Auto merge of #77172 - jonas-schievink:rollup-a041rou, r=jonas-schievink

Rollup of 15 pull requests

Successful merges:

 - #75438 (Use adaptive SVG favicon for rustdoc like other rust sites)
 - #76304 (Make delegation methods of `std::net::IpAddr` unstably const)
 - #76724 (Allow a unique name to be assigned to dataflow graphviz output)
 - #76978 (Documented From impls in std/sync/mpsc/mod.rs)
 - #77044 (Liballoc bench vec use mem take not replace)
 - #77050 (Typo fix: "satsify" -> "satisfy")
 - #77074 (add array::from_ref)
 - #77078 (Don't use an if guard to check equality with a constant)
 - #77079 (Use `Self` in docs when possible)
 - #77081 (Merge two almost identical match arms)
 - #77121 (Updated html_root_url for compiler crates)
 - #77136 (Suggest `const_mut_refs`, not `const_fn` for mutable references in `const fn`)
 - #77160 (Suggest `const_fn_transmute`, not `const_fn`)
 - #77164 (Remove workaround for deref issue that no longer exists.)
 - #77165 (Followup to #76673)

Failed merges:

r? `@ghost`

compiler/rustc_apfloat/src/lib.rs

@@ -30,7 +30,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![no_std]
 #![forbid(unsafe_code)]
 #![feature(nll)]

compiler/rustc_arena/src/lib.rs

@@ -8,7 +8,7 @@
 //! This crate implements several kinds of arena.
 
 #![doc(
-    html_root_url = "https://doc.rust-lang.org/nightly/",
+    html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
     test(no_crate_inject, attr(deny(warnings)))
 )]
 #![feature(dropck_eyepatch)]

compiler/rustc_ast/src/lib.rs

@@ -4,7 +4,10 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/", test(attr(deny(warnings))))]
+#![doc(
+    html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
+    test(attr(deny(warnings)))
+)]
 #![feature(box_syntax)]
 #![feature(const_fn)] // For the `transmute` in `P::new`
 #![feature(const_fn_transmute)]

compiler/rustc_attr/src/builtin.rs

@@ -301,7 +301,7 @@ where
                                                 .emit();
                                             };
                                             match issue.parse() {
-                                                Ok(num) if num == 0 => {
+                                                Ok(0) => {
                                                     emit_diag(
                                                         "`issue` must not be \"0\", \
                                                         use \"none\" instead",

compiler/rustc_builtin_macros/src/format_foreign.rs

@@ -518,8 +518,7 @@ pub mod printf {
                         .and_then(|end| end.at_next_cp())
                         .map(|end| (next.slice_between(end).unwrap(), end));
                     let end = match end {
-                        Some(("32", end)) => end,
-                        Some(("64", end)) => end,
+                        Some(("32" | "64", end)) => end,
                         _ => next,
                     };
                     state = Type;

compiler/rustc_builtin_macros/src/lib.rs

@@ -1,7 +1,7 @@
 //! This crate contains implementations of built-in macros and other code generating facilities
 //! injecting code into the crate before it is lowered to HIR.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(bool_to_option)]
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]

compiler/rustc_codegen_llvm/src/lib.rs

@@ -4,7 +4,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(bool_to_option)]
 #![feature(const_cstr_unchecked)]
 #![feature(crate_visibility_modifier)]

compiler/rustc_codegen_ssa/src/lib.rs

@@ -1,4 +1,4 @@
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(bool_to_option)]
 #![feature(option_expect_none)]
 #![feature(box_patterns)]

compiler/rustc_data_structures/src/lib.rs

@@ -6,7 +6,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![allow(incomplete_features)]
 #![feature(array_windows)]
 #![feature(control_flow_enum)]

compiler/rustc_driver/src/lib.rs

@@ -4,7 +4,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(nll)]
 #![feature(once_cell)]
 #![recursion_limit = "256"]

compiler/rustc_errors/src/lib.rs

@@ -2,7 +2,7 @@
 //!
 //! This module contains the code for creating and emitting diagnostics.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(crate_visibility_modifier)]
 #![feature(backtrace)]
 #![feature(nll)]

compiler/rustc_graphviz/src/lib.rs

@@ -272,7 +272,7 @@
 //! * [DOT language](http://www.graphviz.org/doc/info/lang.html)
 
 #![doc(
-    html_root_url = "https://doc.rust-lang.org/nightly/",
+    html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
     test(attr(allow(unused_variables), deny(warnings)))
 )]
 #![feature(nll)]

compiler/rustc_incremental/src/lib.rs

@@ -1,6 +1,6 @@
 //! Support for serializing the dep-graph and reloading it.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
 #![recursion_limit = "256"]

compiler/rustc_infer/src/lib.rs

@@ -12,7 +12,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(bool_to_option)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]

compiler/rustc_lint/src/lib.rs

@@ -25,7 +25,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![cfg_attr(test, feature(test))]
 #![feature(array_windows)]
 #![feature(bool_to_option)]

compiler/rustc_llvm/src/lib.rs

@@ -1,6 +1,6 @@
 #![feature(nll)]
 #![feature(static_nobundle)]
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 
 // NOTE: This crate only exists to allow linking on mingw targets.
 

compiler/rustc_metadata/src/lib.rs

@@ -1,4 +1,4 @@
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(bool_to_option)]
 #![feature(core_intrinsics)]
 #![feature(crate_visibility_modifier)]

compiler/rustc_middle/src/lib.rs

@@ -22,7 +22,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(array_windows)]
 #![feature(backtrace)]
 #![feature(bool_to_option)]

compiler/rustc_middle/src/mir/terminator/mod.rs

@@ -96,6 +96,8 @@ pub enum TerminatorKind<'tcx> {
     ///   P <- V
     /// }
     /// ```
+    ///
+    /// Note that DropAndReplace is eliminated as part of the `ElaborateDrops` pass.
     DropAndReplace {
         place: Place<'tcx>,
         value: Operand<'tcx>,

compiler/rustc_mir/src/borrow_check/mod.rs

@@ -205,6 +205,7 @@ fn do_mir_borrowck<'a, 'tcx>(
 
     let mut flow_inits = MaybeInitializedPlaces::new(tcx, &body, &mdpe)
         .into_engine(tcx, &body, def.did.to_def_id())
+        .pass_name("borrowck")
         .iterate_to_fixpoint()
         .into_results_cursor(&body);
 
@@ -264,12 +265,15 @@ fn do_mir_borrowck<'a, 'tcx>(
 
     let flow_borrows = Borrows::new(tcx, &body, regioncx.clone(), &borrow_set)
         .into_engine(tcx, &body, def.did.to_def_id())
+        .pass_name("borrowck")
         .iterate_to_fixpoint();
     let flow_uninits = MaybeUninitializedPlaces::new(tcx, &body, &mdpe)
         .into_engine(tcx, &body, def.did.to_def_id())
+        .pass_name("borrowck")
         .iterate_to_fixpoint();
     let flow_ever_inits = EverInitializedPlaces::new(tcx, &body, &mdpe)
         .into_engine(tcx, &body, def.did.to_def_id())
+        .pass_name("borrowck")
         .iterate_to_fixpoint();
 
     let movable_generator = match tcx.hir().get(id) {

compiler/rustc_mir/src/dataflow/framework/engine.rs

@@ -84,6 +84,7 @@ where
     def_id: DefId,
     dead_unwinds: Option<&'a BitSet<BasicBlock>>,
     entry_sets: IndexVec<BasicBlock, A::Domain>,
+    pass_name: Option<&'static str>,
     analysis: A,
 
     /// Cached, cumulative transfer functions for each block.
@@ -174,6 +175,7 @@ where
             body,
             def_id,
             dead_unwinds: None,
+            pass_name: None,
             entry_sets,
             apply_trans_for_block,
         }
@@ -189,6 +191,15 @@ where
         self
     }
 
+    /// Adds an identifier to the graphviz output for this particular run of a dataflow analysis.
+    ///
+    /// Some analyses are run multiple times in the compilation pipeline. Give them a `pass_name`
+    /// to differentiate them. Otherwise, only the results for the latest run will be saved.
+    pub fn pass_name(mut self, name: &'static str) -> Self {
+        self.pass_name = Some(name);
+        self
+    }
+
     /// Computes the fixpoint for this dataflow problem and returns it.
     pub fn iterate_to_fixpoint(self) -> Results<'tcx, A>
     where
@@ -202,6 +213,7 @@ where
             mut entry_sets,
             tcx,
             apply_trans_for_block,
+            pass_name,
             ..
         } = self;
 
@@ -249,7 +261,7 @@ where
 
         let results = Results { analysis, entry_sets };
 
-        let res = write_graphviz_results(tcx, def_id, &body, &results);
+        let res = write_graphviz_results(tcx, def_id, &body, &results, pass_name);
         if let Err(e) = res {
             warn!("Failed to write graphviz dataflow results: {}", e);
         }
@@ -267,6 +279,7 @@ fn write_graphviz_results<A>(
     def_id: DefId,
     body: &mir::Body<'tcx>,
     results: &Results<'tcx, A>,
+    pass_name: Option<&'static str>,
 ) -> std::io::Result<()>
 where
     A: Analysis<'tcx>,
@@ -285,12 +298,17 @@ where
         None if tcx.sess.opts.debugging_opts.dump_mir_dataflow
             && dump_enabled(tcx, A::NAME, def_id) =>
         {
+            // FIXME: Use some variant of `pretty::dump_path` for this
             let mut path = PathBuf::from(&tcx.sess.opts.debugging_opts.dump_mir_dir);
 
+            let crate_name = tcx.crate_name(def_id.krate);
             let item_name = ty::print::with_forced_impl_filename_line(|| {
                 tcx.def_path(def_id).to_filename_friendly_no_crate()
             });
-            path.push(format!("rustc.{}.{}.dot", item_name, A::NAME));
+
+            let pass_name = pass_name.map(|s| format!(".{}", s)).unwrap_or_default();
+
+            path.push(format!("{}.{}.{}{}.dot", crate_name, item_name, A::NAME, pass_name));
             path
         }
 

compiler/rustc_mir/src/transform/check_consts/ops.rs

@@ -489,7 +489,14 @@ impl NonConstOp for Transmute {
     }
 
     fn emit_error(&self, ccx: &ConstCx<'_, '_>, span: Span) {
-        mcf_emit_error(ccx, span, "can only call `transmute` from const items, not `const fn`");
+        feature_err(
+            &ccx.tcx.sess.parse_sess,
+            sym::const_fn_transmute,
+            span,
+            &format!("`transmute` is not allowed in {}s", ccx.const_kind()),
+        )
+        .note("`transmute` is only allowed in constants and statics for now")
+        .emit();
     }
 }
 
@@ -535,6 +542,7 @@ impl NonConstOp for UnsizingCast {
     }
 }
 
+// Types that cannot appear in the signature or locals of a `const fn`.
 pub mod ty {
     use super::*;
 
@@ -548,7 +556,13 @@ pub mod ty {
         }
 
         fn emit_error(&self, ccx: &ConstCx<'_, '_>, span: Span) {
-            mcf_emit_error(ccx, span, "mutable references in const fn are unstable");
+            feature_err(
+                &ccx.tcx.sess.parse_sess,
+                sym::const_mut_refs,
+                span,
+                &format!("mutable references are not allowed in {}s", ccx.const_kind()),
+            )
+            .emit()
         }
     }
 

compiler/rustc_mir/src/transform/check_consts/validation.rs

@@ -59,6 +59,7 @@ impl Qualifs<'mir, 'tcx> {
             MaybeMutBorrowedLocals::mut_borrows_only(tcx, &body, param_env)
                 .unsound_ignore_borrow_on_drop()
                 .into_engine(tcx, &body, def_id.to_def_id())
+                .pass_name("const_qualification")
                 .iterate_to_fixpoint()
                 .into_results_cursor(&body)
         });

compiler/rustc_mir/src/transform/elaborate_drops.rs

@@ -44,6 +44,7 @@ impl<'tcx> MirPass<'tcx> for ElaborateDrops {
             let inits = MaybeInitializedPlaces::new(tcx, body, &env)
                 .into_engine(tcx, body, def_id)
                 .dead_unwinds(&dead_unwinds)
+                .pass_name("elaborate_drops")
                 .iterate_to_fixpoint()
                 .into_results_cursor(body);
 
@@ -51,6 +52,7 @@ impl<'tcx> MirPass<'tcx> for ElaborateDrops {
                 .mark_inactive_variants_as_uninit()
                 .into_engine(tcx, body, def_id)
                 .dead_unwinds(&dead_unwinds)
+                .pass_name("elaborate_drops")
                 .iterate_to_fixpoint()
                 .into_results_cursor(body);
 
@@ -83,6 +85,7 @@ fn find_dead_unwinds<'tcx>(
     let mut dead_unwinds = BitSet::new_empty(body.basic_blocks().len());
     let mut flow_inits = MaybeInitializedPlaces::new(tcx, body, &env)
         .into_engine(tcx, body, def_id)
+        .pass_name("find_dead_unwinds")
         .iterate_to_fixpoint()
         .into_results_cursor(body);
     for (bb, bb_data) in body.basic_blocks().iter_enumerated() {

compiler/rustc_mir/src/transform/generator.rs

@@ -467,8 +467,10 @@ fn locals_live_across_suspend_points(
 
     // Calculate the MIR locals which have been previously
     // borrowed (even if they are still active).
-    let borrowed_locals_results =
-        MaybeBorrowedLocals::all_borrows().into_engine(tcx, body_ref, def_id).iterate_to_fixpoint();
+    let borrowed_locals_results = MaybeBorrowedLocals::all_borrows()
+        .into_engine(tcx, body_ref, def_id)
+        .pass_name("generator")
+        .iterate_to_fixpoint();
 
     let mut borrowed_locals_cursor =
         dataflow::ResultsCursor::new(body_ref, &borrowed_locals_results);
@@ -484,6 +486,7 @@ fn locals_live_across_suspend_points(
     // Calculate the liveness of MIR locals ignoring borrows.
     let mut liveness = MaybeLiveLocals
         .into_engine(tcx, body_ref, def_id)
+        .pass_name("generator")
         .iterate_to_fixpoint()
         .into_results_cursor(body_ref);
 

compiler/rustc_mir/src/transform/remove_unneeded_drops.rs

@@ -38,8 +38,7 @@ impl<'tcx> MirPass<'tcx> for RemoveUnneededDrops {
 impl<'a, 'tcx> Visitor<'tcx> for RemoveUnneededDropsOptimizationFinder<'a, 'tcx> {
     fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
         match terminator.kind {
-            TerminatorKind::Drop { place, target, .. }
-            | TerminatorKind::DropAndReplace { place, target, .. } => {
+            TerminatorKind::Drop { place, target, .. } => {
                 let ty = place.ty(self.body, self.tcx);
                 let needs_drop = ty.ty.needs_drop(self.tcx, self.tcx.param_env(self.def_id));
                 if !needs_drop {

compiler/rustc_parse_format/src/lib.rs

@@ -5,7 +5,7 @@
 //! generated instead.
 
 #![doc(
-    html_root_url = "https://doc.rust-lang.org/nightly/",
+    html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
     html_playground_url = "https://play.rust-lang.org/",
     test(attr(deny(warnings)))
 )]

compiler/rustc_passes/src/lib.rs

@@ -4,7 +4,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
 #![feature(or_patterns)]

compiler/rustc_plugin_impl/src/lib.rs

@@ -6,7 +6,7 @@
 //! feature](https://doc.rust-lang.org/nightly/unstable-book/language-features/plugin.html)
 //! of the Unstable Book for some examples.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(nll)]
 #![recursion_limit = "256"]
 

compiler/rustc_privacy/src/lib.rs

@@ -1,4 +1,4 @@
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
 #![recursion_limit = "256"]

compiler/rustc_resolve/src/lib.rs

@@ -8,7 +8,7 @@
 //!
 //! Type-relative name resolution (methods, fields, associated items) happens in `librustc_typeck`.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(bool_to_option)]
 #![feature(crate_visibility_modifier)]
 #![feature(nll)]

compiler/rustc_save_analysis/src/lib.rs

@@ -1,4 +1,4 @@
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(nll)]
 #![feature(or_patterns)]
 #![recursion_limit = "256"]

compiler/rustc_serialize/src/lib.rs

@@ -5,7 +5,7 @@ Core encoding and decoding interfaces.
 */
 
 #![doc(
-    html_root_url = "https://doc.rust-lang.org/nightly/",
+    html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
     html_playground_url = "https://play.rust-lang.org/",
     test(attr(allow(unused_variables), deny(warnings)))
 )]

compiler/rustc_span/src/lib.rs

@@ -4,7 +4,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(array_windows)]
 #![feature(crate_visibility_modifier)]
 #![feature(const_fn)]

compiler/rustc_symbol_mangling/src/lib.rs

@@ -87,7 +87,7 @@
 //! virtually impossible. Thus, symbol hash generation exclusively relies on
 //! DefPaths which are much more robust in the face of changes to the code base.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(never_type)]
 #![feature(nll)]
 #![feature(or_patterns)]

compiler/rustc_target/src/lib.rs

@@ -7,7 +7,7 @@
 //! more 'stuff' here in the future. It does not have a dependency on
 //! LLVM.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(bool_to_option)]
 #![feature(const_fn)]
 #![feature(const_panic)]

compiler/rustc_trait_selection/src/lib.rs

@@ -10,7 +10,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(bool_to_option)]
 #![feature(box_patterns)]
 #![feature(drain_filter)]

compiler/rustc_ty/src/lib.rs

@@ -4,7 +4,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(nll)]
 #![recursion_limit = "256"]
 

compiler/rustc_typeck/src/lib.rs

@@ -55,7 +55,7 @@ This API is completely unstable and subject to change.
 
 */
 
-#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![allow(non_camel_case_types)]
 #![feature(bool_to_option)]
 #![feature(box_syntax)]