assoc item for them, this avoids emitting errors with `{type error}` in them. The substs are not relevant for these errors since we don't take into account the substs when resolving the assoc item.

r? ``@compiler-errors``

Author: matthiaskrgr

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -1159,7 +1159,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             // those that do.
             self.one_bound_for_assoc_type(
                 || traits::supertraits(tcx, trait_ref),
-                trait_ref.print_only_trait_path(),
+                trait_ref.skip_binder().print_only_trait_name(),
                 binding.item_name,
                 path_span,
                 match binding.kind {

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -700,7 +700,7 @@ pub trait PrettyPrinter<'tcx>:
                     if verbose { p!(write("{:?}", infer_ty)) } else { p!(write("{}", infer_ty)) }
                 }
             }
-            ty::Error(_) => p!("[type error]"),
+            ty::Error(_) => p!("{{type error}}"),
             ty::Param(ref param_ty) => p!(print(param_ty)),
             ty::Bound(debruijn, bound_ty) => match bound_ty.kind {
                 ty::BoundTyKind::Anon => debug_bound_var(&mut self, debruijn, bound_ty.var)?,
@@ -1379,8 +1379,8 @@ pub trait PrettyPrinter<'tcx>:
             },
             // FIXME(generic_const_exprs):
             // write out some legible representation of an abstract const?
-            ty::ConstKind::Expr(_) => p!("[const expr]"),
-            ty::ConstKind::Error(_) => p!("[const error]"),
+            ty::ConstKind::Expr(_) => p!("{{const expr}}"),
+            ty::ConstKind::Error(_) => p!("{{const error}}"),
         };
         Ok(self)
     }

tests/ui/const-generics/transmute-fail.stderr

@@ -4,8 +4,8 @@ error[E0512]: cannot transmute between types of different sizes, or dependently-
 LL |     std::mem::transmute(v)
    |     ^^^^^^^^^^^^^^^^^^^
    |
-   = note: source type: `[[u32; H+1]; W]` (generic size [const expr])
-   = note: target type: `[[u32; W+1]; H]` (generic size [const expr])
+   = note: source type: `[[u32; H+1]; W]` (generic size {const expr})
+   = note: target type: `[[u32; W+1]; H]` (generic size {const expr})
 
 error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
   --> $DIR/transmute-fail.rs:16:5
@@ -34,8 +34,8 @@ error[E0512]: cannot transmute between types of different sizes, or dependently-
 LL |     std::mem::transmute(v)
    |     ^^^^^^^^^^^^^^^^^^^
    |
-   = note: source type: `[[u32; H]; W]` (generic size [const expr])
-   = note: target type: `[u32; W * H * H]` (generic size [const expr])
+   = note: source type: `[[u32; H]; W]` (generic size {const expr})
+   = note: target type: `[u32; W * H * H]` (generic size {const expr})
 
 error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
   --> $DIR/transmute-fail.rs:30:5

tests/ui/unboxed-closures/unboxed-closure-sugar-wrong-number-number-type-parameters-1.rs

@@ -2,7 +2,7 @@
 
 trait One<A> { fn foo(&self) -> A; }
 
-fn foo(_: &dyn One()) //~ ERROR associated type `Output` not found for `One<()>`
+fn foo(_: &dyn One()) //~ ERROR associated type `Output` not found for `One`
 {}
 
 fn main() { }

tests/ui/unboxed-closures/unboxed-closure-sugar-wrong-number-number-type-parameters-1.stderr

@@ -1,4 +1,4 @@
-error[E0220]: associated type `Output` not found for `One<()>`
+error[E0220]: associated type `Output` not found for `One`
   --> $DIR/unboxed-closure-sugar-wrong-number-number-type-parameters-1.rs:5:16
    |
 LL | fn foo(_: &dyn One())

tests/ui/unboxed-closures/unboxed-closure-sugar-wrong-number-number-type-parameters-3.stderr

@@ -12,7 +12,7 @@ note: trait defined here, with 3 generic parameters: `A`, `B`, `C`
 LL | trait Three<A,B,C> { fn dummy(&self) -> (A,B,C); }
    |       ^^^^^ - - -
 
-error[E0220]: associated type `Output` not found for `Three<(), [type error], [type error]>`
+error[E0220]: associated type `Output` not found for `Three`
   --> $DIR/unboxed-closure-sugar-wrong-number-number-type-parameters-3.rs:5:16
    |
 LL | fn foo(_: &dyn Three())