Auto merge of #116815 - Nilstrieb:more-funny-pretty-printers, r=compiler-errors

Remove lots of generics from `ty::print`

All of these generics mostly resolve to the same thing, which means we can remove them, greatly simplifying the types involved in pretty printing and unlocking another simplification (that is not performed in this PR): Using `&mut self` instead of passing `self` through the return type.

cc `@eddyb` you probably know why it's like this, just checking in and making sure I didn't do anything bad

r? oli-obk

compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs

@@ -60,10 +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>, Output = 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,
@@ -73,10 +70,7 @@ pub trait TypeErrCtxtExt<'tcx> {
         mutate: impl FnOnce(&mut Diagnostic),
     ) -> !
     where
-        T: fmt::Display
-            + TypeFoldable<TyCtxt<'tcx>>
-            + Print<'tcx, FmtPrinter<'tcx, 'tcx>, Output = 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;
 
@@ -227,10 +221,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         mutate: impl FnOnce(&mut Diagnostic),
     ) -> !
     where
-        T: fmt::Display
-            + TypeFoldable<TyCtxt<'tcx>>
-            + Print<'tcx, FmtPrinter<'tcx, 'tcx>, Output = 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>>,
     {
         let mut err = self.build_overflow_error(predicate, span, suggest_increasing_limit);
         mutate(&mut err);
@@ -247,10 +238,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         suggest_increasing_limit: bool,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>
     where
-        T: fmt::Display
-            + TypeFoldable<TyCtxt<'tcx>>
-            + Print<'tcx, FmtPrinter<'tcx, 'tcx>, Output = 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>>,
     {
         let predicate = self.resolve_vars_if_possible(predicate.clone());
         let mut pred_str = predicate.to_string();