Rollup of 8 pull requests

compiler/rustc_codegen_llvm/src/context.rs

@@ -215,16 +215,19 @@ pub unsafe fn create_module<'ll>(
     // to ensure intrinsic calls don't use it.
     if !sess.needs_plt() {
         let avoid_plt = "RtLibUseGOT\0".as_ptr().cast();
-        llvm::LLVMRustAddModuleFlag(llmod, avoid_plt, 1);
+        llvm::LLVMRustAddModuleFlag(llmod, llvm::LLVMModFlagBehavior::Warning, avoid_plt, 1);
     }
 
     if sess.is_sanitizer_cfi_enabled() {
         // FIXME(rcvalle): Add support for non canonical jump tables.
         let canonical_jump_tables = "CFI Canonical Jump Tables\0".as_ptr().cast();
-        // FIXME(rcvalle): Add it with Override behavior flag--LLVMRustAddModuleFlag adds it with
-        // Warning behavior flag. Add support for specifying the behavior flag to
-        // LLVMRustAddModuleFlag.
-        llvm::LLVMRustAddModuleFlag(llmod, canonical_jump_tables, 1);
+        // FIXME(rcvalle): Add it with Override behavior flag.
+        llvm::LLVMRustAddModuleFlag(
+            llmod,
+            llvm::LLVMModFlagBehavior::Warning,
+            canonical_jump_tables,
+            1,
+        );
     }
 
     // Control Flow Guard is currently only supported by the MSVC linker on Windows.
@@ -233,11 +236,21 @@ pub unsafe fn create_module<'ll>(
             CFGuard::Disabled => {}
             CFGuard::NoChecks => {
                 // Set `cfguard=1` module flag to emit metadata only.
-                llvm::LLVMRustAddModuleFlag(llmod, "cfguard\0".as_ptr() as *const _, 1)
+                llvm::LLVMRustAddModuleFlag(
+                    llmod,
+                    llvm::LLVMModFlagBehavior::Warning,
+                    "cfguard\0".as_ptr() as *const _,
+                    1,
+                )
             }
             CFGuard::Checks => {
                 // Set `cfguard=2` module flag to emit metadata and checks.
-                llvm::LLVMRustAddModuleFlag(llmod, "cfguard\0".as_ptr() as *const _, 2)
+                llvm::LLVMRustAddModuleFlag(
+                    llmod,
+                    llvm::LLVMModFlagBehavior::Warning,
+                    "cfguard\0".as_ptr() as *const _,
+                    2,
+                )
             }
         }
     }
@@ -247,24 +260,28 @@ pub unsafe fn create_module<'ll>(
 
         llvm::LLVMRustAddModuleFlag(
             llmod,
+            llvm::LLVMModFlagBehavior::Error,
             "branch-target-enforcement\0".as_ptr().cast(),
             bti.into(),
         );
 
         llvm::LLVMRustAddModuleFlag(
             llmod,
+            llvm::LLVMModFlagBehavior::Error,
             "sign-return-address\0".as_ptr().cast(),
             pac.is_some().into(),
         );
         let pac_opts = pac.unwrap_or(PacRet { leaf: false, key: PAuthKey::A });
         llvm::LLVMRustAddModuleFlag(
             llmod,
+            llvm::LLVMModFlagBehavior::Error,
             "sign-return-address-all\0".as_ptr().cast(),
             pac_opts.leaf.into(),
         );
         let is_bkey = if pac_opts.key == PAuthKey::A { false } else { true };
         llvm::LLVMRustAddModuleFlag(
             llmod,
+            llvm::LLVMModFlagBehavior::Error,
             "sign-return-address-with-bkey\0".as_ptr().cast(),
             is_bkey.into(),
         );

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs

@@ -9,6 +9,7 @@ use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefIdSet;
 use rustc_llvm::RustString;
+use rustc_middle::bug;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::coverage::CodeRegion;
 use rustc_middle::ty::TyCtxt;
@@ -76,10 +77,18 @@ pub fn finalize<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) {
         let coverage_mapping_buffer = llvm::build_byte_buffer(|coverage_mapping_buffer| {
             mapgen.write_coverage_mapping(expressions, counter_regions, coverage_mapping_buffer);
         });
-        debug_assert!(
-            !coverage_mapping_buffer.is_empty(),
-            "Every `FunctionCoverage` should have at least one counter"
-        );
+
+        if coverage_mapping_buffer.is_empty() {
+            if function_coverage.is_used() {
+                bug!(
+                    "A used function should have had coverage mapping data but did not: {}",
+                    mangled_function_name
+                );
+            } else {
+                debug!("unused function had no coverage mapping data: {}", mangled_function_name);
+                continue;
+            }
+        }
 
         function_data.push((mangled_function_name, source_hash, is_used, coverage_mapping_buffer));
     }

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -108,18 +108,29 @@ impl<'a, 'tcx> CrateDebugContext<'a, 'tcx> {
             // This can be overridden using --llvm-opts -dwarf-version,N.
             // Android has the same issue (#22398)
             if let Some(version) = sess.target.dwarf_version {
-                llvm::LLVMRustAddModuleFlag(self.llmod, "Dwarf Version\0".as_ptr().cast(), version)
+                llvm::LLVMRustAddModuleFlag(
+                    self.llmod,
+                    llvm::LLVMModFlagBehavior::Warning,
+                    "Dwarf Version\0".as_ptr().cast(),
+                    version,
+                )
             }
 
             // Indicate that we want CodeView debug information on MSVC
             if sess.target.is_like_msvc {
-                llvm::LLVMRustAddModuleFlag(self.llmod, "CodeView\0".as_ptr().cast(), 1)
+                llvm::LLVMRustAddModuleFlag(
+                    self.llmod,
+                    llvm::LLVMModFlagBehavior::Warning,
+                    "CodeView\0".as_ptr().cast(),
+                    1,
+                )
             }
 
             // Prevent bitcode readers from deleting the debug info.
             let ptr = "Debug Info Version\0".as_ptr();
             llvm::LLVMRustAddModuleFlag(
                 self.llmod,
+                llvm::LLVMModFlagBehavior::Warning,
                 ptr.cast(),
                 llvm::LLVMRustDebugMetadataVersion(),
             );

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -61,6 +61,26 @@ pub enum LLVMMachineType {
     ARM = 0x01c0,
 }
 
+/// LLVM's Module::ModFlagBehavior, defined in llvm/include/llvm/IR/Module.h.
+///
+/// When merging modules (e.g. during LTO), their metadata flags are combined. Conflicts are
+/// resolved according to the merge behaviors specified here. Flags differing only in merge
+/// behavior are still considered to be in conflict.
+///
+/// In order for Rust-C LTO to work, we must specify behaviors compatible with Clang. Notably,
+/// 'Error' and 'Warning' cannot be mixed for a given flag.
+#[derive(Copy, Clone, PartialEq)]
+#[repr(C)]
+pub enum LLVMModFlagBehavior {
+    Error = 1,
+    Warning = 2,
+    Require = 3,
+    Override = 4,
+    Append = 5,
+    AppendUnique = 6,
+    Max = 7,
+}
+
 // Consts for the LLVM CallConv type, pre-cast to usize.
 
 /// LLVM CallingConv::ID. Should we wrap this?
@@ -1895,7 +1915,16 @@ extern "C" {
 
     pub fn LLVMRustIsRustLLVM() -> bool;
 
-    pub fn LLVMRustAddModuleFlag(M: &Module, name: *const c_char, value: u32);
+    /// Add LLVM module flags.
+    ///
+    /// In order for Rust-C LTO to work, module flags must be compatible with Clang. What
+    /// "compatible" means depends on the merge behaviors involved.
+    pub fn LLVMRustAddModuleFlag(
+        M: &Module,
+        merge_behavior: LLVMModFlagBehavior,
+        name: *const c_char,
+        value: u32,
+    );
 
     pub fn LLVMRustMetadataAsValue<'a>(C: &'a Context, MD: &'a Metadata) -> &'a Value;
 

compiler/rustc_feature/src/builtin_attrs.rs

@@ -697,6 +697,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     rustc_attr!(TEST, rustc_capture_analysis, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_insignificant_dtor, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_strict_coherence, Normal, template!(Word), WarnFollowing),
+    rustc_attr!(TEST, rustc_with_negative_coherence, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_variance, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_layout, Normal, template!(List: "field1, field2, ..."), WarnFollowing),
     rustc_attr!(TEST, rustc_regions, Normal, template!(Word), WarnFollowing),

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -722,9 +722,12 @@ extern "C" bool LLVMRustIsRustLLVM() {
 #endif
 }
 
-extern "C" void LLVMRustAddModuleFlag(LLVMModuleRef M, const char *Name,
-                                      uint32_t Value) {
-  unwrap(M)->addModuleFlag(Module::Warning, Name, Value);
+extern "C" void LLVMRustAddModuleFlag(
+    LLVMModuleRef M,
+    Module::ModFlagBehavior MergeBehavior,
+    const char *Name,
+    uint32_t Value) {
+  unwrap(M)->addModuleFlag(MergeBehavior, Name, Value);
 }
 
 extern "C" LLVMValueRef LLVMRustMetadataAsValue(LLVMContextRef C, LLVMMetadataRef MD) {

compiler/rustc_span/src/symbol.rs

@@ -1204,6 +1204,7 @@ symbols! {
         rustc_trivial_field_reads,
         rustc_unsafe_specialization_marker,
         rustc_variance,
+        rustc_with_negative_coherence,
         rustdoc,
         rustdoc_internals,
         rustfmt,

compiler/rustc_trait_selection/src/traits/coherence.rs

@@ -7,9 +7,11 @@
 use crate::infer::{CombinedSnapshot, InferOk, TyCtxtInferExt};
 use crate::traits::query::evaluate_obligation::InferCtxtExt;
 use crate::traits::select::IntercrateAmbiguityCause;
+use crate::traits::util::impl_trait_ref_and_oblig;
 use crate::traits::SkipLeakCheck;
 use crate::traits::{
-    self, Normalized, Obligation, ObligationCause, PredicateObligation, SelectionContext,
+    self, FulfillmentContext, Normalized, Obligation, ObligationCause, PredicateObligation,
+    PredicateObligations, SelectionContext,
 };
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_middle::ty::fast_reject::{self, SimplifyParams, StripReferences};
@@ -135,45 +137,83 @@ fn with_fresh_ty_vars<'cx, 'tcx>(
     header
 }
 
+/// What kind of overlap check are we doing -- this exists just for testing and feature-gating
+/// purposes.
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+enum OverlapMode {
+    /// The 1.0 rules (either types fail to unify, or where clauses are not implemented for crate-local types)
+    Stable,
+    /// Feature-gated test: Stable, *or* there is an explicit negative impl that rules out one of the where-clauses.
+    WithNegative,
+    /// Just check for negative impls, not for "where clause not implemented": used for testing.
+    Strict,
+}
+
+impl OverlapMode {
+    fn use_negative_impl(&self) -> bool {
+        *self == OverlapMode::Strict || *self == OverlapMode::WithNegative
+    }
+
+    fn use_implicit_negative(&self) -> bool {
+        *self == OverlapMode::Stable || *self == OverlapMode::WithNegative
+    }
+}
+
+fn overlap_mode<'tcx>(tcx: TyCtxt<'tcx>, impl1_def_id: DefId, impl2_def_id: DefId) -> OverlapMode {
+    if tcx.has_attr(impl1_def_id, sym::rustc_strict_coherence)
+        != tcx.has_attr(impl2_def_id, sym::rustc_strict_coherence)
+    {
+        bug!("Use strict coherence on both impls",);
+    }
+
+    if tcx.has_attr(impl1_def_id, sym::rustc_with_negative_coherence)
+        != tcx.has_attr(impl2_def_id, sym::rustc_with_negative_coherence)
+    {
+        bug!("Use with negative coherence on both impls",);
+    }
+
+    if tcx.has_attr(impl1_def_id, sym::rustc_strict_coherence) {
+        OverlapMode::Strict
+    } else if tcx.has_attr(impl1_def_id, sym::rustc_with_negative_coherence) {
+        OverlapMode::WithNegative
+    } else {
+        OverlapMode::Stable
+    }
+}
+
 /// Can both impl `a` and impl `b` be satisfied by a common type (including
 /// where-clauses)? If so, returns an `ImplHeader` that unifies the two impls.
 fn overlap<'cx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'tcx>,
     skip_leak_check: SkipLeakCheck,
-    a_def_id: DefId,
-    b_def_id: DefId,
+    impl1_def_id: DefId,
+    impl2_def_id: DefId,
 ) -> Option<OverlapResult<'tcx>> {
-    debug!("overlap(a_def_id={:?}, b_def_id={:?})", a_def_id, b_def_id);
+    debug!("overlap(impl1_def_id={:?}, impl2_def_id={:?})", impl1_def_id, impl2_def_id);
 
     selcx.infcx().probe_maybe_skip_leak_check(skip_leak_check.is_yes(), |snapshot| {
-        overlap_within_probe(selcx, skip_leak_check, a_def_id, b_def_id, snapshot)
+        overlap_within_probe(selcx, skip_leak_check, impl1_def_id, impl2_def_id, snapshot)
     })
 }
 
 fn overlap_within_probe<'cx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'tcx>,
     skip_leak_check: SkipLeakCheck,
-    a_def_id: DefId,
-    b_def_id: DefId,
+    impl1_def_id: DefId,
+    impl2_def_id: DefId,
     snapshot: &CombinedSnapshot<'_, 'tcx>,
 ) -> Option<OverlapResult<'tcx>> {
-    fn loose_check<'cx, 'tcx>(
-        selcx: &mut SelectionContext<'cx, 'tcx>,
-        o: &PredicateObligation<'tcx>,
-    ) -> bool {
-        !selcx.predicate_may_hold_fatal(o)
-    }
+    let infcx = selcx.infcx();
+    let tcx = infcx.tcx;
 
-    fn strict_check<'cx, 'tcx>(
-        selcx: &SelectionContext<'cx, 'tcx>,
-        o: &PredicateObligation<'tcx>,
-    ) -> bool {
-        let infcx = selcx.infcx();
-        let tcx = infcx.tcx;
-        o.flip_polarity(tcx)
-            .as_ref()
-            .map(|o| selcx.infcx().predicate_must_hold_modulo_regions(o))
-            .unwrap_or(false)
+    let overlap_mode = overlap_mode(tcx, impl1_def_id, impl2_def_id);
+
+    if overlap_mode.use_negative_impl() {
+        if negative_impl(selcx, impl1_def_id, impl2_def_id)
+            || negative_impl(selcx, impl2_def_id, impl1_def_id)
+        {
+            return None;
+        }
     }
 
     // For the purposes of this check, we don't bring any placeholder
@@ -182,26 +222,61 @@ fn overlap_within_probe<'cx, 'tcx>(
     // empty environment.
     let param_env = ty::ParamEnv::empty();
 
-    let a_impl_header = with_fresh_ty_vars(selcx, param_env, a_def_id);
-    let b_impl_header = with_fresh_ty_vars(selcx, param_env, b_def_id);
+    let impl1_header = with_fresh_ty_vars(selcx, param_env, impl1_def_id);
+    let impl2_header = with_fresh_ty_vars(selcx, param_env, impl2_def_id);
 
-    debug!("overlap: a_impl_header={:?}", a_impl_header);
-    debug!("overlap: b_impl_header={:?}", b_impl_header);
+    debug!("overlap: impl1_header={:?}", impl1_header);
+    debug!("overlap: impl2_header={:?}", impl2_header);
 
-    // Do `a` and `b` unify? If not, no overlap.
-    let obligations = match selcx
-        .infcx()
-        .at(&ObligationCause::dummy(), param_env)
-        .eq_impl_headers(&a_impl_header, &b_impl_header)
-    {
-        Ok(InferOk { obligations, value: () }) => obligations,
-        Err(_) => {
+    let obligations = equate_impl_headers(selcx, &impl1_header, &impl2_header)?;
+    debug!("overlap: unification check succeeded");
+
+    if overlap_mode.use_implicit_negative() {
+        if implicit_negative(selcx, param_env, &impl1_header, impl2_header, obligations) {
             return None;
         }
-    };
+    }
 
-    debug!("overlap: unification check succeeded");
+    if !skip_leak_check.is_yes() {
+        if infcx.leak_check(true, snapshot).is_err() {
+            debug!("overlap: leak check failed");
+            return None;
+        }
+    }
+
+    let intercrate_ambiguity_causes = selcx.take_intercrate_ambiguity_causes();
+    debug!("overlap: intercrate_ambiguity_causes={:#?}", intercrate_ambiguity_causes);
+
+    let involves_placeholder =
+        matches!(selcx.infcx().region_constraints_added_in_snapshot(snapshot), Some(true));
+
+    let impl_header = selcx.infcx().resolve_vars_if_possible(impl1_header);
+    Some(OverlapResult { impl_header, intercrate_ambiguity_causes, involves_placeholder })
+}
+
+fn equate_impl_headers<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
+    impl1_header: &ty::ImplHeader<'tcx>,
+    impl2_header: &ty::ImplHeader<'tcx>,
+) -> Option<PredicateObligations<'tcx>> {
+    // Do `a` and `b` unify? If not, no overlap.
+    selcx
+        .infcx()
+        .at(&ObligationCause::dummy(), ty::ParamEnv::empty())
+        .eq_impl_headers(impl1_header, impl2_header)
+        .map(|infer_ok| infer_ok.obligations)
+        .ok()
+}
 
+/// Given impl1 and impl2 check if both impls can be satisfied by a common type (including
+/// where-clauses) If so, return false, otherwise return true, they are disjoint.
+fn implicit_negative<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
+    impl1_header: &ty::ImplHeader<'tcx>,
+    impl2_header: ty::ImplHeader<'tcx>,
+    obligations: PredicateObligations<'tcx>,
+) -> bool {
     // There's no overlap if obligations are unsatisfiable or if the obligation negated is
     // satisfied.
     //
@@ -225,11 +300,11 @@ fn overlap_within_probe<'cx, 'tcx>(
     // at some point an impl for `&'?a str: Error` could be added.
     let infcx = selcx.infcx();
     let tcx = infcx.tcx;
-    let opt_failing_obligation = a_impl_header
+    let opt_failing_obligation = impl1_header
         .predicates
         .iter()
         .copied()
-        .chain(b_impl_header.predicates)
+        .chain(impl2_header.predicates)
         .map(|p| infcx.resolve_vars_if_possible(p))
         .map(|p| Obligation {
             cause: ObligationCause::dummy(),
@@ -239,40 +314,105 @@ fn overlap_within_probe<'cx, 'tcx>(
         })
         .chain(obligations)
         .find(|o| {
-            // if both impl headers are set to strict coherence it means that this will be accepted
-            // only if it's stated that T: !Trait. So only prove that the negated obligation holds.
-            if tcx.has_attr(a_def_id, sym::rustc_strict_coherence)
-                && tcx.has_attr(b_def_id, sym::rustc_strict_coherence)
-            {
-                strict_check(selcx, o)
-            } else {
-                loose_check(selcx, o) || tcx.features().negative_impls && strict_check(selcx, o)
-            }
+            loose_check(selcx, o) || tcx.features().negative_impls && negative_impl_exists(selcx, o)
         });
     // FIXME: the call to `selcx.predicate_may_hold_fatal` above should be ported
     // to the canonical trait query form, `infcx.predicate_may_hold`, once
     // the new system supports intercrate mode (which coherence needs).
 
     if let Some(failing_obligation) = opt_failing_obligation {
         debug!("overlap: obligation unsatisfiable {:?}", failing_obligation);
-        return None;
+        true
+    } else {
+        false
     }
+}
 
-    if !skip_leak_check.is_yes() {
-        if infcx.leak_check(true, snapshot).is_err() {
-            debug!("overlap: leak check failed");
-            return None;
-        }
-    }
+/// Given impl1 and impl2 check if both impls are never satisfied by a common type (including
+/// where-clauses) If so, return true, they are disjoint and false otherwise.
+fn negative_impl<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
+    impl1_def_id: DefId,
+    impl2_def_id: DefId,
+) -> bool {
+    let tcx = selcx.infcx().tcx;
 
-    let impl_header = selcx.infcx().resolve_vars_if_possible(a_impl_header);
-    let intercrate_ambiguity_causes = selcx.take_intercrate_ambiguity_causes();
-    debug!("overlap: intercrate_ambiguity_causes={:#?}", intercrate_ambiguity_causes);
+    // create a parameter environment corresponding to a (placeholder) instantiation of impl1
+    let impl1_env = tcx.param_env(impl1_def_id);
+    let impl1_trait_ref = tcx.impl_trait_ref(impl1_def_id).unwrap();
 
-    let involves_placeholder =
-        matches!(selcx.infcx().region_constraints_added_in_snapshot(snapshot), Some(true));
+    // Create an infcx, taking the predicates of impl1 as assumptions:
+    tcx.infer_ctxt().enter(|infcx| {
+        // Normalize the trait reference. The WF rules ought to ensure
+        // that this always succeeds.
+        let impl1_trait_ref = match traits::fully_normalize(
+            &infcx,
+            FulfillmentContext::new(),
+            ObligationCause::dummy(),
+            impl1_env,
+            impl1_trait_ref,
+        ) {
+            Ok(impl1_trait_ref) => impl1_trait_ref,
+            Err(err) => {
+                bug!("failed to fully normalize {:?}: {:?}", impl1_trait_ref, err);
+            }
+        };
+
+        // Attempt to prove that impl2 applies, given all of the above.
+        let selcx = &mut SelectionContext::new(&infcx);
+        let impl2_substs = infcx.fresh_substs_for_item(DUMMY_SP, impl2_def_id);
+        let (impl2_trait_ref, obligations) =
+            impl_trait_ref_and_oblig(selcx, impl1_env, impl2_def_id, impl2_substs);
+
+        // do the impls unify? If not, not disjoint.
+        let more_obligations = match infcx
+            .at(&ObligationCause::dummy(), impl1_env)
+            .eq(impl1_trait_ref, impl2_trait_ref)
+        {
+            Ok(InferOk { obligations, .. }) => obligations,
+            Err(_) => {
+                debug!(
+                    "explicit_disjoint: {:?} does not unify with {:?}",
+                    impl1_trait_ref, impl2_trait_ref
+                );
+                return false;
+            }
+        };
 
-    Some(OverlapResult { impl_header, intercrate_ambiguity_causes, involves_placeholder })
+        let opt_failing_obligation = obligations
+            .into_iter()
+            .chain(more_obligations)
+            .find(|o| negative_impl_exists(selcx, o));
+
+        if let Some(failing_obligation) = opt_failing_obligation {
+            debug!("overlap: obligation unsatisfiable {:?}", failing_obligation);
+            true
+        } else {
+            false
+        }
+    })
+}
+
+fn loose_check<'cx, 'tcx>(
+    selcx: &mut SelectionContext<'cx, 'tcx>,
+    o: &PredicateObligation<'tcx>,
+) -> bool {
+    !selcx.predicate_may_hold_fatal(o)
+}
+
+fn negative_impl_exists<'cx, 'tcx>(
+    selcx: &SelectionContext<'cx, 'tcx>,
+    o: &PredicateObligation<'tcx>,
+) -> bool {
+    let infcx = selcx.infcx();
+    let tcx = infcx.tcx;
+    o.flip_polarity(tcx)
+        .as_ref()
+        .map(|o| {
+            // FIXME This isn't quite correct, regions should be included
+            selcx.infcx().predicate_must_hold_modulo_regions(o)
+        })
+        .unwrap_or(false)
 }
 
 pub fn trait_ref_is_knowable<'tcx>(

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

@@ -765,14 +765,38 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             debug!(?result, "CACHE MISS");
             self.insert_evaluation_cache(param_env, fresh_trait_pred, dep_node, result);
 
-            stack.cache().on_completion(stack.dfn, |fresh_trait_pred, provisional_result| {
-                self.insert_evaluation_cache(
-                    param_env,
-                    fresh_trait_pred,
-                    dep_node,
-                    provisional_result.max(result),
-                );
-            });
+            stack.cache().on_completion(
+                stack.dfn,
+                |fresh_trait_pred, provisional_result, provisional_dep_node| {
+                    // Create a new `DepNode` that has dependencies on:
+                    // * The `DepNode` for the original evaluation that resulted in a provisional cache
+                    // entry being crated
+                    // * The `DepNode` for the *current* evaluation, which resulted in us completing
+                    // provisional caches entries and inserting them into the evaluation cache
+                    //
+                    // This ensures that when a query reads this entry from the evaluation cache,
+                    // it will end up (transitively) dependening on all of the incr-comp dependencies
+                    // created during the evaluation of this trait. For example, evaluating a trait
+                    // will usually require us to invoke `type_of(field_def_id)` to determine the
+                    // constituent types, and we want any queries reading from this evaluation
+                    // cache entry to end up with a transitive `type_of(field_def_id`)` dependency.
+                    //
+                    // By using `in_task`, we're also creating an edge from the *current* query
+                    // to the newly-created `combined_dep_node`. This is probably redundant,
+                    // but it's better to add too many dep graph edges than to add too few
+                    // dep graph edges.
+                    let ((), combined_dep_node) = self.in_task(|this| {
+                        this.tcx().dep_graph.read_index(provisional_dep_node);
+                        this.tcx().dep_graph.read_index(dep_node);
+                    });
+                    self.insert_evaluation_cache(
+                        param_env,
+                        fresh_trait_pred,
+                        combined_dep_node,
+                        provisional_result.max(result),
+                    );
+                },
+            );
         } else {
             debug!(?result, "PROVISIONAL");
             debug!(
@@ -781,7 +805,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 fresh_trait_pred, stack.depth, reached_depth,
             );
 
-            stack.cache().insert_provisional(stack.dfn, reached_depth, fresh_trait_pred, result);
+            stack.cache().insert_provisional(
+                stack.dfn,
+                reached_depth,
+                fresh_trait_pred,
+                result,
+                dep_node,
+            );
         }
 
         Ok(result)
@@ -2506,6 +2536,11 @@ struct ProvisionalEvaluation {
     from_dfn: usize,
     reached_depth: usize,
     result: EvaluationResult,
+    /// The `DepNodeIndex` created for the `evaluate_stack` call for this provisional
+    /// evaluation. When we create an entry in the evaluation cache using this provisional
+    /// cache entry (see `on_completion`), we use this `dep_node` to ensure that future reads from
+    /// the cache will have all of the necessary incr comp dependencies tracked.
+    dep_node: DepNodeIndex,
 }
 
 impl<'tcx> Default for ProvisionalEvaluationCache<'tcx> {
@@ -2548,6 +2583,7 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> {
         reached_depth: usize,
         fresh_trait_pred: ty::PolyTraitPredicate<'tcx>,
         result: EvaluationResult,
+        dep_node: DepNodeIndex,
     ) {
         debug!(?from_dfn, ?fresh_trait_pred, ?result, "insert_provisional");
 
@@ -2573,7 +2609,10 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> {
             }
         }
 
-        map.insert(fresh_trait_pred, ProvisionalEvaluation { from_dfn, reached_depth, result });
+        map.insert(
+            fresh_trait_pred,
+            ProvisionalEvaluation { from_dfn, reached_depth, result, dep_node },
+        );
     }
 
     /// Invoked when the node with dfn `dfn` does not get a successful
@@ -2624,7 +2663,7 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> {
     fn on_completion(
         &self,
         dfn: usize,
-        mut op: impl FnMut(ty::PolyTraitPredicate<'tcx>, EvaluationResult),
+        mut op: impl FnMut(ty::PolyTraitPredicate<'tcx>, EvaluationResult, DepNodeIndex),
     ) {
         debug!(?dfn, "on_completion");
 
@@ -2633,7 +2672,7 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> {
         {
             debug!(?fresh_trait_pred, ?eval, "on_completion");
 
-            op(fresh_trait_pred, eval.result);
+            op(fresh_trait_pred, eval.result, eval.dep_node);
         }
     }
 }

library/std/src/os/fd/owned.rs

@@ -8,6 +8,8 @@ use crate::fmt;
 use crate::fs;
 use crate::marker::PhantomData;
 use crate::mem::forget;
+#[cfg(not(target_os = "wasi"))]
+use crate::sys::cvt;
 use crate::sys_common::{AsInner, FromInner, IntoInner};
 
 /// A borrowed file descriptor.
@@ -67,6 +69,37 @@ impl BorrowedFd<'_> {
     }
 }
 
+impl OwnedFd {
+    /// Creates a new `OwnedFd` instance that shares the same underlying file handle
+    /// as the existing `OwnedFd` instance.
+    #[cfg(not(target_os = "wasi"))]
+    pub fn try_clone(&self) -> crate::io::Result<Self> {
+        // We want to atomically duplicate this file descriptor and set the
+        // CLOEXEC flag, and currently that's done via F_DUPFD_CLOEXEC. This
+        // is a POSIX flag that was added to Linux in 2.6.24.
+        #[cfg(not(target_os = "espidf"))]
+        let cmd = libc::F_DUPFD_CLOEXEC;
+
+        // For ESP-IDF, F_DUPFD is used instead, because the CLOEXEC semantics
+        // will never be supported, as this is a bare metal framework with
+        // no capabilities for multi-process execution.  While F_DUPFD is also
+        // not supported yet, it might be (currently it returns ENOSYS).
+        #[cfg(target_os = "espidf")]
+        let cmd = libc::F_DUPFD;
+
+        let fd = cvt(unsafe { libc::fcntl(self.as_raw_fd(), cmd, 0) })?;
+        Ok(unsafe { Self::from_raw_fd(fd) })
+    }
+
+    #[cfg(target_os = "wasi")]
+    pub fn try_clone(&self) -> crate::io::Result<Self> {
+        Err(crate::io::Error::new_const(
+            crate::io::ErrorKind::Unsupported,
+            &"operation not supported on WASI yet",
+        ))
+    }
+}
+
 #[unstable(feature = "io_safety", issue = "87074")]
 impl AsRawFd for BorrowedFd<'_> {
     #[inline]

library/std/src/os/windows/io/handle.rs

@@ -6,9 +6,11 @@ use super::raw::{AsRawHandle, FromRawHandle, IntoRawHandle, RawHandle};
 use crate::convert::TryFrom;
 use crate::fmt;
 use crate::fs;
+use crate::io;
 use crate::marker::PhantomData;
 use crate::mem::forget;
 use crate::sys::c;
+use crate::sys::cvt;
 use crate::sys_common::{AsInner, FromInner, IntoInner};
 
 /// A borrowed handle.
@@ -144,6 +146,36 @@ impl TryFrom<HandleOrNull> for OwnedHandle {
     }
 }
 
+impl OwnedHandle {
+    /// Creates a new `OwnedHandle` instance that shares the same underlying file handle
+    /// as the existing `OwnedHandle` instance.
+    pub fn try_clone(&self) -> crate::io::Result<Self> {
+        self.duplicate(0, false, c::DUPLICATE_SAME_ACCESS)
+    }
+
+    pub(crate) fn duplicate(
+        &self,
+        access: c::DWORD,
+        inherit: bool,
+        options: c::DWORD,
+    ) -> io::Result<Self> {
+        let mut ret = 0 as c::HANDLE;
+        cvt(unsafe {
+            let cur_proc = c::GetCurrentProcess();
+            c::DuplicateHandle(
+                cur_proc,
+                self.as_raw_handle(),
+                cur_proc,
+                &mut ret,
+                access,
+                inherit as c::BOOL,
+                options,
+            )
+        })?;
+        unsafe { Ok(Self::from_raw_handle(ret)) }
+    }
+}
+
 impl TryFrom<HandleOrInvalid> for OwnedHandle {
     type Error = ();
 

library/std/src/os/windows/io/socket.rs

@@ -4,9 +4,13 @@
 
 use super::raw::{AsRawSocket, FromRawSocket, IntoRawSocket, RawSocket};
 use crate::fmt;
+use crate::io;
 use crate::marker::PhantomData;
+use crate::mem;
 use crate::mem::forget;
+use crate::sys;
 use crate::sys::c;
+use crate::sys::cvt;
 
 /// A borrowed socket.
 ///
@@ -69,6 +73,77 @@ impl BorrowedSocket<'_> {
     }
 }
 
+impl OwnedSocket {
+    /// Creates a new `OwnedSocket` instance that shares the same underlying socket
+    /// as the existing `OwnedSocket` instance.
+    pub fn try_clone(&self) -> io::Result<Self> {
+        let mut info = unsafe { mem::zeroed::<c::WSAPROTOCOL_INFO>() };
+        let result = unsafe {
+            c::WSADuplicateSocketW(self.as_raw_socket(), c::GetCurrentProcessId(), &mut info)
+        };
+        sys::net::cvt(result)?;
+        let socket = unsafe {
+            c::WSASocketW(
+                info.iAddressFamily,
+                info.iSocketType,
+                info.iProtocol,
+                &mut info,
+                0,
+                c::WSA_FLAG_OVERLAPPED | c::WSA_FLAG_NO_HANDLE_INHERIT,
+            )
+        };
+
+        if socket != c::INVALID_SOCKET {
+            unsafe { Ok(OwnedSocket::from_raw_socket(socket)) }
+        } else {
+            let error = unsafe { c::WSAGetLastError() };
+
+            if error != c::WSAEPROTOTYPE && error != c::WSAEINVAL {
+                return Err(io::Error::from_raw_os_error(error));
+            }
+
+            let socket = unsafe {
+                c::WSASocketW(
+                    info.iAddressFamily,
+                    info.iSocketType,
+                    info.iProtocol,
+                    &mut info,
+                    0,
+                    c::WSA_FLAG_OVERLAPPED,
+                )
+            };
+
+            if socket == c::INVALID_SOCKET {
+                return Err(last_error());
+            }
+
+            unsafe {
+                let socket = OwnedSocket::from_raw_socket(socket);
+                socket.set_no_inherit()?;
+                Ok(socket)
+            }
+        }
+    }
+
+    #[cfg(not(target_vendor = "uwp"))]
+    pub(crate) fn set_no_inherit(&self) -> io::Result<()> {
+        cvt(unsafe {
+            c::SetHandleInformation(self.as_raw_socket() as c::HANDLE, c::HANDLE_FLAG_INHERIT, 0)
+        })
+        .map(drop)
+    }
+
+    #[cfg(target_vendor = "uwp")]
+    pub(crate) fn set_no_inherit(&self) -> io::Result<()> {
+        Err(io::Error::new_const(io::ErrorKind::Unsupported, &"Unavailable on UWP"))
+    }
+}
+
+/// Returns the last error from the Windows socket interface.
+fn last_error() -> io::Error {
+    io::Error::from_raw_os_error(unsafe { c::WSAGetLastError() })
+}
+
 impl AsRawSocket for BorrowedSocket<'_> {
     #[inline]
     fn as_raw_socket(&self) -> RawSocket {

library/std/src/sys/unix/fd.rs

@@ -259,22 +259,9 @@ impl FileDesc {
         }
     }
 
+    #[inline]
     pub fn duplicate(&self) -> io::Result<FileDesc> {
-        // We want to atomically duplicate this file descriptor and set the
-        // CLOEXEC flag, and currently that's done via F_DUPFD_CLOEXEC. This
-        // is a POSIX flag that was added to Linux in 2.6.24.
-        #[cfg(not(target_os = "espidf"))]
-        let cmd = libc::F_DUPFD_CLOEXEC;
-
-        // For ESP-IDF, F_DUPFD is used instead, because the CLOEXEC semantics
-        // will never be supported, as this is a bare metal framework with
-        // no capabilities for multi-process execution.  While F_DUPFD is also
-        // not supported yet, it might be (currently it returns ENOSYS).
-        #[cfg(target_os = "espidf")]
-        let cmd = libc::F_DUPFD;
-
-        let fd = cvt(unsafe { libc::fcntl(self.as_raw_fd(), cmd, 0) })?;
-        Ok(unsafe { FileDesc::from_raw_fd(fd) })
+        Ok(Self(self.0.try_clone()?))
     }
 }
 

library/std/src/sys/windows/fs.rs

@@ -460,7 +460,7 @@ impl File {
     }
 
     pub fn duplicate(&self) -> io::Result<File> {
-        Ok(File { handle: self.handle.duplicate(0, false, c::DUPLICATE_SAME_ACCESS)? })
+        Ok(Self { handle: self.handle.try_clone()? })
     }
 
     fn reparse_point<'a>(

library/std/src/sys/windows/handle.rs

@@ -262,26 +262,17 @@ impl Handle {
         Ok(written as usize)
     }
 
+    pub fn try_clone(&self) -> io::Result<Self> {
+        Ok(Self(self.0.try_clone()?))
+    }
+
     pub fn duplicate(
         &self,
         access: c::DWORD,
         inherit: bool,
         options: c::DWORD,
-    ) -> io::Result<Handle> {
-        let mut ret = 0 as c::HANDLE;
-        cvt(unsafe {
-            let cur_proc = c::GetCurrentProcess();
-            c::DuplicateHandle(
-                cur_proc,
-                self.as_raw_handle(),
-                cur_proc,
-                &mut ret,
-                access,
-                inherit as c::BOOL,
-                options,
-            )
-        })?;
-        unsafe { Ok(Handle::from_raw_handle(ret)) }
+    ) -> io::Result<Self> {
+        Ok(Self(self.0.duplicate(access, inherit, options)?))
     }
 }
 

library/std/src/sys/windows/net.rs

@@ -134,7 +134,7 @@ impl Socket {
 
             unsafe {
                 let socket = Self::from_raw_socket(socket);
-                socket.set_no_inherit()?;
+                socket.0.set_no_inherit()?;
                 Ok(socket)
             }
         }
@@ -213,52 +213,7 @@ impl Socket {
     }
 
     pub fn duplicate(&self) -> io::Result<Socket> {
-        let mut info = unsafe { mem::zeroed::<c::WSAPROTOCOL_INFO>() };
-        let result = unsafe {
-            c::WSADuplicateSocketW(self.as_raw_socket(), c::GetCurrentProcessId(), &mut info)
-        };
-        cvt(result)?;
-        let socket = unsafe {
-            c::WSASocketW(
-                info.iAddressFamily,
-                info.iSocketType,
-                info.iProtocol,
-                &mut info,
-                0,
-                c::WSA_FLAG_OVERLAPPED | c::WSA_FLAG_NO_HANDLE_INHERIT,
-            )
-        };
-
-        if socket != c::INVALID_SOCKET {
-            unsafe { Ok(Self::from_inner(OwnedSocket::from_raw_socket(socket))) }
-        } else {
-            let error = unsafe { c::WSAGetLastError() };
-
-            if error != c::WSAEPROTOTYPE && error != c::WSAEINVAL {
-                return Err(io::Error::from_raw_os_error(error));
-            }
-
-            let socket = unsafe {
-                c::WSASocketW(
-                    info.iAddressFamily,
-                    info.iSocketType,
-                    info.iProtocol,
-                    &mut info,
-                    0,
-                    c::WSA_FLAG_OVERLAPPED,
-                )
-            };
-
-            if socket == c::INVALID_SOCKET {
-                return Err(last_error());
-            }
-
-            unsafe {
-                let socket = Self::from_inner(OwnedSocket::from_raw_socket(socket));
-                socket.set_no_inherit()?;
-                Ok(socket)
-            }
-        }
+        Ok(Self(self.0.try_clone()?))
     }
 
     fn recv_with_flags(&self, buf: &mut [u8], flags: c_int) -> io::Result<usize> {
@@ -421,19 +376,6 @@ impl Socket {
         }
     }
 
-    #[cfg(not(target_vendor = "uwp"))]
-    fn set_no_inherit(&self) -> io::Result<()> {
-        sys::cvt(unsafe {
-            c::SetHandleInformation(self.as_raw_socket() as c::HANDLE, c::HANDLE_FLAG_INHERIT, 0)
-        })
-        .map(drop)
-    }
-
-    #[cfg(target_vendor = "uwp")]
-    fn set_no_inherit(&self) -> io::Result<()> {
-        Err(io::Error::new_const(io::ErrorKind::Unsupported, &"Unavailable on UWP"))
-    }
-
     pub fn shutdown(&self, how: Shutdown) -> io::Result<()> {
         let how = match how {
             Shutdown::Write => c::SD_SEND,

src/librustdoc/clean/blanket_impl.rs

@@ -101,6 +101,27 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
 
                     cx.generated_synthetics.insert((ty, trait_def_id));
 
+                    let hir_imp = impl_def_id.as_local()
+                        .map(|local| cx.tcx.hir().expect_item(local))
+                        .and_then(|item| if let hir::ItemKind::Impl(i) = &item.kind {
+                            Some(i)
+                        } else {
+                            None
+                        });
+
+                    let items = match hir_imp {
+                        Some(imp) => imp
+                            .items
+                            .iter()
+                            .map(|ii| cx.tcx.hir().impl_item(ii.id).clean(cx))
+                            .collect::<Vec<_>>(),
+                        None => cx.tcx
+                            .associated_items(impl_def_id)
+                            .in_definition_order()
+                            .map(|x| x.clean(cx))
+                            .collect::<Vec<_>>(),
+                    };
+
                     impls.push(Item {
                         name: None,
                         attrs: Default::default(),
@@ -117,12 +138,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                             // the post-inference `trait_ref`, as it's more accurate.
                             trait_: Some(trait_ref.clean(cx)),
                             for_: ty.clean(cx),
-                            items: cx
-                                .tcx
-                                .associated_items(impl_def_id)
-                                .in_definition_order()
-                                .map(|x| x.clean(cx))
-                                .collect::<Vec<_>>(),
+                            items,
                             polarity: ty::ImplPolarity::Positive,
                             kind: ImplKind::Blanket(box trait_ref.self_ty().clean(cx)),
                         }),

src/librustdoc/html/render/mod.rs

@@ -376,25 +376,21 @@ impl Setting {
                 description,
             ),
             Setting::Select { js_data_name, description, default_value, ref options } => format!(
-                "<div class=\"setting-line\">\
-                     <div>{}</div>\
-                     <label class=\"select-wrapper\">\
-                         <select id=\"{}\" autocomplete=\"off\">{}</select>\
-                         <img src=\"{}down-arrow{}.svg\" alt=\"Select item\">\
-                     </label>\
-                 </div>",
-                description,
+                "<div class=\"setting-line\"><div class=\"radio-line\" id=\"{}\"><span class=\"setting-name\">{}</span>{}</div></div>",
                 js_data_name,
+                description,
                 options
                     .iter()
                     .map(|opt| format!(
-                        "<option value=\"{name}\" {}>{name}</option>",
-                        if opt == default_value { "selected" } else { "" },
+                        "<label for=\"{js_data_name}-{name}\" class=\"choice\">
+                           <input type=\"radio\" name=\"{js_data_name}\" id=\"{js_data_name}-{name}\" value=\"{name}\" {checked}>\
+                           {name}\
+                         </label>",
+                        js_data_name = js_data_name,
                         name = opt,
+                        checked = if opt == default_value { "checked" } else { "" },
                     ))
                     .collect::<String>(),
-                root_path,
-                suffix,
             ),
         }
     }
@@ -418,31 +414,25 @@ impl<T: Into<Setting>> From<(&'static str, Vec<T>)> for Setting {
 fn settings(root_path: &str, suffix: &str, theme_names: Vec<String>) -> Result<String, Error> {
     // (id, explanation, default value)
     let settings: &[Setting] = &[
-        (
-            "Theme preferences",
-            vec![
-                Setting::from(("use-system-theme", "Use system theme", true)),
-                Setting::Select {
-                    js_data_name: "theme",
-                    description: "Theme",
-                    default_value: "light",
-                    options: theme_names.clone(),
-                },
-                Setting::Select {
-                    js_data_name: "preferred-dark-theme",
-                    description: "Preferred dark theme",
-                    default_value: "dark",
-                    options: theme_names.clone(),
-                },
-                Setting::Select {
-                    js_data_name: "preferred-light-theme",
-                    description: "Preferred light theme",
-                    default_value: "light",
-                    options: theme_names,
-                },
-            ],
-        )
-            .into(),
+        Setting::from(("use-system-theme", "Use system theme", true)),
+        Setting::Select {
+            js_data_name: "theme",
+            description: "Theme",
+            default_value: "light",
+            options: theme_names.clone(),
+        },
+        Setting::Select {
+            js_data_name: "preferred-light-theme",
+            description: "Preferred light theme",
+            default_value: "light",
+            options: theme_names.clone(),
+        },
+        Setting::Select {
+            js_data_name: "preferred-dark-theme",
+            description: "Preferred dark theme",
+            default_value: "dark",
+            options: theme_names,
+        },
         ("auto-hide-large-items", "Auto-hide item contents for large items.", true).into(),
         ("auto-hide-method-docs", "Auto-hide item methods' documentation", false).into(),
         ("auto-hide-trait-implementations", "Auto-hide trait implementation documentation", false)
@@ -454,9 +444,14 @@ fn settings(root_path: &str, suffix: &str, theme_names: Vec<String>) -> Result<S
     ];
 
     Ok(format!(
-        "<h1 class=\"fqn\">\
-            <span class=\"in-band\">Rustdoc settings</span>\
-        </h1>\
+        "<div class=\"main-heading\">
+            <h1 class=\"fqn\">\
+                <span class=\"in-band\">Rustdoc settings</span>\
+            </h1>\
+            <span class=\"out-of-band\">\
+            <a id=\"back\" href=\"javascript:void(0)\">Back</a>\
+            </span>\
+        </div>\
         <div class=\"settings\">{}</div>\
         <link rel=\"stylesheet\" href=\"{root_path}settings{suffix}.css\">\
         <script src=\"{root_path}settings{suffix}.js\"></script>",

src/librustdoc/html/static/css/settings.css

@@ -17,6 +17,30 @@
 	border-bottom: 1px solid;
 }
 
+.setting-line .radio-line {
+	display: flex;
+	flex-wrap: wrap;
+}
+
+.setting-line .radio-line > * {
+	padding: 0.3em;
+}
+
+.setting-line .radio-line .setting-name {
+	flex-grow: 1;
+}
+
+.setting-line .radio-line input {
+	margin-right: 0.3em;
+}
+
+.radio-line .choice {
+	border-radius: 0.1em;
+	border: 1px solid;
+	margin-left: 0.5em;
+	min-width: 3.5em;
+}
+
 .toggle {
 	position: relative;
 	display: inline-block;

src/librustdoc/html/static/js/settings.js

@@ -33,19 +33,15 @@
     }
 
     function showLightAndDark() {
-        addClass(document.getElementById("theme").parentElement.parentElement, "hidden");
-        removeClass(document.getElementById("preferred-light-theme").parentElement.parentElement,
-            "hidden");
-        removeClass(document.getElementById("preferred-dark-theme").parentElement.parentElement,
-            "hidden");
+        addClass(document.getElementById("theme").parentElement, "hidden");
+        removeClass(document.getElementById("preferred-light-theme").parentElement, "hidden");
+        removeClass(document.getElementById("preferred-dark-theme").parentElement, "hidden");
     }
 
     function hideLightAndDark() {
-        addClass(document.getElementById("preferred-light-theme").parentElement.parentElement,
-            "hidden");
-        addClass(document.getElementById("preferred-dark-theme").parentElement.parentElement,
-            "hidden");
-        removeClass(document.getElementById("theme").parentElement.parentElement, "hidden");
+        addClass(document.getElementById("preferred-light-theme").parentElement, "hidden");
+        addClass(document.getElementById("preferred-dark-theme").parentElement, "hidden");
+        removeClass(document.getElementById("theme").parentElement, "hidden");
     }
 
     function updateLightAndDark() {
@@ -82,6 +78,19 @@
                 changeSetting(this.id, this.value);
             };
         });
+        onEachLazy(document.querySelectorAll("input[type=\"radio\"]"), function(elem) {
+            const settingId = elem.name;
+            const settingValue = getSettingValue(settingId);
+            if (settingValue !== null && settingValue !== "null") {
+                elem.checked = settingValue === elem.value;
+            }
+            elem.addEventListener("change", function(ev) {
+                changeSetting(ev.target.name, ev.target.value);
+            });
+        });
+        document.getElementById("back").addEventListener("click", function() {
+            history.back();
+        });
     }
 
     window.addEventListener("DOMContentLoaded", setEvents);

src/librustdoc/json/mod.rs

@@ -172,21 +172,8 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
     /// the hashmap because certain items (traits and types) need to have their mappings for trait
     /// implementations filled out before they're inserted.
     fn item(&mut self, item: clean::Item) -> Result<(), Error> {
-        let local_blanket_impl = match item.def_id {
-            clean::ItemId::Blanket { impl_id, .. } => impl_id.is_local(),
-            clean::ItemId::Auto { .. }
-            | clean::ItemId::DefId(_)
-            | clean::ItemId::Primitive(_, _) => false,
-        };
-
         // Flatten items that recursively store other items
-        // FIXME(CraftSpider): We skip children of local blanket implementations, as we'll have
-        //     already seen the actual generic impl, and the generated ones don't need documenting.
-        //     This is necessary due to the visibility, return type, and self arg of the generated
-        //     impls not quite matching, and will no longer be necessary when the mismatch is fixed.
-        if !local_blanket_impl {
-            item.kind.inner_items().for_each(|i| self.item(i.clone()).unwrap());
-        }
+        item.kind.inner_items().for_each(|i| self.item(i.clone()).unwrap());
 
         let id = item.def_id;
         if let Some(mut new_item) = self.convert_item(item) {

src/test/incremental/issue-92987-provisional-dep-node.rs

@@ -0,0 +1,24 @@
+// revisions: rpass1 rpass2
+
+// Regression test for issue #92987
+// Tests that we properly manage `DepNode`s during trait evaluation
+// involing an auto-trait cycle.
+
+#[cfg(rpass1)]
+struct CycleOne(Box<CycleTwo>);
+
+#[cfg(rpass2)]
+enum CycleOne {
+    Variant(Box<CycleTwo>)
+}
+
+struct CycleTwo(CycleOne);
+
+fn assert_send<T: Send>() {}
+
+fn bar() {
+    assert_send::<CycleOne>();
+    assert_send::<CycleTwo>();
+}
+
+fn main() {}

src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.issue-93054.txt

@@ -0,0 +1,29 @@
+    1|       |// Regression test for #93054: Functions using uninhabited types often only have a single,
+    2|       |// unreachable basic block which doesn't get instrumented. This should not cause llvm-cov to fail.
+    3|       |// Since these kinds functions can't be invoked anyway, it's ok to not have coverage data for them.
+    4|       |
+    5|       |// compile-flags: --edition=2021
+    6|       |
+    7|       |enum Never { }
+    8|       |
+    9|       |impl Never {
+   10|       |    fn foo(self) {
+   11|       |        match self { }
+   12|       |        make().map(|never| match never { });
+   13|       |    }
+   14|       |
+   15|       |    fn bar(&self) {
+   16|       |        match *self { }
+   17|       |    }
+   18|       |}
+   19|       |
+   20|      0|async fn foo2(never: Never) {
+   21|       |    match never { }
+   22|       |}
+   23|       |
+   24|      0|fn make() -> Option<Never> {
+   25|      0|    None
+   26|      0|}
+   27|       |
+   28|      1|fn main() { }
+

src/test/run-make-fulldeps/coverage/issue-93054.rs

@@ -0,0 +1,28 @@
+// Regression test for #93054: Functions using uninhabited types often only have a single,
+// unreachable basic block which doesn't get instrumented. This should not cause llvm-cov to fail.
+// Since these kinds functions can't be invoked anyway, it's ok to not have coverage data for them.
+
+// compile-flags: --edition=2021
+
+enum Never { }
+
+impl Never {
+    fn foo(self) {
+        match self { }
+        make().map(|never| match never { });
+    }
+
+    fn bar(&self) {
+        match *self { }
+    }
+}
+
+async fn foo2(never: Never) {
+    match never { }
+}
+
+fn make() -> Option<Never> {
+    None
+}
+
+fn main() { }

src/test/rustdoc-json/impls/blanket_with_local.rs

@@ -3,11 +3,15 @@
 
 // @has blanket_with_local.json "$.index[*][?(@.name=='Load')]"
 pub trait Load {
+    // @has - "$.index[*][?(@.name=='load')]"
     fn load() {}
+    // @has - "$.index[*][?(@.name=='write')]"
+    fn write(self) {}
 }
 
 impl<P> Load for P {
     fn load() {}
+    fn write(self) {}
 }
 
 // @has - "$.index[*][?(@.name=='Wrapper')]"

src/test/ui/coherence/auxiliary/option_future.rs

@@ -0,0 +1,8 @@
+#![crate_type = "lib"]
+#![feature(negative_impls)]
+#![feature(rustc_attrs)]
+
+pub trait Future {}
+
+#[rustc_with_negative_coherence]
+impl<E> !Future for Option<E> where E: Sized {}

src/test/ui/coherence/coherence-overlap-negative-trait2.rs

@@ -0,0 +1,18 @@
+// check-pass
+// aux-build:option_future.rs
+//
+// Check that if we promise to not impl what would overlap it doesn't actually overlap
+
+#![feature(rustc_attrs)]
+
+extern crate option_future as lib;
+use lib::Future;
+
+trait Termination {}
+
+#[rustc_with_negative_coherence]
+impl<E> Termination for Option<E> where E: Sized {}
+#[rustc_with_negative_coherence]
+impl<F> Termination for F where F: Future + Sized {}
+
+fn main() {}

src/test/ui/mismatched_types/overloaded-calls-bad.rs

@@ -30,4 +30,5 @@ fn main() {
     //~^ ERROR this function takes 1 argument but 0 arguments were supplied
     let ans = s("burma", "shave");
     //~^ ERROR this function takes 1 argument but 2 arguments were supplied
+    //~| ERROR mismatched types
 }

src/test/ui/mismatched_types/overloaded-calls-bad.stderr

@@ -18,6 +18,12 @@ note: associated function defined here
 LL |     extern "rust-call" fn call_mut(&mut self, args: Args) -> Self::Output;
    |                           ^^^^^^^^
 
+error[E0308]: mismatched types
+  --> $DIR/overloaded-calls-bad.rs:31:17
+   |
+LL |     let ans = s("burma", "shave");
+   |                 ^^^^^^^ expected `isize`, found `&str`
+
 error[E0057]: this function takes 1 argument but 2 arguments were supplied
   --> $DIR/overloaded-calls-bad.rs:31:15
    |
@@ -32,7 +38,7 @@ note: associated function defined here
 LL |     extern "rust-call" fn call_mut(&mut self, args: Args) -> Self::Output;
    |                           ^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0057, E0308.
 For more information about an error, try `rustc --explain E0057`.