session: diagnostic migration lint on more fns

Apply the diagnostic migration lint to more functions on `Session`.

Signed-off-by: David Wood <david.wood@huawei.com>

3 files changed, 29 insertions, 15 deletions

diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index 305f0427e50..31a3ffbb1d8 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -201,7 +201,9 @@ use rustc_target::abi::Size;
 use std::ops::Range;
 use std::path::PathBuf;
 
-use crate::errors::{LargeAssignmentsLint, RecursionLimit, TypeLengthLimit};
+use crate::errors::{
+    EncounteredErrorWhileInstantiating, LargeAssignmentsLint, RecursionLimit, TypeLengthLimit,
+};
 
 #[derive(PartialEq)]
 pub enum MonoItemCollectionMode {
@@ -524,10 +526,10 @@ fn collect_items_rec<'tcx>(
         && starting_point.node.is_user_defined()
     {
         let formatted_item = with_no_trimmed_paths!(starting_point.node.to_string());
-        tcx.sess.span_note_without_error(
-            starting_point.span,
-            &format!("the above error was encountered while instantiating `{formatted_item}`"),
-        );
+        tcx.sess.emit_note(EncounteredErrorWhileInstantiating {
+            span: starting_point.span,
+            formatted_item,
+        });
     }
     inlining_map.lock_mut().record_accesses(starting_point.node, &neighbors.items);
 
diff --git a/compiler/rustc_monomorphize/src/errors.rs b/compiler/rustc_monomorphize/src/errors.rs
index 5233cfb2120..a53bd7e1fef 100644
--- a/compiler/rustc_monomorphize/src/errors.rs
+++ b/compiler/rustc_monomorphize/src/errors.rs
@@ -83,3 +83,17 @@ pub struct SymbolAlreadyDefined {
 pub struct CouldntDumpMonoStats {
     pub error: String,
 }
+
+#[derive(Diagnostic)]
+#[diag(monomorphize_encountered_error_while_instantiating)]
+pub struct EncounteredErrorWhileInstantiating {
+    #[primary_span]
+    pub span: Span,
+    pub formatted_item: String,
+}
+
+#[derive(Diagnostic)]
+#[diag(monomorphize_unknown_cgu_collection_mode)]
+pub struct UnknownCguCollectionMode<'a> {
+    pub mode: &'a str,
+}
diff --git a/compiler/rustc_monomorphize/src/partitioning/mod.rs b/compiler/rustc_monomorphize/src/partitioning/mod.rs
index fd6bcad1898..af3f60bb932 100644
--- a/compiler/rustc_monomorphize/src/partitioning/mod.rs
+++ b/compiler/rustc_monomorphize/src/partitioning/mod.rs
@@ -114,7 +114,9 @@ use rustc_span::symbol::Symbol;
 
 use crate::collector::InliningMap;
 use crate::collector::{self, MonoItemCollectionMode};
-use crate::errors::{CouldntDumpMonoStats, SymbolAlreadyDefined, UnknownPartitionStrategy};
+use crate::errors::{
+    CouldntDumpMonoStats, SymbolAlreadyDefined, UnknownCguCollectionMode, UnknownPartitionStrategy,
+};
 
 pub struct PartitioningCx<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
@@ -348,17 +350,13 @@ where
 fn collect_and_partition_mono_items(tcx: TyCtxt<'_>, (): ()) -> (&DefIdSet, &[CodegenUnit<'_>]) {
     let collection_mode = match tcx.sess.opts.unstable_opts.print_mono_items {
         Some(ref s) => {
-            let mode_string = s.to_lowercase();
-            let mode_string = mode_string.trim();
-            if mode_string == "eager" {
+            let mode = s.to_lowercase();
+            let mode = mode.trim();
+            if mode == "eager" {
                 MonoItemCollectionMode::Eager
             } else {
-                if mode_string != "lazy" {
-                    let message = format!(
-                        "Unknown codegen-item collection mode '{mode_string}'. \
-                                           Falling back to 'lazy' mode."
-                    );
-                    tcx.sess.warn(&message);
+                if mode != "lazy" {
+                    tcx.sess.emit_warning(UnknownCguCollectionMode { mode });
                 }
 
                 MonoItemCollectionMode::Lazy