Add support for shortening `Instance` and use it

Replace ad-hoc type path shortening logic for recursive mono instantiation errors to use `tcx.short_string()` instead.

2 files changed, 4 insertions, 3 deletions

diff --git a/tests/ui/limits/type-length-limit-enforcement.rs b/tests/ui/limits/type-length-limit-enforcement.rs
index 3b34d6eb5c8..604435dc326 100644
--- a/tests/ui/limits/type-length-limit-enforcement.rs
+++ b/tests/ui/limits/type-length-limit-enforcement.rs
@@ -3,7 +3,7 @@
 //! Checks the enforcement of the type-length limit
 //! and its configurability via `#![type_length_limit]`.
 
-//@ compile-flags: -Copt-level=0 -Zenforce-type-length-limit
+//@ compile-flags: -Copt-level=0 -Zenforce-type-length-limit --diagnostic-width=100 -Zwrite-long-types-to-disk=yes
 
 //@ build-fail
 
diff --git a/tests/ui/limits/type-length-limit-enforcement.stderr b/tests/ui/limits/type-length-limit-enforcement.stderr
index 516230ae832..bfea0b5a448 100644
--- a/tests/ui/limits/type-length-limit-enforcement.stderr
+++ b/tests/ui/limits/type-length-limit-enforcement.stderr
@@ -1,11 +1,12 @@
-error: reached the type-length limit while instantiating `std::mem::drop::<Option<((((..., ..., ...), ..., ...), ..., ...), ..., ...)>>`
+error: reached the type-length limit while instantiating `drop::<Option<((..., ..., ...), ..., ...)>>`
   --> $DIR/type-length-limit-enforcement.rs:34:5
    |
 LL |     drop::<Option<A>>(None);
    |     ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider adding a `#![type_length_limit="4010"]` attribute to your crate
-   = note: the full type name has been written to '$TEST_BUILD_DIR/type-length-limit-enforcement.long-type.txt'
+   = note: the full name for the type has been written to '$TEST_BUILD_DIR/type-length-limit-enforcement.long-type-$LONG_TYPE_HASH.txt'
+   = note: consider using `--verbose` to print the full type name to the console
 
 error: reached the type-length limit while instantiating `<{closure@rt::lang_start<()>::{closure#0}} as FnMut<()>>::call_mut`
    |