diff --git a/compiler/rustc_error_messages/locales/en-US/passes.ftl b/compiler/rustc_error_messages/locales/en-US/passes.ftl
index b075568ae13e..9499ad56aa93 100644
--- a/compiler/rustc_error_messages/locales/en-US/passes.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/passes.ftl
@@ -383,9 +383,6 @@ passes_unknown_lang_item =
     definition of an unknown language item: `{$name}`
     .label = definition of unknown language item `{$name}`
 
-passes_local_duplicate_lang_item =
-    found duplicate lang item `{$name}`
-
 passes_invalid_attr_at_crate_level =
     `{$name}` attribute cannot be used at crate level
     .suggestion = perhaps you meant to use an outer attribute
@@ -534,3 +531,30 @@ passes_no_main_function =
     .consider_adding_main_at_crate = consider adding a `main` function at the crate level
     .teach_note = If you don't know the basics of Rust, you can go look to the Rust Book to get started: https://doc.rust-lang.org/book/
     .non_function_main = non-function item at `crate::main` is found
+
+passes_duplicate_lang_item =
+    {$message ->
+        *[duplicate] found duplicate lang item `{$lang_item_name}`
+        [duplicate_in_crate] duplicate lang item in crate `{$crate_name}`: `{$lang_item_name}`.
+        [duplicate_in_crate_depends] duplicate lang item in crate `{$crate_name}` (which `{$dependency_of}` depends on): `{$lang_item_name}`.
+    }
+    .first_defined_span = the lang item is first defined here
+    .first_defined_crate_depends = the lang item is first defined in crate `{$orig_crate_name}` (which `{$orig_dependency_of}` depends on)
+    .first_defined_crate = the lang item is first defined in crate `{$orig_crate_name}`.
+    .first_definition_local = first definition in the local crate (`{$orig_crate_name}`)
+    .second_definition_local = second definition in the local crate (`{$crate_name}`)
+    .first_definition_path = first definition in `{$orig_crate_name}` loaded from {$orig_path}
+    .second_definition_path = second definition in `{$crate_name}` loaded from {$path}
+
+passes_incorrect_target =
+    `{$name}` language item must be applied to a {$kind} with {$at_least ->
+        [true] at least {$num}
+        *[false] {$num}
+    } generic {$num ->
+        [one] argument
+        *[other] arguments
+    }
+    .label = this {$kind} has {$actual_num} generic {$actual_num ->
+        [one] argument
+        *[other] arguments
+    }
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 56e184ab25ee..bf3350129b0b 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -1191,3 +1191,77 @@ impl<'a> IntoDiagnostic<'a> for NoMainErr {
         diag
     }
 }
+
+pub struct DuplicateLangItem<'a> {
+    pub local_span: Option<Span>,
+    pub lang_item_name: Symbol,
+    pub crate_name: Symbol,
+    pub dependency_of: Symbol,
+    pub is_local: bool,
+    pub path: String,
+    pub first_defined_span: Option<Span>,
+    pub orig_crate_name: Symbol,
+    pub orig_dependency_of: Symbol,
+    pub orig_is_local: bool,
+    pub orig_path: String,
+    pub message: &'a str,
+}
+
+impl<'a, 'b> IntoDiagnostic<'a> for DuplicateLangItem<'b> {
+    fn into_diagnostic(
+        self,
+        handler: &'a rustc_errors::Handler,
+    ) -> rustc_errors::DiagnosticBuilder<'a, ErrorGuaranteed> {
+        let mut diag = handler.struct_err_with_code(
+            rustc_errors::fluent::passes::duplicate_lang_item,
+            error_code!(E0152),
+        );
+        diag.set_arg("lang_item_name", self.lang_item_name);
+        diag.set_arg("crate_name", self.crate_name);
+        diag.set_arg("dependency_of", self.dependency_of);
+        diag.set_arg("path", self.path);
+        diag.set_arg("orig_crate_name", self.orig_crate_name);
+        diag.set_arg("orig_dependency_of", self.orig_dependency_of);
+        diag.set_arg("orig_path", self.orig_path);
+        diag.set_arg("message", self.message);
+        if let Some(span) = self.local_span {
+            diag.set_span(span);
+        }
+        if let Some(span) = self.first_defined_span {
+            diag.span_note(span, rustc_errors::fluent::passes::first_defined_span);
+        } else {
+            if self.orig_dependency_of.is_empty() {
+                diag.note(rustc_errors::fluent::passes::first_defined_crate);
+            } else {
+                diag.note(rustc_errors::fluent::passes::first_defined_crate_depends);
+            }
+
+            if self.orig_is_local {
+                diag.note(rustc_errors::fluent::passes::first_definition_local);
+            } else {
+                diag.note(rustc_errors::fluent::passes::first_definition_path);
+            }
+
+            if self.is_local {
+                diag.note(rustc_errors::fluent::passes::second_definition_local);
+            } else {
+                diag.note(rustc_errors::fluent::passes::second_definition_path);
+            }
+        }
+        diag
+    }
+}
+
+#[derive(Diagnostic)]
+#[diag(passes::incorrect_target, code = "E0718")]
+pub struct IncorrectTarget<'a> {
+    #[primary_span]
+    pub span: Span,
+    #[label]
+    pub generics_span: Span,
+    pub name: &'a str,
+    pub kind: &'static str,
+    pub num: usize,
+    pub actual_num: usize,
+    pub at_least: bool,
+}
diff --git a/compiler/rustc_passes/src/lang_items.rs b/compiler/rustc_passes/src/lang_items.rs
index 2b090e036fe9..0af7c0cd3fcc 100644
--- a/compiler/rustc_passes/src/lang_items.rs
+++ b/compiler/rustc_passes/src/lang_items.rs
@@ -8,10 +8,11 @@
 //! * Functions called by the compiler itself.
 
 use crate::check_attr::target_from_impl_item;
-use crate::errors::{LangItemOnIncorrectTarget, UnknownLangItem};
+use crate::errors::{
+    DuplicateLangItem, IncorrectTarget, LangItemOnIncorrectTarget, UnknownLangItem,
+};
 use crate::weak_lang_items;
 
-use rustc_errors::{pluralize, struct_span_err};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
@@ -19,7 +20,7 @@ use rustc_hir::lang_items::{extract, GenericRequirement, ITEM_REFS};
 use rustc_hir::{HirId, LangItem, LanguageItems, Target};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::cstore::ExternCrate;
-use rustc_span::Span;
+use rustc_span::{Span, Symbol};
 
 use rustc_middle::ty::query::Providers;
 
@@ -62,74 +63,72 @@ impl<'tcx> LanguageItemCollector<'tcx> {
         // Check for duplicates.
         if let Some(original_def_id) = self.items.items[item_index] {
             if original_def_id != item_def_id {
-                let lang_item = LangItem::from_u32(item_index as u32).unwrap();
-                let name = lang_item.name();
-                let mut err = match self.tcx.hir().span_if_local(item_def_id) {
-                    Some(span) => struct_span_err!(
-                        self.tcx.sess,
-                        span,
-                        E0152,
-                        "found duplicate lang item `{}`",
-                        name
-                    ),
-                    None => match self.tcx.extern_crate(item_def_id) {
-                        Some(ExternCrate { dependency_of, .. }) => {
-                            self.tcx.sess.struct_err(&format!(
-                                "duplicate lang item in crate `{}` (which `{}` depends on): `{}`.",
-                                self.tcx.crate_name(item_def_id.krate),
-                                self.tcx.crate_name(*dependency_of),
-                                name
-                            ))
-                        }
-                        _ => self.tcx.sess.struct_err(&format!(
-                            "duplicate lang item in crate `{}`: `{}`.",
-                            self.tcx.crate_name(item_def_id.krate),
-                            name
-                        )),
-                    },
-                };
-                if let Some(span) = self.tcx.hir().span_if_local(original_def_id) {
-                    err.span_note(span, "the lang item is first defined here");
+                let local_span = self.tcx.hir().span_if_local(item_def_id);
+                let lang_item_name = LangItem::from_u32(item_index as u32).unwrap().name();
+                let crate_name = self.tcx.crate_name(item_def_id.krate);
+                let mut dependency_of = Symbol::intern("");
+                let is_local = item_def_id.is_local();
+                let path = if is_local {
+                    String::new()
                 } else {
-                    match self.tcx.extern_crate(original_def_id) {
-                        Some(ExternCrate { dependency_of, .. }) => {
-                            err.note(&format!(
-                                "the lang item is first defined in crate `{}` (which `{}` depends on)",
-                                self.tcx.crate_name(original_def_id.krate),
-                                self.tcx.crate_name(*dependency_of)
-                            ));
-                        }
-                        _ => {
-                            err.note(&format!(
-                                "the lang item is first defined in crate `{}`.",
-                                self.tcx.crate_name(original_def_id.krate)
-                            ));
-                        }
+                    self.tcx
+                        .crate_extern_paths(item_def_id.krate)
+                        .iter()
+                        .map(|p| p.display().to_string())
+                        .collect::<Vec<_>>()
+                        .join(", ")
+                        .into()
+                };
+                let first_defined_span = self.tcx.hir().span_if_local(original_def_id);
+                let mut orig_crate_name = Symbol::intern("");
+                let mut orig_dependency_of = Symbol::intern("");
+                let orig_is_local = original_def_id.is_local();
+                let orig_path = if orig_is_local {
+                    String::new()
+                } else {
+                    self.tcx
+                        .crate_extern_paths(original_def_id.krate)
+                        .iter()
+                        .map(|p| p.display().to_string())
+                        .collect::<Vec<_>>()
+                        .join(", ")
+                        .into()
+                };
+                if first_defined_span.is_none() {
+                    orig_crate_name = self.tcx.crate_name(original_def_id.krate);
+                    if let Some(ExternCrate { dependency_of: inner_dependency_of, .. }) =
+                        self.tcx.extern_crate(original_def_id)
+                    {
+                        orig_dependency_of = self.tcx.crate_name(*inner_dependency_of);
                     }
-                    let mut note_def = |which, def_id: DefId| {
-                        let crate_name = self.tcx.crate_name(def_id.krate);
-                        let note = if def_id.is_local() {
-                            format!("{} definition in the local crate (`{}`)", which, crate_name)
-                        } else {
-                            let paths: Vec<_> = self
-                                .tcx
-                                .crate_extern_paths(def_id.krate)
-                                .iter()
-                                .map(|p| p.display().to_string())
-                                .collect();
-                            format!(
-                                "{} definition in `{}` loaded from {}",
-                                which,
-                                crate_name,
-                                paths.join(", ")
-                            )
-                        };
-                        err.note(&note);
-                    };
-                    note_def("first", original_def_id);
-                    note_def("second", item_def_id);
                 }
-                err.emit();
+
+                let message = if local_span.is_some() {
+                    "duplicate"
+                } else {
+                    match self.tcx.extern_crate(item_def_id) {
+                        Some(ExternCrate { dependency_of: inner_dependency_of, .. }) => {
+                            dependency_of = self.tcx.crate_name(*inner_dependency_of);
+                            "duplicate_in_crate_depends"
+                        }
+                        _ => "duplicate_in_crate",
+                    }
+                };
+
+                self.tcx.sess.emit_err(DuplicateLangItem {
+                    local_span,
+                    lang_item_name,
+                    crate_name,
+                    dependency_of,
+                    is_local,
+                    path,
+                    first_defined_span,
+                    orig_crate_name,
+                    orig_dependency_of,
+                    orig_is_local,
+                    orig_path,
+                    message,
+                });
             }
         }
 
@@ -162,41 +161,30 @@ impl<'tcx> LanguageItemCollector<'tcx> {
                 None => (0, *item_span),
             };
 
+            let mut at_least = false;
             let required = match lang_item.required_generics() {
-                GenericRequirement::Exact(num) if num != actual_num => {
-                    Some((format!("{}", num), pluralize!(num)))
-                }
+                GenericRequirement::Exact(num) if num != actual_num => Some(num),
                 GenericRequirement::Minimum(num) if actual_num < num => {
-                    Some((format!("at least {}", num), pluralize!(num)))
-                }
+                    at_least = true;
+                    Some(num)}
+                ,
                 // If the number matches, or there is no requirement, handle it normally
                 _ => None,
             };
 
-            if let Some((range_str, pluralized)) = required {
+            if let Some(num) = required {
                 // We are issuing E0718 "incorrect target" here, because while the
                 // item kind of the target is correct, the target is still wrong
                 // because of the wrong number of generic arguments.
-                struct_span_err!(
-                    self.tcx.sess,
+                self.tcx.sess.emit_err(IncorrectTarget {
                     span,
-                    E0718,
-                    "`{}` language item must be applied to a {} with {} generic argument{}",
-                    name,
-                    kind.descr(),
-                    range_str,
-                    pluralized,
-                )
-                .span_label(
                     generics_span,
-                    format!(
-                        "this {} has {} generic argument{}",
-                        kind.descr(),
-                        actual_num,
-                        pluralize!(actual_num),
-                    ),
-                )
-                .emit();
+                    name: name.as_str(),
+                    kind: kind.descr(),
+                    num,
+                    actual_num,
+                    at_least,
+                });
 
                 // return early to not collect the lang item
                 return;