diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index ea5300bdfc04c..8f0a245a5658a 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -99,9 +99,21 @@ struct StepDescription {
     name: &'static str,
 }
 
+/// Collection of paths used to match a task rule.
 #[derive(Debug, Clone, PartialOrd, Ord, PartialEq, Eq)]
 pub enum PathSet {
+    /// A collection of individual paths.
+    ///
+    /// These are generally matched as a path suffix. For example, a
+    /// command-line value of `libstd` will match if `src/libstd` is in the
+    /// set.
     Set(BTreeSet<PathBuf>),
+    /// A "suite" of paths.
+    ///
+    /// These can match as a path suffix (like `Set`), or as a prefix. For
+    /// example, a command-line value of `src/test/ui/abi/variadic-ffi.rs`
+    /// will match `src/test/ui`. A command-line value of `ui` would also
+    /// match `src/test/ui`.
     Suite(PathBuf),
 }
 
@@ -251,21 +263,33 @@ impl<'a> ShouldRun<'a> {
         self
     }
 
-    // Unlike `krate` this will create just one pathset. As such, it probably shouldn't actually
-    // ever be used, but as we transition to having all rules properly handle passing krate(...) by
-    // actually doing something different for every crate passed.
+    /// Indicates it should run if the command-line selects the given crate or
+    /// any of its (local) dependencies.
+    ///
+    /// Compared to `krate`, this treats the dependencies as aliases for the
+    /// same job. Generally it is preferred to use `krate`, and treat each
+    /// individual path separately. For example `./x.py test src/liballoc`
+    /// (which uses `krate`) will test just `liballoc`. However, `./x.py check
+    /// src/liballoc` (which uses `all_krates`) will check all of `libtest`.
+    /// `all_krates` should probably be removed at some point.
     pub fn all_krates(mut self, name: &str) -> Self {
         let mut set = BTreeSet::new();
         for krate in self.builder.in_tree_crates(name) {
-            set.insert(PathBuf::from(&krate.path));
+            let path = krate.local_path(self.builder);
+            set.insert(path);
         }
         self.paths.insert(PathSet::Set(set));
         self
     }
 
+    /// Indicates it should run if the command-line selects the given crate or
+    /// any of its (local) dependencies.
+    ///
+    /// `make_run` will be called separately for each matching command-line path.
     pub fn krate(mut self, name: &str) -> Self {
         for krate in self.builder.in_tree_crates(name) {
-            self.paths.insert(PathSet::one(&krate.path));
+            let path = krate.local_path(self.builder);
+            self.paths.insert(PathSet::one(path));
         }
         self
     }
@@ -488,13 +512,19 @@ impl<'a> Builder<'a> {
             should_run = (desc.should_run)(should_run);
         }
         let mut help = String::from("Available paths:\n");
+        let mut add_path = |path: &Path| {
+            help.push_str(&format!("    ./x.py {} {}\n", subcommand, path.display()));
+        };
         for pathset in should_run.paths {
-            if let PathSet::Set(set) = pathset {
-                set.iter().for_each(|path| {
-                    help.push_str(
-                        format!("    ./x.py {} {}\n", subcommand, path.display()).as_str(),
-                    )
-                })
+            match pathset {
+                PathSet::Set(set) => {
+                    for path in set {
+                        add_path(&path);
+                    }
+                }
+                PathSet::Suite(path) => {
+                    add_path(&path.join("..."));
+                }
             }
         }
         Some(help)
@@ -1176,7 +1206,7 @@ impl<'a> Builder<'a> {
             );
         }
 
-        // If Control Flow Guard is enabled, pass the `control_flow_guard=checks` flag to rustc
+        // If Control Flow Guard is enabled, pass the `control-flow-guard` flag to rustc
         // when compiling the standard library, since this might be linked into the final outputs
         // produced by rustc. Since this mitigation is only available on Windows, only enable it
         // for the standard library in case the compiler is run on a non-Windows platform.
@@ -1187,7 +1217,7 @@ impl<'a> Builder<'a> {
             && self.config.control_flow_guard
             && compiler.stage >= 1
         {
-            rustflags.arg("-Zcontrol_flow_guard=checks");
+            rustflags.arg("-Zcontrol-flow-guard");
         }
 
         // For `cargo doc` invocations, make rustdoc print the Rust version into the docs
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index 5c01c5e852c48..6d7fb7acfcb04 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -548,8 +548,8 @@ impl Step for Rustc {
         // Find dependencies for top level crates.
         let mut compiler_crates = HashSet::new();
         for root_crate in &["rustc_driver", "rustc_codegen_llvm", "rustc_codegen_ssa"] {
-            let interned_root_crate = INTERNER.intern_str(root_crate);
-            find_compiler_crates(builder, &interned_root_crate, &mut compiler_crates);
+            compiler_crates
+                .extend(builder.in_tree_crates(root_crate).into_iter().map(|krate| krate.name));
         }
 
         for krate in &compiler_crates {
@@ -564,22 +564,6 @@ impl Step for Rustc {
     }
 }
 
-fn find_compiler_crates(
-    builder: &Builder<'_>,
-    name: &Interned<String>,
-    crates: &mut HashSet<Interned<String>>,
-) {
-    // Add current crate.
-    crates.insert(*name);
-
-    // Look for dependencies.
-    for dep in builder.crates.get(name).unwrap().deps.iter() {
-        if builder.crates.get(dep).unwrap().is_local(builder) {
-            find_compiler_crates(builder, dep, crates);
-        }
-    }
-}
-
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct Rustdoc {
     stage: u32,
diff --git a/src/bootstrap/flags.rs b/src/bootstrap/flags.rs
index 3726115357436..0cf3f2e83bf9f 100644
--- a/src/bootstrap/flags.rs
+++ b/src/bootstrap/flags.rs
@@ -10,12 +10,10 @@ use std::process;
 use getopts::Options;
 
 use crate::builder::Builder;
+use crate::cache::{Interned, INTERNER};
 use crate::config::Config;
-use crate::metadata;
 use crate::{Build, DocTests};
 
-use crate::cache::{Interned, INTERNER};
-
 /// Deserialized version of all flags for this compile.
 pub struct Flags {
     pub verbose: usize, // number of -v args; each extra -v after the first is passed to Cargo
@@ -449,8 +447,7 @@ Arguments:
         // All subcommands except `clean` can have an optional "Available paths" section
         if matches.opt_present("verbose") {
             let config = Config::parse(&["build".to_string()]);
-            let mut build = Build::new(config);
-            metadata::build(&mut build);
+            let build = Build::new(config);
 
             let maybe_rules_help = Builder::get_help(&build, subcommand.as_str());
             extra_help.push_str(maybe_rules_help.unwrap_or_default().as_str());
diff --git a/src/bootstrap/install.rs b/src/bootstrap/install.rs
index fafd3cdf927c0..fbdef9d8272f7 100644
--- a/src/bootstrap/install.rs
+++ b/src/bootstrap/install.rs
@@ -70,7 +70,10 @@ fn install_sh(
     let libdir_default = PathBuf::from("lib");
     let mandir_default = datadir_default.join("man");
     let prefix = builder.config.prefix.as_ref().map_or(prefix_default, |p| {
-        fs::canonicalize(p).unwrap_or_else(|_| panic!("could not canonicalize {}", p.display()))
+        fs::create_dir_all(p)
+            .unwrap_or_else(|err| panic!("could not create {}: {}", p.display(), err));
+        fs::canonicalize(p)
+            .unwrap_or_else(|err| panic!("could not canonicalize {}: {}", p.display(), err))
     });
     let sysconfdir = builder.config.sysconfdir.as_ref().unwrap_or(&sysconfdir_default);
     let datadir = builder.config.datadir.as_ref().unwrap_or(&datadir_default);
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 8d8a036caef88..9d3830da39066 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -270,12 +270,7 @@ struct Crate {
 }
 
 impl Crate {
-    fn is_local(&self, build: &Build) -> bool {
-        self.path.starts_with(&build.config.src) && !self.path.to_string_lossy().ends_with("_shim")
-    }
-
     fn local_path(&self, build: &Build) -> PathBuf {
-        assert!(self.is_local(build));
         self.path.strip_prefix(&build.config.src).unwrap().into()
     }
 }
@@ -1079,17 +1074,29 @@ impl Build {
         }
     }
 
+    /// Returns a Vec of all the dependencies of the given root crate,
+    /// including transitive dependencies and the root itself. Only includes
+    /// "local" crates (those in the local source tree, not from a registry).
     fn in_tree_crates(&self, root: &str) -> Vec<&Crate> {
         let mut ret = Vec::new();
         let mut list = vec![INTERNER.intern_str(root)];
         let mut visited = HashSet::new();
         while let Some(krate) = list.pop() {
             let krate = &self.crates[&krate];
-            if krate.is_local(self) {
-                ret.push(krate);
-            }
+            ret.push(krate);
             for dep in &krate.deps {
-                if visited.insert(dep) && dep != "build_helper" {
+                // Don't include optional deps if their features are not
+                // enabled. Ideally this would be computed from `cargo
+                // metadata --features …`, but that is somewhat slow. Just
+                // skip `build_helper` since there aren't any operations we
+                // want to perform on it. In the future, we may want to
+                // consider just filtering all build and dev dependencies in
+                // metadata::build.
+                if visited.insert(dep)
+                    && dep != "build_helper"
+                    && (dep != "profiler_builtins" || self.config.profiler)
+                    && (dep != "rustc_codegen_llvm" || self.config.llvm_enabled())
+                {
                     list.push(*dep);
                 }
             }
diff --git a/src/bootstrap/metadata.rs b/src/bootstrap/metadata.rs
index 292aa3b1e24a7..a38391c7b88f2 100644
--- a/src/bootstrap/metadata.rs
+++ b/src/bootstrap/metadata.rs
@@ -1,5 +1,3 @@
-use std::collections::HashMap;
-use std::collections::HashSet;
 use std::path::PathBuf;
 use std::process::Command;
 
@@ -12,7 +10,6 @@ use crate::{Build, Crate};
 #[derive(Deserialize)]
 struct Output {
     packages: Vec<Package>,
-    resolve: Resolve,
 }
 
 #[derive(Deserialize)]
@@ -21,63 +18,25 @@ struct Package {
     name: String,
     source: Option<String>,
     manifest_path: String,
+    dependencies: Vec<Dependency>,
 }
 
 #[derive(Deserialize)]
-struct Resolve {
-    nodes: Vec<ResolveNode>,
-}
-
-#[derive(Deserialize)]
-struct ResolveNode {
-    id: String,
-    dependencies: Vec<String>,
+struct Dependency {
+    name: String,
+    source: Option<String>,
 }
 
 pub fn build(build: &mut Build) {
-    let mut resolves = Vec::new();
-    build_krate(&build.std_features(), build, &mut resolves, "src/libstd");
-    build_krate("", build, &mut resolves, "src/libtest");
-    build_krate(&build.rustc_features(), build, &mut resolves, "src/rustc");
-
-    let mut id2name = HashMap::with_capacity(build.crates.len());
-    for (name, krate) in build.crates.iter() {
-        id2name.insert(krate.id.clone(), name.clone());
-    }
-
-    for node in resolves {
-        let name = match id2name.get(&node.id) {
-            Some(name) => name,
-            None => continue,
-        };
-
-        let krate = build.crates.get_mut(name).unwrap();
-        for dep in node.dependencies.iter() {
-            let dep = match id2name.get(dep) {
-                Some(dep) => dep,
-                None => continue,
-            };
-            krate.deps.insert(*dep);
-        }
-    }
-}
-
-fn build_krate(features: &str, build: &mut Build, resolves: &mut Vec<ResolveNode>, krate: &str) {
     // Run `cargo metadata` to figure out what crates we're testing.
-    //
-    // Down below we're going to call `cargo test`, but to test the right set
-    // of packages we're going to have to know what `-p` arguments to pass it
-    // to know what crates to test. Here we run `cargo metadata` to learn about
-    // the dependency graph and what `-p` arguments there are.
     let mut cargo = Command::new(&build.initial_cargo);
     cargo
         .arg("metadata")
         .arg("--format-version")
         .arg("1")
-        .arg("--features")
-        .arg(features)
+        .arg("--no-deps")
         .arg("--manifest-path")
-        .arg(build.src.join(krate).join("Cargo.toml"));
+        .arg(build.src.join("Cargo.toml"));
     let output = output(&mut cargo);
     let output: Output = serde_json::from_str(&output).unwrap();
     for package in output.packages {
@@ -85,8 +44,13 @@ fn build_krate(features: &str, build: &mut Build, resolves: &mut Vec<ResolveNode
             let name = INTERNER.intern_string(package.name);
             let mut path = PathBuf::from(package.manifest_path);
             path.pop();
-            build.crates.insert(name, Crate { name, id: package.id, deps: HashSet::new(), path });
+            let deps = package
+                .dependencies
+                .into_iter()
+                .filter(|dep| dep.source.is_none())
+                .map(|dep| INTERNER.intern_string(dep.name))
+                .collect();
+            build.crates.insert(name, Crate { name, id: package.id, deps, path });
         }
     }
-    resolves.extend(output.resolve.nodes);
 }
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index 161f5d5ffd8f5..8a37a70d60d9a 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -1648,14 +1648,8 @@ impl Step for Crate {
     type Output = ();
     const DEFAULT: bool = true;
 
-    fn should_run(mut run: ShouldRun<'_>) -> ShouldRun<'_> {
-        let builder = run.builder;
-        for krate in run.builder.in_tree_crates("test") {
-            if !(krate.name.starts_with("rustc_") && krate.name.ends_with("san")) {
-                run = run.path(krate.local_path(&builder).to_str().unwrap());
-            }
-        }
-        run
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        run.krate("test")
     }
 
     fn make_run(run: RunConfig<'_>) {
diff --git a/src/doc/unstable-book/src/compiler-flags/control-flow-guard.md b/src/doc/unstable-book/src/compiler-flags/control-flow-guard.md
index 48dea213e8cee..4115825e92083 100644
--- a/src/doc/unstable-book/src/compiler-flags/control-flow-guard.md
+++ b/src/doc/unstable-book/src/compiler-flags/control-flow-guard.md
@@ -1,10 +1,10 @@
-# `control_flow_guard`
+# `control-flow-guard`
 
 The tracking issue for this feature is: [#68793](https://github.com/rust-lang/rust/issues/68793).
 
 ------------------------
 
-The rustc flag `-Z control_flow_guard=checks` enables the Windows [Control Flow Guard](https://docs.microsoft.com/en-us/windows/win32/secbp/control-flow-guard) (CFG) platform security feature.
+The rustc flag `-Z control-flow-guard` enables the Windows [Control Flow Guard](https://docs.microsoft.com/en-us/windows/win32/secbp/control-flow-guard) (CFG) platform security feature.
 
 CFG is an exploit mitigation designed to enforce control-flow integrity for software running on supported Windows platforms (Windows 8.1 onwards). Specifically, CFG uses runtime checks to validate the target address of every indirect call/jump before allowing the call to complete. 
 
@@ -29,7 +29,7 @@ The CFG checks and metadata can potentially increase binary size and runtime ove
 
 ## Testing Control Flow Guard
 
-The rustc flag `-Z control_flow_guard=nochecks` instructs LLVM to emit the list of valid call targets without inserting runtime checks. This flag should only be used for testing purposes as it does not provide security enforcement.
+The rustc flag `-Z control-flow-guard=nochecks` instructs LLVM to emit the list of valid call targets without inserting runtime checks. This flag should only be used for testing purposes as it does not provide security enforcement.
 
 
 ## Control Flow Guard in libraries
@@ -44,14 +44,14 @@ For example:
 ```cmd
 rustup toolchain install --force nightly
 rustup component add rust-src
-SET RUSTFLAGS=-Z control_flow_guard=checks
+SET RUSTFLAGS=-Z control-flow-guard
 cargo +nightly build -Z build-std --target x86_64-pc-windows-msvc
 ```
 
 ```PowerShell
 rustup toolchain install --force nightly
 rustup component add rust-src
-$Env:RUSTFLAGS = "-Z control_flow_guard=checks"
+$Env:RUSTFLAGS = "-Z control-flow-guard"
 cargo +nightly build -Z build-std --target x86_64-pc-windows-msvc
 ```
 
diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs
index 99ef226f94aae..997762efcb3e5 100644
--- a/src/librustc_error_codes/error_codes.rs
+++ b/src/librustc_error_codes/error_codes.rs
@@ -443,6 +443,7 @@ E0759: include_str!("./error_codes/E0759.md"),
 E0760: include_str!("./error_codes/E0760.md"),
 E0761: include_str!("./error_codes/E0761.md"),
 E0762: include_str!("./error_codes/E0762.md"),
+E0763: include_str!("./error_codes/E0763.md"),
 ;
 //  E0006, // merged with E0005
 //  E0008, // cannot bind by-move into a pattern guard
diff --git a/src/librustc_error_codes/error_codes/E0763.md b/src/librustc_error_codes/error_codes/E0763.md
new file mode 100644
index 0000000000000..095b779f3e78a
--- /dev/null
+++ b/src/librustc_error_codes/error_codes/E0763.md
@@ -0,0 +1,13 @@
+A byte constant wasn't correctly ended.
+
+Erroneous code example:
+
+```compile_fail,E0763
+let c = b'a; // error!
+```
+
+To fix this error, add the missing quote:
+
+```
+let c = b'a'; // ok!
+```
diff --git a/src/librustc_hir/hir.rs b/src/librustc_hir/hir.rs
index bed2044c70855..e1fe80ec08d8d 100644
--- a/src/librustc_hir/hir.rs
+++ b/src/librustc_hir/hir.rs
@@ -12,6 +12,7 @@ use rustc_ast::node_id::NodeMap;
 use rustc_ast::util::parser::ExprPrecedence;
 use rustc_data_structures::sync::{par_for_each_in, Send, Sync};
 use rustc_macros::HashStable_Generic;
+use rustc_span::def_id::LocalDefId;
 use rustc_span::source_map::{SourceMap, Spanned};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{MultiSpan, Span, DUMMY_SP};
@@ -2651,25 +2652,11 @@ pub type CaptureModeMap = NodeMap<CaptureBy>;
 // has length > 0 if the trait is found through an chain of imports, starting with the
 // import/use statement in the scope where the trait is used.
 #[derive(Clone, Debug)]
-pub struct TraitCandidate<ID = HirId> {
+pub struct TraitCandidate {
     pub def_id: DefId,
-    pub import_ids: SmallVec<[ID; 1]>,
+    pub import_ids: SmallVec<[LocalDefId; 1]>,
 }
 
-impl<ID> TraitCandidate<ID> {
-    pub fn map_import_ids<F, T>(self, f: F) -> TraitCandidate<T>
-    where
-        F: Fn(ID) -> T,
-    {
-        let TraitCandidate { def_id, import_ids } = self;
-        let import_ids = import_ids.into_iter().map(f).collect();
-        TraitCandidate { def_id, import_ids }
-    }
-}
-
-// Trait method resolution
-pub type TraitMap<ID = HirId> = NodeMap<Vec<TraitCandidate<ID>>>;
-
 #[derive(Copy, Clone, Debug, HashStable_Generic)]
 pub enum Node<'hir> {
     Param(&'hir Param<'hir>),
diff --git a/src/librustc_interface/tests.rs b/src/librustc_interface/tests.rs
index 87647f3b0b017..bbe2e8da12e7c 100644
--- a/src/librustc_interface/tests.rs
+++ b/src/librustc_interface/tests.rs
@@ -463,7 +463,6 @@ fn test_debugging_options_tracking_hash() {
     untracked!(ast_json_noexpand, true);
     untracked!(borrowck, String::from("other"));
     untracked!(borrowck_stats, true);
-    untracked!(control_flow_guard, CFGuard::Checks);
     untracked!(deduplicate_diagnostics, true);
     untracked!(dep_tasks, true);
     untracked!(dont_buffer_diagnostics, true);
@@ -537,6 +536,7 @@ fn test_debugging_options_tracking_hash() {
     tracked!(binary_dep_depinfo, true);
     tracked!(chalk, true);
     tracked!(codegen_backend, Some("abc".to_string()));
+    tracked!(control_flow_guard, CFGuard::Checks);
     tracked!(crate_attr, vec!["abc".to_string()]);
     tracked!(debug_macros, true);
     tracked!(dep_info_omit_d_target, true);
diff --git a/src/librustc_lint/early.rs b/src/librustc_lint/early.rs
index 06987ffa3d569..d891466611ad3 100644
--- a/src/librustc_lint/early.rs
+++ b/src/librustc_lint/early.rs
@@ -55,7 +55,8 @@ impl<'a, T: EarlyLintPass> EarlyContextAndPass<'a, T> {
     where
         F: FnOnce(&mut Self),
     {
-        let push = self.context.builder.push(attrs, &self.context.lint_store);
+        let is_crate_node = id == ast::CRATE_NODE_ID;
+        let push = self.context.builder.push(attrs, &self.context.lint_store, is_crate_node);
         self.check_id(id);
         self.enter_attrs(attrs);
         f(self);
diff --git a/src/librustc_lint/levels.rs b/src/librustc_lint/levels.rs
index 05e7c9a0c780d..f875e2750a5c5 100644
--- a/src/librustc_lint/levels.rs
+++ b/src/librustc_lint/levels.rs
@@ -29,7 +29,7 @@ fn lint_levels(tcx: TyCtxt<'_>, cnum: CrateNum) -> LintLevelMap {
     let mut builder = LintLevelMapBuilder { levels, tcx, store };
     let krate = tcx.hir().krate();
 
-    let push = builder.levels.push(&krate.item.attrs, &store);
+    let push = builder.levels.push(&krate.item.attrs, &store, true);
     builder.levels.register_id(hir::CRATE_HIR_ID);
     for macro_def in krate.exported_macros {
         builder.levels.register_id(macro_def.hir_id);
@@ -109,7 +109,12 @@ impl<'s> LintLevelsBuilder<'s> {
     ///   `#[allow]`
     ///
     /// Don't forget to call `pop`!
-    pub fn push(&mut self, attrs: &[ast::Attribute], store: &LintStore) -> BuilderPush {
+    pub fn push(
+        &mut self,
+        attrs: &[ast::Attribute],
+        store: &LintStore,
+        is_crate_node: bool,
+    ) -> BuilderPush {
         let mut specs = FxHashMap::default();
         let sess = self.sess;
         let bad_attr = |span| struct_span_err!(sess, span, E0452, "malformed lint attribute input");
@@ -333,6 +338,40 @@ impl<'s> LintLevelsBuilder<'s> {
             }
         }
 
+        if !is_crate_node {
+            for (id, &(level, ref src)) in specs.iter() {
+                if !id.lint.crate_level_only {
+                    continue;
+                }
+
+                let (lint_attr_name, lint_attr_span) = match *src {
+                    LintSource::Node(name, span, _) => (name, span),
+                    _ => continue,
+                };
+
+                let lint = builtin::UNUSED_ATTRIBUTES;
+                let (lint_level, lint_src) =
+                    self.sets.get_lint_level(lint, self.cur, Some(&specs), self.sess);
+                struct_lint_level(
+                    self.sess,
+                    lint,
+                    lint_level,
+                    lint_src,
+                    Some(lint_attr_span.into()),
+                    |lint| {
+                        let mut db = lint.build(&format!(
+                            "{}({}) is ignored unless specified at crate level",
+                            level.as_str(),
+                            lint_attr_name
+                        ));
+                        db.emit();
+                    },
+                );
+                // don't set a separate error for every lint in the group
+                break;
+            }
+        }
+
         for (id, &(level, ref src)) in specs.iter() {
             if level == Level::Forbid {
                 continue;
@@ -449,7 +488,8 @@ impl LintLevelMapBuilder<'_, '_> {
     where
         F: FnOnce(&mut Self),
     {
-        let push = self.levels.push(attrs, self.store);
+        let is_crate_hir = id == hir::CRATE_HIR_ID;
+        let push = self.levels.push(attrs, self.store, is_crate_hir);
         if push.changed {
             self.levels.register_id(id);
         }
diff --git a/src/librustc_lint/non_ascii_idents.rs b/src/librustc_lint/non_ascii_idents.rs
index ad02b2637d22f..064b0255397ce 100644
--- a/src/librustc_lint/non_ascii_idents.rs
+++ b/src/librustc_lint/non_ascii_idents.rs
@@ -8,20 +8,23 @@ use std::ops::Deref;
 declare_lint! {
     pub NON_ASCII_IDENTS,
     Allow,
-    "detects non-ASCII identifiers"
+    "detects non-ASCII identifiers",
+    crate_level_only
 }
 
 declare_lint! {
     pub UNCOMMON_CODEPOINTS,
     Warn,
-    "detects uncommon Unicode codepoints in identifiers"
+    "detects uncommon Unicode codepoints in identifiers",
+    crate_level_only
 }
 
 // FIXME: Change this to warn.
 declare_lint! {
     pub CONFUSABLE_IDENTS,
     Allow,
-    "detects visually confusable pairs between identifiers"
+    "detects visually confusable pairs between identifiers",
+    crate_level_only
 }
 
 declare_lint_pass!(NonAsciiIdents => [NON_ASCII_IDENTS, UNCOMMON_CODEPOINTS, CONFUSABLE_IDENTS]);
diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs
index 1dd6d837d4eaf..3d4d5d2ef4b97 100644
--- a/src/librustc_lint/types.rs
+++ b/src/librustc_lint/types.rs
@@ -927,22 +927,33 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
     fn check_for_opaque_ty(&mut self, sp: Span, ty: Ty<'tcx>) -> bool {
         use rustc_middle::ty::TypeFoldable;
 
-        struct ProhibitOpaqueTypes<'tcx> {
+        struct ProhibitOpaqueTypes<'a, 'tcx> {
+            cx: &'a LateContext<'a, 'tcx>,
             ty: Option<Ty<'tcx>>,
         };
 
-        impl<'tcx> ty::fold::TypeVisitor<'tcx> for ProhibitOpaqueTypes<'tcx> {
+        impl<'a, 'tcx> ty::fold::TypeVisitor<'tcx> for ProhibitOpaqueTypes<'a, 'tcx> {
             fn visit_ty(&mut self, ty: Ty<'tcx>) -> bool {
-                if let ty::Opaque(..) = ty.kind {
-                    self.ty = Some(ty);
-                    true
-                } else {
-                    ty.super_visit_with(self)
+                match ty.kind {
+                    ty::Opaque(..) => {
+                        self.ty = Some(ty);
+                        true
+                    }
+                    // Consider opaque types within projections FFI-safe if they do not normalize
+                    // to more opaque types.
+                    ty::Projection(..) => {
+                        let ty = self.cx.tcx.normalize_erasing_regions(self.cx.param_env, ty);
+
+                        // If `ty` is a opaque type directly then `super_visit_with` won't invoke
+                        // this function again.
+                        if ty.has_opaque_types() { self.visit_ty(ty) } else { false }
+                    }
+                    _ => ty.super_visit_with(self),
                 }
             }
         }
 
-        let mut visitor = ProhibitOpaqueTypes { ty: None };
+        let mut visitor = ProhibitOpaqueTypes { cx: self.cx, ty: None };
         ty.visit_with(&mut visitor);
         if let Some(ty) = visitor.ty {
             self.emit_ffi_unsafe_type_lint(ty, sp, "opaque types have no C equivalent", None);
diff --git a/src/librustc_metadata/rmeta/decoder.rs b/src/librustc_metadata/rmeta/decoder.rs
index 0335aa8358c3c..65cb45653c0d0 100644
--- a/src/librustc_metadata/rmeta/decoder.rs
+++ b/src/librustc_metadata/rmeta/decoder.rs
@@ -294,15 +294,36 @@ impl<'a, 'tcx> TyDecoder<'tcx> for DecodeContext<'a, 'tcx> {
 
         let key = ty::CReaderCacheKey { cnum: self.cdata().cnum, pos: shorthand };
 
-        if let Some(&ty) = tcx.rcache.borrow().get(&key) {
+        if let Some(&ty) = tcx.ty_rcache.borrow().get(&key) {
             return Ok(ty);
         }
 
         let ty = or_insert_with(self)?;
-        tcx.rcache.borrow_mut().insert(key, ty);
+        tcx.ty_rcache.borrow_mut().insert(key, ty);
         Ok(ty)
     }
 
+    fn cached_predicate_for_shorthand<F>(
+        &mut self,
+        shorthand: usize,
+        or_insert_with: F,
+    ) -> Result<ty::Predicate<'tcx>, Self::Error>
+    where
+        F: FnOnce(&mut Self) -> Result<ty::Predicate<'tcx>, Self::Error>,
+    {
+        let tcx = self.tcx();
+
+        let key = ty::CReaderCacheKey { cnum: self.cdata().cnum, pos: shorthand };
+
+        if let Some(&pred) = tcx.pred_rcache.borrow().get(&key) {
+            return Ok(pred);
+        }
+
+        let pred = or_insert_with(self)?;
+        tcx.pred_rcache.borrow_mut().insert(key, pred);
+        Ok(pred)
+    }
+
     fn with_position<F, R>(&mut self, pos: usize, f: F) -> R
     where
         F: FnOnce(&mut Self) -> R,
diff --git a/src/librustc_metadata/rmeta/encoder.rs b/src/librustc_metadata/rmeta/encoder.rs
index d797e6d4a34af..5ecc6ced119e9 100644
--- a/src/librustc_metadata/rmeta/encoder.rs
+++ b/src/librustc_metadata/rmeta/encoder.rs
@@ -239,6 +239,17 @@ where
     }
 }
 
+impl<'b, 'tcx> SpecializedEncoder<ty::Predicate<'b>> for EncodeContext<'tcx> {
+    fn specialized_encode(&mut self, predicate: &ty::Predicate<'b>) -> Result<(), Self::Error> {
+        debug_assert!(self.tcx.lift(predicate).is_some());
+        let predicate =
+            unsafe { std::mem::transmute::<&ty::Predicate<'b>, &ty::Predicate<'tcx>>(predicate) };
+        ty_codec::encode_with_shorthand(self, predicate, |encoder| {
+            &mut encoder.predicate_shorthands
+        })
+    }
+}
+
 impl<'tcx> SpecializedEncoder<interpret::AllocId> for EncodeContext<'tcx> {
     fn specialized_encode(&mut self, alloc_id: &interpret::AllocId) -> Result<(), Self::Error> {
         use std::collections::hash_map::Entry;
@@ -256,22 +267,6 @@ impl<'tcx> SpecializedEncoder<interpret::AllocId> for EncodeContext<'tcx> {
     }
 }
 
-impl<'a, 'b, 'tcx> SpecializedEncoder<&'a [(ty::Predicate<'b>, Span)]> for EncodeContext<'tcx> {
-    fn specialized_encode(
-        &mut self,
-        predicates: &&'a [(ty::Predicate<'b>, Span)],
-    ) -> Result<(), Self::Error> {
-        debug_assert!(self.tcx.lift(*predicates).is_some());
-        let predicates = unsafe {
-            std::mem::transmute::<
-                &&'a [(ty::Predicate<'b>, Span)],
-                &&'tcx [(ty::Predicate<'tcx>, Span)],
-            >(predicates)
-        };
-        ty_codec::encode_spanned_predicates(self, &predicates, |ecx| &mut ecx.predicate_shorthands)
-    }
-}
-
 impl<'tcx> SpecializedEncoder<Fingerprint> for EncodeContext<'tcx> {
     fn specialized_encode(&mut self, f: &Fingerprint) -> Result<(), Self::Error> {
         f.encode_opaque(&mut self.opaque)
diff --git a/src/librustc_middle/arena.rs b/src/librustc_middle/arena.rs
index f861d63aba0f3..4f1889aeb162a 100644
--- a/src/librustc_middle/arena.rs
+++ b/src/librustc_middle/arena.rs
@@ -100,6 +100,7 @@ macro_rules! arena_types {
 
             // Interned types
             [] tys: rustc_middle::ty::TyS<$tcx>, rustc_middle::ty::TyS<'_x>;
+            [] predicates: rustc_middle::ty::PredicateInner<$tcx>, rustc_middle::ty::PredicateInner<'_x>;
 
             // HIR query types
             [few] indexed_hir: rustc_middle::hir::map::IndexedHir<$tcx>, rustc_middle::hir::map::IndexedHir<'_x>;
@@ -114,6 +115,7 @@ macro_rules! arena_types {
 
             // This is used to decode the &'tcx [Span] for InlineAsm's line_spans.
             [decode] span: rustc_span::Span, rustc_span::Span;
+            [decode] used_trait_imports: rustc_data_structures::fx::FxHashSet<rustc_hir::def_id::LocalDefId>, rustc_data_structures::fx::FxHashSet<rustc_hir::def_id::LocalDefId>;
         ], $tcx);
     )
 }
diff --git a/src/librustc_middle/ich/impls_hir.rs b/src/librustc_middle/ich/impls_hir.rs
index f668cc99754f4..78b9167ddd967 100644
--- a/src/librustc_middle/ich/impls_hir.rs
+++ b/src/librustc_middle/ich/impls_hir.rs
@@ -210,16 +210,15 @@ impl<'a> HashStable<StableHashingContext<'a>> for hir::TraitCandidate {
 }
 
 impl<'a> ToStableHashKey<StableHashingContext<'a>> for hir::TraitCandidate {
-    type KeyType = (DefPathHash, SmallVec<[(DefPathHash, hir::ItemLocalId); 1]>);
+    type KeyType = (DefPathHash, SmallVec<[DefPathHash; 1]>);
 
     fn to_stable_hash_key(&self, hcx: &StableHashingContext<'a>) -> Self::KeyType {
         let hir::TraitCandidate { def_id, import_ids } = self;
 
-        let import_keys = import_ids
-            .iter()
-            .map(|hir_id| (hcx.local_def_path_hash(hir_id.owner), hir_id.local_id))
-            .collect();
-        (hcx.def_path_hash(*def_id), import_keys)
+        (
+            hcx.def_path_hash(*def_id),
+            import_ids.iter().map(|def_id| hcx.local_def_path_hash(*def_id)).collect(),
+        )
     }
 }
 
diff --git a/src/librustc_middle/query/mod.rs b/src/librustc_middle/query/mod.rs
index 3b6d54a1bc1ee..b3751beede25a 100644
--- a/src/librustc_middle/query/mod.rs
+++ b/src/librustc_middle/query/mod.rs
@@ -526,7 +526,7 @@ rustc_queries! {
     }
 
     Other {
-        query used_trait_imports(key: LocalDefId) -> &'tcx DefIdSet {
+        query used_trait_imports(key: LocalDefId) -> &'tcx FxHashSet<LocalDefId> {
             desc { |tcx| "used_trait_imports `{}`", tcx.def_path_str(key.to_def_id()) }
             cache_on_disk_if { true }
         }
diff --git a/src/librustc_middle/ty/codec.rs b/src/librustc_middle/ty/codec.rs
index 1a8e5c45dd2f7..67ceaca103e9f 100644
--- a/src/librustc_middle/ty/codec.rs
+++ b/src/librustc_middle/ty/codec.rs
@@ -10,7 +10,7 @@ use crate::arena::ArenaAllocatable;
 use crate::infer::canonical::{CanonicalVarInfo, CanonicalVarInfos};
 use crate::mir::{self, interpret::Allocation};
 use crate::ty::subst::SubstsRef;
-use crate::ty::{self, List, ToPredicate, Ty, TyCtxt};
+use crate::ty::{self, List, Ty, TyCtxt};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def_id::{CrateNum, DefId};
 use rustc_serialize::{opaque, Decodable, Decoder, Encodable, Encoder};
@@ -95,23 +95,6 @@ where
     Ok(())
 }
 
-pub fn encode_spanned_predicates<'tcx, E, C>(
-    encoder: &mut E,
-    predicates: &[(ty::Predicate<'tcx>, Span)],
-    cache: C,
-) -> Result<(), E::Error>
-where
-    E: TyEncoder,
-    C: for<'b> Fn(&'b mut E) -> &'b mut FxHashMap<ty::Predicate<'tcx>, usize>,
-{
-    predicates.len().encode(encoder)?;
-    for (predicate, span) in predicates {
-        encode_with_shorthand(encoder, predicate, &cache)?;
-        span.encode(encoder)?;
-    }
-    Ok(())
-}
-
 pub trait TyDecoder<'tcx>: Decoder {
     fn tcx(&self) -> TyCtxt<'tcx>;
 
@@ -127,6 +110,14 @@ pub trait TyDecoder<'tcx>: Decoder {
     where
         F: FnOnce(&mut Self) -> Result<Ty<'tcx>, Self::Error>;
 
+    fn cached_predicate_for_shorthand<F>(
+        &mut self,
+        shorthand: usize,
+        or_insert_with: F,
+    ) -> Result<ty::Predicate<'tcx>, Self::Error>
+    where
+        F: FnOnce(&mut Self) -> Result<ty::Predicate<'tcx>, Self::Error>;
+
     fn with_position<F, R>(&mut self, pos: usize, f: F) -> R
     where
         F: FnOnce(&mut Self) -> R;
@@ -188,6 +179,26 @@ where
     }
 }
 
+#[inline]
+pub fn decode_predicate<D>(decoder: &mut D) -> Result<ty::Predicate<'tcx>, D::Error>
+where
+    D: TyDecoder<'tcx>,
+{
+    // Handle shorthands first, if we have an usize > 0x80.
+    if decoder.positioned_at_shorthand() {
+        let pos = decoder.read_usize()?;
+        assert!(pos >= SHORTHAND_OFFSET);
+        let shorthand = pos - SHORTHAND_OFFSET;
+
+        decoder.cached_predicate_for_shorthand(shorthand, |decoder| {
+            decoder.with_position(shorthand, ty::Predicate::decode)
+        })
+    } else {
+        let tcx = decoder.tcx();
+        Ok(tcx.mk_predicate(ty::PredicateKind::decode(decoder)?))
+    }
+}
+
 #[inline]
 pub fn decode_spanned_predicates<D>(
     decoder: &mut D,
@@ -198,20 +209,7 @@ where
     let tcx = decoder.tcx();
     Ok(tcx.arena.alloc_from_iter(
         (0..decoder.read_usize()?)
-            .map(|_| {
-                // Handle shorthands first, if we have an usize > 0x80.
-                let predicate_kind = if decoder.positioned_at_shorthand() {
-                    let pos = decoder.read_usize()?;
-                    assert!(pos >= SHORTHAND_OFFSET);
-                    let shorthand = pos - SHORTHAND_OFFSET;
-
-                    decoder.with_position(shorthand, ty::PredicateKind::decode)
-                } else {
-                    ty::PredicateKind::decode(decoder)
-                }?;
-                let predicate = predicate_kind.to_predicate(tcx);
-                Ok((predicate, Decodable::decode(decoder)?))
-            })
+            .map(|_| Decodable::decode(decoder))
             .collect::<Result<Vec<_>, _>>()?,
     ))
 }
@@ -421,7 +419,6 @@ macro_rules! implement_ty_decoder {
             // FIXME(#36588): These impls are horribly unsound as they allow
             // the caller to pick any lifetime for `'tcx`, including `'static`.
 
-            rustc_hir::arena_types!(impl_arena_allocatable_decoders, [$DecoderName [$($typaram),*]], 'tcx);
             arena_types!(impl_arena_allocatable_decoders, [$DecoderName [$($typaram),*]], 'tcx);
 
             impl<$($typaram),*> SpecializedDecoder<CrateNum>
@@ -436,7 +433,24 @@ macro_rules! implement_ty_decoder {
             where &'_x ty::TyS<'_y>: UseSpecializedDecodable
             {
                 fn specialized_decode(&mut self) -> Result<&'_x ty::TyS<'_y>, Self::Error> {
-                    unsafe { transmute::<Result<ty::Ty<'tcx>, Self::Error>, Result<&'_x ty::TyS<'_y>, Self::Error>>(decode_ty(self)) }
+                    unsafe {
+                        transmute::<
+                            Result<ty::Ty<'tcx>, Self::Error>,
+                            Result<&'_x ty::TyS<'_y>, Self::Error>,
+                        >(decode_ty(self))
+                    }
+                }
+            }
+
+            impl<'_x, $($typaram),*> SpecializedDecoder<ty::Predicate<'_x>>
+            for $DecoderName<$($typaram),*> {
+                fn specialized_decode(&mut self) -> Result<ty::Predicate<'_x>, Self::Error> {
+                    unsafe {
+                        transmute::<
+                            Result<ty::Predicate<'tcx>, Self::Error>,
+                            Result<ty::Predicate<'_x>, Self::Error>,
+                        >(decode_predicate(self))
+                    }
                 }
             }
 
diff --git a/src/librustc_middle/ty/context.rs b/src/librustc_middle/ty/context.rs
index 62d6de2d71e6d..4f8803f3e7f91 100644
--- a/src/librustc_middle/ty/context.rs
+++ b/src/librustc_middle/ty/context.rs
@@ -19,8 +19,9 @@ use crate::ty::TyKind::*;
 use crate::ty::{
     self, query, AdtDef, AdtKind, BindingMode, BoundVar, CanonicalPolyFnSig, Const, ConstVid,
     DefIdTree, ExistentialPredicate, FloatVar, FloatVid, GenericParamDefKind, InferConst, InferTy,
-    IntVar, IntVid, List, ParamConst, ParamTy, PolyFnSig, Predicate, PredicateKind, ProjectionTy,
-    Region, RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyS, TyVar, TyVid, TypeAndMut,
+    IntVar, IntVid, List, ParamConst, ParamTy, PolyFnSig, Predicate, PredicateInner, PredicateKind,
+    ProjectionTy, Region, RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyS, TyVar,
+    TyVid, TypeAndMut,
 };
 use rustc_ast::ast;
 use rustc_ast::expand::allocator::AllocatorKind;
@@ -35,7 +36,7 @@ use rustc_data_structures::sync::{self, Lock, Lrc, WorkerLocal};
 use rustc_errors::ErrorReported;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefIdSet, LocalDefId, LOCAL_CRATE};
+use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LOCAL_CRATE};
 use rustc_hir::definitions::{DefPathHash, Definitions};
 use rustc_hir::lang_items::{self, PanicLocationLangItem};
 use rustc_hir::{HirId, ItemKind, ItemLocalId, ItemLocalMap, ItemLocalSet, Node, TraitCandidate};
@@ -76,7 +77,7 @@ pub struct CtxtInterners<'tcx> {
     canonical_var_infos: InternedSet<'tcx, List<CanonicalVarInfo>>,
     region: InternedSet<'tcx, RegionKind>,
     existential_predicates: InternedSet<'tcx, List<ExistentialPredicate<'tcx>>>,
-    predicate_kind: InternedSet<'tcx, PredicateKind<'tcx>>,
+    predicate: InternedSet<'tcx, PredicateInner<'tcx>>,
     predicates: InternedSet<'tcx, List<Predicate<'tcx>>>,
     projs: InternedSet<'tcx, List<ProjectionKind>>,
     place_elems: InternedSet<'tcx, List<PlaceElem<'tcx>>>,
@@ -95,7 +96,7 @@ impl<'tcx> CtxtInterners<'tcx> {
             region: Default::default(),
             existential_predicates: Default::default(),
             canonical_var_infos: Default::default(),
-            predicate_kind: Default::default(),
+            predicate: Default::default(),
             predicates: Default::default(),
             projs: Default::default(),
             place_elems: Default::default(),
@@ -123,6 +124,23 @@ impl<'tcx> CtxtInterners<'tcx> {
             })
             .0
     }
+
+    #[inline(never)]
+    fn intern_predicate(&self, kind: PredicateKind<'tcx>) -> &'tcx PredicateInner<'tcx> {
+        self.predicate
+            .intern(kind, |kind| {
+                let flags = super::flags::FlagComputation::for_predicate(&kind);
+
+                let predicate_struct = PredicateInner {
+                    kind,
+                    flags: flags.flags,
+                    outer_exclusive_binder: flags.outer_exclusive_binder,
+                };
+
+                Interned(self.arena.alloc(predicate_struct))
+            })
+            .0
+    }
 }
 
 pub struct CommonTypes<'tcx> {
@@ -390,7 +408,7 @@ pub struct TypeckTables<'tcx> {
     /// This is used for warning unused imports. During type
     /// checking, this `Lrc` should not be cloned: it must have a ref-count
     /// of 1 so that we can insert things into the set mutably.
-    pub used_trait_imports: Lrc<DefIdSet>,
+    pub used_trait_imports: Lrc<FxHashSet<LocalDefId>>,
 
     /// If any errors occurred while type-checking this body,
     /// this field will be set to `Some(ErrorReported)`.
@@ -936,8 +954,9 @@ pub struct GlobalCtxt<'tcx> {
     /// via `extern crate` item and not `--extern` option or compiler built-in.
     pub extern_prelude: FxHashMap<Symbol, bool>,
 
-    // Internal cache for metadata decoding. No need to track deps on this.
-    pub rcache: Lock<FxHashMap<ty::CReaderCacheKey, Ty<'tcx>>>,
+    // Internal caches for metadata decoding. No need to track deps on this.
+    pub ty_rcache: Lock<FxHashMap<ty::CReaderCacheKey, Ty<'tcx>>>,
+    pub pred_rcache: Lock<FxHashMap<ty::CReaderCacheKey, Predicate<'tcx>>>,
 
     /// Caches the results of trait selection. This cache is used
     /// for things that do not have to do with the parameters in scope.
@@ -1126,7 +1145,8 @@ impl<'tcx> TyCtxt<'tcx> {
             definitions,
             def_path_hash_to_def_id,
             queries: query::Queries::new(providers, extern_providers, on_disk_query_result_cache),
-            rcache: Default::default(),
+            ty_rcache: Default::default(),
+            pred_rcache: Default::default(),
             selection_cache: Default::default(),
             evaluation_cache: Default::default(),
             crate_name: Symbol::intern(crate_name),
@@ -1623,7 +1643,7 @@ macro_rules! nop_list_lift {
 nop_lift! {type_; Ty<'a> => Ty<'tcx>}
 nop_lift! {region; Region<'a> => Region<'tcx>}
 nop_lift! {const_; &'a Const<'a> => &'tcx Const<'tcx>}
-nop_lift! {predicate_kind; &'a PredicateKind<'a> => &'tcx PredicateKind<'tcx>}
+nop_lift! {predicate; &'a PredicateInner<'a> => &'tcx PredicateInner<'tcx>}
 
 nop_list_lift! {type_list; Ty<'a> => Ty<'tcx>}
 nop_list_lift! {existential_predicates; ExistentialPredicate<'a> => ExistentialPredicate<'tcx>}
@@ -1982,6 +2002,26 @@ impl<'tcx> Borrow<TyKind<'tcx>> for Interned<'tcx, TyS<'tcx>> {
         &self.0.kind
     }
 }
+// N.B., an `Interned<PredicateInner>` compares and hashes as a `PredicateKind`.
+impl<'tcx> PartialEq for Interned<'tcx, PredicateInner<'tcx>> {
+    fn eq(&self, other: &Interned<'tcx, PredicateInner<'tcx>>) -> bool {
+        self.0.kind == other.0.kind
+    }
+}
+
+impl<'tcx> Eq for Interned<'tcx, PredicateInner<'tcx>> {}
+
+impl<'tcx> Hash for Interned<'tcx, PredicateInner<'tcx>> {
+    fn hash<H: Hasher>(&self, s: &mut H) {
+        self.0.kind.hash(s)
+    }
+}
+
+impl<'tcx> Borrow<PredicateKind<'tcx>> for Interned<'tcx, PredicateInner<'tcx>> {
+    fn borrow<'a>(&'a self) -> &'a PredicateKind<'tcx> {
+        &self.0.kind
+    }
+}
 
 // N.B., an `Interned<List<T>>` compares and hashes as its elements.
 impl<'tcx, T: PartialEq> PartialEq for Interned<'tcx, List<T>> {
@@ -2048,11 +2088,10 @@ macro_rules! direct_interners {
     }
 }
 
-direct_interners!(
+direct_interners! {
     region: mk_region(RegionKind),
     const_: mk_const(Const<'tcx>),
-    predicate_kind: intern_predicate_kind(PredicateKind<'tcx>),
-);
+}
 
 macro_rules! slice_interners {
     ($($field:ident: $method:ident($ty:ty)),+) => (
@@ -2116,8 +2155,8 @@ impl<'tcx> TyCtxt<'tcx> {
 
     #[inline]
     pub fn mk_predicate(&self, kind: PredicateKind<'tcx>) -> Predicate<'tcx> {
-        let kind = self.intern_predicate_kind(kind);
-        Predicate { kind }
+        let inner = self.interners.intern_predicate(kind);
+        Predicate { inner }
     }
 
     pub fn mk_mach_int(self, tm: ast::IntTy) -> Ty<'tcx> {
diff --git a/src/librustc_middle/ty/flags.rs b/src/librustc_middle/ty/flags.rs
index bee42be8a5388..941a93bb27697 100644
--- a/src/librustc_middle/ty/flags.rs
+++ b/src/librustc_middle/ty/flags.rs
@@ -1,5 +1,6 @@
 use crate::ty::subst::{GenericArg, GenericArgKind};
 use crate::ty::{self, InferConst, Ty, TypeFlags};
+use std::slice;
 
 #[derive(Debug)]
 pub struct FlagComputation {
@@ -21,6 +22,12 @@ impl FlagComputation {
         result
     }
 
+    pub fn for_predicate(kind: &ty::PredicateKind<'_>) -> FlagComputation {
+        let mut result = FlagComputation::new();
+        result.add_predicate_kind(kind);
+        result
+    }
+
     pub fn for_const(c: &ty::Const<'_>) -> TypeFlags {
         let mut result = FlagComputation::new();
         result.add_const(c);
@@ -32,7 +39,7 @@ impl FlagComputation {
     }
 
     /// indicates that `self` refers to something at binding level `binder`
-    fn add_binder(&mut self, binder: ty::DebruijnIndex) {
+    fn add_bound_var(&mut self, binder: ty::DebruijnIndex) {
         let exclusive_binder = binder.shifted_in(1);
         self.add_exclusive_binder(exclusive_binder);
     }
@@ -46,7 +53,7 @@ impl FlagComputation {
 
     /// Adds the flags/depth from a set of types that appear within the current type, but within a
     /// region binder.
-    fn add_bound_computation(&mut self, computation: &FlagComputation) {
+    fn add_bound_computation(&mut self, computation: FlagComputation) {
         self.add_flags(computation.flags);
 
         // The types that contributed to `computation` occurred within
@@ -84,7 +91,7 @@ impl FlagComputation {
             &ty::GeneratorWitness(ref ts) => {
                 let mut computation = FlagComputation::new();
                 computation.add_tys(&ts.skip_binder()[..]);
-                self.add_bound_computation(&computation);
+                self.add_bound_computation(computation);
             }
 
             &ty::Closure(_, ref substs) => {
@@ -92,7 +99,7 @@ impl FlagComputation {
             }
 
             &ty::Bound(debruijn, _) => {
-                self.add_binder(debruijn);
+                self.add_bound_var(debruijn);
                 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
             }
 
@@ -134,12 +141,12 @@ impl FlagComputation {
                         ty::ExistentialPredicate::Projection(p) => {
                             let mut proj_computation = FlagComputation::new();
                             proj_computation.add_existential_projection(&p);
-                            self.add_bound_computation(&proj_computation);
+                            self.add_bound_computation(proj_computation);
                         }
                         ty::ExistentialPredicate::AutoTrait(_) => {}
                     }
                 }
-                self.add_bound_computation(&computation);
+                self.add_bound_computation(computation);
                 self.add_region(r);
             }
 
@@ -173,6 +180,63 @@ impl FlagComputation {
         }
     }
 
+    fn add_predicate_kind(&mut self, kind: &ty::PredicateKind<'_>) {
+        match kind {
+            ty::PredicateKind::Trait(trait_pred, _constness) => {
+                let mut computation = FlagComputation::new();
+                computation.add_substs(trait_pred.skip_binder().trait_ref.substs);
+
+                self.add_bound_computation(computation);
+            }
+            ty::PredicateKind::RegionOutlives(poly_outlives) => {
+                let mut computation = FlagComputation::new();
+                let ty::OutlivesPredicate(a, b) = poly_outlives.skip_binder();
+                computation.add_region(a);
+                computation.add_region(b);
+
+                self.add_bound_computation(computation);
+            }
+            ty::PredicateKind::TypeOutlives(poly_outlives) => {
+                let mut computation = FlagComputation::new();
+                let ty::OutlivesPredicate(ty, region) = poly_outlives.skip_binder();
+                computation.add_ty(ty);
+                computation.add_region(region);
+
+                self.add_bound_computation(computation);
+            }
+            ty::PredicateKind::Subtype(poly_subtype) => {
+                let mut computation = FlagComputation::new();
+                let ty::SubtypePredicate { a_is_expected: _, a, b } = poly_subtype.skip_binder();
+                computation.add_ty(a);
+                computation.add_ty(b);
+
+                self.add_bound_computation(computation);
+            }
+            ty::PredicateKind::Projection(projection) => {
+                let mut computation = FlagComputation::new();
+                let ty::ProjectionPredicate { projection_ty, ty } = projection.skip_binder();
+                computation.add_projection_ty(projection_ty);
+                computation.add_ty(ty);
+
+                self.add_bound_computation(computation);
+            }
+            ty::PredicateKind::WellFormed(arg) => {
+                self.add_substs(slice::from_ref(arg));
+            }
+            ty::PredicateKind::ObjectSafe(_def_id) => {}
+            ty::PredicateKind::ClosureKind(_def_id, substs, _kind) => {
+                self.add_substs(substs);
+            }
+            ty::PredicateKind::ConstEvaluatable(_def_id, substs) => {
+                self.add_substs(substs);
+            }
+            ty::PredicateKind::ConstEquate(expected, found) => {
+                self.add_const(expected);
+                self.add_const(found);
+            }
+        }
+    }
+
     fn add_ty(&mut self, ty: Ty<'_>) {
         self.add_flags(ty.flags);
         self.add_exclusive_binder(ty.outer_exclusive_binder);
@@ -190,13 +254,13 @@ impl FlagComputation {
         computation.add_tys(fn_sig.skip_binder().inputs());
         computation.add_ty(fn_sig.skip_binder().output());
 
-        self.add_bound_computation(&computation);
+        self.add_bound_computation(computation);
     }
 
     fn add_region(&mut self, r: ty::Region<'_>) {
         self.add_flags(r.type_flags());
         if let ty::ReLateBound(debruijn, _) = *r {
-            self.add_binder(debruijn);
+            self.add_bound_var(debruijn);
         }
     }
 
@@ -215,7 +279,7 @@ impl FlagComputation {
                 }
             }
             ty::ConstKind::Bound(debruijn, _) => {
-                self.add_binder(debruijn);
+                self.add_bound_var(debruijn);
                 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
             }
             ty::ConstKind::Param(_) => {
diff --git a/src/librustc_middle/ty/fold.rs b/src/librustc_middle/ty/fold.rs
index 248dd00ef47be..ed1bf655d19a9 100644
--- a/src/librustc_middle/ty/fold.rs
+++ b/src/librustc_middle/ty/fold.rs
@@ -31,6 +31,7 @@
 //! These methods return true to indicate that the visitor has found what it is
 //! looking for, and does not need to visit anything else.
 
+use crate::ty::structural_impls::PredicateVisitor;
 use crate::ty::{self, flags::FlagComputation, Binder, Ty, TyCtxt, TypeFlags};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
@@ -905,6 +906,12 @@ impl<'tcx> TypeVisitor<'tcx> for HasEscapingVarsVisitor {
     }
 }
 
+impl<'tcx> PredicateVisitor<'tcx> for HasEscapingVarsVisitor {
+    fn visit_predicate(&mut self, predicate: ty::Predicate<'tcx>) -> bool {
+        predicate.inner.outer_exclusive_binder > self.outer_index
+    }
+}
+
 // FIXME: Optimize for checking for infer flags
 struct HasTypeFlagsVisitor {
     flags: ty::TypeFlags,
@@ -929,6 +936,15 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
     }
 }
 
+impl<'tcx> PredicateVisitor<'tcx> for HasTypeFlagsVisitor {
+    fn visit_predicate(&mut self, predicate: ty::Predicate<'tcx>) -> bool {
+        debug!(
+            "HasTypeFlagsVisitor: predicate={:?} predicate.flags={:?} self.flags={:?}",
+            predicate, predicate.inner.flags, self.flags
+        );
+        predicate.inner.flags.intersects(self.flags)
+    }
+}
 /// Collects all the late-bound regions at the innermost binding level
 /// into a hash set.
 struct LateBoundRegionsCollector {
diff --git a/src/librustc_middle/ty/mod.rs b/src/librustc_middle/ty/mod.rs
index 93ef73171993c..7c7f7d5c1c7e4 100644
--- a/src/librustc_middle/ty/mod.rs
+++ b/src/librustc_middle/ty/mod.rs
@@ -121,7 +121,7 @@ pub struct ResolverOutputs {
     pub definitions: rustc_hir::definitions::Definitions,
     pub cstore: Box<CrateStoreDyn>,
     pub extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
-    pub trait_map: FxHashMap<hir::HirId, Vec<hir::TraitCandidate<hir::HirId>>>,
+    pub trait_map: FxHashMap<hir::HirId, Vec<hir::TraitCandidate>>,
     pub maybe_unused_trait_imports: FxHashSet<LocalDefId>,
     pub maybe_unused_extern_crates: Vec<(LocalDefId, Span)>,
     pub export_map: ExportMap<LocalDefId>,
@@ -628,7 +628,7 @@ impl<'tcx> Hash for TyS<'tcx> {
     }
 }
 
-impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for ty::TyS<'tcx> {
+impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TyS<'tcx> {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
         let ty::TyS {
             ref kind,
@@ -1002,16 +1002,35 @@ impl<'tcx> GenericPredicates<'tcx> {
     }
 }
 
-#[derive(Clone, Copy, Hash, RustcEncodable, RustcDecodable, Lift)]
-#[derive(HashStable)]
+#[derive(Debug)]
+crate struct PredicateInner<'tcx> {
+    kind: PredicateKind<'tcx>,
+    flags: TypeFlags,
+    /// See the comment for the corresponding field of [TyS].
+    outer_exclusive_binder: ty::DebruijnIndex,
+}
+
+#[cfg(target_arch = "x86_64")]
+static_assert_size!(PredicateInner<'_>, 40);
+
+#[derive(Clone, Copy, Lift)]
 pub struct Predicate<'tcx> {
-    kind: &'tcx PredicateKind<'tcx>,
+    inner: &'tcx PredicateInner<'tcx>,
 }
 
+impl rustc_serialize::UseSpecializedEncodable for Predicate<'_> {}
+impl rustc_serialize::UseSpecializedDecodable for Predicate<'_> {}
+
 impl<'tcx> PartialEq for Predicate<'tcx> {
     fn eq(&self, other: &Self) -> bool {
         // `self.kind` is always interned.
-        ptr::eq(self.kind, other.kind)
+        ptr::eq(self.inner, other.inner)
+    }
+}
+
+impl Hash for Predicate<'_> {
+    fn hash<H: Hasher>(&self, s: &mut H) {
+        (self.inner as *const PredicateInner<'_>).hash(s)
     }
 }
 
@@ -1020,7 +1039,22 @@ impl<'tcx> Eq for Predicate<'tcx> {}
 impl<'tcx> Predicate<'tcx> {
     #[inline(always)]
     pub fn kind(self) -> &'tcx PredicateKind<'tcx> {
-        self.kind
+        &self.inner.kind
+    }
+}
+
+impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for Predicate<'tcx> {
+    fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
+        let PredicateInner {
+            ref kind,
+
+            // The other fields just provide fast access to information that is
+            // also contained in `kind`, so no need to hash them.
+            flags: _,
+            outer_exclusive_binder: _,
+        } = self.inner;
+
+        kind.hash_stable(hcx, hasher);
     }
 }
 
diff --git a/src/librustc_middle/ty/query/on_disk_cache.rs b/src/librustc_middle/ty/query/on_disk_cache.rs
index 5374dff422425..c84a7c38d0a0e 100644
--- a/src/librustc_middle/ty/query/on_disk_cache.rs
+++ b/src/librustc_middle/ty/query/on_disk_cache.rs
@@ -524,16 +524,39 @@ impl<'a, 'tcx> TyDecoder<'tcx> for CacheDecoder<'a, 'tcx> {
         let cache_key =
             ty::CReaderCacheKey { cnum: CrateNum::ReservedForIncrCompCache, pos: shorthand };
 
-        if let Some(&ty) = tcx.rcache.borrow().get(&cache_key) {
+        if let Some(&ty) = tcx.ty_rcache.borrow().get(&cache_key) {
             return Ok(ty);
         }
 
         let ty = or_insert_with(self)?;
         // This may overwrite the entry, but it should overwrite with the same value.
-        tcx.rcache.borrow_mut().insert_same(cache_key, ty);
+        tcx.ty_rcache.borrow_mut().insert_same(cache_key, ty);
         Ok(ty)
     }
 
+    fn cached_predicate_for_shorthand<F>(
+        &mut self,
+        shorthand: usize,
+        or_insert_with: F,
+    ) -> Result<ty::Predicate<'tcx>, Self::Error>
+    where
+        F: FnOnce(&mut Self) -> Result<ty::Predicate<'tcx>, Self::Error>,
+    {
+        let tcx = self.tcx();
+
+        let cache_key =
+            ty::CReaderCacheKey { cnum: CrateNum::ReservedForIncrCompCache, pos: shorthand };
+
+        if let Some(&pred) = tcx.pred_rcache.borrow().get(&cache_key) {
+            return Ok(pred);
+        }
+
+        let pred = or_insert_with(self)?;
+        // This may overwrite the entry, but it should overwrite with the same value.
+        tcx.pred_rcache.borrow_mut().insert_same(cache_key, pred);
+        Ok(pred)
+    }
+
     fn with_position<F, R>(&mut self, pos: usize, f: F) -> R
     where
         F: FnOnce(&mut Self) -> R,
@@ -820,24 +843,16 @@ where
     }
 }
 
-impl<'a, 'b, 'c, 'tcx, E> SpecializedEncoder<&'b [(ty::Predicate<'c>, Span)]>
-    for CacheEncoder<'a, 'tcx, E>
+impl<'a, 'b, 'tcx, E> SpecializedEncoder<ty::Predicate<'b>> for CacheEncoder<'a, 'tcx, E>
 where
     E: 'a + TyEncoder,
 {
     #[inline]
-    fn specialized_encode(
-        &mut self,
-        predicates: &&'b [(ty::Predicate<'c>, Span)],
-    ) -> Result<(), Self::Error> {
-        debug_assert!(self.tcx.lift(*predicates).is_some());
-        let predicates = unsafe {
-            std::mem::transmute::<
-                &&'b [(ty::Predicate<'c>, Span)],
-                &&'tcx [(ty::Predicate<'tcx>, Span)],
-            >(predicates)
-        };
-        ty_codec::encode_spanned_predicates(self, predicates, |encoder| {
+    fn specialized_encode(&mut self, predicate: &ty::Predicate<'b>) -> Result<(), Self::Error> {
+        debug_assert!(self.tcx.lift(predicate).is_some());
+        let predicate =
+            unsafe { std::mem::transmute::<&ty::Predicate<'b>, &ty::Predicate<'tcx>>(predicate) };
+        ty_codec::encode_with_shorthand(self, predicate, |encoder| {
             &mut encoder.predicate_shorthands
         })
     }
diff --git a/src/librustc_middle/ty/structural_impls.rs b/src/librustc_middle/ty/structural_impls.rs
index f04d31601ea5b..f736037b5c15a 100644
--- a/src/librustc_middle/ty/structural_impls.rs
+++ b/src/librustc_middle/ty/structural_impls.rs
@@ -987,12 +987,34 @@ impl<'tcx> TypeFoldable<'tcx> for ty::Region<'tcx> {
 
 impl<'tcx> TypeFoldable<'tcx> for ty::Predicate<'tcx> {
     fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
-        let new = ty::PredicateKind::super_fold_with(self.kind, folder);
-        if new != *self.kind { folder.tcx().mk_predicate(new) } else { *self }
+        let new = ty::PredicateKind::super_fold_with(&self.inner.kind, folder);
+        if new != self.inner.kind { folder.tcx().mk_predicate(new) } else { *self }
     }
 
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        ty::PredicateKind::super_visit_with(self.kind, visitor)
+        ty::PredicateKind::super_visit_with(&self.inner.kind, visitor)
+    }
+
+    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
+        visitor.visit_predicate(*self)
+    }
+
+    fn has_vars_bound_at_or_above(&self, binder: ty::DebruijnIndex) -> bool {
+        self.inner.outer_exclusive_binder > binder
+    }
+
+    fn has_type_flags(&self, flags: ty::TypeFlags) -> bool {
+        self.inner.flags.intersects(flags)
+    }
+}
+
+pub(super) trait PredicateVisitor<'tcx>: TypeVisitor<'tcx> {
+    fn visit_predicate(&mut self, predicate: ty::Predicate<'tcx>) -> bool;
+}
+
+impl<T: TypeVisitor<'tcx>> PredicateVisitor<'tcx> for T {
+    default fn visit_predicate(&mut self, predicate: ty::Predicate<'tcx>) -> bool {
+        predicate.super_visit_with(self)
     }
 }
 
diff --git a/src/librustc_parse/lexer/mod.rs b/src/librustc_parse/lexer/mod.rs
index 84b3335a0f628..2e3cf4e746ae9 100644
--- a/src/librustc_parse/lexer/mod.rs
+++ b/src/librustc_parse/lexer/mod.rs
@@ -339,8 +339,15 @@ impl<'a> StringReader<'a> {
             }
             rustc_lexer::LiteralKind::Byte { terminated } => {
                 if !terminated {
-                    self.fatal_span_(start + BytePos(1), suffix_start, "unterminated byte constant")
-                        .raise()
+                    self.sess
+                        .span_diagnostic
+                        .struct_span_fatal_with_code(
+                            self.mk_sp(start + BytePos(1), suffix_start),
+                            "unterminated byte constant",
+                            error_code!(E0763),
+                        )
+                        .emit();
+                    FatalError.raise();
                 }
                 (token::Byte, Mode::Byte, 2, 1) // b' '
             }
diff --git a/src/librustc_resolve/late.rs b/src/librustc_resolve/late.rs
index 7166fef2d1395..61f20df8cc6c0 100644
--- a/src/librustc_resolve/late.rs
+++ b/src/librustc_resolve/late.rs
@@ -24,6 +24,7 @@ use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX};
 use rustc_hir::TraitCandidate;
 use rustc_middle::{bug, span_bug};
 use rustc_session::lint;
+use rustc_span::def_id::LocalDefId;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::Span;
 use smallvec::{smallvec, SmallVec};
@@ -2188,7 +2189,7 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         &mut self,
         mut ident: Ident,
         ns: Namespace,
-    ) -> Vec<TraitCandidate<NodeId>> {
+    ) -> Vec<TraitCandidate> {
         debug!("(getting traits containing item) looking for '{}'", ident.name);
 
         let mut found_traits = Vec::new();
@@ -2233,7 +2234,7 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         ident: Ident,
         ns: Namespace,
         module: Module<'a>,
-        found_traits: &mut Vec<TraitCandidate<NodeId>>,
+        found_traits: &mut Vec<TraitCandidate>,
     ) {
         assert!(ns == TypeNS || ns == ValueNS);
         let mut traits = module.traits.borrow_mut();
@@ -2292,13 +2293,13 @@ impl<'a, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
         &mut self,
         mut kind: &NameBindingKind<'_>,
         trait_name: Ident,
-    ) -> SmallVec<[NodeId; 1]> {
+    ) -> SmallVec<[LocalDefId; 1]> {
         let mut import_ids = smallvec![];
         while let NameBindingKind::Import { import, binding, .. } = kind {
             let id = self.r.definitions.local_def_id(import.id);
             self.r.maybe_unused_trait_imports.insert(id);
             self.r.add_to_glob_map(&import, trait_name);
-            import_ids.push(import.id);
+            import_ids.push(id);
             kind = &binding.kind;
         }
         import_ids
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index cca9eabe7bcf8..66e5612b627b4 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -38,7 +38,7 @@ use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
 use rustc_hir::definitions::{DefKey, Definitions};
 use rustc_hir::PrimTy::{self, Bool, Char, Float, Int, Str, Uint};
-use rustc_hir::TraitMap;
+use rustc_hir::TraitCandidate;
 use rustc_metadata::creader::{CStore, CrateLoader};
 use rustc_middle::hir::exports::ExportMap;
 use rustc_middle::middle::cstore::{CrateStore, MetadataLoaderDyn};
@@ -881,7 +881,7 @@ pub struct Resolver<'a> {
     /// `CrateNum` resolutions of `extern crate` items.
     extern_crate_map: FxHashMap<LocalDefId, CrateNum>,
     export_map: ExportMap<LocalDefId>,
-    trait_map: TraitMap<NodeId>,
+    trait_map: NodeMap<Vec<TraitCandidate>>,
 
     /// A map from nodes to anonymous modules.
     /// Anonymous modules are pseudo-modules that are implicitly created around items
@@ -1287,14 +1287,7 @@ impl<'a> Resolver<'a> {
         let trait_map = self
             .trait_map
             .into_iter()
-            .map(|(k, v)| {
-                (
-                    definitions.node_id_to_hir_id(k),
-                    v.into_iter()
-                        .map(|tc| tc.map_import_ids(|id| definitions.node_id_to_hir_id(id)))
-                        .collect(),
-                )
-            })
+            .map(|(k, v)| (definitions.node_id_to_hir_id(k), v))
             .collect();
         let maybe_unused_trait_imports = self.maybe_unused_trait_imports;
         let maybe_unused_extern_crates = self.maybe_unused_extern_crates;
@@ -1325,17 +1318,7 @@ impl<'a> Resolver<'a> {
             trait_map: self
                 .trait_map
                 .iter()
-                .map(|(&k, v)| {
-                    (
-                        self.definitions.node_id_to_hir_id(k),
-                        v.iter()
-                            .cloned()
-                            .map(|tc| {
-                                tc.map_import_ids(|id| self.definitions.node_id_to_hir_id(id))
-                            })
-                            .collect(),
-                    )
-                })
+                .map(|(&k, v)| (self.definitions.node_id_to_hir_id(k), v.clone()))
                 .collect(),
             glob_map: self.glob_map.clone(),
             maybe_unused_trait_imports: self.maybe_unused_trait_imports.clone(),
diff --git a/src/librustc_session/config.rs b/src/librustc_session/config.rs
index 411a6eecbba15..562f71e8e9287 100644
--- a/src/librustc_session/config.rs
+++ b/src/librustc_session/config.rs
@@ -82,7 +82,7 @@ pub enum Strip {
     Symbols,
 }
 
-/// The different settings that the `-Z control_flow_guard` flag can have.
+/// The different settings that the `-Z control-flow-guard` flag can have.
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
 pub enum CFGuard {
     /// Do not emit Control Flow Guard metadata or checks.
diff --git a/src/librustc_session/lint.rs b/src/librustc_session/lint.rs
index ffb4579309075..0dcbee08abea1 100644
--- a/src/librustc_session/lint.rs
+++ b/src/librustc_session/lint.rs
@@ -88,6 +88,8 @@ pub struct Lint {
 
     /// `Some` if this lint is feature gated, otherwise `None`.
     pub feature_gate: Option<Symbol>,
+
+    pub crate_level_only: bool,
 }
 
 /// Extra information for a future incompatibility lint.
@@ -111,6 +113,7 @@ impl Lint {
             report_in_external_macro: false,
             future_incompatible: None,
             feature_gate: None,
+            crate_level_only: false,
         }
     }
 
@@ -336,6 +339,7 @@ macro_rules! declare_tool_lint {
             future_incompatible: None,
             is_plugin: true,
             feature_gate: None,
+            crate_level_only: false,
         };
     );
 }
diff --git a/src/librustc_session/lint/builtin.rs b/src/librustc_session/lint/builtin.rs
index 58388bafbeddf..8229f7e94ffd6 100644
--- a/src/librustc_session/lint/builtin.rs
+++ b/src/librustc_session/lint/builtin.rs
@@ -17,6 +17,7 @@ declare_lint! {
         reference: "issue #57571 <https://github.com/rust-lang/rust/issues/57571>",
         edition: None,
     };
+    crate_level_only
 }
 
 declare_lint! {
@@ -75,7 +76,8 @@ declare_lint! {
 declare_lint! {
     pub UNUSED_CRATE_DEPENDENCIES,
     Allow,
-    "crate dependencies that are never used"
+    "crate dependencies that are never used",
+    crate_level_only
 }
 
 declare_lint! {
@@ -166,7 +168,8 @@ declare_lint! {
 declare_lint! {
     pub UNKNOWN_CRATE_TYPES,
     Deny,
-    "unknown crate type found in `#[crate_type]` directive"
+    "unknown crate type found in `#[crate_type]` directive",
+    crate_level_only
 }
 
 declare_lint! {
@@ -339,7 +342,8 @@ declare_lint! {
 declare_lint! {
     pub ELIDED_LIFETIMES_IN_PATHS,
     Allow,
-    "hidden lifetime parameters in types are deprecated"
+    "hidden lifetime parameters in types are deprecated",
+    crate_level_only
 }
 
 declare_lint! {
@@ -459,6 +463,7 @@ declare_lint! {
         reference: "issue #52234 <https://github.com/rust-lang/rust/issues/52234>",
         edition: None,
     };
+    crate_level_only
 }
 
 declare_lint! {
diff --git a/src/librustc_session/options.rs b/src/librustc_session/options.rs
index d22c6ec9d7d01..e822e79bf4fa2 100644
--- a/src/librustc_session/options.rs
+++ b/src/librustc_session/options.rs
@@ -251,7 +251,8 @@ macro_rules! options {
         pub const parse_sanitizer: &str = "one of: `address`, `leak`, `memory` or `thread`";
         pub const parse_sanitizer_list: &str = "comma separated list of sanitizers";
         pub const parse_sanitizer_memory_track_origins: &str = "0, 1, or 2";
-        pub const parse_cfguard: &str = "either `disabled`, `nochecks`, or `checks`";
+        pub const parse_cfguard: &str =
+            "either a boolean (`yes`, `no`, `on`, `off`, etc), `checks`, or `nochecks`";
         pub const parse_strip: &str = "either `none`, `debuginfo`, or `symbols`";
         pub const parse_linker_flavor: &str = ::rustc_target::spec::LinkerFlavor::one_of();
         pub const parse_optimization_fuel: &str = "crate=integer";
@@ -505,12 +506,24 @@ macro_rules! options {
         }
 
         fn parse_cfguard(slot: &mut CFGuard, v: Option<&str>) -> bool {
-            match v {
-                Some("disabled") => *slot = CFGuard::Disabled,
-                Some("nochecks") => *slot = CFGuard::NoChecks,
-                Some("checks") => *slot = CFGuard::Checks,
-                _ => return false,
+            if v.is_some() {
+                let mut bool_arg = None;
+                if parse_opt_bool(&mut bool_arg, v) {
+                    *slot = if bool_arg.unwrap() {
+                        CFGuard::Checks
+                    } else {
+                        CFGuard::Disabled
+                    };
+                    return true
+                }
             }
+
+            *slot = match v {
+                None => CFGuard::Checks,
+                Some("checks") => CFGuard::Checks,
+                Some("nochecks") => CFGuard::NoChecks,
+                Some(_) => return false,
+            };
             true
         }
 
@@ -806,8 +819,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "enable the experimental Chalk-based trait solving engine"),
     codegen_backend: Option<String> = (None, parse_opt_string, [TRACKED],
         "the backend to use"),
-    control_flow_guard: CFGuard = (CFGuard::Disabled, parse_cfguard, [UNTRACKED],
-        "use Windows Control Flow Guard (`disabled`, `nochecks` or `checks`)"),
+    control_flow_guard: CFGuard = (CFGuard::Disabled, parse_cfguard, [TRACKED],
+        "use Windows Control Flow Guard (default: no)"),
     crate_attr: Vec<String> = (Vec::new(), parse_string_push, [TRACKED],
         "inject the given attribute in the crate"),
     debug_macros: bool = (false, parse_bool, [TRACKED],
diff --git a/src/librustc_trait_selection/traits/fulfill.rs b/src/librustc_trait_selection/traits/fulfill.rs
index 106753ed809a5..32ab63458e752 100644
--- a/src/librustc_trait_selection/traits/fulfill.rs
+++ b/src/librustc_trait_selection/traits/fulfill.rs
@@ -321,7 +321,7 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> {
             ty::PredicateKind::Trait(ref data, _) => {
                 let trait_obligation = obligation.with(*data);
 
-                if data.is_global() {
+                if obligation.predicate.is_global() {
                     // no type variables present, can use evaluation for better caching.
                     // FIXME: consider caching errors too.
                     if infcx.predicate_must_hold_considering_regions(&obligation) {
diff --git a/src/librustc_typeck/check/expr.rs b/src/librustc_typeck/check/expr.rs
index 69cfafc21648f..5273b9b7a8263 100644
--- a/src/librustc_typeck/check/expr.rs
+++ b/src/librustc_typeck/check/expr.rs
@@ -913,10 +913,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     rcvr,
                     probe::ProbeScope::AllTraits,
                 ) {
-                    err.span_label(
-                        pick.item.ident.span,
-                        &format!("the method is available for `{}` here", new_rcvr_t),
-                    );
+                    debug!("try_alt_rcvr: pick candidate {:?}", pick);
+                    // Make sure the method is defined for the *actual* receiver:
+                    // we don't want to treat `Box<Self>` as a receiver if
+                    // it only works because of an autoderef to `&self`
+                    if pick.autoderefs == 0 {
+                        err.span_label(
+                            pick.item.ident.span,
+                            &format!("the method is available for `{}` here", new_rcvr_t),
+                        );
+                    }
                 }
             }
         };
diff --git a/src/librustc_typeck/check/method/mod.rs b/src/librustc_typeck/check/method/mod.rs
index ac3fa15417e9c..259c4a8664f1b 100644
--- a/src/librustc_typeck/check/method/mod.rs
+++ b/src/librustc_typeck/check/method/mod.rs
@@ -194,11 +194,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self.lookup_probe(span, segment.ident, self_ty, call_expr, ProbeScope::TraitsInScope)?;
 
         for import_id in &pick.import_ids {
-            let import_def_id = self.tcx.hir().local_def_id(*import_id);
-            debug!("used_trait_import: {:?}", import_def_id);
+            debug!("used_trait_import: {:?}", import_id);
             Lrc::get_mut(&mut self.tables.borrow_mut().used_trait_imports)
                 .unwrap()
-                .insert(import_def_id.to_def_id());
+                .insert(*import_id);
         }
 
         self.tcx.check_stability(pick.item.def_id, Some(call_expr.hir_id), span);
@@ -461,9 +460,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             let mut tables = self.tables.borrow_mut();
             let used_trait_imports = Lrc::get_mut(&mut tables.used_trait_imports).unwrap();
             for import_id in pick.import_ids {
-                let import_def_id = tcx.hir().local_def_id(import_id);
-                debug!("resolve_ufcs: used_trait_import: {:?}", import_def_id);
-                used_trait_imports.insert(import_def_id.to_def_id());
+                debug!("resolve_ufcs: used_trait_import: {:?}", import_id);
+                used_trait_imports.insert(import_id);
             }
         }
 
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 93bcd5cf29149..eb8f76687174e 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -28,6 +28,7 @@ use rustc_middle::ty::{
 };
 use rustc_session::config::nightly_options;
 use rustc_session::lint;
+use rustc_span::def_id::LocalDefId;
 use rustc_span::{symbol::Ident, Span, Symbol, DUMMY_SP};
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
 use rustc_trait_selection::traits::query::method_autoderef::MethodAutoderefBadTy;
@@ -129,7 +130,7 @@ struct Candidate<'tcx> {
     xform_ret_ty: Option<Ty<'tcx>>,
     item: ty::AssocItem,
     kind: CandidateKind<'tcx>,
-    import_ids: SmallVec<[hir::HirId; 1]>,
+    import_ids: SmallVec<[LocalDefId; 1]>,
 }
 
 #[derive(Debug)]
@@ -158,7 +159,7 @@ enum ProbeResult {
 pub struct Pick<'tcx> {
     pub item: ty::AssocItem,
     pub kind: PickKind<'tcx>,
-    pub import_ids: SmallVec<[hir::HirId; 1]>,
+    pub import_ids: SmallVec<[LocalDefId; 1]>,
 
     // Indicates that the source expression should be autoderef'd N times
     //
@@ -930,7 +931,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
 
     fn assemble_extension_candidates_for_trait(
         &mut self,
-        import_ids: &SmallVec<[hir::HirId; 1]>,
+        import_ids: &SmallVec<[LocalDefId; 1]>,
         trait_def_id: DefId,
     ) -> Result<(), MethodError<'tcx>> {
         debug!("assemble_extension_candidates_for_trait(trait_def_id={:?})", trait_def_id);
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index b60b06567d6fa..3281c216a1573 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -96,7 +96,7 @@ use rustc_errors::ErrorReported;
 use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder, DiagnosticId};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorOf, DefKind, Res};
-use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefIdSet, LocalDefId, LOCAL_CRATE};
+use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LOCAL_CRATE};
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_hir::lang_items::{
@@ -840,7 +840,7 @@ fn has_typeck_tables(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     }
 }
 
-fn used_trait_imports(tcx: TyCtxt<'_>, def_id: LocalDefId) -> &DefIdSet {
+fn used_trait_imports(tcx: TyCtxt<'_>, def_id: LocalDefId) -> &FxHashSet<LocalDefId> {
     &*tcx.typeck_tables_of(def_id).used_trait_imports
 }
 
diff --git a/src/librustc_typeck/check/writeback.rs b/src/librustc_typeck/check/writeback.rs
index ba806430f17fd..4704d8fc7666f 100644
--- a/src/librustc_typeck/check/writeback.rs
+++ b/src/librustc_typeck/check/writeback.rs
@@ -4,10 +4,8 @@
 
 use crate::check::FnCtxt;
 
-use rustc_data_structures::sync::Lrc;
 use rustc_errors::ErrorReported;
 use rustc_hir as hir;
-use rustc_hir::def_id::DefIdSet;
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_infer::infer::error_reporting::TypeAnnotationNeeded::E0282;
 use rustc_infer::infer::InferCtxt;
@@ -67,10 +65,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         wbcx.visit_user_provided_sigs();
         wbcx.visit_generator_interior_types();
 
-        let used_trait_imports = mem::replace(
-            &mut self.tables.borrow_mut().used_trait_imports,
-            Lrc::new(DefIdSet::default()),
-        );
+        let used_trait_imports = mem::take(&mut self.tables.borrow_mut().used_trait_imports);
         debug!("used_trait_imports({:?}) = {:?}", item_def_id, used_trait_imports);
         wbcx.tables.used_trait_imports = used_trait_imports;
 
diff --git a/src/librustc_typeck/check_unused.rs b/src/librustc_typeck/check_unused.rs
index eaaff70472bfb..81daf064bb368 100644
--- a/src/librustc_typeck/check_unused.rs
+++ b/src/librustc_typeck/check_unused.rs
@@ -1,14 +1,14 @@
-use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::Applicability;
 use rustc_hir as hir;
-use rustc_hir::def_id::{DefId, DefIdSet, LocalDefId, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE};
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::lint;
 use rustc_span::{Span, Symbol};
 
 pub fn check_crate(tcx: TyCtxt<'_>) {
-    let mut used_trait_imports = DefIdSet::default();
+    let mut used_trait_imports = FxHashSet::default();
     for &body_id in tcx.hir().krate().bodies.keys() {
         let item_def_id = tcx.hir().body_owner_def_id(body_id);
         let imports = tcx.used_trait_imports(item_def_id);
@@ -39,7 +39,7 @@ impl ItemLikeVisitor<'v> for CheckVisitor<'tcx> {
 
 struct CheckVisitor<'tcx> {
     tcx: TyCtxt<'tcx>,
-    used_trait_imports: DefIdSet,
+    used_trait_imports: FxHashSet<LocalDefId>,
 }
 
 impl CheckVisitor<'tcx> {
@@ -49,7 +49,7 @@ impl CheckVisitor<'tcx> {
             return;
         }
 
-        if self.used_trait_imports.contains(&def_id.to_def_id()) {
+        if self.used_trait_imports.contains(&def_id) {
             return;
         }
 
diff --git a/src/rustllvm/PassWrapper.cpp b/src/rustllvm/PassWrapper.cpp
index 3d252fe70afeb..323bd26c698a3 100644
--- a/src/rustllvm/PassWrapper.cpp
+++ b/src/rustllvm/PassWrapper.cpp
@@ -424,6 +424,12 @@ extern "C" void LLVMRustPrintTargetFeatures(LLVMTargetMachineRef TM) {
   printf("Available features for this target:\n");
   for (auto &Feature : FeatTable)
     printf("    %-*s - %s.\n", MaxFeatLen, Feature.Key, Feature.Desc);
+  printf("\nRust-specific features:\n");
+  printf("    %-*s - %s.\n",
+    MaxFeatLen,
+    "crt-static",
+    "Enables libraries with C Run-time Libraries(CRT) to be statically linked"
+  );
   printf("\n");
 
   printf("Use +feature to enable a feature, or -feature to disable it.\n"
diff --git a/src/test/codegen/cfguard_checks.rs b/src/test/codegen/cfguard_checks.rs
index 40a7353eac045..96f9158f9d394 100644
--- a/src/test/codegen/cfguard_checks.rs
+++ b/src/test/codegen/cfguard_checks.rs
@@ -1,4 +1,4 @@
-// compile-flags: -Z control_flow_guard=checks
+// compile-flags: -Z control-flow-guard=checks
 
 #![crate_type = "lib"]
 
diff --git a/src/test/codegen/cfguard_disabled.rs b/src/test/codegen/cfguard_disabled.rs
index d1747931e15c8..1325ffc0f2595 100644
--- a/src/test/codegen/cfguard_disabled.rs
+++ b/src/test/codegen/cfguard_disabled.rs
@@ -1,4 +1,4 @@
-// compile-flags: -Z control_flow_guard=disabled
+// compile-flags: -Z control-flow-guard=no
 
 #![crate_type = "lib"]
 
diff --git a/src/test/codegen/cfguard_nochecks.rs b/src/test/codegen/cfguard_nochecks.rs
index c5d7afbae257b..ae1de4c4d26d5 100644
--- a/src/test/codegen/cfguard_nochecks.rs
+++ b/src/test/codegen/cfguard_nochecks.rs
@@ -1,4 +1,4 @@
-// compile-flags: -Z control_flow_guard=nochecks
+// compile-flags: -Z control-flow-guard=nochecks
 
 #![crate_type = "lib"]
 
diff --git a/src/test/ui/impl-trait/no-method-suggested-traits.stderr b/src/test/ui/impl-trait/no-method-suggested-traits.stderr
index b5135b53e1890..3cd4d0dd391af 100644
--- a/src/test/ui/impl-trait/no-method-suggested-traits.stderr
+++ b/src/test/ui/impl-trait/no-method-suggested-traits.stderr
@@ -49,14 +49,6 @@ LL | use foo::Bar;
 error[E0599]: no method named `method` found for struct `std::rc::Rc<&mut std::boxed::Box<&char>>` in the current scope
   --> $DIR/no-method-suggested-traits.rs:32:43
    |
-LL |         fn method(&self) {}
-   |            ------
-   |            |
-   |            the method is available for `std::boxed::Box<std::rc::Rc<&mut std::boxed::Box<&char>>>` here
-   |            the method is available for `std::pin::Pin<std::rc::Rc<&mut std::boxed::Box<&char>>>` here
-   |            the method is available for `std::sync::Arc<std::rc::Rc<&mut std::boxed::Box<&char>>>` here
-   |            the method is available for `std::rc::Rc<std::rc::Rc<&mut std::boxed::Box<&char>>>` here
-...
 LL |     std::rc::Rc::new(&mut Box::new(&'a')).method();
    |                                           ^^^^^^ method not found in `std::rc::Rc<&mut std::boxed::Box<&char>>`
    |
@@ -83,16 +75,6 @@ error[E0599]: no method named `method` found for struct `std::rc::Rc<&mut std::b
    |
 LL |     std::rc::Rc::new(&mut Box::new(&1i32)).method();
    |                                            ^^^^^^ method not found in `std::rc::Rc<&mut std::boxed::Box<&i32>>`
-   | 
-  ::: $DIR/auxiliary/no_method_suggested_traits.rs:8:12
-   |
-LL |         fn method(&self) {}
-   |            ------
-   |            |
-   |            the method is available for `std::boxed::Box<std::rc::Rc<&mut std::boxed::Box<&i32>>>` here
-   |            the method is available for `std::pin::Pin<std::rc::Rc<&mut std::boxed::Box<&i32>>>` here
-   |            the method is available for `std::sync::Arc<std::rc::Rc<&mut std::boxed::Box<&i32>>>` here
-   |            the method is available for `std::rc::Rc<std::rc::Rc<&mut std::boxed::Box<&i32>>>` here
    |
    = help: items from traits can only be used if the trait is in scope
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
diff --git a/src/test/ui/issues/issue-48508.rs b/src/test/ui/issues/issue-48508.rs
index 87965c204ada7..8dc9351260ebc 100644
--- a/src/test/ui/issues/issue-48508.rs
+++ b/src/test/ui/issues/issue-48508.rs
@@ -11,7 +11,7 @@
 // ignore-asmjs wasm2js does not support source maps yet
 
 #![feature(non_ascii_idents)]
-#[allow(uncommon_codepoints)]
+#![allow(uncommon_codepoints)]
 
 #[path = "issue-48508-aux.rs"]
 mod other_file;
diff --git a/src/test/ui/lint/crate_level_only_lint.rs b/src/test/ui/lint/crate_level_only_lint.rs
new file mode 100644
index 0000000000000..d9673faa2142e
--- /dev/null
+++ b/src/test/ui/lint/crate_level_only_lint.rs
@@ -0,0 +1,22 @@
+#![deny(uncommon_codepoints, unused_attributes)]
+
+mod foo {
+#![allow(uncommon_codepoints)]
+//~^ ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+
+#[allow(uncommon_codepoints)]
+//~^ ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+const BAR: f64 = 0.000001;
+
+}
+
+#[allow(uncommon_codepoints)]
+//~^ ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+//~| ERROR allow(uncommon_codepoints) is ignored unless specified at crate level [unused_attributes]
+fn main() {
+}
diff --git a/src/test/ui/lint/crate_level_only_lint.stderr b/src/test/ui/lint/crate_level_only_lint.stderr
new file mode 100644
index 0000000000000..8fb06df2a481a
--- /dev/null
+++ b/src/test/ui/lint/crate_level_only_lint.stderr
@@ -0,0 +1,62 @@
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:4:10
+   |
+LL | #![allow(uncommon_codepoints)]
+   |          ^^^^^^^^^^^^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/crate_level_only_lint.rs:1:30
+   |
+LL | #![deny(uncommon_codepoints, unused_attributes)]
+   |                              ^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:9:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:17:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:4:10
+   |
+LL | #![allow(uncommon_codepoints)]
+   |          ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:9:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:17:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:4:10
+   |
+LL | #![allow(uncommon_codepoints)]
+   |          ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:9:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: allow(uncommon_codepoints) is ignored unless specified at crate level
+  --> $DIR/crate_level_only_lint.rs:17:9
+   |
+LL | #[allow(uncommon_codepoints)]
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 9 previous errors
+
diff --git a/src/test/ui/lint/lint-ctypes-73251-1.rs b/src/test/ui/lint/lint-ctypes-73251-1.rs
new file mode 100644
index 0000000000000..2ce80982f5ca1
--- /dev/null
+++ b/src/test/ui/lint/lint-ctypes-73251-1.rs
@@ -0,0 +1,24 @@
+#![feature(type_alias_impl_trait)]
+#![deny(improper_ctypes)]
+
+pub trait Baz { }
+
+impl Baz for u32 { }
+
+type Qux = impl Baz;
+
+pub trait Foo {
+    type Assoc;
+}
+
+impl Foo for u32 {
+    type Assoc = Qux;
+}
+
+fn assign() -> Qux { 1 }
+
+extern "C" {
+    pub fn lint_me() -> <u32 as Foo>::Assoc; //~ ERROR: uses type `impl Baz`
+}
+
+fn main() {}
diff --git a/src/test/ui/lint/lint-ctypes-73251-1.stderr b/src/test/ui/lint/lint-ctypes-73251-1.stderr
new file mode 100644
index 0000000000000..0b4237bb96fb7
--- /dev/null
+++ b/src/test/ui/lint/lint-ctypes-73251-1.stderr
@@ -0,0 +1,15 @@
+error: `extern` block uses type `impl Baz`, which is not FFI-safe
+  --> $DIR/lint-ctypes-73251-1.rs:21:25
+   |
+LL |     pub fn lint_me() -> <u32 as Foo>::Assoc;
+   |                         ^^^^^^^^^^^^^^^^^^^ not FFI-safe
+   |
+note: the lint level is defined here
+  --> $DIR/lint-ctypes-73251-1.rs:2:9
+   |
+LL | #![deny(improper_ctypes)]
+   |         ^^^^^^^^^^^^^^^
+   = note: opaque types have no C equivalent
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/lint/lint-ctypes-73251-2.rs b/src/test/ui/lint/lint-ctypes-73251-2.rs
new file mode 100644
index 0000000000000..3427c657b42ac
--- /dev/null
+++ b/src/test/ui/lint/lint-ctypes-73251-2.rs
@@ -0,0 +1,32 @@
+#![feature(type_alias_impl_trait)]
+#![deny(improper_ctypes)]
+
+pub trait TraitA {
+    type Assoc;
+}
+
+impl TraitA for u32 {
+    type Assoc = u32;
+}
+
+pub trait TraitB {
+    type Assoc;
+}
+
+impl<T> TraitB for T where T: TraitA {
+    type Assoc = <T as TraitA>::Assoc;
+}
+
+type AliasA = impl TraitA<Assoc = u32>;
+
+type AliasB = impl TraitB<Assoc = AliasA>;
+
+fn use_of_a() -> AliasA { 3 }
+
+fn use_of_b() -> AliasB { 3 }
+
+extern "C" {
+    pub fn lint_me() -> <AliasB as TraitB>::Assoc; //~ ERROR: uses type `impl TraitA`
+}
+
+fn main() {}
diff --git a/src/test/ui/lint/lint-ctypes-73251-2.stderr b/src/test/ui/lint/lint-ctypes-73251-2.stderr
new file mode 100644
index 0000000000000..43f7629b043a9
--- /dev/null
+++ b/src/test/ui/lint/lint-ctypes-73251-2.stderr
@@ -0,0 +1,15 @@
+error: `extern` block uses type `impl TraitA`, which is not FFI-safe
+  --> $DIR/lint-ctypes-73251-2.rs:29:25
+   |
+LL |     pub fn lint_me() -> <AliasB as TraitB>::Assoc;
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^ not FFI-safe
+   |
+note: the lint level is defined here
+  --> $DIR/lint-ctypes-73251-2.rs:2:9
+   |
+LL | #![deny(improper_ctypes)]
+   |         ^^^^^^^^^^^^^^^
+   = note: opaque types have no C equivalent
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/lint/lint-ctypes-73251.rs b/src/test/ui/lint/lint-ctypes-73251.rs
new file mode 100644
index 0000000000000..ebc2ca77b67a1
--- /dev/null
+++ b/src/test/ui/lint/lint-ctypes-73251.rs
@@ -0,0 +1,22 @@
+// check-pass
+
+#![feature(type_alias_impl_trait)]
+#![deny(improper_ctypes)]
+
+pub trait Foo {
+    type Assoc;
+}
+
+impl Foo for () {
+    type Assoc = u32;
+}
+
+type Bar = impl Foo<Assoc = u32>;
+
+fn assign() -> Bar {}
+
+extern "C" {
+    pub fn lint_me() -> <Bar as Foo>::Assoc;
+}
+
+fn main() {}
diff --git a/src/test/ui/parser/byte-literals.rs b/src/test/ui/parser/byte-literals.rs
index dadf3971220f7..9683a83e72095 100644
--- a/src/test/ui/parser/byte-literals.rs
+++ b/src/test/ui/parser/byte-literals.rs
@@ -8,5 +8,5 @@ pub fn main() {
     b'	';  //~ ERROR byte constant must be escaped
     b''';  //~ ERROR byte constant must be escaped
     b'é';  //~ ERROR byte constant must be ASCII
-    b'a  //~ ERROR unterminated byte constant
+    b'a  //~ ERROR unterminated byte constant [E0763]
 }
diff --git a/src/test/ui/parser/byte-literals.stderr b/src/test/ui/parser/byte-literals.stderr
index 53d50af88d33b..7bbdc07cd835f 100644
--- a/src/test/ui/parser/byte-literals.stderr
+++ b/src/test/ui/parser/byte-literals.stderr
@@ -34,7 +34,7 @@ error: byte constant must be ASCII. Use a \xHH escape for a non-ASCII byte
 LL |     b'é';
    |       ^
 
-error: unterminated byte constant
+error[E0763]: unterminated byte constant
   --> $DIR/byte-literals.rs:11:6
    |
 LL |     b'a
@@ -42,3 +42,4 @@ LL |     b'a
 
 error: aborting due to 7 previous errors
 
+For more information about this error, try `rustc --explain E0763`.
diff --git a/src/test/ui/traits/trait-item-privacy.stderr b/src/test/ui/traits/trait-item-privacy.stderr
index 7fd5c11fcf090..3be4f11097311 100644
--- a/src/test/ui/traits/trait-item-privacy.stderr
+++ b/src/test/ui/traits/trait-item-privacy.stderr
@@ -20,13 +20,6 @@ error[E0599]: no method named `b` found for struct `S` in the current scope
 LL | struct S;
    | --------- method `b` not found for this
 ...
-LL |         fn b(&self) { }
-   |            -
-   |            |
-   |            the method is available for `std::boxed::Box<S>` here
-   |            the method is available for `std::sync::Arc<S>` here
-   |            the method is available for `std::rc::Rc<S>` here
-...
 LL |     S.b();
    |       ^ method not found in `S`
    |