Auto merge of #121055 - matthiaskrgr:rollup-bzn5sda, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #118882 (Check normalized call signature for WF in mir typeck)
 - #120999 (rustdoc: replace `clean::InstantiationParam` with `clean::GenericArg`)
 - #121002 (remove unnecessary calls to `commit_if_ok`)
 - #121005 (Remove jsha from the rustdoc review rotation)
 - #121014 (Remove `force_print_diagnostic`)
 - #121043 (add lcnr to the compiler-team assignment group)
 - #121046 (Fix incorrect use of `compile_fail`)
 - #121047 (Do not assemble candidates for default impls)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1432,7 +1432,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         return;
                     }
                 };
-                let (sig, map) = tcx.instantiate_bound_regions(sig, |br| {
+                let (unnormalized_sig, map) = tcx.instantiate_bound_regions(sig, |br| {
                     use crate::renumber::RegionCtxt;
 
                     let region_ctxt_fn = || {
@@ -1454,7 +1454,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         region_ctxt_fn,
                     )
                 });
-                debug!(?sig);
+                debug!(?unnormalized_sig);
                 // IMPORTANT: We have to prove well formed for the function signature before
                 // we normalize it, as otherwise types like `<&'a &'b () as Trait>::Assoc`
                 // get normalized away, causing us to ignore the `'b: 'a` bound used by the function.
@@ -1464,7 +1464,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 //
                 // See #91068 for an example.
                 self.prove_predicates(
-                    sig.inputs_and_output.iter().map(|ty| {
+                    unnormalized_sig.inputs_and_output.iter().map(|ty| {
                         ty::Binder::dummy(ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(
                             ty.into(),
                         )))
@@ -1472,7 +1472,23 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                     term_location.to_locations(),
                     ConstraintCategory::Boring,
                 );
-                let sig = self.normalize(sig, term_location);
+
+                let sig = self.normalize(unnormalized_sig, term_location);
+                // HACK(#114936): `WF(sig)` does not imply `WF(normalized(sig))`
+                // with built-in `Fn` implementations, since the impl may not be
+                // well-formed itself.
+                if sig != unnormalized_sig {
+                    self.prove_predicates(
+                        sig.inputs_and_output.iter().map(|ty| {
+                            ty::Binder::dummy(ty::PredicateKind::Clause(
+                                ty::ClauseKind::WellFormed(ty.into()),
+                            ))
+                        }),
+                        term_location.to_locations(),
+                        ConstraintCategory::Boring,
+                    );
+                }
+
                 self.check_call_dest(body, term, &sig, *destination, *target, term_location);
 
                 // The ordinary liveness rules will ensure that all

compiler/rustc_errors/src/lib.rs

@@ -78,6 +78,7 @@ use std::fmt;
 use std::hash::Hash;
 use std::io::Write;
 use std::num::NonZeroUsize;
+use std::ops::DerefMut;
 use std::panic;
 use std::path::{Path, PathBuf};
 
@@ -666,22 +667,51 @@ impl DiagCtxt {
     /// tools that want to reuse a `Parser` cleaning the previously emitted diagnostics as well as
     /// the overall count of emitted error diagnostics.
     pub fn reset_err_count(&self) {
+        // Use destructuring so that if a field gets added to `DiagCtxtInner`, it's impossible to
+        // fail to update this method as well.
         let mut inner = self.inner.borrow_mut();
-        inner.stashed_err_count = 0;
+        let DiagCtxtInner {
-        inner.deduplicated_err_count = 0;
+            flags: _,
-        inner.deduplicated_warn_count = 0;
+            err_guars,
-        inner.must_produce_diag = false;
+            lint_err_guars,
-        inner.has_printed = false;
+            delayed_bugs,
-        inner.suppressed_expected_diag = false;
+            stashed_err_count,
+            deduplicated_err_count,
+            deduplicated_warn_count,
+            emitter: _,
+            must_produce_diag,
+            has_printed,
+            suppressed_expected_diag,
+            taught_diagnostics,
+            emitted_diagnostic_codes,
+            emitted_diagnostics,
+            stashed_diagnostics,
+            future_breakage_diagnostics,
+            check_unstable_expect_diagnostics,
+            unstable_expect_diagnostics,
+            fulfilled_expectations,
+            ice_file: _,
+        } = inner.deref_mut();
 
-        // actually free the underlying memory (which `clear` would not do)
+        // For the `Vec`s and `HashMap`s, we overwrite with an empty container to free the
-        inner.err_guars = Default::default();
+        // underlying memory (which `clear` would not do).
-        inner.lint_err_guars = Default::default();
+        *err_guars = Default::default();
-        inner.delayed_bugs = Default::default();
+        *lint_err_guars = Default::default();
-        inner.taught_diagnostics = Default::default();
+        *delayed_bugs = Default::default();
-        inner.emitted_diagnostic_codes = Default::default();
+        *stashed_err_count = 0;
-        inner.emitted_diagnostics = Default::default();
+        *deduplicated_err_count = 0;
-        inner.stashed_diagnostics = Default::default();
+        *deduplicated_warn_count = 0;
+        *must_produce_diag = false;
+        *has_printed = false;
+        *suppressed_expected_diag = false;
+        *taught_diagnostics = Default::default();
+        *emitted_diagnostic_codes = Default::default();
+        *emitted_diagnostics = Default::default();
+        *stashed_diagnostics = Default::default();
+        *future_breakage_diagnostics = Default::default();
+        *check_unstable_expect_diagnostics = false;
+        *unstable_expect_diagnostics = Default::default();
+        *fulfilled_expectations = Default::default();
     }
 
     /// Stash a given diagnostic with the given `Span` and [`StashKey`] as the key.
@@ -780,11 +810,12 @@ impl DiagCtxt {
         match (errors.len(), warnings.len()) {
             (0, 0) => return,
             (0, _) => {
-                // Use `inner.emitter` directly, otherwise the warning might not be emitted, e.g.
+                // Use `ForceWarning` rather than `Warning` to guarantee emission, e.g. with a
-                // with a configuration like `--cap-lints allow --force-warn bare_trait_objects`.
+                // configuration like `--cap-lints allow --force-warn bare_trait_objects`.
-                inner
+                inner.emit_diagnostic(Diagnostic::new(
-                    .emitter
+                    ForceWarning(None),
-                    .emit_diagnostic(Diagnostic::new(Warning, DiagnosticMessage::Str(warnings)));
+                    DiagnosticMessage::Str(warnings),
+                ));
             }
             (_, 0) => {
                 inner.emit_diagnostic(Diagnostic::new(Error, errors));
@@ -812,20 +843,23 @@ impl DiagCtxt {
                 error_codes.sort();
                 if error_codes.len() > 1 {
                     let limit = if error_codes.len() > 9 { 9 } else { error_codes.len() };
-                    inner.failure_note(format!(
+                    let msg1 = format!(
                         "Some errors have detailed explanations: {}{}",
                         error_codes[..limit].join(", "),
                         if error_codes.len() > 9 { "..." } else { "." }
-                    ));
+                    );
-                    inner.failure_note(format!(
+                    let msg2 = format!(
                         "For more information about an error, try `rustc --explain {}`.",
                         &error_codes[0]
-                    ));
+                    );
+                    inner.emit_diagnostic(Diagnostic::new(FailureNote, msg1));
+                    inner.emit_diagnostic(Diagnostic::new(FailureNote, msg2));
                 } else {
-                    inner.failure_note(format!(
+                    let msg = format!(
                         "For more information about this error, try `rustc --explain {}`.",
                         &error_codes[0]
-                    ));
+                    );
+                    inner.emit_diagnostic(Diagnostic::new(FailureNote, msg));
                 }
             }
         }
@@ -848,10 +882,6 @@ impl DiagCtxt {
         self.inner.borrow_mut().taught_diagnostics.insert(code)
     }
 
-    pub fn force_print_diagnostic(&self, db: Diagnostic) {
-        self.inner.borrow_mut().emitter.emit_diagnostic(db);
-    }
-
     pub fn emit_diagnostic(&self, diagnostic: Diagnostic) -> Option<ErrorGuaranteed> {
         self.inner.borrow_mut().emit_diagnostic(diagnostic)
     }
@@ -1179,7 +1209,7 @@ impl DiagCtxt {
         span: impl Into<MultiSpan>,
         msg: impl Into<DiagnosticMessage>,
     ) -> DiagnosticBuilder<'_, ()> {
-        DiagnosticBuilder::new(self, Note, msg).with_span(span)
+        self.struct_note(msg).with_span(span)
     }
 
     #[rustc_lint_diagnostics]
@@ -1207,6 +1237,15 @@ impl DiagCtxt {
         DiagnosticBuilder::new(self, Help, msg)
     }
 
+    #[rustc_lint_diagnostics]
+    #[track_caller]
+    pub fn struct_failure_note(
+        &self,
+        msg: impl Into<DiagnosticMessage>,
+    ) -> DiagnosticBuilder<'_, ()> {
+        DiagnosticBuilder::new(self, FailureNote, msg)
+    }
+
     #[rustc_lint_diagnostics]
     #[track_caller]
     pub fn struct_allow(&self, msg: impl Into<DiagnosticMessage>) -> DiagnosticBuilder<'_, ()> {
@@ -1406,10 +1445,6 @@ impl DiagCtxtInner {
             .or_else(|| self.delayed_bugs.get(0).map(|(_, guar)| guar).copied())
     }
 
-    fn failure_note(&mut self, msg: impl Into<DiagnosticMessage>) {
-        self.emit_diagnostic(Diagnostic::new(FailureNote, msg));
-    }
-
     fn flush_delayed(&mut self) {
         if self.delayed_bugs.is_empty() {
             return;

compiler/rustc_infer/src/infer/at.rs

@@ -285,13 +285,11 @@ impl<'a, 'tcx> Trace<'a, 'tcx> {
         T: Relate<'tcx>,
     {
         let Trace { at, trace, a_is_expected } = self;
-        at.infcx.commit_if_ok(|_| {
         let mut fields = at.infcx.combine_fields(trace, at.param_env, define_opaque_types);
         fields
             .sub(a_is_expected)
             .relate(a, b)
             .map(move |_| InferOk { value: (), obligations: fields.obligations })
-        })
     }
 
     /// Makes `a == b`; the expectation is set by the call to
@@ -302,13 +300,11 @@ impl<'a, 'tcx> Trace<'a, 'tcx> {
         T: Relate<'tcx>,
     {
         let Trace { at, trace, a_is_expected } = self;
-        at.infcx.commit_if_ok(|_| {
         let mut fields = at.infcx.combine_fields(trace, at.param_env, define_opaque_types);
         fields
             .equate(a_is_expected)
             .relate(a, b)
             .map(move |_| InferOk { value: (), obligations: fields.obligations })
-        })
     }
 
     #[instrument(skip(self), level = "debug")]
@@ -317,13 +313,11 @@ impl<'a, 'tcx> Trace<'a, 'tcx> {
         T: Relate<'tcx>,
     {
         let Trace { at, trace, a_is_expected } = self;
-        at.infcx.commit_if_ok(|_| {
         let mut fields = at.infcx.combine_fields(trace, at.param_env, define_opaque_types);
         fields
             .lub(a_is_expected)
             .relate(a, b)
             .map(move |t| InferOk { value: t, obligations: fields.obligations })
-        })
     }
 
     #[instrument(skip(self), level = "debug")]
@@ -332,13 +326,11 @@ impl<'a, 'tcx> Trace<'a, 'tcx> {
         T: Relate<'tcx>,
     {
         let Trace { at, trace, a_is_expected } = self;
-        at.infcx.commit_if_ok(|_| {
         let mut fields = at.infcx.combine_fields(trace, at.param_env, define_opaque_types);
         fields
             .glb(a_is_expected)
             .relate(a, b)
             .map(move |t| InferOk { value: t, obligations: fields.obligations })
-        })
     }
 }
 

compiler/rustc_infer/src/infer/canonical/query_response.rs

@@ -620,7 +620,6 @@ impl<'tcx> InferCtxt<'tcx> {
         variables1: &OriginalQueryValues<'tcx>,
         variables2: impl Fn(BoundVar) -> GenericArg<'tcx>,
     ) -> InferResult<'tcx, ()> {
-        self.commit_if_ok(|_| {
         let mut obligations = vec![];
         for (index, value1) in variables1.var_values.iter().enumerate() {
             let value2 = variables2(BoundVar::new(index));
@@ -655,7 +654,6 @@ impl<'tcx> InferCtxt<'tcx> {
             }
         }
         Ok(InferOk { value: (), obligations })
-        })
     }
 }
 

compiler/rustc_query_system/src/query/job.rs

@@ -4,7 +4,7 @@ use crate::query::plumbing::CycleError;
 use crate::query::DepKind;
 use crate::query::{QueryContext, QueryStackFrame};
 use rustc_data_structures::fx::FxHashMap;
-use rustc_errors::{DiagCtxt, Diagnostic, DiagnosticBuilder, Level};
+use rustc_errors::{DiagCtxt, DiagnosticBuilder};
 use rustc_hir::def::DefKind;
 use rustc_session::Session;
 use rustc_span::Span;
@@ -628,15 +628,15 @@ pub fn print_query_stack<Qcx: QueryContext>(
         };
         if Some(count_printed) < num_frames || num_frames.is_none() {
             // Only print to stderr as many stack frames as `num_frames` when present.
-            let mut diag = Diagnostic::new(
+            // FIXME: needs translation
-                Level::FailureNote,
+            #[allow(rustc::diagnostic_outside_of_impl)]
-                format!(
+            #[allow(rustc::untranslatable_diagnostic)]
+            dcx.struct_failure_note(format!(
                 "#{} [{:?}] {}",
                 count_printed, query_info.query.dep_kind, query_info.query.description
-                ),
+            ))
-            );
+            .with_span(query_info.job.span)
-            diag.span = query_info.job.span.into();
+            .emit();
-            dcx.force_print_diagnostic(diag);
             count_printed += 1;
         }
 

compiler/rustc_trait_selection/src/solve/assembly/mod.rs

@@ -337,6 +337,13 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         let mut consider_impls_for_simplified_type = |simp| {
             if let Some(impls_for_type) = trait_impls.non_blanket_impls().get(&simp) {
                 for &impl_def_id in impls_for_type {
+                    // For every `default impl`, there's always a non-default `impl`
+                    // that will *also* apply. There's no reason to register a candidate
+                    // for this impl, since it is *not* proof that the trait goal holds.
+                    if tcx.defaultness(impl_def_id).is_default() {
+                        return;
+                    }
+
                     match G::consider_impl_candidate(self, goal, impl_def_id) {
                         Ok(candidate) => candidates.push(candidate),
                         Err(NoSolution) => (),
@@ -440,6 +447,13 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         let tcx = self.tcx();
         let trait_impls = tcx.trait_impls_of(goal.predicate.trait_def_id(tcx));
         for &impl_def_id in trait_impls.blanket_impls() {
+            // For every `default impl`, there's always a non-default `impl`
+            // that will *also* apply. There's no reason to register a candidate
+            // for this impl, since it is *not* proof that the trait goal holds.
+            if tcx.defaultness(impl_def_id).is_default() {
+                return;
+            }
+
             match G::consider_impl_candidate(self, goal, impl_def_id) {
                 Ok(candidate) => candidates.push(candidate),
                 Err(NoSolution) => (),

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -566,6 +566,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 {
                     return;
                 }
+
+                // For every `default impl`, there's always a non-default `impl`
+                // that will *also* apply. There's no reason to register a candidate
+                // for this impl, since it is *not* proof that the trait goal holds.
+                if self.tcx().defaultness(impl_def_id).is_default() {
+                    return;
+                }
+
                 if self.reject_fn_ptr_impls(
                     impl_def_id,
                     obligation,

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -192,13 +192,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             &mut obligations,
         );
 
-        obligations.extend(self.infcx.commit_if_ok(|_| {
+        obligations.extend(
             self.infcx
                 .at(&obligation.cause, obligation.param_env)
                 .sup(DefineOpaqueTypes::No, placeholder_trait_predicate, candidate)
                 .map(|InferOk { obligations, .. }| obligations)
-                .map_err(|_| Unimplemented)
+                .map_err(|_| Unimplemented)?,
-        })?);
+        );
 
         // FIXME(compiler-errors): I don't think this is needed.
         if let ty::Alias(ty::Projection, alias_ty) = placeholder_self_ty.kind() {
@@ -532,13 +532,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             &mut nested,
         );
 
-        nested.extend(self.infcx.commit_if_ok(|_| {
+        nested.extend(
             self.infcx
                 .at(&obligation.cause, obligation.param_env)
                 .sup(DefineOpaqueTypes::No, obligation_trait_ref, upcast_trait_ref)
                 .map(|InferOk { obligations, .. }| obligations)
-                .map_err(|_| Unimplemented)
+                .map_err(|_| Unimplemented)?,
-        })?);
+        );
 
         // Check supertraits hold. This is so that their associated type bounds
         // will be checked in the code below.

library/std/src/process.rs

@@ -171,7 +171,7 @@ pub struct Child {
     /// The handle for writing to the child's standard input (stdin), if it
     /// has been captured. You might find it helpful to do
     ///
-    /// ```compile_fail,E0425
+    /// ```ignore (incomplete)
     /// let stdin = child.stdin.take().unwrap();
     /// ```
     ///
@@ -183,7 +183,7 @@ pub struct Child {
     /// The handle for reading from the child's standard output (stdout), if it
     /// has been captured. You might find it helpful to do
     ///
-    /// ```compile_fail,E0425
+    /// ```ignore (incomplete)
     /// let stdout = child.stdout.take().unwrap();
     /// ```
     ///
@@ -195,7 +195,7 @@ pub struct Child {
     /// The handle for reading from the child's standard error (stderr), if it
     /// has been captured. You might find it helpful to do
     ///
-    /// ```compile_fail,E0425
+    /// ```ignore (incomplete)
     /// let stderr = child.stderr.take().unwrap();
     /// ```
     ///

src/librustdoc/clean/mod.rs

@@ -254,16 +254,14 @@ fn clean_poly_trait_ref_with_bindings<'tcx>(
 }
 
 fn clean_lifetime<'tcx>(lifetime: &hir::Lifetime, cx: &mut DocContext<'tcx>) -> Lifetime {
-    let def = cx.tcx.named_bound_var(lifetime.hir_id);
     if let Some(
-        rbv::ResolvedArg::EarlyBound(node_id)
+        rbv::ResolvedArg::EarlyBound(did)
-        | rbv::ResolvedArg::LateBound(_, _, node_id)
+        | rbv::ResolvedArg::LateBound(_, _, did)
-        | rbv::ResolvedArg::Free(_, node_id),
+        | rbv::ResolvedArg::Free(_, did),
-    ) = def
+    ) = cx.tcx.named_bound_var(lifetime.hir_id)
+        && let Some(lt) = cx.args.get(&did).and_then(|arg| arg.as_lt())
     {
-        if let Some(lt) = cx.args.get(&node_id).and_then(|p| p.as_lt()).cloned() {
+        return lt.clone();
-            return lt;
-        }
     }
     Lifetime(lifetime.ident.name)
 }
@@ -1791,12 +1789,12 @@ fn maybe_expand_private_type_alias<'tcx>(
                     _ => None,
                 });
                 if let Some(lt) = lifetime {
-                    let cleaned = if !lt.is_anonymous() {
+                    let lt = if !lt.is_anonymous() {
                         clean_lifetime(lt, cx)
                     } else {
                         Lifetime::elided()
                     };
-                    args.insert(param.def_id.to_def_id(), InstantiationParam::Lifetime(cleaned));
+                    args.insert(param.def_id.to_def_id(), GenericArg::Lifetime(lt));
                 }
                 indices.lifetimes += 1;
             }
@@ -1805,44 +1803,20 @@ fn maybe_expand_private_type_alias<'tcx>(
                 let type_ = generic_args.args.iter().find_map(|arg| match arg {
                     hir::GenericArg::Type(ty) => {
                         if indices.types == j {
-                            return Some(ty);
+                            return Some(*ty);
                         }
                         j += 1;
                         None
                     }
                     _ => None,
                 });
-                if let Some(ty) = type_ {
+                if let Some(ty) = type_.or(*default) {
-                    args.insert(
+                    args.insert(param.def_id.to_def_id(), GenericArg::Type(clean_ty(ty, cx)));
-                        param.def_id.to_def_id(),
-                        InstantiationParam::Type(clean_ty(ty, cx)),
-                    );
-                } else if let Some(default) = *default {
-                    args.insert(
-                        param.def_id.to_def_id(),
-                        InstantiationParam::Type(clean_ty(default, cx)),
-                    );
                 }
                 indices.types += 1;
             }
-            hir::GenericParamKind::Const { .. } => {
+            // FIXME(#82852): Instantiate const parameters.
-                let mut j = 0;
+            hir::GenericParamKind::Const { .. } => {}
-                let const_ = generic_args.args.iter().find_map(|arg| match arg {
-                    hir::GenericArg::Const(ct) => {
-                        if indices.consts == j {
-                            return Some(ct);
-                        }
-                        j += 1;
-                        None
-                    }
-                    _ => None,
-                });
-                if let Some(_) = const_ {
-                    args.insert(param.def_id.to_def_id(), InstantiationParam::Constant);
-                }
-                // FIXME(const_generics_defaults)
-                indices.consts += 1;
-            }
         }
     }
 

src/librustdoc/clean/types.rs

@@ -2228,6 +2228,16 @@ pub(crate) enum GenericArg {
     Infer,
 }
 
+impl GenericArg {
+    pub(crate) fn as_lt(&self) -> Option<&Lifetime> {
+        if let Self::Lifetime(lt) = self { Some(lt) } else { None }
+    }
+
+    pub(crate) fn as_ty(&self) -> Option<&Type> {
+        if let Self::Type(ty) = self { Some(ty) } else { None }
+    }
+}
+
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub(crate) enum GenericArgs {
     AngleBracketed { args: Box<[GenericArg]>, bindings: ThinVec<TypeBinding> },
@@ -2530,35 +2540,6 @@ pub(crate) enum TypeBindingKind {
     Constraint { bounds: Vec<GenericBound> },
 }
 
-/// The type, lifetime, or constant that a private type alias's parameter should be
-/// replaced with when expanding a use of that type alias.
-///
-/// For example:
-///
-/// ```
-/// type PrivAlias<T> = Vec<T>;
-///
-/// pub fn public_fn() -> PrivAlias<i32> { vec![] }
-/// ```
-///
-/// `public_fn`'s docs will show it as returning `Vec<i32>`, since `PrivAlias` is private.
-/// [`InstantiationParam`] is used to record that `T` should be mapped to `i32`.
-pub(crate) enum InstantiationParam {
-    Type(Type),
-    Lifetime(Lifetime),
-    Constant,
-}
-
-impl InstantiationParam {
-    pub(crate) fn as_ty(&self) -> Option<&Type> {
-        if let Self::Type(ty) = self { Some(ty) } else { None }
-    }
-
-    pub(crate) fn as_lt(&self) -> Option<&Lifetime> {
-        if let Self::Lifetime(lt) = self { Some(lt) } else { None }
-    }
-}
-
 // Some nodes are used a lot. Make sure they don't unintentionally get bigger.
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 mod size_asserts {

src/librustdoc/core.rs

@@ -44,10 +44,13 @@ pub(crate) struct DocContext<'tcx> {
     /// Used while populating `external_traits` to ensure we don't process the same trait twice at
     /// the same time.
     pub(crate) active_extern_traits: DefIdSet,
-    // The current set of parameter instantiations,
+    /// The current set of parameter instantiations for expanding type aliases at the HIR level.
-    // for expanding type aliases at the HIR level:
+    ///
-    /// Table `DefId` of type, lifetime, or const parameter -> instantiated type, lifetime, or const
+    /// Maps from the `DefId` of a lifetime or type parameter to the
-    pub(crate) args: DefIdMap<clean::InstantiationParam>,
+    /// generic argument it's currently instantiated to in this context.
+    // FIXME(#82852): We don't record const params since we don't visit const exprs at all and
+    // therefore wouldn't use the corresp. generic arg anyway. Add support for them.
+    pub(crate) args: DefIdMap<clean::GenericArg>,
     pub(crate) current_type_aliases: DefIdMap<usize>,
     /// Table synthetic type parameter for `impl Trait` in argument position -> bounds
     pub(crate) impl_trait_bounds: FxHashMap<ImplTraitParam, Vec<clean::GenericBound>>,
@@ -87,7 +90,7 @@ impl<'tcx> DocContext<'tcx> {
     /// the generic parameters for a type alias' RHS.
     pub(crate) fn enter_alias<F, R>(
         &mut self,
-        args: DefIdMap<clean::InstantiationParam>,
+        args: DefIdMap<clean::GenericArg>,
         def_id: DefId,
         f: F,
     ) -> R

tests/ui/closure-expected-type/expect-infer-var-appearing-twice.stderr

@@ -9,8 +9,8 @@ LL | |
 LL | |     });
    | |______^ expected due to this
    |
-   = note: expected closure signature `fn(_, _) -> _`
+   = note: expected closure signature `fn(_, u32) -> _`
-              found closure signature `fn(u32, i32) -> _`
+              found closure signature `fn(_, i32) -> _`
 note: required by a bound in `with_closure`
   --> $DIR/expect-infer-var-appearing-twice.rs:2:14
    |

tests/ui/nll/check-normalized-sig-for-wf.rs

@@ -0,0 +1,27 @@
+// <https://github.com/rust-lang/rust/issues/114936>
+fn whoops(
+    s: String,
+    f: impl for<'s> FnOnce(&'s str) -> (&'static str, [&'static &'s (); 0]),
+) -> &'static str
+{
+    f(&s).0
+    //~^ ERROR `s` does not live long enough
+}
+
+// <https://github.com/rust-lang/rust/issues/118876>
+fn extend<T>(input: &T) -> &'static T {
+    struct Bounded<'a, 'b: 'static, T>(&'a T, [&'b (); 0]);
+    let n: Box<dyn FnOnce(&T) -> Bounded<'static, '_, T>> = Box::new(|x| Bounded(x, []));
+    n(input).0
+    //~^ ERROR borrowed data escapes outside of function
+}
+
+// <https://github.com/rust-lang/rust/issues/118876>
+fn extend_mut<'a, T>(input: &'a mut T) -> &'static mut T {
+    struct Bounded<'a, 'b: 'static, T>(&'a mut T, [&'b (); 0]);
+    let mut n: Box<dyn FnMut(&mut T) -> Bounded<'static, '_, T>> = Box::new(|x| Bounded(x, []));
+    n(input).0
+    //~^ ERROR borrowed data escapes outside of function
+}
+
+fn main() {}

tests/ui/nll/check-normalized-sig-for-wf.stderr

@@ -0,0 +1,47 @@
+error[E0597]: `s` does not live long enough
+  --> $DIR/check-normalized-sig-for-wf.rs:7:7
+   |
+LL |     s: String,
+   |     - binding `s` declared here
+...
+LL |     f(&s).0
+   |     --^^-
+   |     | |
+   |     | borrowed value does not live long enough
+   |     argument requires that `s` is borrowed for `'static`
+LL |
+LL | }
+   | - `s` dropped here while still borrowed
+
+error[E0521]: borrowed data escapes outside of function
+  --> $DIR/check-normalized-sig-for-wf.rs:15:5
+   |
+LL | fn extend<T>(input: &T) -> &'static T {
+   |              -----  - let's call the lifetime of this reference `'1`
+   |              |
+   |              `input` is a reference that is only valid in the function body
+...
+LL |     n(input).0
+   |     ^^^^^^^^
+   |     |
+   |     `input` escapes the function body here
+   |     argument requires that `'1` must outlive `'static`
+
+error[E0521]: borrowed data escapes outside of function
+  --> $DIR/check-normalized-sig-for-wf.rs:23:5
+   |
+LL | fn extend_mut<'a, T>(input: &'a mut T) -> &'static mut T {
+   |               --     ----- `input` is a reference that is only valid in the function body
+   |               |
+   |               lifetime `'a` defined here
+...
+LL |     n(input).0
+   |     ^^^^^^^^
+   |     |
+   |     `input` escapes the function body here
+   |     argument requires that `'a` must outlive `'static`
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0521, E0597.
+For more information about an error, try `rustc --explain E0521`.

tests/ui/specialization/defaultimpl/specialization-trait-not-implemented.rs

@@ -20,5 +20,5 @@ default impl<T> Foo for T {
 
 fn main() {
     println!("{}", MyStruct.foo_one());
-    //~^ ERROR the method
+    //~^ ERROR no method named `foo_one` found for struct `MyStruct` in the current scope
 }

tests/ui/specialization/defaultimpl/specialization-trait-not-implemented.stderr

@@ -8,27 +8,15 @@ LL | #![feature(specialization)]
    = help: consider using `min_specialization` instead, which is more stable and complete
    = note: `#[warn(incomplete_features)]` on by default
 
-error[E0599]: the method `foo_one` exists for struct `MyStruct`, but its trait bounds were not satisfied
+error[E0599]: no method named `foo_one` found for struct `MyStruct` in the current scope
   --> $DIR/specialization-trait-not-implemented.rs:22:29
    |
 LL | struct MyStruct;
-   | --------------- method `foo_one` not found for this struct because it doesn't satisfy `MyStruct: Foo`
+   | --------------- method `foo_one` not found for this struct
 ...
 LL |     println!("{}", MyStruct.foo_one());
-   |                             ^^^^^^^ method cannot be called on `MyStruct` due to unsatisfied trait bounds
+   |                             ^^^^^^^ method not found in `MyStruct`
    |
-note: trait bound `MyStruct: Foo` was not satisfied
-  --> $DIR/specialization-trait-not-implemented.rs:14:1
-   |
-LL | default impl<T> Foo for T {
-   | ^^^^^^^^^^^^^^^^---^^^^^-
-   | |
-   | unsatisfied trait bound introduced here
-note: the trait `Foo` must be implemented
-  --> $DIR/specialization-trait-not-implemented.rs:7:1
-   |
-LL | trait Foo {
-   | ^^^^^^^^^
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `Foo` defines an item `foo_one`, perhaps you need to implement it
   --> $DIR/specialization-trait-not-implemented.rs:7:1

tests/ui/specialization/defaultimpl/validation.rs

@@ -7,6 +7,7 @@ struct Z;
 default impl S {} //~ ERROR inherent impls cannot be `default`
 
 default unsafe impl Send for S {} //~ ERROR impls of auto traits cannot be default
+//~^ ERROR `S` cannot be sent between threads safely
 default impl !Send for Z {} //~ ERROR impls of auto traits cannot be default
                             //~^ ERROR negative impls cannot be default impls
 

tests/ui/specialization/defaultimpl/validation.stderr

@@ -26,8 +26,19 @@ LL | default unsafe impl Send for S {}
    | |
    | default because of this
 
+error[E0277]: `S` cannot be sent between threads safely
+  --> $DIR/validation.rs:9:1
+   |
+LL | default unsafe impl Send for S {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `S` cannot be sent between threads safely
+   |
+   = help: the trait `Send` is not implemented for `S`
+   = help: the trait `Send` is implemented for `S`
+   = help: see issue #48214
+   = help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
+
 error: impls of auto traits cannot be default
-  --> $DIR/validation.rs:10:15
+  --> $DIR/validation.rs:11:15
    |
 LL | default impl !Send for Z {}
    | -------       ^^^^ auto trait
@@ -35,17 +46,18 @@ LL | default impl !Send for Z {}
    | default because of this
 
 error[E0750]: negative impls cannot be default impls
-  --> $DIR/validation.rs:10:1
+  --> $DIR/validation.rs:11:1
    |
 LL | default impl !Send for Z {}
    | ^^^^^^^      ^
 
 error[E0750]: negative impls cannot be default impls
-  --> $DIR/validation.rs:14:1
+  --> $DIR/validation.rs:15:1
    |
 LL | default impl !Tr for S {}
    | ^^^^^^^      ^
 
-error: aborting due to 5 previous errors; 1 warning emitted
+error: aborting due to 6 previous errors; 1 warning emitted
 
-For more information about this error, try `rustc --explain E0750`.
+Some errors have detailed explanations: E0277, E0750.
+For more information about an error, try `rustc --explain E0277`.

tests/ui/specialization/issue-45814.current.stderr

@@ -1,14 +1,12 @@
-error[E0275]: overflow evaluating the requirement `T: Trait<_>`
+error[E0119]: conflicting implementations of trait `Trait<_>`
-   |
+  --> $DIR/issue-45814.rs:10:1
-   = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`issue_45814`)
-note: required for `T` to implement `Trait<_>`
-  --> $DIR/issue-45814.rs:9:20
    |
 LL | default impl<T, U> Trait<T> for U {}
-   |                    ^^^^^^^^     ^
+   | --------------------------------- first implementation here
-   = note: 128 redundant requirements hidden
+LL |
-   = note: required for `T` to implement `Trait<_>`
+LL | impl<T> Trait<<T as Iterator>::Item> for T {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0275`.
+For more information about this error, try `rustc --explain E0119`.

tests/ui/specialization/issue-45814.negative.stderr

@@ -1,14 +1,12 @@
-error[E0275]: overflow evaluating the requirement `T: Trait<_>`
+error[E0119]: conflicting implementations of trait `Trait<_>`
-   |
+  --> $DIR/issue-45814.rs:10:1
-   = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`issue_45814`)
-note: required for `T` to implement `Trait<_>`
-  --> $DIR/issue-45814.rs:9:20
    |
 LL | default impl<T, U> Trait<T> for U {}
-   |                    ^^^^^^^^     ^
+   | --------------------------------- first implementation here
-   = note: 128 redundant requirements hidden
+LL |
-   = note: required for `T` to implement `Trait<_>`
+LL | impl<T> Trait<<T as Iterator>::Item> for T {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0275`.
+For more information about this error, try `rustc --explain E0119`.

tests/ui/specialization/issue-45814.rs

@@ -1,4 +1,3 @@
-//~ ERROR overflow evaluating the requirement `T: Trait<_>`
 // revisions: current negative
 #![feature(specialization)]
 #![cfg_attr(negative, feature(with_negative_coherence))]
@@ -9,5 +8,6 @@ pub trait Trait<T> {}
 default impl<T, U> Trait<T> for U {}
 
 impl<T> Trait<<T as Iterator>::Item> for T {}
+//~^ ERROR conflicting implementations of trait `Trait<_>`
 
 fn main() {}

triagebot.toml

@@ -651,6 +651,7 @@ compiler-team = [
     "@petrochenkov",
     "@davidtwco",
     "@estebank",
+    "@lcnr",
     "@oli-obk",
     "@pnkfelix",
     "@wesleywiser",
@@ -680,7 +681,6 @@ infra-ci = [
     "@Kobzol",
 ]
 rustdoc = [
-    "@jsha",
     "@GuillaumeGomez",
     "@notriddle",
     "@fmease",