From 6a3897f023e9824ddfe05657d3447b0fb64d4202 Mon Sep 17 00:00:00 2001
From: AndyJado <101876416+AndyJado@users.noreply.github.com>
Date: Sun, 28 Aug 2022 16:23:59 +0800
Subject: [PATCH 1/6] pass without effor

---
 compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs | 3 +++
 compiler/rustc_borrowck/src/diagnostics/find_all_local_uses.rs | 3 +++
 compiler/rustc_borrowck/src/diagnostics/find_use.rs            | 3 +++
 3 files changed, 9 insertions(+)

diff --git a/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
index b1def189230f..12f2b31addda 100644
--- a/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs
@@ -1,3 +1,6 @@
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
+
 use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
 use rustc_infer::infer::canonical::Canonical;
 use rustc_infer::infer::error_reporting::nice_region_error::NiceRegionError;
diff --git a/compiler/rustc_borrowck/src/diagnostics/find_all_local_uses.rs b/compiler/rustc_borrowck/src/diagnostics/find_all_local_uses.rs
index b3edc35dc364..498e9834354b 100644
--- a/compiler/rustc_borrowck/src/diagnostics/find_all_local_uses.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/find_all_local_uses.rs
@@ -1,3 +1,6 @@
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
+
 use std::collections::BTreeSet;
 
 use rustc_middle::mir::visit::{PlaceContext, Visitor};
diff --git a/compiler/rustc_borrowck/src/diagnostics/find_use.rs b/compiler/rustc_borrowck/src/diagnostics/find_use.rs
index b5a3081e56a7..15f42e26cbf4 100644
--- a/compiler/rustc_borrowck/src/diagnostics/find_use.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/find_use.rs
@@ -1,3 +1,6 @@
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
+
 use std::collections::VecDeque;
 use std::rc::Rc;
 

From 877d3390d7ebe167977cd9f6f572787747a7dc4d Mon Sep 17 00:00:00 2001
From: AndyJado <101876416+AndyJado@users.noreply.github.com>
Date: Thu, 1 Sep 2022 12:35:10 +0800
Subject: [PATCH 2/6] BorrowUsedHere|Later

---
 .../src/diagnostics/explain_borrow.rs         | 59 +++++++++++++------
 .../rustc_borrowck/src/session_diagnostics.rs | 49 +++++++++++++++
 .../locales/en-US/borrowck.ftl                | 57 ++++++++++++++++++
 3 files changed, 147 insertions(+), 18 deletions(-)

diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index 2f61849c383c..b165297ad30f 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -16,6 +16,7 @@ use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{sym, DesugaringKind, Span};
 
 use crate::region_infer::BlameConstraint;
+use crate::session_diagnostics::{BorrowUsedHere, BorrowUsedLater};
 use crate::{
     borrow_set::BorrowData, nll::ConstraintDescription, region_infer::Cause, MirBorrowckCtxt,
     WriteKind,
@@ -67,20 +68,28 @@ impl<'tcx> BorrowExplanation<'tcx> {
     ) {
         match *self {
             BorrowExplanation::UsedLater(later_use_kind, var_or_use_span, path_span) => {
-                let message = match later_use_kind {
-                    LaterUseKind::TraitCapture => "captured here by trait object",
-                    LaterUseKind::ClosureCapture => "captured here by closure",
-                    LaterUseKind::Call => "used by call",
-                    LaterUseKind::FakeLetRead => "stored here",
-                    LaterUseKind::Other => "used here",
-                };
                 // We can use `var_or_use_span` if either `path_span` is not present, or both spans are the same
                 if path_span.map(|path_span| path_span == var_or_use_span).unwrap_or(true) {
                     if borrow_span.map(|sp| !sp.overlaps(var_or_use_span)).unwrap_or(true) {
-                        err.span_label(
-                            var_or_use_span,
-                            format!("{}borrow later {}", borrow_desc, message),
-                        );
+                        let sub_err = match later_use_kind {
+                            LaterUseKind::TraitCapture => {
+                                BorrowUsedLater::TraitCapture { borrow_desc, span: var_or_use_span }
+                            }
+                            LaterUseKind::ClosureCapture => BorrowUsedLater::ClosureCapture {
+                                borrow_desc,
+                                span: var_or_use_span,
+                            },
+                            LaterUseKind::Call => {
+                                BorrowUsedLater::Call { borrow_desc, span: var_or_use_span }
+                            }
+                            LaterUseKind::FakeLetRead => {
+                                BorrowUsedLater::FakeLetRead { borrow_desc, span: var_or_use_span }
+                            }
+                            LaterUseKind::Other => {
+                                BorrowUsedLater::Other { borrow_desc, span: var_or_use_span }
+                            }
+                        };
+                        err.subdiagnostic(sub_err);
                     }
                 } else {
                     // path_span must be `Some` as otherwise the if condition is true
@@ -88,13 +97,27 @@ impl<'tcx> BorrowExplanation<'tcx> {
                     // path_span is only present in the case of closure capture
                     assert!(matches!(later_use_kind, LaterUseKind::ClosureCapture));
                     if !borrow_span.map_or(false, |sp| sp.overlaps(var_or_use_span)) {
-                        let path_label = "used here by closure";
-                        let capture_kind_label = message;
-                        err.span_label(
-                            var_or_use_span,
-                            format!("{}borrow later {}", borrow_desc, capture_kind_label),
-                        );
-                        err.span_label(path_span, path_label);
+                        let sub_err = match later_use_kind {
+                            LaterUseKind::TraitCapture => {
+                                BorrowUsedLater::TraitCapture { borrow_desc, span: var_or_use_span }
+                            }
+                            LaterUseKind::ClosureCapture => BorrowUsedLater::ClosureCapture {
+                                borrow_desc,
+                                span: var_or_use_span,
+                            },
+                            LaterUseKind::Call => {
+                                BorrowUsedLater::Call { borrow_desc, span: var_or_use_span }
+                            }
+                            LaterUseKind::FakeLetRead => {
+                                BorrowUsedLater::FakeLetRead { borrow_desc, span: var_or_use_span }
+                            }
+                            LaterUseKind::Other => {
+                                BorrowUsedLater::Other { borrow_desc, span: var_or_use_span }
+                            }
+                        };
+                        err.subdiagnostic(sub_err);
+                        let sub_label = BorrowUsedHere::ByClosure { path_span };
+                        err.subdiagnostic(sub_label);
                     }
                 }
             }
diff --git a/compiler/rustc_borrowck/src/session_diagnostics.rs b/compiler/rustc_borrowck/src/session_diagnostics.rs
index 5d750c6ca8c7..c322289d7bc6 100644
--- a/compiler/rustc_borrowck/src/session_diagnostics.rs
+++ b/compiler/rustc_borrowck/src/session_diagnostics.rs
@@ -157,3 +157,52 @@ pub(crate) enum RequireStaticErr {
         multi_span: MultiSpan,
     },
 }
+
+//explain_borrow.rs
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum BorrowUsedHere {
+    #[label(borrowck::used_here_by_closure)]
+    ByClosure {
+        #[primary_span]
+        path_span: Span,
+    },
+}
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum BorrowUsedLater<'a> {
+    #[label(borrowck::borrow_later_captured_by_trait_object)]
+    TraitCapture {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+
+    #[label(borrowck::borrow_later_captured_by_closure)]
+    ClosureCapture {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+
+    #[label(borrowck::borrow_later_used_by_call)]
+    Call {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+
+    #[label(borrowck::borrow_later_stored_here)]
+    FakeLetRead {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+
+    #[label(borrowck::borrow_later_used_here)]
+    Other {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+}
diff --git a/compiler/rustc_error_messages/locales/en-US/borrowck.ftl b/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
index 67f2156f32e5..0505e3cbaa37 100644
--- a/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
@@ -58,3 +58,60 @@ borrowck_returned_lifetime_short =
 
 borrowck_used_impl_require_static =
     the used `impl` has a `'static` requirement
+
+borrowck_borrow_later_captured_by_trait_object =
+    {$borrow_desc}borrow later captured here by trait object
+
+borrowck_borrow_later_captured_by_closure =
+    {$borrow_desc}borrow later captured here by closure
+
+borrowck_borrow_later_used_by_call =
+    {$borrow_desc}borrow later used by call
+
+borrowck_borrow_later_stored_here =
+    {$borrow_desc}borrow later stored here
+
+borrowck_borrow_later_used_here =
+    {$borrow_desc}borrow later used here
+
+borrowck_used_here_by_closure =
+    used here by closure
+
+borrowck_trait_capture_borrow_in_later_iteration_loop =
+    {$borrow_desc}borrow later borrow captured here by trait object, in later iteration of loop
+
+borrowck_closure_capture_borrow_in_later_iteration_loop =
+    {$borrow_desc}borrow later borrow captured here by closure, in later iteration of loop
+
+borrowck_call_used_borrow_in_later_iteration_loop =
+    {$borrow_desc}borrow later borrow used by call, in later iteration of loop
+
+borrowck_used_borrow_in_later_iteration_loop =
+    {$borrow_desc}borrow later borrow used here, in later iteration of loop
+
+borrowck_drop_local_might_cause_borrow =
+    {$borrow_desc}borrow might be used here, when `{$local_name}` is dropped and runs the {$dtor_name} for {$type_name}
+
+borrowck_var_dropped_in_wrong_order =
+    values in a scope are dropped in the opposite order they are defined
+
+borrowck_temporary_access_to_borrow =
+    a temporary with access to the {$borrow_desc}borrow is created here ...
+
+borrowck_drop_temporary_might_cause_borrow = ... and the {$borrow_desc}borrow might be used here, when that temporary is dropped and runs the {$dtor_name} for {$type_name}
+
+borrowck_consider_add_semicolon =
+    consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
+
+borrowck_consider_forcing_temporary_drop_sooner =
+    the temporary is part of an expression at the end of a block;
+    consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
+
+borrowck_perhaps_save_in_new_local_to_drop =
+    for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
+
+borrowck_outlive_constraint_need_borrow_for =
+    {$category}requires that `{$desc}` is borrowed for `{$region_name}`
+
+borrowck_outlive_constraint_need_borrow_lasts =
+    {$category}requires that `{$borrow_desc}` lasts for `{$region_name}`

From 19269fef0a7ec464d09a7ff970697d166c2a5dcf Mon Sep 17 00:00:00 2001
From: AndyJado <101876416+AndyJado@users.noreply.github.com>
Date: Thu, 1 Sep 2022 12:51:02 +0800
Subject: [PATCH 3/6] BLBLinloop

---
 .../src/diagnostics/explain_borrow.rs         | 76 ++++++++++++++-----
 .../rustc_borrowck/src/session_diagnostics.rs | 71 ++++++++++++++++-
 .../locales/en-US/borrowck.ftl                | 21 ++++-
 3 files changed, 141 insertions(+), 27 deletions(-)

diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index b165297ad30f..f4f12cf9fadb 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -16,7 +16,9 @@ use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{sym, DesugaringKind, Span};
 
 use crate::region_infer::BlameConstraint;
-use crate::session_diagnostics::{BorrowUsedHere, BorrowUsedLater};
+use crate::session_diagnostics::{
+    BorrowLaterBorrowUsedLaterInLoop, BorrowUsedHere, BorrowUsedLater, BorrowUsedLaterInLoop,
+};
 use crate::{
     borrow_set::BorrowData, nll::ConstraintDescription, region_infer::Cause, MirBorrowckCtxt,
     WriteKind,
@@ -122,33 +124,67 @@ impl<'tcx> BorrowExplanation<'tcx> {
                 }
             }
             BorrowExplanation::UsedLaterInLoop(later_use_kind, var_or_use_span, path_span) => {
-                let message = match later_use_kind {
-                    LaterUseKind::TraitCapture => {
-                        "borrow captured here by trait object, in later iteration of loop"
-                    }
-                    LaterUseKind::ClosureCapture => {
-                        "borrow captured here by closure, in later iteration of loop"
-                    }
-                    LaterUseKind::Call => "borrow used by call, in later iteration of loop",
-                    LaterUseKind::FakeLetRead => "borrow later stored here",
-                    LaterUseKind::Other => "borrow used here, in later iteration of loop",
-                };
                 // We can use `var_or_use_span` if either `path_span` is not present, or both spans are the same
                 if path_span.map(|path_span| path_span == var_or_use_span).unwrap_or(true) {
-                    err.span_label(var_or_use_span, format!("{}{}", borrow_desc, message));
+                    let sub_err = match later_use_kind {
+                        LaterUseKind::TraitCapture => BorrowUsedLaterInLoop::TraitCapture {
+                            borrow_desc,
+                            span: var_or_use_span,
+                        },
+                        LaterUseKind::ClosureCapture => BorrowUsedLaterInLoop::ClosureCapture {
+                            borrow_desc,
+                            span: var_or_use_span,
+                        },
+                        LaterUseKind::Call => {
+                            BorrowUsedLaterInLoop::Call { borrow_desc, span: var_or_use_span }
+                        }
+                        LaterUseKind::FakeLetRead => BorrowUsedLaterInLoop::FakeLetRead {
+                            borrow_desc,
+                            span: var_or_use_span,
+                        },
+                        LaterUseKind::Other => {
+                            BorrowUsedLaterInLoop::Other { borrow_desc, span: var_or_use_span }
+                        }
+                    };
+                    err.subdiagnostic(sub_err);
+                    // err.span_label(var_or_use_span, format!("{}{}", borrow_desc, message));
                 } else {
                     // path_span must be `Some` as otherwise the if condition is true
                     let path_span = path_span.unwrap();
                     // path_span is only present in the case of closure capture
                     assert!(matches!(later_use_kind, LaterUseKind::ClosureCapture));
                     if borrow_span.map(|sp| !sp.overlaps(var_or_use_span)).unwrap_or(true) {
-                        let path_label = "used here by closure";
-                        let capture_kind_label = message;
-                        err.span_label(
-                            var_or_use_span,
-                            format!("{}borrow later {}", borrow_desc, capture_kind_label),
-                        );
-                        err.span_label(path_span, path_label);
+                        let sub_err = match later_use_kind {
+                            LaterUseKind::TraitCapture => {
+                                BorrowLaterBorrowUsedLaterInLoop::TraitCapture {
+                                    borrow_desc,
+                                    span: var_or_use_span,
+                                }
+                            }
+                            LaterUseKind::ClosureCapture => {
+                                BorrowLaterBorrowUsedLaterInLoop::ClosureCapture {
+                                    borrow_desc,
+                                    span: var_or_use_span,
+                                }
+                            }
+                            LaterUseKind::Call => BorrowLaterBorrowUsedLaterInLoop::Call {
+                                borrow_desc,
+                                span: var_or_use_span,
+                            },
+                            LaterUseKind::FakeLetRead => {
+                                BorrowLaterBorrowUsedLaterInLoop::FakeLetRead {
+                                    borrow_desc,
+                                    span: var_or_use_span,
+                                }
+                            }
+                            LaterUseKind::Other => BorrowLaterBorrowUsedLaterInLoop::Other {
+                                borrow_desc,
+                                span: var_or_use_span,
+                            },
+                        };
+                        err.subdiagnostic(sub_err);
+                        let sub_label = BorrowUsedHere::ByClosure { path_span };
+                        err.subdiagnostic(sub_label);
                     }
                 }
             }
diff --git a/compiler/rustc_borrowck/src/session_diagnostics.rs b/compiler/rustc_borrowck/src/session_diagnostics.rs
index c322289d7bc6..3f6c4401bc22 100644
--- a/compiler/rustc_borrowck/src/session_diagnostics.rs
+++ b/compiler/rustc_borrowck/src/session_diagnostics.rs
@@ -177,28 +177,24 @@ pub(crate) enum BorrowUsedLater<'a> {
         #[primary_span]
         span: Span,
     },
-
     #[label(borrowck::borrow_later_captured_by_closure)]
     ClosureCapture {
         borrow_desc: &'a str,
         #[primary_span]
         span: Span,
     },
-
     #[label(borrowck::borrow_later_used_by_call)]
     Call {
         borrow_desc: &'a str,
         #[primary_span]
         span: Span,
     },
-
     #[label(borrowck::borrow_later_stored_here)]
     FakeLetRead {
         borrow_desc: &'a str,
         #[primary_span]
         span: Span,
     },
-
     #[label(borrowck::borrow_later_used_here)]
     Other {
         borrow_desc: &'a str,
@@ -206,3 +202,70 @@ pub(crate) enum BorrowUsedLater<'a> {
         span: Span,
     },
 }
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum BorrowUsedLaterInLoop<'a> {
+    #[label(borrowck::trait_capture_borrow_in_later_iteration_loop)]
+    TraitCapture {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[label(borrowck::closure_capture_borrow_in_later_iteration_loop)]
+    ClosureCapture {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[label(borrowck::call_used_borrow_in_later_iteration_loop)]
+    Call {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[label(borrowck::borrow_later_stored_here)]
+    FakeLetRead {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[label(borrowck::used_borrow_in_later_iteration_loop)]
+    Other {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+}
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum BorrowLaterBorrowUsedLaterInLoop<'a> {
+    #[label(borrowck::bl_trait_capture_borrow_in_later_iteration_loop)]
+    TraitCapture {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[label(borrowck::bl_closure_capture_borrow_in_later_iteration_loop)]
+    ClosureCapture {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[label(borrowck::call_used_borrow_in_later_iteration_loop)]
+    Call {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[label(borrowck::bl_borrow_later_stored_here)]
+    FakeLetRead {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[label(borrowck::bl_used_borrow_in_later_iteration_loop)]
+    Other {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+}
diff --git a/compiler/rustc_error_messages/locales/en-US/borrowck.ftl b/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
index 0505e3cbaa37..e3d0d68115fb 100644
--- a/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
@@ -78,15 +78,30 @@ borrowck_used_here_by_closure =
     used here by closure
 
 borrowck_trait_capture_borrow_in_later_iteration_loop =
-    {$borrow_desc}borrow later borrow captured here by trait object, in later iteration of loop
+    {$borrow_desc}borrow captured here by trait object, in later iteration of loop
 
 borrowck_closure_capture_borrow_in_later_iteration_loop =
-    {$borrow_desc}borrow later borrow captured here by closure, in later iteration of loop
+    {$borrow_desc}borrow captured here by closure, in later iteration of loop
 
 borrowck_call_used_borrow_in_later_iteration_loop =
-    {$borrow_desc}borrow later borrow used by call, in later iteration of loop
+    {$borrow_desc}borrow used by call, in later iteration of loop
 
 borrowck_used_borrow_in_later_iteration_loop =
+    {$borrow_desc}borrow used here, in later iteration of loop
+
+borrowck_bl_trait_capture_borrow_in_later_iteration_loop =
+    {$borrow_desc}borrow later borrow captured here by trait object, in later iteration of loop
+
+borrowck_bl_closure_capture_borrow_in_later_iteration_loop =
+    {$borrow_desc}borrow later borrow captured here by closure, in later iteration of loop
+
+borrowck_bl_call_used_borrow_in_later_iteration_loop =
+    {$borrow_desc}borrow later borrow used by call, in later iteration of loop
+
+borrowck_bl_borrow_later_stored_here =
+    {$borrow_desc}borrow later borrow later stored here
+
+borrowck_bl_used_borrow_in_later_iteration_loop =
     {$borrow_desc}borrow later borrow used here, in later iteration of loop
 
 borrowck_drop_local_might_cause_borrow =

From c480d9a18ef4250a8cfd3604ddeece75c8c7a37c Mon Sep 17 00:00:00 2001
From: AndyJado <101876416+AndyJado@users.noreply.github.com>
Date: Thu, 1 Sep 2022 14:28:13 +0800
Subject: [PATCH 4/6] explain_borrow need help

---
 .../src/diagnostics/explain_borrow.rs         | 91 ++++++++-----------
 .../rustc_borrowck/src/session_diagnostics.rs | 53 +++++++++++
 .../locales/en-US/borrowck.ftl                |  6 +-
 3 files changed, 96 insertions(+), 54 deletions(-)

diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index f4f12cf9fadb..1ade0eb2e04c 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -1,3 +1,6 @@
+// #![deny(rustc::untranslatable_diagnostic)]
+// #![deny(rustc::diagnostic_outside_of_impl)]
+
 //! Print diagnostics to explain why values are borrowed.
 
 use std::collections::VecDeque;
@@ -18,6 +21,7 @@ use rustc_span::{sym, DesugaringKind, Span};
 use crate::region_infer::BlameConstraint;
 use crate::session_diagnostics::{
     BorrowLaterBorrowUsedLaterInLoop, BorrowUsedHere, BorrowUsedLater, BorrowUsedLaterInLoop,
+    MustValidFor, UsedLaterDropped,
 };
 use crate::{
     borrow_set::BorrowData, nll::ConstraintDescription, region_infer::Cause, MirBorrowckCtxt,
@@ -220,41 +224,33 @@ impl<'tcx> BorrowExplanation<'tcx> {
 
                 match local_names[dropped_local] {
                     Some(local_name) if !local_decl.from_compiler_desugaring() => {
-                        let message = format!(
-                            "{B}borrow might be used here, when `{LOC}` is dropped \
-                             and runs the {DTOR} for {TYPE}",
-                            B = borrow_desc,
-                            LOC = local_name,
-                            TYPE = type_desc,
-                            DTOR = dtor_desc
-                        );
-                        err.span_label(body.source_info(drop_loc).span, message);
+                        let sub_label = UsedLaterDropped::UsedHere {
+                            borrow_desc,
+                            local_name: &local_name.to_ident_string(),
+                            type_desc: &type_desc,
+                            dtor_desc,
+                            span: body.source_info(drop_loc).span,
+                        };
+                        err.subdiagnostic(sub_label);
 
                         if should_note_order {
-                            err.note(
-                                "values in a scope are dropped \
-                                 in the opposite order they are defined",
-                            );
+                            let sub_note = UsedLaterDropped::OppositeOrder {};
+                            err.subdiagnostic(sub_note);
                         }
                     }
                     _ => {
-                        err.span_label(
-                            local_decl.source_info.span,
-                            format!(
-                                "a temporary with access to the {B}borrow \
-                                 is created here ...",
-                                B = borrow_desc
-                            ),
-                        );
-                        let message = format!(
-                            "... and the {B}borrow might be used here, \
-                             when that temporary is dropped \
-                             and runs the {DTOR} for {TYPE}",
-                            B = borrow_desc,
-                            TYPE = type_desc,
-                            DTOR = dtor_desc
-                        );
-                        err.span_label(body.source_info(drop_loc).span, message);
+                        let sub_label = UsedLaterDropped::TemporaryCreatedHere {
+                            borrow_desc,
+                            span: local_decl.source_info.span,
+                        };
+                        err.subdiagnostic(sub_label);
+                        let sub_label_2 = UsedLaterDropped::MightUsedHere {
+                            borrow_desc,
+                            type_desc: &type_desc,
+                            dtor_desc,
+                            span: body.source_info(drop_loc).span,
+                        };
+                        err.subdiagnostic(sub_label_2);
 
                         if let Some(info) = &local_decl.is_block_tail {
                             if info.tail_result_is_ignored {
@@ -266,21 +262,16 @@ impl<'tcx> BorrowExplanation<'tcx> {
                                     })
                                     .unwrap_or(false)
                                 {
-                                    err.span_suggestion_verbose(
-                                        info.span.shrink_to_hi(),
-                                        "consider adding semicolon after the expression so its \
-                                        temporaries are dropped sooner, before the local variables \
-                                        declared by the block are dropped",
-                                        ";",
-                                        Applicability::MaybeIncorrect,
-                                    );
+                                    let sub_suggest = UsedLaterDropped::AddSemicolon {
+                                        span: info.span.shrink_to_hi(),
+                                    };
+                                    err.subdiagnostic(sub_suggest);
                                 }
                             } else {
-                                err.note(
-                                    "the temporary is part of an expression at the end of a \
-                                     block;\nconsider forcing this temporary to be dropped sooner, \
-                                     before the block's local variables are dropped",
-                                );
+                                let sub_note = UsedLaterDropped::ManualDrop {};
+                                err.subdiagnostic(sub_note);
+
+                                //FIXME: waiting for multipart suggestion derive
                                 err.multipart_suggestion(
                                     "for example, you could save the expression's value in a new \
                                      local variable `x` and then make `x` be the expression at the \
@@ -306,15 +297,13 @@ impl<'tcx> BorrowExplanation<'tcx> {
                 region_name.highlight_region_name(err);
 
                 if let Some(desc) = opt_place_desc {
-                    err.span_label(
+                    let sub_label = MustValidFor::Borrowed {
+                        category: category.description(),
+                        desc,
+                        region_name,
                         span,
-                        format!(
-                            "{}requires that `{}` is borrowed for `{}`",
-                            category.description(),
-                            desc,
-                            region_name,
-                        ),
-                    );
+                    };
+                    err.subdiagnostic(sub_label);
                 } else {
                     err.span_label(
                         span,
diff --git a/compiler/rustc_borrowck/src/session_diagnostics.rs b/compiler/rustc_borrowck/src/session_diagnostics.rs
index 3f6c4401bc22..d826a5dfff99 100644
--- a/compiler/rustc_borrowck/src/session_diagnostics.rs
+++ b/compiler/rustc_borrowck/src/session_diagnostics.rs
@@ -269,3 +269,56 @@ pub(crate) enum BorrowLaterBorrowUsedLaterInLoop<'a> {
         span: Span,
     },
 }
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum UsedLaterDropped<'a> {
+    #[label(borrowck::drop_local_might_cause_borrow)]
+    UsedHere {
+        borrow_desc: &'a str,
+        local_name: &'a str,
+        type_desc: &'a str,
+        dtor_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[note(borrowck::var_dropped_in_wrong_order)]
+    OppositeOrder {},
+    #[label(borrowck::temporary_access_to_borrow)]
+    TemporaryCreatedHere {
+        borrow_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[label(borrowck::drop_temporary_might_cause_borrow_use)]
+    MightUsedHere {
+        borrow_desc: &'a str,
+        type_desc: &'a str,
+        dtor_desc: &'a str,
+        #[primary_span]
+        span: Span,
+    },
+    #[suggestion_verbose(
+        borrowck::consider_add_semicolon,
+        applicability = "maybe-incorrect",
+        code = ";"
+    )]
+    AddSemicolon {
+        #[primary_span]
+        span: Span,
+    },
+
+    #[note(borrowck::consider_forcing_temporary_drop_sooner)]
+    ManualDrop {},
+}
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum MustValidFor<'a> {
+    #[label(borrowck::outlive_constraint_need_borrow_for)]
+    Borrowed {
+        category: &'a str,
+        desc: &'a str,
+        region_name: &'a RegionName,
+        #[primary_span]
+        span: Span,
+    },
+}
diff --git a/compiler/rustc_error_messages/locales/en-US/borrowck.ftl b/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
index e3d0d68115fb..c57bd0f3e3c9 100644
--- a/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
@@ -105,7 +105,7 @@ borrowck_bl_used_borrow_in_later_iteration_loop =
     {$borrow_desc}borrow later borrow used here, in later iteration of loop
 
 borrowck_drop_local_might_cause_borrow =
-    {$borrow_desc}borrow might be used here, when `{$local_name}` is dropped and runs the {$dtor_name} for {$type_name}
+    {$borrow_desc}borrow might be used here, when `{$local_name}` is dropped and runs the {$dtor_desc} for {$type_desc}
 
 borrowck_var_dropped_in_wrong_order =
     values in a scope are dropped in the opposite order they are defined
@@ -113,7 +113,7 @@ borrowck_var_dropped_in_wrong_order =
 borrowck_temporary_access_to_borrow =
     a temporary with access to the {$borrow_desc}borrow is created here ...
 
-borrowck_drop_temporary_might_cause_borrow = ... and the {$borrow_desc}borrow might be used here, when that temporary is dropped and runs the {$dtor_name} for {$type_name}
+borrowck_drop_temporary_might_cause_borrow_use = ... and the {$borrow_desc}borrow might be used here, when that temporary is dropped and runs the {$dtor_desc} for {$type_desc}
 
 borrowck_consider_add_semicolon =
     consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
@@ -128,5 +128,5 @@ borrowck_perhaps_save_in_new_local_to_drop =
 borrowck_outlive_constraint_need_borrow_for =
     {$category}requires that `{$desc}` is borrowed for `{$region_name}`
 
-borrowck_outlive_constraint_need_borrow_lasts =
+borrowck_outlive_constraint_need_borrow_lasts_for =
     {$category}requires that `{$borrow_desc}` lasts for `{$region_name}`

From 71d17621cf65dbba0c9b3497fa7317e8558c54eb Mon Sep 17 00:00:00 2001
From: AndyJado <101876416+AndyJado@users.noreply.github.com>
Date: Thu, 1 Sep 2022 16:25:58 +0800
Subject: [PATCH 5/6] How to call this bug?

---
 .../src/diagnostics/explain_borrow.rs             | 15 +++++++--------
 .../rustc_borrowck/src/session_diagnostics.rs     |  9 +++++++++
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index 1ade0eb2e04c..40a1ebd3f77f 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -305,15 +305,14 @@ impl<'tcx> BorrowExplanation<'tcx> {
                     };
                     err.subdiagnostic(sub_label);
                 } else {
-                    err.span_label(
+                    //FIXME: src/test/ui/consts/const-eval/const-eval-intrinsic-promotion.rs
+                    let sub_label = MustValidFor::Lasts {
+                        category: category.description(),
+                        borrow_desc,
+                        region_name,
                         span,
-                        format!(
-                            "{}requires that {}borrow lasts for `{}`",
-                            category.description(),
-                            borrow_desc,
-                            region_name,
-                        ),
-                    );
+                    };
+                    err.subdiagnostic(sub_label);
                 };
 
                 self.add_lifetime_bound_suggestion_to_diagnostic(err, &category, span, region_name);
diff --git a/compiler/rustc_borrowck/src/session_diagnostics.rs b/compiler/rustc_borrowck/src/session_diagnostics.rs
index d826a5dfff99..8131e40b721d 100644
--- a/compiler/rustc_borrowck/src/session_diagnostics.rs
+++ b/compiler/rustc_borrowck/src/session_diagnostics.rs
@@ -321,4 +321,13 @@ pub(crate) enum MustValidFor<'a> {
         #[primary_span]
         span: Span,
     },
+
+    #[label(borrowck::outlive_constraint_need_borrow_lasts_for)]
+    Lasts {
+        category: &'a str,
+        borrow_desc: &'a str,
+        region_name: &'a RegionName,
+        #[primary_span]
+        span: Span,
+    },
 }

From 2cab61d2e6b2949145eec73ac8fec3a3215d0966 Mon Sep 17 00:00:00 2001
From: AndyJado <101876416+AndyJado@users.noreply.github.com>
Date: Thu, 1 Sep 2022 17:06:23 +0800
Subject: [PATCH 6/6] MutatingUpvar

---
 .../src/diagnostics/mutability_errors.rs          | 15 +++++++--------
 .../rustc_borrowck/src/session_diagnostics.rs     | 14 +++++++++-----
 .../locales/en-US/borrowck.ftl                    |  3 +++
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index dd9590016b99..a9f6a4df9209 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -1,3 +1,6 @@
+// #![deny(rustc::untranslatable_diagnostic)]
+// #![deny(rustc::diagnostic_outside_of_impl)]
+
 use rustc_errors::{
     Applicability, Diagnostic, DiagnosticBuilder, EmissionGuarantee, ErrorGuaranteed,
 };
@@ -19,6 +22,7 @@ use rustc_span::symbol::{kw, Symbol};
 use rustc_span::{sym, BytePos, Span};
 
 use crate::diagnostics::BorrowedContentSource;
+use crate::session_diagnostics::ShowMutatingUpvar;
 use crate::MirBorrowckCtxt;
 use rustc_const_eval::util::collect_writes::FindAssignments;
 
@@ -864,14 +868,9 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             } else {
                 bug!("not an upvar")
             };
-            err.span_label(
-                *span,
-                format!(
-                    "calling `{}` requires mutable binding due to {}",
-                    self.describe_place(the_place_err).unwrap(),
-                    reason
-                ),
-            );
+            let place = self.describe_place(the_place_err).unwrap();
+            let sub_label = ShowMutatingUpvar::RequireMutableBinding { place, reason, span: *span };
+            err.subdiagnostic(sub_label);
         }
     }
 
diff --git a/compiler/rustc_borrowck/src/session_diagnostics.rs b/compiler/rustc_borrowck/src/session_diagnostics.rs
index 8131e40b721d..ec4b1cffa96f 100644
--- a/compiler/rustc_borrowck/src/session_diagnostics.rs
+++ b/compiler/rustc_borrowck/src/session_diagnostics.rs
@@ -321,12 +321,16 @@ pub(crate) enum MustValidFor<'a> {
         #[primary_span]
         span: Span,
     },
+}
 
-    #[label(borrowck::outlive_constraint_need_borrow_lasts_for)]
-    Lasts {
-        category: &'a str,
-        borrow_desc: &'a str,
-        region_name: &'a RegionName,
+//mutability_errors.rs
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum ShowMutatingUpvar {
+    #[label(borrowck::require_mutable_binding)]
+    RequireMutableBinding {
+        place: String,
+        reason: String,
         #[primary_span]
         span: Span,
     },
diff --git a/compiler/rustc_error_messages/locales/en-US/borrowck.ftl b/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
index c57bd0f3e3c9..2ac71d29cc25 100644
--- a/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
@@ -130,3 +130,6 @@ borrowck_outlive_constraint_need_borrow_for =
 
 borrowck_outlive_constraint_need_borrow_lasts_for =
     {$category}requires that `{$borrow_desc}` lasts for `{$region_name}`
+
+borrowck_require_mutable_binding =
+    calling `{$place}` requires mutable binding due to {$reason}