move DiagnosticArgFromDisplay into rustc_errors

compiler/rustc_errors/src/diagnostic.rs

@@ -40,6 +40,26 @@ pub trait IntoDiagnosticArg {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static>;
 }
 
+pub struct DiagnosticArgFromDisplay<'a>(pub &'a dyn fmt::Display);
+
+impl IntoDiagnosticArg for DiagnosticArgFromDisplay<'_> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        self.0.to_string().into_diagnostic_arg()
+    }
+}
+
+impl<'a> From<&'a dyn fmt::Display> for DiagnosticArgFromDisplay<'a> {
+    fn from(t: &'a dyn fmt::Display) -> Self {
+        DiagnosticArgFromDisplay(t)
+    }
+}
+
+impl<'a, T: fmt::Display> From<&'a T> for DiagnosticArgFromDisplay<'a> {
+    fn from(t: &'a T) -> Self {
+        DiagnosticArgFromDisplay(t)
+    }
+}
+
 macro_rules! into_diagnostic_arg_using_display {
     ($( $ty:ty ),+ $(,)?) => {
         $(

compiler/rustc_errors/src/lib.rs

@@ -371,8 +371,8 @@ impl fmt::Display for ExplicitBug {
 impl error::Error for ExplicitBug {}
 
 pub use diagnostic::{
-    AddSubdiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgValue, DiagnosticId,
-    DiagnosticStyledString, IntoDiagnosticArg, SubDiagnostic,
+    AddSubdiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgFromDisplay,
+    DiagnosticArgValue, DiagnosticId, DiagnosticStyledString, IntoDiagnosticArg, SubDiagnostic,
 };
 pub use diagnostic_builder::{DiagnosticBuilder, EmissionGuarantee, LintDiagnosticBuilder};
 use std::backtrace::Backtrace;

compiler/rustc_privacy/src/errors.rs

@@ -1,6 +1,4 @@
-use std::fmt::Display;
-
-use rustc_errors::IntoDiagnosticArg;
+use rustc_errors::DiagnosticArgFromDisplay;
 use rustc_macros::{LintDiagnostic, SessionDiagnostic, SessionSubdiagnostic};
 use rustc_span::{Span, Symbol};
 
@@ -38,7 +36,7 @@ pub struct ItemIsPrivate<'a> {
     #[label]
     pub span: Span,
     pub kind: &'a str,
-    pub descr: FromDisplay<'a>,
+    pub descr: DiagnosticArgFromDisplay<'a>,
 }
 
 #[derive(SessionDiagnostic)]
@@ -58,7 +56,7 @@ pub struct InPublicInterfaceTraits<'a> {
     pub span: Span,
     pub vis_descr: &'static str,
     pub kind: &'a str,
-    pub descr: FromDisplay<'a>,
+    pub descr: DiagnosticArgFromDisplay<'a>,
     #[label(privacy::visibility_label)]
     pub vis_span: Span,
 }
@@ -72,7 +70,7 @@ pub struct InPublicInterface<'a> {
     pub span: Span,
     pub vis_descr: &'static str,
     pub kind: &'a str,
-    pub descr: FromDisplay<'a>,
+    pub descr: DiagnosticArgFromDisplay<'a>,
     #[label(privacy::visibility_label)]
     pub vis_span: Span,
 }
@@ -81,7 +79,7 @@ pub struct InPublicInterface<'a> {
 #[lint(privacy::from_private_dep_in_public_interface)]
 pub struct FromPrivateDependencyInPublicInterface<'a> {
     pub kind: &'a str,
-    pub descr: FromDisplay<'a>,
+    pub descr: DiagnosticArgFromDisplay<'a>,
     pub krate: Symbol,
 }
 
@@ -90,13 +88,5 @@ pub struct FromPrivateDependencyInPublicInterface<'a> {
 pub struct PrivateInPublicLint<'a> {
     pub vis_descr: &'static str,
     pub kind: &'a str,
-    pub descr: FromDisplay<'a>,
-}
-
-pub struct FromDisplay<'a>(pub &'a dyn Display);
-
-impl IntoDiagnosticArg for FromDisplay<'_> {
-    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
-        self.0.to_string().into_diagnostic_arg()
-    }
+    pub descr: DiagnosticArgFromDisplay<'a>,
 }

compiler/rustc_privacy/src/lib.rs

@@ -38,9 +38,8 @@ use std::ops::ControlFlow;
 use std::{cmp, fmt, mem};
 
 use errors::{
-    FieldIsPrivate, FieldIsPrivateLabel, FromDisplay, FromPrivateDependencyInPublicInterface,
-    InPublicInterface, InPublicInterfaceTraits, ItemIsPrivate, PrivateInPublicLint,
-    UnnamedItemIsPrivate,
+    FieldIsPrivate, FieldIsPrivateLabel, FromPrivateDependencyInPublicInterface, InPublicInterface,
+    InPublicInterfaceTraits, ItemIsPrivate, PrivateInPublicLint, UnnamedItemIsPrivate,
 };
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -1080,11 +1079,7 @@ impl<'tcx> TypePrivacyVisitor<'tcx> {
     fn check_def_id(&mut self, def_id: DefId, kind: &str, descr: &dyn fmt::Display) -> bool {
         let is_error = !self.item_is_accessible(def_id);
         if is_error {
-            self.tcx.sess.emit_err(ItemIsPrivate {
-                span: self.span,
-                kind,
-                descr: FromDisplay(descr),
-            });
+            self.tcx.sess.emit_err(ItemIsPrivate { span: self.span, kind, descr: descr.into() });
         }
         is_error
     }
@@ -1257,7 +1252,7 @@ impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
                 let kind = kind.descr(def_id);
                 let _ = match name {
                     Some(name) => {
-                        sess.emit_err(ItemIsPrivate { span, kind, descr: FromDisplay(&name) })
+                        sess.emit_err(ItemIsPrivate { span, kind, descr: (&name).into() })
                     }
                     None => sess.emit_err(UnnamedItemIsPrivate { span, kind }),
                 };
@@ -1726,7 +1721,7 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
                 self.tcx.def_span(self.item_def_id.to_def_id()),
                 FromPrivateDependencyInPublicInterface {
                     kind,
-                    descr: FromDisplay(descr),
+                    descr: descr.into(),
                     krate: self.tcx.crate_name(def_id.krate),
                 },
             );
@@ -1763,7 +1758,7 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
                         span,
                         vis_descr,
                         kind,
-                        descr: FromDisplay(descr),
+                        descr: descr.into(),
                         vis_span,
                     });
                 } else {
@@ -1771,7 +1766,7 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
                         span,
                         vis_descr,
                         kind,
-                        descr: FromDisplay(descr),
+                        descr: descr.into(),
                         vis_span,
                     });
                 }
@@ -1780,7 +1775,7 @@ impl SearchInterfaceForPrivateItemsVisitor<'_> {
                     lint::builtin::PRIVATE_IN_PUBLIC,
                     hir_id,
                     span,
-                    PrivateInPublicLint { vis_descr, kind, descr: FromDisplay(descr) },
+                    PrivateInPublicLint { vis_descr, kind, descr: descr.into() },
                 );
             }
         }