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, 35 insertions, 34 deletions

diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index 35b80a9b96f..26ca8518434 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -206,7 +206,6 @@
 //! regardless of whether it is actually needed or not.
 
 use std::cell::OnceCell;
-use std::path::PathBuf;
 
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sync::{MTLock, par_for_each_in};
@@ -224,7 +223,6 @@ use rustc_middle::mir::{self, Location, MentionedItem, traversal};
 use rustc_middle::query::TyCtxtAt;
 use rustc_middle::ty::adjustment::{CustomCoerceUnsized, PointerCoercion};
 use rustc_middle::ty::layout::ValidityRequirement;
-use rustc_middle::ty::print::{shrunk_instance_name, with_no_trimmed_paths};
 use rustc_middle::ty::{
     self, GenericArgs, GenericParamDefKind, Instance, InstanceKind, Ty, TyCtxt, TypeFoldable,
     TypeVisitableExt, VtblEntry,
@@ -237,7 +235,10 @@ use rustc_span::source_map::{Spanned, dummy_spanned, respan};
 use rustc_span::{DUMMY_SP, Span};
 use tracing::{debug, instrument, trace};
 
-use crate::errors::{self, EncounteredErrorWhileInstantiating, NoOptimizedMir, RecursionLimit};
+use crate::errors::{
+    self, EncounteredErrorWhileInstantiating, EncounteredErrorWhileInstantiatingGlobalAsm,
+    NoOptimizedMir, RecursionLimit,
+};
 
 #[derive(PartialEq)]
 pub(crate) enum MonoItemCollectionStrategy {
@@ -525,11 +526,23 @@ fn collect_items_rec<'tcx>(
         && starting_item.node.is_generic_fn()
         && starting_item.node.is_user_defined()
     {
-        let formatted_item = with_no_trimmed_paths!(starting_item.node.to_string());
-        tcx.dcx().emit_note(EncounteredErrorWhileInstantiating {
-            span: starting_item.span,
-            formatted_item,
-        });
+        match starting_item.node {
+            MonoItem::Fn(instance) => tcx.dcx().emit_note(EncounteredErrorWhileInstantiating {
+                span: starting_item.span,
+                kind: "fn",
+                instance,
+            }),
+            MonoItem::Static(def_id) => tcx.dcx().emit_note(EncounteredErrorWhileInstantiating {
+                span: starting_item.span,
+                kind: "static",
+                instance: Instance::new_raw(def_id, GenericArgs::empty()),
+            }),
+            MonoItem::GlobalAsm(_) => {
+                tcx.dcx().emit_note(EncounteredErrorWhileInstantiatingGlobalAsm {
+                    span: starting_item.span,
+                })
+            }
+        }
     }
     // Only updating `usage_map` for used items as otherwise we may be inserting the same item
     // multiple times (if it is first 'mentioned' and then later actually used), and the usage map
@@ -612,22 +625,7 @@ fn check_recursion_limit<'tcx>(
     if !recursion_limit.value_within_limit(adjusted_recursion_depth) {
         let def_span = tcx.def_span(def_id);
         let def_path_str = tcx.def_path_str(def_id);
-        let (shrunk, written_to_path) = shrunk_instance_name(tcx, instance);
-        let mut path = PathBuf::new();
-        let was_written = if let Some(written_to_path) = written_to_path {
-            path = written_to_path;
-            true
-        } else {
-            false
-        };
-        tcx.dcx().emit_fatal(RecursionLimit {
-            span,
-            shrunk,
-            def_span,
-            def_path_str,
-            was_written,
-            path,
-        });
+        tcx.dcx().emit_fatal(RecursionLimit { span, instance, def_span, def_path_str });
     }
 
     recursion_depths.insert(def_id, recursion_depth + 1);
diff --git a/compiler/rustc_monomorphize/src/errors.rs b/compiler/rustc_monomorphize/src/errors.rs
index 938c427b56c..89a78897dea 100644
--- a/compiler/rustc_monomorphize/src/errors.rs
+++ b/compiler/rustc_monomorphize/src/errors.rs
@@ -1,21 +1,16 @@
-use std::path::PathBuf;
-
 use rustc_macros::{Diagnostic, LintDiagnostic};
-use rustc_middle::ty::Ty;
+use rustc_middle::ty::{Instance, Ty};
 use rustc_span::{Span, Symbol};
 
 #[derive(Diagnostic)]
 #[diag(monomorphize_recursion_limit)]
-pub(crate) struct RecursionLimit {
+pub(crate) struct RecursionLimit<'tcx> {
     #[primary_span]
     pub span: Span,
-    pub shrunk: String,
+    pub instance: Instance<'tcx>,
     #[note]
     pub def_span: Span,
     pub def_path_str: String,
-    #[note(monomorphize_written_to_path)]
-    pub was_written: bool,
-    pub path: PathBuf,
 }
 
 #[derive(Diagnostic)]
@@ -53,10 +48,18 @@ pub(crate) struct CouldntDumpMonoStats {
 
 #[derive(Diagnostic)]
 #[diag(monomorphize_encountered_error_while_instantiating)]
-pub(crate) struct EncounteredErrorWhileInstantiating {
+pub(crate) struct EncounteredErrorWhileInstantiating<'tcx> {
+    #[primary_span]
+    pub span: Span,
+    pub kind: &'static str,
+    pub instance: Instance<'tcx>,
+}
+
+#[derive(Diagnostic)]
+#[diag(monomorphize_encountered_error_while_instantiating_global_asm)]
+pub(crate) struct EncounteredErrorWhileInstantiatingGlobalAsm {
     #[primary_span]
     pub span: Span,
-    pub formatted_item: String,
 }
 
 #[derive(Diagnostic)]