region_names.rs : diag-mig

compiler/rustc_borrowck/src/diagnostics/region_name.rs

@@ -1,3 +1,6 @@
+// #![deny(rustc::untranslatable_diagnostic)]
+// #![deny(rustc::diagnostic_outside_of_impl)]
+
 use std::fmt::{self, Display};
 use std::iter;
 
@@ -10,6 +13,7 @@ use rustc_middle::ty::{self, DefIdTree, RegionVid, Ty};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
 
+use crate::session_diagnostics::RegionNameLabels;
 use crate::{nll::ToRegionVid, universal_regions::DefiningTy, MirBorrowckCtxt};
 
 /// A name for a particular region used in emitting diagnostics. This name could be a generated
@@ -133,48 +137,58 @@ impl RegionName {
                 RegionNameHighlight::MatchedAdtAndSegment(span),
                 _,
             ) => {
-                diag.span_label(*span, format!("let's call this `{self}`"));
+                diag.subdiagnostic(RegionNameLabels::NameRegion { span: *span, rg_name: self });
             }
             RegionNameSource::AnonRegionFromArgument(RegionNameHighlight::Occluded(
                 span,
                 type_name,
             )) => {
-                diag.span_label(
-                    *span,
-                    format!("lifetime `{self}` appears in the type {type_name}"),
-                );
+                diag.subdiagnostic(RegionNameLabels::LifetimeInType {
+                    span: *span,
+                    type_name: &type_name,
+                    rg_name: self,
+                });
             }
             RegionNameSource::AnonRegionFromOutput(
                 RegionNameHighlight::Occluded(span, type_name),
                 mir_description,
             ) => {
-                diag.span_label(
-                    *span,
-                    format!(
-                        "return type{mir_description} `{type_name}` contains a lifetime `{self}`"
-                    ),
-                );
+                diag.subdiagnostic(RegionNameLabels::LifetimeInReturned {
+                    span: *span,
+                    mir_description,
+                    type_name: &type_name,
+                    rg_name: self,
+                });
             }
             RegionNameSource::AnonRegionFromUpvar(span, upvar_name) => {
-                diag.span_label(
-                    *span,
-                    format!("lifetime `{self}` appears in the type of `{upvar_name}`"),
-                );
+                diag.subdiagnostic(RegionNameLabels::LifetimeInTypeOf {
+                    span: *span,
+                    upvar_name: upvar_name.to_ident_string(),
+                    rg_name: self,
+                });
             }
             RegionNameSource::AnonRegionFromOutput(
                 RegionNameHighlight::CannotMatchHirTy(span, type_name),
                 mir_description,
             ) => {
-                diag.span_label(*span, format!("return type{mir_description} is {type_name}"));
+                diag.subdiagnostic(RegionNameLabels::ReturnTypeIsTpye {
+                    span: *span,
+                    mir_description,
+                    type_name: &type_name,
+                });
             }
             RegionNameSource::AnonRegionFromYieldTy(span, type_name) => {
-                diag.span_label(*span, format!("yield type is {type_name}"));
+                diag.subdiagnostic(RegionNameLabels::YieldTypeIsTpye {
+                    span: *span,
+                    type_name: &type_name,
+                });
             }
             RegionNameSource::AnonRegionFromImplSignature(span, location) => {
-                diag.span_label(
-                    *span,
-                    format!("lifetime `{self}` appears in the `impl`'s {location}"),
-                );
+                diag.subdiagnostic(RegionNameLabels::LifetimeInImpl {
+                    span: *span,
+                    rg_name: self,
+                    location: &location,
+                });
             }
             RegionNameSource::Static => {}
         }

compiler/rustc_borrowck/src/session_diagnostics.rs

@@ -157,3 +157,55 @@ pub(crate) enum RequireStaticErr {
         multi_span: MultiSpan,
     },
 }
+
+#[derive(SessionSubdiagnostic)]
+pub(crate) enum RegionNameLabels<'a> {
+    #[label(borrowck::name_this_region)]
+    NameRegion {
+        #[primary_span]
+        span: Span,
+        rg_name: &'a RegionName,
+    },
+    #[label(borrowck::lifetime_appears_in_type)]
+    LifetimeInType {
+        #[primary_span]
+        span: Span,
+        type_name: &'a str,
+        rg_name: &'a RegionName,
+    },
+    #[label(borrowck::return_type_has_lifetime)]
+    LifetimeInReturned {
+        #[primary_span]
+        span: Span,
+        mir_description: &'a str,
+        type_name: &'a str,
+        rg_name: &'a RegionName,
+    },
+    #[label(borrowck::lifetime_appears_in_type_of)]
+    LifetimeInTypeOf {
+        #[primary_span]
+        span: Span,
+        upvar_name: String,
+        rg_name: &'a RegionName,
+    },
+    #[label(borrowck::return_type_is_type)]
+    ReturnTypeIsTpye {
+        #[primary_span]
+        span: Span,
+        mir_description: &'a str,
+        type_name: &'a str,
+    },
+    #[label(borrowck::yield_type_is_type)]
+    YieldTypeIsTpye {
+        #[primary_span]
+        span: Span,
+        type_name: &'a str,
+    },
+    #[label(borrowck::lifetime_appears_here_in_impl)]
+    LifetimeInImpl {
+        #[primary_span]
+        span: Span,
+        rg_name: &'a RegionName,
+        location: &'a str,
+    },
+}

compiler/rustc_error_messages/locales/en-US/borrowck.ftl

@@ -58,3 +58,24 @@ borrowck_returned_lifetime_short =
 
 borrowck_used_impl_require_static =
     the used `impl` has a `'static` requirement
+
+borrowck_name_this_region =
+    let's call this `{$rg_name}`
+
+borrowck_lifetime_appears_in_type =
+    lifetime `{$rg_name}` appears in the type {$type_name}
+
+borrowck_return_type_has_lifetime =
+    return type{$mir_description} `{$type_name}` contains a lifetime `{$rg_name}`
+
+borrowck_lifetime_appears_in_type_of =
+    lifetime `{$rg_name}` appears in the type of `{$upvar_name}`
+
+borrowck_return_type_is_type =
+    return type{$mir_description} is {$type_name}
+
+borrowck_yield_type_is_type =
+    yield type is {$type_name}
+
+borrowck_lifetime_appears_here_in_impl =
+    lifetime `{$rg_name}` appears in the `impl`'s {$location}