Remove Print::Error

All printing goes through `fmt::Error` now.
rust-lang · Oct 17, 2023 · 6fc6a6d · 6fc6a6d
1 parent 6038888
commit 6fc6a6d
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Showing 6 changed files with 17 additions and 32 deletions.
diff --git a/compiler/rustc_const_eval/src/util/type_name.rs b/compiler/rustc_const_eval/src/util/type_name.rs
@@ -138,7 +138,7 @@ impl<'tcx> PrettyPrinter<'tcx> for AbsolutePathPrinter<'tcx> {
     }
     fn comma_sep<T>(mut self, mut elems: impl Iterator<Item = T>) -> Result<Self, PrintError>
     where
-        T: Print<'tcx, Self, Error = PrintError>,
+        T: Print<'tcx, Self>,
     {
         if let Some(first) = elems.next() {
             self = first.print(self)?;

diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_error.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_error.rs
@@ -28,7 +28,7 @@ pub struct Highlighted<'tcx, T> {
 
 impl<'tcx, T> IntoDiagnosticArg for Highlighted<'tcx, T>
 where
-    T: for<'a> Print<'tcx, FmtPrinter<'a, 'tcx>, Error = fmt::Error>,
+    T: for<'a> Print<'tcx, FmtPrinter<'a, 'tcx>>,
 {
     fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
         rustc_errors::DiagnosticArgValue::Str(self.to_string().into())
@@ -43,7 +43,7 @@ impl<'tcx, T> Highlighted<'tcx, T> {
 
 impl<'tcx, T> fmt::Display for Highlighted<'tcx, T>
 where
-    T: for<'a> Print<'tcx, FmtPrinter<'a, 'tcx>, Error = fmt::Error>,
+    T: for<'a> Print<'tcx, FmtPrinter<'a, 'tcx>>,
 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut printer = ty::print::FmtPrinter::new(self.tcx, Namespace::TypeNS);

diff --git a/compiler/rustc_middle/src/ty/print/mod.rs b/compiler/rustc_middle/src/ty/print/mod.rs
@@ -15,8 +15,6 @@ pub type PrintError = std::fmt::Error;
 // FIXME(eddyb) false positive, the lifetime parameters are used with `P:  Printer<...>`.
 #[allow(unused_lifetimes)]
 pub trait Print<'tcx, P> {
-    type Error;
-
     fn print(&self, cx: P) -> Result<P, PrintError>;
 }
 
@@ -288,29 +286,24 @@ pub fn characteristic_def_id_of_type(ty: Ty<'_>) -> Option<DefId> {
 }
 
 impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for ty::Region<'tcx> {
-    type Error = PrintError;
     fn print(&self, cx: P) -> Result<P, PrintError> {
         cx.print_region(*self)
     }
 }
 
 impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for Ty<'tcx> {
-    type Error = PrintError;
-
     fn print(&self, cx: P) -> Result<P, PrintError> {
         cx.print_type(*self)
     }
 }
 
 impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>> {
-    type Error = PrintError;
     fn print(&self, cx: P) -> Result<P, PrintError> {
         cx.print_dyn_existential(self)
     }
 }
 
 impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for ty::Const<'tcx> {
-    type Error = PrintError;
     fn print(&self, cx: P) -> Result<P, PrintError> {
         cx.print_const(*self)
     }

diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -217,7 +217,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
 
     fn in_binder<T>(self, value: &ty::Binder<'tcx, T>) -> Result<Self, PrintError>
     where
-        T: Print<'tcx, Self, Error = PrintError> + TypeFoldable<TyCtxt<'tcx>>,
+        T: Print<'tcx, Self> + TypeFoldable<TyCtxt<'tcx>>,
     {
         value.as_ref().skip_binder().print(self)
     }
@@ -228,15 +228,15 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
         f: F,
     ) -> Result<Self, PrintError>
     where
-        T: Print<'tcx, Self, Error = PrintError> + TypeFoldable<TyCtxt<'tcx>>,
+        T: Print<'tcx, Self> + TypeFoldable<TyCtxt<'tcx>>,
     {
         f(value.as_ref().skip_binder(), self)
     }
 
     /// Prints comma-separated elements.
     fn comma_sep<T>(mut self, mut elems: impl Iterator<Item = T>) -> Result<Self, PrintError>
     where
-        T: Print<'tcx, Self, Error = PrintError>,
+        T: Print<'tcx, Self>,
     {
         if let Some(first) = elems.next() {
             self = first.print(self)?;
@@ -2083,7 +2083,7 @@ impl<'tcx> PrettyPrinter<'tcx> for FmtPrinter<'_, 'tcx> {
 
     fn in_binder<T>(self, value: &ty::Binder<'tcx, T>) -> Result<Self, PrintError>
     where
-        T: Print<'tcx, Self, Error = PrintError> + TypeFoldable<TyCtxt<'tcx>>,
+        T: Print<'tcx, Self> + TypeFoldable<TyCtxt<'tcx>>,
     {
         self.pretty_in_binder(value)
     }
@@ -2094,7 +2094,7 @@ impl<'tcx> PrettyPrinter<'tcx> for FmtPrinter<'_, 'tcx> {
         f: C,
     ) -> Result<Self, PrintError>
     where
-        T: Print<'tcx, Self, Error = PrintError> + TypeFoldable<TyCtxt<'tcx>>,
+        T: Print<'tcx, Self> + TypeFoldable<TyCtxt<'tcx>>,
     {
         self.pretty_wrap_binder(value, f)
     }
@@ -2343,7 +2343,7 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
         value: &ty::Binder<'tcx, T>,
     ) -> Result<(Self, T, BTreeMap<ty::BoundRegion, ty::Region<'tcx>>), fmt::Error>
     where
-        T: Print<'tcx, Self, Error = fmt::Error> + TypeFoldable<TyCtxt<'tcx>>,
+        T: Print<'tcx, Self> + TypeFoldable<TyCtxt<'tcx>>,
     {
         fn name_by_region_index(
             index: usize,
@@ -2513,7 +2513,7 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
 
     pub fn pretty_in_binder<T>(self, value: &ty::Binder<'tcx, T>) -> Result<Self, fmt::Error>
     where
-        T: Print<'tcx, Self, Error = fmt::Error> + TypeFoldable<TyCtxt<'tcx>>,
+        T: Print<'tcx, Self> + TypeFoldable<TyCtxt<'tcx>>,
     {
         let old_region_index = self.region_index;
         let (new, new_value, _) = self.name_all_regions(value)?;
@@ -2529,7 +2529,7 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
         f: C,
     ) -> Result<Self, fmt::Error>
     where
-        T: Print<'tcx, Self, Error = fmt::Error> + TypeFoldable<TyCtxt<'tcx>>,
+        T: Print<'tcx, Self> + TypeFoldable<TyCtxt<'tcx>>,
     {
         let old_region_index = self.region_index;
         let (new, new_value, _) = self.name_all_regions(value)?;
@@ -2594,21 +2594,18 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
 
 impl<'tcx, T, P: PrettyPrinter<'tcx>> Print<'tcx, P> for ty::Binder<'tcx, T>
 where
-    T: Print<'tcx, P, Error = PrintError> + TypeFoldable<TyCtxt<'tcx>>,
+    T: Print<'tcx, P> + TypeFoldable<TyCtxt<'tcx>>,
 {
-    type Error = PrintError;
-
     fn print(&self, cx: P) -> Result<P, PrintError> {
         cx.in_binder(self)
     }
 }
 
 impl<'tcx, T, U, P: PrettyPrinter<'tcx>> Print<'tcx, P> for ty::OutlivesPredicate<T, U>
 where
-    T: Print<'tcx, P, Error = PrintError>,
-    U: Print<'tcx, P, Error = PrintError>,
+    T: Print<'tcx, P>,
+    U: Print<'tcx, P>,
 {
-    type Error = PrintError;
     fn print(&self, mut cx: P) -> Result<P, PrintError> {
         define_scoped_cx!(cx);
         p!(print(self.0), ": ", print(self.1));
@@ -2636,7 +2633,6 @@ macro_rules! forward_display_to_print {
 macro_rules! define_print_and_forward_display {
     (($self:ident, $cx:ident): $($ty:ty $print:block)+) => {
         $(impl<'tcx, P: PrettyPrinter<'tcx>> Print<'tcx, P> for $ty {
-            type Error = fmt::Error;
             fn print(&$self, $cx: P) -> Result<P, PrintError> {
                 #[allow(unused_mut)]
                 let mut $cx = $cx;

diff --git a/compiler/rustc_symbol_mangling/src/legacy.rs b/compiler/rustc_symbol_mangling/src/legacy.rs
@@ -365,7 +365,7 @@ impl<'tcx> PrettyPrinter<'tcx> for &mut SymbolPrinter<'tcx> {
     }
     fn comma_sep<T>(mut self, mut elems: impl Iterator<Item = T>) -> Result<Self, PrintError>
     where
-        T: Print<'tcx, Self, Error = PrintError>,
+        T: Print<'tcx, Self>,
     {
         if let Some(first) = elems.next() {
             self = first.print(self)?;

diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
@@ -60,8 +60,7 @@ pub trait TypeErrCtxtExt<'tcx> {
         suggest_increasing_limit: bool,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>
     where
-        T: fmt::Display + TypeFoldable<TyCtxt<'tcx>> + Print<'tcx, FmtPrinter<'tcx, 'tcx>>,
-        <T as Print<'tcx, FmtPrinter<'tcx, 'tcx>>>::Error: std::fmt::Debug;
+        T: fmt::Display + TypeFoldable<TyCtxt<'tcx>> + Print<'tcx, FmtPrinter<'tcx, 'tcx>>;
 
     fn report_overflow_error<T>(
         &self,
@@ -71,8 +70,7 @@ pub trait TypeErrCtxtExt<'tcx> {
         mutate: impl FnOnce(&mut Diagnostic),
     ) -> !
     where
-        T: fmt::Display + TypeFoldable<TyCtxt<'tcx>> + Print<'tcx, FmtPrinter<'tcx, 'tcx>>,
-        <T as Print<'tcx, FmtPrinter<'tcx, 'tcx>>>::Error: std::fmt::Debug;
+        T: fmt::Display + TypeFoldable<TyCtxt<'tcx>> + Print<'tcx, FmtPrinter<'tcx, 'tcx>>;
 
     fn report_overflow_no_abort(&self, obligation: PredicateObligation<'tcx>) -> ErrorGuaranteed;
 
@@ -224,7 +222,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
     ) -> !
     where
         T: fmt::Display + TypeFoldable<TyCtxt<'tcx>> + Print<'tcx, FmtPrinter<'tcx, 'tcx>>,
-        <T as Print<'tcx, FmtPrinter<'tcx, 'tcx>>>::Error: std::fmt::Debug,
     {
         let mut err = self.build_overflow_error(predicate, span, suggest_increasing_limit);
         mutate(&mut err);
@@ -242,7 +239,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>
     where
         T: fmt::Display + TypeFoldable<TyCtxt<'tcx>> + Print<'tcx, FmtPrinter<'tcx, 'tcx>>,
-        <T as Print<'tcx, FmtPrinter<'tcx, 'tcx>>>::Error: std::fmt::Debug,
     {
         let predicate = self.resolve_vars_if_possible(predicate.clone());
         let mut pred_str = predicate.to_string();