Rollup merge of rust-lang#119813 - oli-obk:even_more_follow_up_errors2, r=estebank

Silence some follow-up errors [2/x]

this is one piece of the requested cleanups from rust-lang#117449

the `type_of` query frequently uses astconv to convert a `hir::Ty` to a `ty::Ty`. This process is infallible, but may produce errors as it goes. All the error reporting sites that had access to the `ItemCtxt` are now tainting it, causing `type_of` to return a `ty::Error` instead of anything else.

Author: matthiaskrgr

compiler/rustc_hir_analysis/src/astconv/bounds.rs

@@ -300,13 +300,15 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
             .expect("missing associated item");
 
         if !assoc_item.visibility(tcx).is_accessible_from(def_scope, tcx) {
-            tcx.dcx()
+            let reported = tcx
+                .dcx()
                 .struct_span_err(
                     binding.span,
                     format!("{} `{}` is private", assoc_item.kind, binding.item_name),
                 )
                 .with_span_label(binding.span, format!("private {}", assoc_item.kind))
                 .emit();
+            self.set_tainted_by_errors(reported);
         }
         tcx.check_stability(assoc_item.def_id, Some(hir_ref_id), binding.span, None);
 

compiler/rustc_hir_analysis/src/astconv/errors.rs

@@ -354,7 +354,9 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         );
         err.span_label(name.span, format!("multiple `{name}` found"));
         self.note_ambiguous_inherent_assoc_type(&mut err, candidates, span);
-        err.emit()
+        let reported = err.emit();
+        self.set_tainted_by_errors(reported);
+        reported
     }
 
     // FIXME(fmease): Heavily adapted from `rustc_hir_typeck::method::suggest`. Deduplicate.
@@ -843,7 +845,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             }
         }
 
-        err.emit();
+        self.set_tainted_by_errors(err.emit());
     }
 }
 

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -389,6 +389,12 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             infer_args,
         );
 
+        if let Err(err) = &arg_count.correct
+            && let Some(reported) = err.reported
+        {
+            self.set_tainted_by_errors(reported);
+        }
+
         // Skip processing if type has no generic parameters.
         // Traits always have `Self` as a generic parameter, which means they will not return early
         // here and so associated type bindings will be handled regardless of whether there are any
@@ -567,6 +573,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 span,
                 modifier: constness.as_str(),
             });
+            self.set_tainted_by_errors(e);
             arg_count.correct =
                 Err(GenericArgCountMismatch { reported: Some(e), invalid_args: vec![] });
         }
@@ -965,7 +972,9 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 }
             }
         }
-        err.emit()
+        let reported = err.emit();
+        self.set_tainted_by_errors(reported);
+        reported
     }
 
     // Search for a bound on a type parameter which includes the associated item
@@ -1042,6 +1051,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 span,
                 binding,
             );
+            self.set_tainted_by_errors(reported);
             return Err(reported);
         };
         debug!(?bound);
@@ -1119,6 +1129,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 ));
             }
             let reported = err.emit();
+            self.set_tainted_by_errors(reported);
             if !where_bounds.is_empty() {
                 return Err(reported);
             }
@@ -1373,6 +1384,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         assoc_ident.name,
                     )
                 };
+                self.set_tainted_by_errors(reported);
                 return Err(reported);
             }
         };
@@ -1615,12 +1627,14 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             let kind = tcx.def_kind_descr(kind, item);
             let msg = format!("{kind} `{name}` is private");
             let def_span = tcx.def_span(item);
-            tcx.dcx()
+            let reported = tcx
+                .dcx()
                 .struct_span_err(span, msg)
                 .with_code(rustc_errors::error_code!(E0624))
                 .with_span_label(span, format!("private {kind}"))
                 .with_span_label(def_span, format!("{kind} defined here"))
                 .emit();
+            self.set_tainted_by_errors(reported);
         }
         tcx.check_stability(item, Some(block), span, None);
     }
@@ -1861,7 +1875,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 err.span_label(span, format!("not allowed on {what}"));
             }
             extend(&mut err);
-            err.emit();
+            self.set_tainted_by_errors(err.emit());
             emitted = true;
         }
 
@@ -2183,7 +2197,9 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     {
                         err.span_note(impl_.self_ty.span, "not a concrete type");
                     }
-                    Ty::new_error(tcx, err.emit())
+                    let reported = err.emit();
+                    self.set_tainted_by_errors(reported);
+                    Ty::new_error(tcx, reported)
                 } else {
                     ty
                 }
@@ -2702,7 +2718,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 );
             }
 
-            diag.emit();
+            self.set_tainted_by_errors(diag.emit());
         }
 
         // Find any late-bound regions declared in return type that do
@@ -2802,7 +2818,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 err.note("consider introducing a named lifetime parameter");
             }
 
-            err.emit();
+            self.set_tainted_by_errors(err.emit());
         }
     }
 
@@ -2841,7 +2857,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         // error.
         let r = derived_region_bounds[0];
         if derived_region_bounds[1..].iter().any(|r1| r != *r1) {
-            tcx.dcx().emit_err(AmbiguousLifetimeBound { span });
+            self.set_tainted_by_errors(tcx.dcx().emit_err(AmbiguousLifetimeBound { span }));
         }
         Some(r)
     }

compiler/rustc_hir_analysis/src/astconv/object_safety.rs

@@ -116,7 +116,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
              for more information on them, visit \
              <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>",
             );
-            err.emit();
+            self.set_tainted_by_errors(err.emit());
         }
 
         if regular_traits.is_empty() && auto_traits.is_empty() {
@@ -127,6 +127,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 .map(|trait_ref| tcx.def_span(trait_ref));
             let reported =
                 tcx.dcx().emit_err(TraitObjectDeclaredWithNoTraits { span, trait_alias_span });
+            self.set_tainted_by_errors(reported);
             return Ty::new_error(tcx, reported);
         }
 
@@ -290,7 +291,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
                 if references_self {
                     let def_id = i.bottom().0.def_id();
-                    struct_span_code_err!(
+                    let reported = struct_span_code_err!(
                         tcx.dcx(),
                         i.bottom().1,
                         E0038,
@@ -303,6 +304,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             .error_msg(),
                     )
                     .emit();
+                    self.set_tainted_by_errors(reported);
                 }
 
                 ty::ExistentialTraitRef { def_id: trait_ref.def_id, args }
@@ -389,6 +391,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         } else {
                             err.emit()
                         };
+                        self.set_tainted_by_errors(e);
                         ty::Region::new_error(tcx, e)
                     })
                 }

compiler/rustc_hir_analysis/src/collect.rs

@@ -35,6 +35,7 @@ use rustc_target::spec::abi;
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::error_reporting::suggestions::NextTypeParamName;
 use rustc_trait_selection::traits::ObligationCtxt;
+use std::cell::Cell;
 use std::iter;
 use std::ops::Bound;
 
@@ -119,6 +120,7 @@ pub fn provide(providers: &mut Providers) {
 pub struct ItemCtxt<'tcx> {
     tcx: TyCtxt<'tcx>,
     item_def_id: LocalDefId,
+    tainted_by_errors: Cell<Option<ErrorGuaranteed>>,
 }
 
 ///////////////////////////////////////////////////////////////////////////
@@ -343,7 +345,7 @@ fn bad_placeholder<'tcx>(
 
 impl<'tcx> ItemCtxt<'tcx> {
     pub fn new(tcx: TyCtxt<'tcx>, item_def_id: LocalDefId) -> ItemCtxt<'tcx> {
-        ItemCtxt { tcx, item_def_id }
+        ItemCtxt { tcx, item_def_id, tainted_by_errors: Cell::new(None) }
     }
 
     pub fn to_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> {
@@ -357,6 +359,13 @@ impl<'tcx> ItemCtxt<'tcx> {
     pub fn node(&self) -> hir::Node<'tcx> {
         self.tcx.hir_node(self.hir_id())
     }
+
+    fn check_tainted_by_errors(&self) -> Result<(), ErrorGuaranteed> {
+        match self.tainted_by_errors.get() {
+            Some(err) => Err(err),
+            None => Ok(()),
+        }
+    }
 }
 
 impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx> {
@@ -492,8 +501,8 @@ impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx> {
         ty.ty_adt_def()
     }
 
-    fn set_tainted_by_errors(&self, _: ErrorGuaranteed) {
-        // There's no obvious place to track this, so just let it go.
+    fn set_tainted_by_errors(&self, err: ErrorGuaranteed) {
+        self.tainted_by_errors.set(Some(err));
     }
 
     fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) {

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -513,7 +513,11 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<Ty
             bug!("unexpected sort of node in type_of(): {:?}", x);
         }
     };
-    ty::EarlyBinder::bind(output)
+    if let Err(e) = icx.check_tainted_by_errors() {
+        ty::EarlyBinder::bind(Ty::new_error(tcx, e))
+    } else {
+        ty::EarlyBinder::bind(output)
+    }
 }
 
 pub(super) fn type_of_opaque(

compiler/rustc_hir_typeck/src/closure.rs

@@ -802,7 +802,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .explicit_item_bounds(def_id)
                 .iter_instantiated_copied(self.tcx, args)
                 .find_map(|(p, s)| get_future_output(p.as_predicate(), s))?,
-            ty::Error(_) => return None,
+            ty::Error(_) => return Some(ret_ty),
             _ => span_bug!(
                 closure_span,
                 "async fn coroutine return type not an inference variable: {ret_ty}"

tests/rustdoc-ui/unable-fulfill-trait.rs

@@ -4,7 +4,6 @@ pub struct Foo<'a, 'b, T> {
     field1: dyn Bar<'a, 'b,>,
     //~^ ERROR
     //~| ERROR
-    //~| ERROR
 }
 
 pub trait Bar<'x, 's, U>

tests/rustdoc-ui/unable-fulfill-trait.stderr

@@ -5,7 +5,7 @@ LL |     field1: dyn Bar<'a, 'b,>,
    |                 ^^^ expected 1 generic argument
    |
 note: trait defined here, with 1 generic parameter: `U`
-  --> $DIR/unable-fulfill-trait.rs:10:11
+  --> $DIR/unable-fulfill-trait.rs:9:11
    |
 LL | pub trait Bar<'x, 's, U>
    |           ^^^         -
@@ -20,24 +20,7 @@ error[E0227]: ambiguous lifetime bound, explicit lifetime bound required
 LL |     field1: dyn Bar<'a, 'b,>,
    |             ^^^^^^^^^^^^^^^^
 
-error[E0478]: lifetime bound not satisfied
-  --> $DIR/unable-fulfill-trait.rs:4:13
-   |
-LL |     field1: dyn Bar<'a, 'b,>,
-   |             ^^^^^^^^^^^^^^^^
-   |
-note: lifetime parameter instantiated with the lifetime `'b` as defined here
-  --> $DIR/unable-fulfill-trait.rs:3:20
-   |
-LL | pub struct Foo<'a, 'b, T> {
-   |                    ^^
-note: but lifetime parameter must outlive the lifetime `'a` as defined here
-  --> $DIR/unable-fulfill-trait.rs:3:16
-   |
-LL | pub struct Foo<'a, 'b, T> {
-   |                ^^
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0107, E0227, E0478.
+Some errors have detailed explanations: E0107, E0227.
 For more information about an error, try `rustc --explain E0107`.

tests/ui/associated-inherent-types/issue-109071.no_gate.stderr

@@ -30,7 +30,7 @@ LL |     type Item = &[T];
    = help: add `#![feature(inherent_associated_types)]` to the crate attributes to enable
 
 error[E0223]: ambiguous associated type
-  --> $DIR/issue-109071.rs:16:22
+  --> $DIR/issue-109071.rs:15:22
    |
 LL |     fn T() -> Option<Self::Item> {}
    |                      ^^^^^^^^^^