Auto merge of #145284 - nnethercote:type_name-print-regions, r=lcnr

Print regions in `type_name`.

Currently they are skipped, which is a bit weird, and it sometimes causes malformed output like `Foo<>` and `dyn Bar<, A = u32>`.

Most regions are erased by the time `type_name` does its work. So all regions are now printed as `'_` in non-optional places. Not perfect, but better than the status quo.

`c_name` is updated to trim lifetimes from MIR pass names, so that the `PASS_NAMES` sanity check still works. It is also renamed as `simplify_pass_type_name` and made non-const, because it doesn't need to be const and the non-const implementation is much shorter.

The commit also renames `should_print_region` as `should_print_optional_region`, which makes it clearer that it only applies to some regions.

Fixes rust-lang/rust#145168.

r? `@lcnr`

1 files changed, 4 insertions, 4 deletions

diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs
index d9163d94710..cb159a0b914 100644
--- a/compiler/rustc_lint/src/context.rs
+++ b/compiler/rustc_lint/src/context.rs
@@ -756,22 +756,22 @@ impl<'tcx> LateContext<'tcx> {
             }
 
             fn print_region(&mut self, _region: ty::Region<'_>) -> Result<(), PrintError> {
-                unreachable!(); // because `path_generic_args` ignores the `GenericArgs`
+                unreachable!(); // because `print_path_with_generic_args` ignores the `GenericArgs`
             }
 
             fn print_type(&mut self, _ty: Ty<'tcx>) -> Result<(), PrintError> {
-                unreachable!(); // because `path_generic_args` ignores the `GenericArgs`
+                unreachable!(); // because `print_path_with_generic_args` ignores the `GenericArgs`
             }
 
             fn print_dyn_existential(
                 &mut self,
                 _predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
             ) -> Result<(), PrintError> {
-                unreachable!(); // because `path_generic_args` ignores the `GenericArgs`
+                unreachable!(); // because `print_path_with_generic_args` ignores the `GenericArgs`
             }
 
             fn print_const(&mut self, _ct: ty::Const<'tcx>) -> Result<(), PrintError> {
-                unreachable!(); // because `path_generic_args` ignores the `GenericArgs`
+                unreachable!(); // because `print_path_with_generic_args` ignores the `GenericArgs`
             }
 
             fn print_crate_name(&mut self, cnum: CrateNum) -> Result<(), PrintError> {