diff --git a/.github/ISSUE_TEMPLATE/tracking_issue.md b/.github/ISSUE_TEMPLATE/tracking_issue.md
index f93591204cd..9457cce11af 100644
--- a/.github/ISSUE_TEMPLATE/tracking_issue.md
+++ b/.github/ISSUE_TEMPLATE/tracking_issue.md
@@ -36,11 +36,11 @@ for larger features an implementation could be broken up into multiple PRs.
 
 - [ ] Implement the RFC (cc @rust-lang/XXX -- can anyone write up mentoring
       instructions?)
-- [ ] Adjust documentation ([see instructions on rustc-guide][doc-guide])
-- [ ] Stabilization PR ([see instructions on rustc-guide][stabilization-guide])
+- [ ] Adjust documentation ([see instructions on rustc-dev-guide][doc-guide])
+- [ ] Stabilization PR ([see instructions on rustc-dev-guide][stabilization-guide])
 
-[stabilization-guide]: https://rust-lang.github.io/rustc-guide/stabilization_guide.html#stabilization-pr
-[doc-guide]: https://rust-lang.github.io/rustc-guide/stabilization_guide.html#documentation-prs
+[stabilization-guide]: https://rustc-dev-guide.rust-lang.org/stabilization_guide.html#stabilization-pr
+[doc-guide]: https://rustc-dev-guide.rust-lang.org/stabilization_guide.html#documentation-prs
 
 ### Unresolved Questions
 <!--
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index a58d4f2a7c6..2843944b2e1 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -19,7 +19,7 @@ hop on the [Rust Discord server][rust-discord] or [Rust Zulip server][rust-zulip
 
 As a reminder, all contributors are expected to follow our [Code of Conduct][coc].
 
-The [rustc-guide] is your friend! It describes how the compiler works and how
+The [rustc-dev-guide] is your friend! It describes how the compiler works and how
 to contribute to it in more detail than this document.
 
 If this is your first time contributing, the [walkthrough] chapter of the guide
@@ -29,8 +29,8 @@ can give you a good example of how a typical contribution would go.
 [rust-discord]: http://discord.gg/rust-lang
 [rust-zulip]: https://rust-lang.zulipchat.com
 [coc]: https://www.rust-lang.org/conduct.html
-[rustc-guide]: https://rust-lang.github.io/rustc-guide/
-[walkthrough]: https://rust-lang.github.io/rustc-guide/walkthrough.html
+[rustc-dev-guide]: https://rustc-dev-guide.rust-lang.org/
+[walkthrough]: https://rustc-dev-guide.rust-lang.org/walkthrough.html
 
 ## Feature Requests
 [feature-requests]: #feature-requests
@@ -103,12 +103,12 @@ $ RUST_BACKTRACE=1 rustc ...
 ## The Build System
 
 For info on how to configure and build the compiler, please see [this
-chapter][rustcguidebuild] of the rustc-guide. This chapter contains info for
+chapter][rustcguidebuild] of the rustc-dev-guide. This chapter contains info for
 contributions to the compiler and the standard library. It also lists some
 really useful commands to the build system (`./x.py`), which could save you a
 lot of time.
 
-[rustcguidebuild]: https://rust-lang.github.io/rustc-guide/building/how-to-build-and-run.html
+[rustcguidebuild]: https://rustc-dev-guide.rust-lang.org/building/how-to-build-and-run.html
 
 ## Pull Requests
 [pull-requests]: #pull-requests
@@ -336,9 +336,9 @@ to check small fixes. For example, `rustdoc src/doc/reference.md` will render
 reference to `doc/reference.html`. The CSS might be messed up, but you can
 verify that the HTML is right.
 
-Additionally, contributions to the [rustc-guide] are always welcome. Contributions
+Additionally, contributions to the [rustc-dev-guide] are always welcome. Contributions
 can be made directly at [the
-rust-lang/rustc-guide](https://github.com/rust-lang/rustc-guide) repo. The issue
+rust-lang/rustc-dev-guide](https://github.com/rust-lang/rustc-dev-guide) repo. The issue
 tracker in that repo is also a great way to find things that need doing. There
 are issues for beginners and advanced compiler devs alike!
 
@@ -434,7 +434,7 @@ For people new to Rust, and just starting to contribute, or even for
 more seasoned developers, some useful places to look for information
 are:
 
-* The [rustc guide] contains information about how various parts of the compiler work and how to contribute to the compiler
+* The [rustc dev guide] contains information about how various parts of the compiler work and how to contribute to the compiler
 * [Rust Forge][rustforge] contains additional documentation, including write-ups of how to achieve common tasks
 * The [Rust Internals forum][rif], a place to ask questions and
   discuss Rust's internals
@@ -448,7 +448,7 @@ are:
 * **Google!** ([search only in Rust Documentation][gsearchdocs] to find types, traits, etc. quickly)
 * Don't be afraid to ask! The Rust community is friendly and helpful.
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/about-this-guide.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/about-this-guide.html
 [gdfrustc]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc/
 [gsearchdocs]: https://www.google.com/search?q=site:doc.rust-lang.org+your+query+here
 [rif]: http://internals.rust-lang.org
@@ -456,5 +456,5 @@ are:
 [rustforge]: https://forge.rust-lang.org/
 [tlgba]: http://tomlee.co/2014/04/a-more-detailed-tour-of-the-rust-compiler/
 [ro]: http://www.rustaceans.org/
-[rctd]: https://rust-lang.github.io/rustc-guide/tests/intro.html
+[rctd]: https://rustc-dev-guide.rust-lang.org/tests/intro.html
 [cheatsheet]: https://buildbot2.rust-lang.org/homu/
diff --git a/README.md b/README.md
index 61d3c9e1157..1cd9b8a3a2a 100644
--- a/README.md
+++ b/README.md
@@ -15,13 +15,13 @@ Read ["Installation"] from [The Book].
 ## Installing from Source
 
 _Note: If you wish to contribute to the compiler, you should read [this
-chapter][rustcguidebuild] of the rustc-guide instead of this section._
+chapter][rustcguidebuild] of the rustc-dev-guide instead of this section._
 
 The Rust build system has a Python script called `x.py` to bootstrap building
 the compiler. More information about it may be found by running `./x.py --help`
-or reading the [rustc guide][rustcguidebuild].
+or reading the [rustc dev guide][rustcguidebuild].
 
-[rustcguidebuild]: https://rust-lang.github.io/rustc-guide/building/how-to-build-and-run.html
+[rustcguidebuild]: https://rustc-dev-guide.rust-lang.org/building/how-to-build-and-run.html
 
 ### Building on *nix
 1. Make sure you have installed the dependencies:
@@ -249,13 +249,13 @@ Most real-time collaboration happens in a variety of channels on the
 community, documentation, and all major contribution areas in the Rust ecosystem.
 A good place to ask for help would be the #help channel.
 
-The [rustc guide] might be a good place to start if you want to find out how
+The [rustc dev guide] might be a good place to start if you want to find out how
 various parts of the compiler work.
 
 Also, you may find the [rustdocs for the compiler itself][rustdocs] useful.
 
 [rust-discord]: https://discord.gg/rust-lang
-[rustc guide]: https://rust-lang.github.io/rustc-guide/about-this-guide.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/about-this-guide.html
 [rustdocs]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc/
 
 ## License
diff --git a/src/README.md b/src/README.md
index 2f7cf90c5f0..b69a92a7237 100644
--- a/src/README.md
+++ b/src/README.md
@@ -3,6 +3,6 @@ This directory contains the source code of the rust project, including:
 - `libstd`
 - Various submodules for tools, like rustdoc, rls, etc.
 
-For more information on how various parts of the compiler work, see the [rustc guide].
+For more information on how various parts of the compiler work, see the [rustc dev guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/about-this-guide.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/about-this-guide.html
diff --git a/src/bootstrap/toolstate.rs b/src/bootstrap/toolstate.rs
index 7cffc472930..f0e0f92af55 100644
--- a/src/bootstrap/toolstate.rs
+++ b/src/bootstrap/toolstate.rs
@@ -215,6 +215,9 @@ impl Step for ToolStateCheck {
                             tool, old_state, state
                         );
                     } else {
+                        // This warning only appears in the logs, which most
+                        // people won't read. It's mostly here for testing and
+                        // debugging.
                         eprintln!(
                             "warning: Tool `{}` is not test-pass (is `{}`), \
                             this should be fixed before beta is branched.",
@@ -222,6 +225,11 @@ impl Step for ToolStateCheck {
                         );
                     }
                 }
+                // `publish_toolstate.py` is responsible for updating
+                // `latest.json` and creating comments/issues warning people
+                // if there is a regression. That all happens in a separate CI
+                // job on the master branch once the PR has passed all tests
+                // on the `auto` branch.
             }
         }
 
@@ -230,7 +238,7 @@ impl Step for ToolStateCheck {
         }
 
         if builder.config.channel == "nightly" && env::var_os("TOOLSTATE_PUBLISH").is_some() {
-            commit_toolstate_change(&toolstates, in_beta_week);
+            commit_toolstate_change(&toolstates);
         }
     }
 
@@ -325,11 +333,11 @@ fn prepare_toolstate_config(token: &str) {
             Err(_) => false,
         };
         if !success {
-            panic!("git config key={} value={} successful (status: {:?})", key, value, status);
+            panic!("git config key={} value={} failed (status: {:?})", key, value, status);
         }
     }
 
-    // If changing anything here, then please check that src/ci/publish_toolstate.sh is up to date
+    // If changing anything here, then please check that `src/ci/publish_toolstate.sh` is up to date
     // as well.
     git_config("user.email", "7378925+rust-toolstate-update@users.noreply.github.com");
     git_config("user.name", "Rust Toolstate Update");
@@ -373,14 +381,14 @@ fn read_old_toolstate() -> Vec<RepoState> {
 ///
 ///       * See <https://help.github.com/articles/about-commit-email-addresses/>
 ///           if a private email by GitHub is wanted.
-fn commit_toolstate_change(current_toolstate: &ToolstateData, in_beta_week: bool) {
-    let old_toolstate = read_old_toolstate();
-
+fn commit_toolstate_change(current_toolstate: &ToolstateData) {
     let message = format!("({} CI update)", OS.expect("linux/windows only"));
     let mut success = false;
     for _ in 1..=5 {
-        // Update the toolstate results (the new commit-to-toolstate mapping) in the toolstate repo.
-        change_toolstate(&current_toolstate, &old_toolstate, in_beta_week);
+        // Upload the test results (the new commit-to-toolstate mapping) to the toolstate repo.
+        // This does *not* change the "current toolstate"; that only happens post-landing
+        // via `src/ci/docker/publish_toolstate.sh`.
+        publish_test_results(&current_toolstate);
 
         // `git commit` failing means nothing to commit.
         let status = t!(Command::new("git")
@@ -429,31 +437,12 @@ fn commit_toolstate_change(current_toolstate: &ToolstateData, in_beta_week: bool
     }
 }
 
-fn change_toolstate(
-    current_toolstate: &ToolstateData,
-    old_toolstate: &[RepoState],
-    in_beta_week: bool,
-) {
-    let mut regressed = false;
-    for repo_state in old_toolstate {
-        let tool = &repo_state.tool;
-        let state = repo_state.state();
-        let new_state = current_toolstate[tool.as_str()];
-
-        if new_state != state {
-            eprintln!("The state of `{}` has changed from `{}` to `{}`", tool, state, new_state);
-            if new_state < state {
-                if !NIGHTLY_TOOLS.iter().any(|(name, _path)| name == tool) {
-                    regressed = true;
-                }
-            }
-        }
-    }
-
-    if regressed && in_beta_week {
-        std::process::exit(1);
-    }
-
+/// Updates the "history" files with the latest results.
+///
+/// These results will later be promoted to `latest.json` by the
+/// `publish_toolstate.py` script if the PR passes all tests and is merged to
+/// master.
+fn publish_test_results(current_toolstate: &ToolstateData) {
     let commit = t!(std::process::Command::new("git").arg("rev-parse").arg("HEAD").output());
     let commit = t!(String::from_utf8(commit.stdout));
 
diff --git a/src/ci/publish_toolstate.sh b/src/ci/publish_toolstate.sh
index 7c43d034d8b..691df04e754 100755
--- a/src/ci/publish_toolstate.sh
+++ b/src/ci/publish_toolstate.sh
@@ -23,7 +23,9 @@ GIT_COMMIT_MSG="$(git log --format=%s -n1 HEAD)"
 cd rust-toolstate
 FAILURE=1
 for RETRY_COUNT in 1 2 3 4 5; do
-    #  The purpose is to publish the new "current" toolstate in the toolstate repo.
+    # The purpose of this is to publish the new "current" toolstate in the toolstate repo.
+    # This happens post-landing, on master.
+    # (Publishing the per-commit test results happens pre-landing in src/bootstrap/toolstate.rs).
     "$(ciCheckoutPath)/src/tools/publish_toolstate.py" "$GIT_COMMIT" \
         "$GIT_COMMIT_MSG" \
         "$MESSAGE_FILE" \
diff --git a/src/doc/index.md b/src/doc/index.md
index 0a2a80e8fd6..2d10230ffcf 100644
--- a/src/doc/index.md
+++ b/src/doc/index.md
@@ -120,7 +120,7 @@ Rust. It's also sometimes called "the 'nomicon."
 
 ## The `rustc` Contribution Guide
 
-[The `rustc` Guide](https://rust-lang.github.io/rustc-guide/) documents how
+[The `rustc` Guide](https://rustc-dev-guide.rust-lang.org/) documents how
 the compiler works and how to contribute to it. This is useful if you want to build
 or modify the Rust compiler from source (e.g. to target something non-standard).
 
diff --git a/src/doc/rustc/src/contributing.md b/src/doc/rustc/src/contributing.md
index 25a5c97b0a1..3b552e7cc0a 100644
--- a/src/doc/rustc/src/contributing.md
+++ b/src/doc/rustc/src/contributing.md
@@ -1,12 +1,12 @@
 # Contributing to rustc
 
 We'd love to have your help improving `rustc`! To that end, we've written [a
-whole book][rustc_guide] on its
+whole book][rustc_dev_guide] on its
 internals, how it works, and how to get started working on it. To learn
 more, you'll want to check that out.
 
 If you would like to contribute to _this_ book, you can find its source in the
 rustc source at [src/doc/rustc][rustc_book].
 
-[rustc_guide]: https://rust-lang.github.io/rustc-guide/
+[rustc_dev_guide]: https://rustc-dev-guide.rust-lang.org/
 [rustc_book]: https://github.com/rust-lang/rust/tree/master/src/doc/rustc
diff --git a/src/liballoc/collections/mod.rs b/src/liballoc/collections/mod.rs
index 0bb62373fab..6b21e54f66a 100644
--- a/src/liballoc/collections/mod.rs
+++ b/src/liballoc/collections/mod.rs
@@ -42,6 +42,7 @@ pub use linked_list::LinkedList;
 pub use vec_deque::VecDeque;
 
 use crate::alloc::{Layout, LayoutErr};
+use core::fmt::Display;
 
 /// The error type for `try_reserve` methods.
 #[derive(Clone, PartialEq, Eq, Debug)]
@@ -77,6 +78,23 @@ impl From<LayoutErr> for TryReserveError {
     }
 }
 
+#[unstable(feature = "try_reserve", reason = "new API", issue = "48043")]
+impl Display for TryReserveError {
+    fn fmt(
+        &self,
+        fmt: &mut core::fmt::Formatter<'_>,
+    ) -> core::result::Result<(), core::fmt::Error> {
+        fmt.write_str("memory allocation failed")?;
+        let reason = match &self {
+            TryReserveError::CapacityOverflow => {
+                " because the computed capacity exceeded the collection's maximum"
+            }
+            TryReserveError::AllocError { .. } => " because the memory allocator returned a error",
+        };
+        fmt.write_str(reason)
+    }
+}
+
 /// An intermediate trait for specialization of `Extend`.
 #[doc(hidden)]
 trait SpecExtend<I: IntoIterator> {
diff --git a/src/libcore/fmt/float.rs b/src/libcore/fmt/float.rs
index 5ef673009bb..52d8349bc9a 100644
--- a/src/libcore/fmt/float.rs
+++ b/src/libcore/fmt/float.rs
@@ -2,8 +2,6 @@ use crate::fmt::{Debug, Display, Formatter, LowerExp, Result, UpperExp};
 use crate::mem::MaybeUninit;
 use crate::num::flt2dec;
 
-// ignore-tidy-undocumented-unsafe
-
 // Don't inline this so callers don't use the stack space this function
 // requires unless they have to.
 #[inline(never)]
@@ -16,6 +14,7 @@ fn float_to_decimal_common_exact<T>(
 where
     T: flt2dec::DecodableFloat,
 {
+    // SAFETY: Possible undefined behavior, see FIXME(#53491)
     unsafe {
         let mut buf = MaybeUninit::<[u8; 1024]>::uninit(); // enough for f32 and f64
         let mut parts = MaybeUninit::<[flt2dec::Part<'_>; 4]>::uninit();
@@ -48,6 +47,7 @@ fn float_to_decimal_common_shortest<T>(
 where
     T: flt2dec::DecodableFloat,
 {
+    // SAFETY: Possible undefined behavior, see FIXME(#53491)
     unsafe {
         // enough for f32 and f64
         let mut buf = MaybeUninit::<[u8; flt2dec::MAX_SIG_DIGITS]>::uninit();
@@ -103,6 +103,7 @@ fn float_to_exponential_common_exact<T>(
 where
     T: flt2dec::DecodableFloat,
 {
+    // SAFETY: Possible undefined behavior, see FIXME(#53491)
     unsafe {
         let mut buf = MaybeUninit::<[u8; 1024]>::uninit(); // enough for f32 and f64
         let mut parts = MaybeUninit::<[flt2dec::Part<'_>; 6]>::uninit();
@@ -132,6 +133,7 @@ fn float_to_exponential_common_shortest<T>(
 where
     T: flt2dec::DecodableFloat,
 {
+    // SAFETY: Possible undefined behavior, see FIXME(#53491)
     unsafe {
         // enough for f32 and f64
         let mut buf = MaybeUninit::<[u8; flt2dec::MAX_SIG_DIGITS]>::uninit();
diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index d2cebf593ab..a93b34fc46c 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -1,7 +1,5 @@
 //! Utilities for formatting and printing strings.
 
-// ignore-tidy-undocumented-unsafe
-
 #![stable(feature = "rust1", since = "1.0.0")]
 
 use crate::cell::{Cell, Ref, RefCell, RefMut, UnsafeCell};
@@ -281,6 +279,14 @@ impl<'a> ArgumentV1<'a> {
     #[doc(hidden)]
     #[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
     pub fn new<'b, T>(x: &'b T, f: fn(&T, &mut Formatter<'_>) -> Result) -> ArgumentV1<'b> {
+        // SAFETY: `mem::transmute(x)` is safe because
+        //     1. `&'b T` keeps the lifetime it originated with `'b`
+        //              (so as to not have an unbounded lifetime)
+        //     2. `&'b T` and `&'b Void` have the same memory layout
+        //              (when `T` is `Sized`, as it is here)
+        // `mem::transmute(f)` is safe since `fn(&T, &mut Formatter<'_>) -> Result`
+        // and `fn(&Void, &mut Formatter<'_>) -> Result` have the same ABI
+        // (as long as `T` is `Sized`)
         unsafe { ArgumentV1 { formatter: mem::transmute(f), value: mem::transmute(x) } }
     }
 
@@ -1399,6 +1405,14 @@ impl<'a> Formatter<'a> {
 
     fn write_formatted_parts(&mut self, formatted: &flt2dec::Formatted<'_>) -> Result {
         fn write_bytes(buf: &mut dyn Write, s: &[u8]) -> Result {
+            // SAFETY: This is used for `flt2dec::Part::Num` and `flt2dec::Part::Copy`.
+            // It's safe to use for `flt2dec::Part::Num` since every char `c` is between
+            // `b'0'` and `b'9'`, which means `s` is valid UTF-8.
+            // It's also probably safe in practice to use for `flt2dec::Part::Copy(buf)`
+            // since `buf` should be plain ASCII, but it's possible for someone to pass
+            // in a bad value for `buf` into `flt2dec::to_shortest_str` since it is a
+            // public function.
+            // FIXME: Determine whether this could result in UB.
             buf.write_str(unsafe { str::from_utf8_unchecked(s) })
         }
 
diff --git a/src/libcore/fmt/num.rs b/src/libcore/fmt/num.rs
index 5dfd3a8ecdb..7d77e33d743 100644
--- a/src/libcore/fmt/num.rs
+++ b/src/libcore/fmt/num.rs
@@ -1,7 +1,5 @@
 //! Integer and floating-point number formatting
 
-// ignore-tidy-undocumented-unsafe
-
 use crate::fmt;
 use crate::mem::MaybeUninit;
 use crate::num::flt2dec;
@@ -84,6 +82,8 @@ trait GenericRadix {
             }
         }
         let buf = &buf[curr..];
+        // SAFETY: The only chars in `buf` are created by `Self::digit` which are assumed to be
+        // valid UTF-8
         let buf = unsafe {
             str::from_utf8_unchecked(slice::from_raw_parts(MaybeUninit::first_ptr(buf), buf.len()))
         };
@@ -189,11 +189,19 @@ static DEC_DIGITS_LUT: &[u8; 200] = b"0001020304050607080910111213141516171819\
 macro_rules! impl_Display {
     ($($t:ident),* as $u:ident via $conv_fn:ident named $name:ident) => {
         fn $name(mut n: $u, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            // 2^128 is about 3*10^38, so 39 gives an extra byte of space
             let mut buf = [MaybeUninit::<u8>::uninit(); 39];
             let mut curr = buf.len() as isize;
             let buf_ptr = MaybeUninit::first_ptr_mut(&mut buf);
             let lut_ptr = DEC_DIGITS_LUT.as_ptr();
 
+            // SAFETY: Since `d1` and `d2` are always less than or equal to `198`, we
+            // can copy from `lut_ptr[d1..d1 + 1]` and `lut_ptr[d2..d2 + 1]`. To show
+            // that it's OK to copy into `buf_ptr`, notice that at the beginning
+            // `curr == buf.len() == 39 > log(n)` since `n < 2^128 < 10^39`, and at
+            // each step this is kept the same as `n` is divided. Since `n` is always
+            // non-negative, this means that `curr > 0` so `buf_ptr[curr..curr + 1]`
+            // is safe to access.
             unsafe {
                 // need at least 16 bits for the 4-characters-at-a-time to work.
                 assert!(crate::mem::size_of::<$u>() >= 2);
@@ -206,6 +214,10 @@ macro_rules! impl_Display {
                     let d1 = (rem / 100) << 1;
                     let d2 = (rem % 100) << 1;
                     curr -= 4;
+
+                    // We are allowed to copy to `buf_ptr[curr..curr + 3]` here since
+                    // otherwise `curr < 0`. But then `n` was originally at least `10000^10`
+                    // which is `10^40 > 2^128 > n`.
                     ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
                     ptr::copy_nonoverlapping(lut_ptr.offset(d2), buf_ptr.offset(curr + 2), 2);
                 }
@@ -232,6 +244,8 @@ macro_rules! impl_Display {
                 }
             }
 
+            // SAFETY: `curr` > 0 (since we made `buf` large enough), and all the chars are valid
+            // UTF-8 since `DEC_DIGITS_LUT` is
             let buf_slice = unsafe {
                 str::from_utf8_unchecked(
                     slice::from_raw_parts(buf_ptr.offset(curr), buf.len() - curr as usize))
@@ -304,6 +318,8 @@ macro_rules! impl_Exp {
             };
 
             // 39 digits (worst case u128) + . = 40
+            // Since `curr` always decreases by the number of digits copied, this means
+            // that `curr >= 0`.
             let mut buf = [MaybeUninit::<u8>::uninit(); 40];
             let mut curr = buf.len() as isize; //index for buf
             let buf_ptr = MaybeUninit::first_ptr_mut(&mut buf);
@@ -313,6 +329,8 @@ macro_rules! impl_Exp {
             while n >= 100 {
                 let d1 = ((n % 100) as isize) << 1;
                 curr -= 2;
+                // SAFETY: `d1 <= 198`, so we can copy from `lut_ptr[d1..d1 + 2]` since
+                // `DEC_DIGITS_LUT` has a length of 200.
                 unsafe {
                     ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
                 }
@@ -324,6 +342,7 @@ macro_rules! impl_Exp {
             // decode second-to-last character
             if n >= 10 {
                 curr -= 1;
+                // SAFETY: Safe since `40 > curr >= 0` (see comment)
                 unsafe {
                     *buf_ptr.offset(curr) = (n as u8 % 10_u8) + b'0';
                 }
@@ -333,11 +352,13 @@ macro_rules! impl_Exp {
             // add decimal point iff >1 mantissa digit will be printed
             if exponent != trailing_zeros || added_precision != 0 {
                 curr -= 1;
+                // SAFETY: Safe since `40 > curr >= 0`
                 unsafe {
                     *buf_ptr.offset(curr) = b'.';
                 }
             }
 
+            // SAFETY: Safe since `40 > curr >= 0`
             let buf_slice = unsafe {
                 // decode last character
                 curr -= 1;
@@ -350,6 +371,8 @@ macro_rules! impl_Exp {
             // stores 'e' (or 'E') and the up to 2-digit exponent
             let mut exp_buf = [MaybeUninit::<u8>::uninit(); 3];
             let exp_ptr = MaybeUninit::first_ptr_mut(&mut exp_buf);
+            // SAFETY: In either case, `exp_buf` is written within bounds and `exp_ptr[..len]`
+            // is contained within `exp_buf` since `len <= 3`.
             let exp_slice = unsafe {
                 *exp_ptr.offset(0) = if upper {b'E'} else {b'e'};
                 let len = if exponent < 10 {
diff --git a/src/libproc_macro/lib.rs b/src/libproc_macro/lib.rs
index c51db695a5b..59ce14c97c0 100644
--- a/src/libproc_macro/lib.rs
+++ b/src/libproc_macro/lib.rs
@@ -41,7 +41,7 @@ pub use diagnostic::{Diagnostic, Level, MultiSpan};
 use std::ops::{Bound, RangeBounds};
 use std::path::PathBuf;
 use std::str::FromStr;
-use std::{fmt, iter, mem};
+use std::{error, fmt, iter, mem};
 
 /// The main type provided by this crate, representing an abstract stream of
 /// tokens, or, more specifically, a sequence of token trees.
@@ -66,6 +66,16 @@ pub struct LexError {
     _inner: (),
 }
 
+#[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")]
+impl fmt::Display for LexError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("cannot parse string into token stream")
+    }
+}
+
+#[stable(feature = "proc_macro_lexerror_impls", since = "1.44.0")]
+impl error::Error for LexError {}
+
 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
 impl !Send for LexError {}
 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
diff --git a/src/librustc/README.md b/src/librustc/README.md
index c0e5c542bdc..de58f546cd3 100644
--- a/src/librustc/README.md
+++ b/src/librustc/README.md
@@ -1,3 +1,3 @@
-For more information about how rustc works, see the [rustc guide].
+For more information about how rustc works, see the [rustc dev guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/
diff --git a/src/librustc/dep_graph/README.md b/src/librustc/dep_graph/README.md
index 91a06e452e5..b9d91cd35a8 100644
--- a/src/librustc/dep_graph/README.md
+++ b/src/librustc/dep_graph/README.md
@@ -1,4 +1,4 @@
 To learn more about how dependency tracking works in rustc, see the [rustc
 guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/query.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/query.html
diff --git a/src/librustc/dep_graph/graph.rs b/src/librustc/dep_graph/graph.rs
index d5cde703411..a2dc1fdb34b 100644
--- a/src/librustc/dep_graph/graph.rs
+++ b/src/librustc/dep_graph/graph.rs
@@ -174,7 +174,7 @@ impl DepGraph {
     /// what state they have access to. In particular, we want to
     /// prevent implicit 'leaks' of tracked state into the task (which
     /// could then be read without generating correct edges in the
-    /// dep-graph -- see the [rustc guide] for more details on
+    /// dep-graph -- see the [rustc dev guide] for more details on
     /// the dep-graph). To this end, the task function gets exactly two
     /// pieces of state: the context `cx` and an argument `arg`. Both
     /// of these bits of state must be of some type that implements
@@ -194,7 +194,7 @@ impl DepGraph {
     /// - If you need 3+ arguments, use a tuple for the
     ///   `arg` parameter.
     ///
-    /// [rustc guide]: https://rust-lang.github.io/rustc-guide/incremental-compilation.html
+    /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/incremental-compilation.html
     pub fn with_task<'a, C, A, R>(
         &self,
         key: DepNode,
diff --git a/src/librustc/hir/map/blocks.rs b/src/librustc/hir/map/blocks.rs
index 618f9a018d1..d9ffe4582e7 100644
--- a/src/librustc/hir/map/blocks.rs
+++ b/src/librustc/hir/map/blocks.rs
@@ -60,7 +60,7 @@ impl MaybeFnLike for hir::ImplItem<'_> {
 impl MaybeFnLike for hir::TraitItem<'_> {
     fn is_fn_like(&self) -> bool {
         match self.kind {
-            hir::TraitItemKind::Method(_, hir::TraitMethod::Provided(_)) => true,
+            hir::TraitItemKind::Fn(_, hir::TraitMethod::Provided(_)) => true,
             _ => false,
         }
     }
@@ -239,7 +239,7 @@ impl<'a> FnLikeNode<'a> {
                 _ => bug!("item FnLikeNode that is not fn-like"),
             },
             Node::TraitItem(ti) => match ti.kind {
-                hir::TraitItemKind::Method(ref sig, hir::TraitMethod::Provided(body)) => {
+                hir::TraitItemKind::Fn(ref sig, hir::TraitMethod::Provided(body)) => {
                     method(ti.hir_id, ti.ident, sig, None, body, ti.span, &ti.attrs)
                 }
                 _ => bug!("trait method FnLikeNode that is not fn-like"),
diff --git a/src/librustc/hir/map/mod.rs b/src/librustc/hir/map/mod.rs
index 0f129904b43..cacb76c2861 100644
--- a/src/librustc/hir/map/mod.rs
+++ b/src/librustc/hir/map/mod.rs
@@ -51,7 +51,7 @@ impl<'hir> Entry<'hir> {
             },
 
             Node::TraitItem(ref item) => match item.kind {
-                TraitItemKind::Method(ref sig, _) => Some(&sig.decl),
+                TraitItemKind::Fn(ref sig, _) => Some(&sig.decl),
                 _ => None,
             },
 
@@ -77,7 +77,7 @@ impl<'hir> Entry<'hir> {
             },
 
             Node::TraitItem(item) => match &item.kind {
-                TraitItemKind::Method(sig, _) => Some(sig),
+                TraitItemKind::Fn(sig, _) => Some(sig),
                 _ => None,
             },
 
@@ -101,7 +101,7 @@ impl<'hir> Entry<'hir> {
 
             Node::TraitItem(item) => match item.kind {
                 TraitItemKind::Const(_, Some(body))
-                | TraitItemKind::Method(_, TraitMethod::Provided(body)) => Some(body),
+                | TraitItemKind::Fn(_, TraitMethod::Provided(body)) => Some(body),
                 _ => None,
             },
 
@@ -326,12 +326,12 @@ impl<'hir> Map<'hir> {
             },
             Node::TraitItem(item) => match item.kind {
                 TraitItemKind::Const(..) => DefKind::AssocConst,
-                TraitItemKind::Method(..) => DefKind::Method,
+                TraitItemKind::Fn(..) => DefKind::AssocFn,
                 TraitItemKind::Type(..) => DefKind::AssocTy,
             },
             Node::ImplItem(item) => match item.kind {
                 ImplItemKind::Const(..) => DefKind::AssocConst,
-                ImplItemKind::Method(..) => DefKind::Method,
+                ImplItemKind::Method(..) => DefKind::AssocFn,
                 ImplItemKind::TyAlias(..) => DefKind::AssocTy,
                 ImplItemKind::OpaqueTy(..) => DefKind::AssocOpaqueTy,
             },
@@ -472,7 +472,7 @@ impl<'hir> Map<'hir> {
             | Node::AnonConst(_) => BodyOwnerKind::Const,
             Node::Ctor(..)
             | Node::Item(&Item { kind: ItemKind::Fn(..), .. })
-            | Node::TraitItem(&TraitItem { kind: TraitItemKind::Method(..), .. })
+            | Node::TraitItem(&TraitItem { kind: TraitItemKind::Fn(..), .. })
             | Node::ImplItem(&ImplItem { kind: ImplItemKind::Method(..), .. }) => BodyOwnerKind::Fn,
             Node::Item(&Item { kind: ItemKind::Static(_, m, _), .. }) => BodyOwnerKind::Static(m),
             Node::Expr(&Expr { kind: ExprKind::Closure(..), .. }) => BodyOwnerKind::Closure,
@@ -800,7 +800,7 @@ impl<'hir> Map<'hir> {
                     _ => false,
                 },
                 Node::TraitItem(ti) => match ti.kind {
-                    TraitItemKind::Method(..) => true,
+                    TraitItemKind::Fn(..) => true,
                     _ => false,
                 },
                 Node::ImplItem(ii) => match ii.kind {
@@ -1311,7 +1311,7 @@ fn hir_id_to_string(map: &Map<'_>, id: HirId, include_id: bool) -> String {
         Some(Node::TraitItem(ti)) => {
             let kind = match ti.kind {
                 TraitItemKind::Const(..) => "assoc constant",
-                TraitItemKind::Method(..) => "trait method",
+                TraitItemKind::Fn(..) => "trait method",
                 TraitItemKind::Type(..) => "assoc type",
             };
 
diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index 1aa3b27bd1a..30c9a2ee769 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -1,6 +1,6 @@
-//! HIR datatypes. See the [rustc guide] for more info.
+//! HIR datatypes. See the [rustc dev guide] for more info.
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/hir.html
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
 
 pub mod exports;
 pub mod map;
diff --git a/src/librustc/infer/canonical.rs b/src/librustc/infer/canonical.rs
index 76d0d57e233..5f7e8c84965 100644
--- a/src/librustc/infer/canonical.rs
+++ b/src/librustc/infer/canonical.rs
@@ -17,9 +17,9 @@
 //! `instantiate_query_result` method.
 //!
 //! For a more detailed look at what is happening here, check
-//! out the [chapter in the rustc guide][c].
+//! out the [chapter in the rustc dev guide][c].
 //!
-//! [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
+//! [c]: https://rustc-dev-guide.rust-lang.org/traits/canonicalization.html
 
 use crate::infer::MemberConstraint;
 use crate::ty::subst::GenericArg;
diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs
index 055d70effc6..24237235e0c 100644
--- a/src/librustc/lib.rs
+++ b/src/librustc/lib.rs
@@ -14,9 +14,9 @@
 //!   (or `tcx`), which is the central context during most of
 //!   compilation, containing the interners and other things.
 //!
-//! For more information about how rustc works, see the [rustc guide].
+//! For more information about how rustc works, see the [rustc dev guide].
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/
 //!
 //! # Note
 //!
diff --git a/src/librustc/middle/region.rs b/src/librustc/middle/region.rs
index 1d043f5dcde..758ba4a1ab0 100644
--- a/src/librustc/middle/region.rs
+++ b/src/librustc/middle/region.rs
@@ -2,9 +2,9 @@
 //! the parent links in the region hierarchy.
 //!
 //! For more information about how MIR-based region-checking works,
-//! see the [rustc guide].
+//! see the [rustc dev guide].
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/borrowck.html
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/mir/borrowck.html
 
 use crate::ich::{NodeIdHashingMode, StableHashingContext};
 use crate::ty::{self, DefIdTree, TyCtxt};
diff --git a/src/librustc/middle/stability.rs b/src/librustc/middle/stability.rs
index cf917daef83..048e24ce3aa 100644
--- a/src/librustc/middle/stability.rs
+++ b/src/librustc/middle/stability.rs
@@ -250,7 +250,7 @@ pub enum EvalResult {
 fn skip_stability_check_due_to_privacy(tcx: TyCtxt<'_>, mut def_id: DefId) -> bool {
     // Check if `def_id` is a trait method.
     match tcx.def_kind(def_id) {
-        Some(DefKind::Method) | Some(DefKind::AssocTy) | Some(DefKind::AssocConst) => {
+        Some(DefKind::AssocFn) | Some(DefKind::AssocTy) | Some(DefKind::AssocConst) => {
             if let ty::TraitContainer(trait_def_id) = tcx.associated_item(def_id).container {
                 // Trait methods do not declare visibility (even
                 // for visibility info in cstore). Use containing
diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs
index b2413f5a2c8..afb585c4aa3 100644
--- a/src/librustc/mir/mod.rs
+++ b/src/librustc/mir/mod.rs
@@ -1,6 +1,6 @@
-//! MIR datatypes and passes. See the [rustc guide] for more info.
+//! MIR datatypes and passes. See the [rustc dev guide] for more info.
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/index.html
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/mir/index.html
 
 use crate::mir::interpret::{GlobalAlloc, Scalar};
 use crate::mir::visit::MirVisitable;
diff --git a/src/librustc/traits/mod.rs b/src/librustc/traits/mod.rs
index 4e02a1744ff..6ebcc8b0754 100644
--- a/src/librustc/traits/mod.rs
+++ b/src/librustc/traits/mod.rs
@@ -1,6 +1,6 @@
-//! Trait Resolution. See the [rustc guide] for more information on how this works.
+//! Trait Resolution. See the [rustc dev guide] for more information on how this works.
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/traits/resolution.html
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/resolution.html
 
 pub mod query;
 pub mod select;
diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs
index ac3d0049c0c..08d78b3a0b2 100644
--- a/src/librustc/traits/select.rs
+++ b/src/librustc/traits/select.rs
@@ -1,6 +1,6 @@
-//! Candidate selection. See the [rustc guide] for more information on how this works.
+//! Candidate selection. See the [rustc dev guide] for more information on how this works.
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/traits/resolution.html#selection
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/resolution.html#selection
 
 use self::EvaluationResult::*;
 
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 48ef81c1d5b..6fab55e9fd9 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -611,7 +611,7 @@ impl<'tcx> TypeckTables<'tcx> {
         }
 
         match self.type_dependent_defs().get(expr.hir_id) {
-            Some(Ok((DefKind::Method, _))) => true,
+            Some(Ok((DefKind::AssocFn, _))) => true,
             _ => false,
         }
     }
@@ -916,9 +916,9 @@ pub struct FreeRegionInfo {
 /// The central data structure of the compiler. It stores references
 /// to the various **arenas** and also houses the results of the
 /// various **compiler queries** that have been performed. See the
-/// [rustc guide] for more details.
+/// [rustc dev guide] for more details.
 ///
-/// [rustc guide]: https://rust-lang.github.io/rustc-guide/ty.html
+/// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/ty.html
 #[derive(Copy, Clone)]
 #[rustc_diagnostic_item = "TyCtxt"]
 pub struct TyCtxt<'tcx> {
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 7bcd63b9655..c2697570dda 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -230,7 +230,7 @@ impl AssocItem {
     pub fn def_kind(&self) -> DefKind {
         match self.kind {
             AssocKind::Const => DefKind::AssocConst,
-            AssocKind::Method => DefKind::Method,
+            AssocKind::Method => DefKind::AssocFn,
             AssocKind::Type => DefKind::AssocTy,
             AssocKind::OpaqueTy => DefKind::AssocOpaqueTy,
         }
@@ -2872,7 +2872,7 @@ impl<'tcx> TyCtxt<'tcx> {
             }
         } else {
             match self.def_kind(def_id).expect("no def for `DefId`") {
-                DefKind::AssocConst | DefKind::Method | DefKind::AssocTy => true,
+                DefKind::AssocConst | DefKind::AssocFn | DefKind::AssocTy => true,
                 _ => false,
             }
         };
@@ -3051,7 +3051,7 @@ impl<'tcx> TyCtxt<'tcx> {
     /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
     pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
         let item = if def_id.krate != LOCAL_CRATE {
-            if let Some(DefKind::Method) = self.def_kind(def_id) {
+            if let Some(DefKind::AssocFn) = self.def_kind(def_id) {
                 Some(self.associated_item(def_id))
             } else {
                 None
diff --git a/src/librustc/ty/query/README.md b/src/librustc/ty/query/README.md
index 4b5e08cecd9..8ec07b9fdeb 100644
--- a/src/librustc/ty/query/README.md
+++ b/src/librustc/ty/query/README.md
@@ -1,3 +1,3 @@
-For more information about how the query system works, see the [rustc guide].
+For more information about how the query system works, see the [rustc dev guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/query.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/query.html
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index 47bf7822b1f..76b9aed8314 100644
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -1396,11 +1396,11 @@ pub type Region<'tcx> = &'tcx RegionKind;
 /// the inference variable is supposed to satisfy the relation
 /// *for every value of the placeholder region*. To ensure that doesn't
 /// happen, you can use `leak_check`. This is more clearly explained
-/// by the [rustc guide].
+/// by the [rustc dev guide].
 ///
 /// [1]: http://smallcultfollowing.com/babysteps/blog/2013/10/29/intermingled-parameter-lists/
 /// [2]: http://smallcultfollowing.com/babysteps/blog/2013/11/04/intermingled-parameter-lists/
-/// [rustc guide]: https://rust-lang.github.io/rustc-guide/traits/hrtb.html
+/// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/hrtb.html
 #[derive(Clone, PartialEq, Eq, Hash, Copy, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
 pub enum RegionKind {
     /// Region bound in a type or fn declaration which will be
diff --git a/src/librustc_ast/README.md b/src/librustc_ast/README.md
index d62e5a5ece0..dd407dba1f4 100644
--- a/src/librustc_ast/README.md
+++ b/src/librustc_ast/README.md
@@ -3,7 +3,7 @@ The `rustc_ast` crate contains those things concerned purely with syntax
 lexer, macro expander, and utilities for traversing ASTs.
 
 For more information about how these things work in rustc, see the
-rustc guide:
+rustc dev guide:
 
-- [Parsing](https://rust-lang.github.io/rustc-guide/the-parser.html)
-- [Macro Expansion](https://rust-lang.github.io/rustc-guide/macro-expansion.html)
+- [Parsing](https://rustc-dev-guide.rust-lang.org/the-parser.html)
+- [Macro Expansion](https://rustc-dev-guide.rust-lang.org/macro-expansion.html)
diff --git a/src/librustc_ast/ast.rs b/src/librustc_ast/ast.rs
index 88a96dc6c69..7faba4600a9 100644
--- a/src/librustc_ast/ast.rs
+++ b/src/librustc_ast/ast.rs
@@ -2118,14 +2118,14 @@ pub enum ImplPolarity {
     /// `impl Trait for Type`
     Positive,
     /// `impl !Trait for Type`
-    Negative,
+    Negative(Span),
 }
 
 impl fmt::Debug for ImplPolarity {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             ImplPolarity::Positive => "positive".fmt(f),
-            ImplPolarity::Negative => "negative".fmt(f),
+            ImplPolarity::Negative(_) => "negative".fmt(f),
         }
     }
 }
diff --git a/src/librustc_ast_lowering/item.rs b/src/librustc_ast_lowering/item.rs
index 46aad99f131..fcc859e3b6d 100644
--- a/src/librustc_ast_lowering/item.rs
+++ b/src/librustc_ast_lowering/item.rs
@@ -761,13 +761,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let names = self.lower_fn_params_to_names(&sig.decl);
                 let (generics, sig) =
                     self.lower_method_sig(generics, sig, trait_item_def_id, false, None);
-                (generics, hir::TraitItemKind::Method(sig, hir::TraitMethod::Required(names)))
+                (generics, hir::TraitItemKind::Fn(sig, hir::TraitMethod::Required(names)))
             }
             AssocItemKind::Fn(_, ref sig, ref generics, Some(ref body)) => {
                 let body_id = self.lower_fn_body_block(i.span, &sig.decl, Some(body));
                 let (generics, sig) =
                     self.lower_method_sig(generics, sig, trait_item_def_id, false, None);
-                (generics, hir::TraitItemKind::Method(sig, hir::TraitMethod::Provided(body_id)))
+                (generics, hir::TraitItemKind::Fn(sig, hir::TraitMethod::Provided(body_id)))
             }
             AssocItemKind::TyAlias(_, ref generics, ref bounds, ref default) => {
                 let ty = default.as_ref().map(|x| self.lower_ty(x, ImplTraitContext::disallowed()));
diff --git a/src/librustc_ast_lowering/path.rs b/src/librustc_ast_lowering/path.rs
index 80d7e3d0d46..db8517bfbf0 100644
--- a/src/librustc_ast_lowering/path.rs
+++ b/src/librustc_ast_lowering/path.rs
@@ -75,7 +75,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             ParenthesizedGenericArgs::Ok
                         }
                         // `a::b::Trait(Args)::TraitItem`
-                        Res::Def(DefKind::Method, _)
+                        Res::Def(DefKind::AssocFn, _)
                         | Res::Def(DefKind::AssocConst, _)
                         | Res::Def(DefKind::AssocTy, _)
                             if i + 2 == proj_start =>
diff --git a/src/librustc_ast_passes/ast_validation.rs b/src/librustc_ast_passes/ast_validation.rs
index 69d5610e016..a2d83a525cc 100644
--- a/src/librustc_ast_passes/ast_validation.rs
+++ b/src/librustc_ast_passes/ast_validation.rs
@@ -9,6 +9,7 @@
 use rustc_ast::ast::*;
 use rustc_ast::attr;
 use rustc_ast::expand::is_proc_macro_attr;
+use rustc_ast::ptr::P;
 use rustc_ast::visit::{self, AssocCtxt, FnCtxt, FnKind, Visitor};
 use rustc_ast::walk_list;
 use rustc_ast_pretty::pprust;
@@ -594,6 +595,54 @@ impl<'a> AstValidator<'a> {
             .span_label(ident.span, format!("`_` is not a valid name for this `{}` item", kind))
             .emit();
     }
+
+    fn deny_generic_params(&self, generics: &Generics, ident_span: Span) {
+        if !generics.params.is_empty() {
+            struct_span_err!(
+                self.session,
+                generics.span,
+                E0567,
+                "auto traits cannot have generic parameters"
+            )
+            .span_label(ident_span, "auto trait cannot have generic parameters")
+            .span_suggestion(
+                generics.span,
+                "remove the parameters",
+                String::new(),
+                Applicability::MachineApplicable,
+            )
+            .emit();
+        }
+    }
+
+    fn deny_super_traits(&self, bounds: &GenericBounds, ident_span: Span) {
+        if let [first @ last] | [first, .., last] = &bounds[..] {
+            let span = first.span().to(last.span());
+            struct_span_err!(self.session, span, E0568, "auto traits cannot have super traits")
+                .span_label(ident_span, "auto trait cannot have super traits")
+                .span_suggestion(
+                    span,
+                    "remove the super traits",
+                    String::new(),
+                    Applicability::MachineApplicable,
+                )
+                .emit();
+        }
+    }
+
+    fn deny_items(&self, trait_items: &[P<AssocItem>], ident_span: Span) {
+        if !trait_items.is_empty() {
+            let spans: Vec<_> = trait_items.iter().map(|i| i.ident.span).collect();
+            struct_span_err!(
+                self.session,
+                spans,
+                E0380,
+                "auto traits cannot have methods or associated items"
+            )
+            .span_label(ident_span, "auto trait cannot have items")
+            .emit();
+        }
+    }
 }
 
 fn validate_generic_param_order<'a>(
@@ -779,7 +828,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 defaultness: _,
                 constness: _,
                 generics: _,
-                of_trait: Some(_),
+                of_trait: Some(ref t),
                 ref self_ty,
                 items: _,
             } => {
@@ -794,13 +843,14 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                             .help("use `auto trait Trait {}` instead")
                             .emit();
                     }
-                    if let (Unsafe::Yes(span), ImplPolarity::Negative) = (unsafety, polarity) {
+                    if let (Unsafe::Yes(span), ImplPolarity::Negative(sp)) = (unsafety, polarity) {
                         struct_span_err!(
                             this.session,
-                            item.span,
+                            sp.to(t.path.span),
                             E0198,
                             "negative impls cannot be unsafe"
                         )
+                        .span_label(sp, "negative because of this")
                         .span_label(span, "unsafe because of this")
                         .emit();
                     }
@@ -816,38 +866,36 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 constness,
                 generics: _,
                 of_trait: None,
-                self_ty: _,
+                ref self_ty,
                 items: _,
             } => {
+                let error = |annotation_span, annotation| {
+                    let mut err = self.err_handler().struct_span_err(
+                        self_ty.span,
+                        &format!("inherent impls cannot be {}", annotation),
+                    );
+                    err.span_label(annotation_span, &format!("{} because of this", annotation));
+                    err.span_label(self_ty.span, "inherent impl for this type");
+                    err
+                };
+
                 self.invalid_visibility(
                     &item.vis,
                     Some("place qualifiers on individual impl items instead"),
                 );
                 if let Unsafe::Yes(span) = unsafety {
-                    struct_span_err!(
-                        self.session,
-                        item.span,
-                        E0197,
-                        "inherent impls cannot be unsafe"
-                    )
-                    .span_label(span, "unsafe because of this")
-                    .emit();
+                    error(span, "unsafe").code(error_code!(E0197)).emit();
                 }
-                if polarity == ImplPolarity::Negative {
-                    self.err_handler().span_err(item.span, "inherent impls cannot be negative");
+                if let ImplPolarity::Negative(span) = polarity {
+                    error(span, "negative").emit();
                 }
                 if let Defaultness::Default(def_span) = defaultness {
-                    let span = self.session.source_map().def_span(item.span);
-                    self.err_handler()
-                        .struct_span_err(span, "inherent impls cannot be `default`")
-                        .span_label(def_span, "`default` because of this")
+                    error(def_span, "`default`")
                         .note("only trait implementations may be annotated with `default`")
                         .emit();
                 }
                 if let Const::Yes(span) = constness {
-                    self.err_handler()
-                        .struct_span_err(item.span, "inherent impls cannot be `const`")
-                        .span_label(span, "`const` because of this")
+                    error(span, "`const`")
                         .note("only trait implementations may be annotated with `const`")
                         .emit();
                 }
@@ -882,33 +930,9 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             ItemKind::Trait(is_auto, _, ref generics, ref bounds, ref trait_items) => {
                 if is_auto == IsAuto::Yes {
                     // Auto traits cannot have generics, super traits nor contain items.
-                    if !generics.params.is_empty() {
-                        struct_span_err!(
-                            self.session,
-                            item.span,
-                            E0567,
-                            "auto traits cannot have generic parameters"
-                        )
-                        .emit();
-                    }
-                    if !bounds.is_empty() {
-                        struct_span_err!(
-                            self.session,
-                            item.span,
-                            E0568,
-                            "auto traits cannot have super traits"
-                        )
-                        .emit();
-                    }
-                    if !trait_items.is_empty() {
-                        struct_span_err!(
-                            self.session,
-                            item.span,
-                            E0380,
-                            "auto traits cannot have methods or associated items"
-                        )
-                        .emit();
-                    }
+                    self.deny_generic_params(generics, item.ident.span);
+                    self.deny_super_traits(bounds, item.ident.span);
+                    self.deny_items(trait_items, item.ident.span);
                 }
                 self.no_questions_in_bounds(bounds, "supertraits", true);
 
@@ -1153,9 +1177,13 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
         }) = fk.header()
         {
             self.err_handler()
-                .struct_span_err(span, "functions cannot be both `const` and `async`")
+                .struct_span_err(
+                    vec![*cspan, *aspan],
+                    "functions cannot be both `const` and `async`",
+                )
                 .span_label(*cspan, "`const` because of this")
                 .span_label(*aspan, "`async` because of this")
+                .span_label(span, "") // Point at the fn header.
                 .emit();
         }
 
diff --git a/src/librustc_ast_passes/feature_gate.rs b/src/librustc_ast_passes/feature_gate.rs
index a4ab54f8b4a..5f36149451d 100644
--- a/src/librustc_ast_passes/feature_gate.rs
+++ b/src/librustc_ast_passes/feature_gate.rs
@@ -337,14 +337,14 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 }
             }
 
-            ast::ItemKind::Impl { polarity, defaultness, .. } => {
-                if polarity == ast::ImplPolarity::Negative {
+            ast::ItemKind::Impl { polarity, defaultness, ref of_trait, .. } => {
+                if let ast::ImplPolarity::Negative(span) = polarity {
                     gate_feature_post!(
                         &self,
                         optin_builtin_traits,
-                        i.span,
+                        span.to(of_trait.as_ref().map(|t| t.path.span).unwrap_or(span)),
                         "negative trait bounds are not yet fully implemented; \
-                                        use marker types for now"
+                         use marker types for now"
                     );
                 }
 
diff --git a/src/librustc_ast_passes/lib.rs b/src/librustc_ast_passes/lib.rs
index 520a7ac3e56..10081d36754 100644
--- a/src/librustc_ast_passes/lib.rs
+++ b/src/librustc_ast_passes/lib.rs
@@ -1,3 +1,4 @@
+#![feature(bindings_after_at)]
 //! The `rustc_ast_passes` crate contains passes which validate the AST in `syntax`
 //! parsed by `rustc_parse` and then lowered, after the passes in this crate,
 //! by `rustc_ast_lowering`.
diff --git a/src/librustc_ast_pretty/pprust.rs b/src/librustc_ast_pretty/pprust.rs
index b11dda8af73..007694f7276 100644
--- a/src/librustc_ast_pretty/pprust.rs
+++ b/src/librustc_ast_pretty/pprust.rs
@@ -1160,7 +1160,7 @@ impl<'a> State<'a> {
                     self.s.space();
                 }
 
-                if polarity == ast::ImplPolarity::Negative {
+                if let ast::ImplPolarity::Negative(_) = polarity {
                     self.s.word("!");
                 }
 
diff --git a/src/librustc_codegen_llvm/README.md b/src/librustc_codegen_llvm/README.md
index dda2e5ac18f..97d8f76623e 100644
--- a/src/librustc_codegen_llvm/README.md
+++ b/src/librustc_codegen_llvm/README.md
@@ -2,6 +2,6 @@ The `codegen` crate contains the code to convert from MIR into LLVM IR,
 and then from LLVM IR into machine code. In general it contains code
 that runs towards the end of the compilation process.
 
-For more information about how codegen works, see the [rustc guide].
+For more information about how codegen works, see the [rustc dev guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/codegen.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/codegen.html
diff --git a/src/librustc_codegen_ssa/README.md b/src/librustc_codegen_ssa/README.md
index 2a3a4fcc5fc..90d991a3a4b 100644
--- a/src/librustc_codegen_ssa/README.md
+++ b/src/librustc_codegen_ssa/README.md
@@ -1,3 +1,3 @@
-Please read the rustc-guide chapter on [Backend Agnostic Codegen][bac].
+Please read the rustc-dev-guide chapter on [Backend Agnostic Codegen][bac].
 
-[bac]: https://rust-lang.github.io/rustc-guide/codegen/backend-agnostic.html
+[bac]: https://rustc-dev-guide.rust-lang.org/codegen/backend-agnostic.html
diff --git a/src/librustc_driver/README.md b/src/librustc_driver/README.md
index c4d73953e9b..37dc7f6ba5f 100644
--- a/src/librustc_driver/README.md
+++ b/src/librustc_driver/README.md
@@ -5,6 +5,6 @@ not contain any of the "main logic" of the compiler (though it does
 have some code related to pretty printing or other minor compiler
 options).
 
-For more information about how the driver works, see the [rustc guide].
+For more information about how the driver works, see the [rustc dev guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/rustc-driver.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/rustc-driver.html
diff --git a/src/librustc_hir/def.rs b/src/librustc_hir/def.rs
index 595543eaf53..5b2c1453de6 100644
--- a/src/librustc_hir/def.rs
+++ b/src/librustc_hir/def.rs
@@ -72,7 +72,7 @@ pub enum DefKind {
     Static,
     /// Refers to the struct or enum variant's constructor.
     Ctor(CtorOf, CtorKind),
-    Method,
+    AssocFn,
     AssocConst,
 
     // Macro namespace
@@ -107,7 +107,8 @@ impl DefKind {
             DefKind::Union => "union",
             DefKind::Trait => "trait",
             DefKind::ForeignTy => "foreign type",
-            DefKind::Method => "method",
+            // FIXME: Update the description to "assoc fn"
+            DefKind::AssocFn => "method",
             DefKind::Const => "constant",
             DefKind::AssocConst => "associated constant",
             DefKind::TyParam => "type parameter",
@@ -150,7 +151,7 @@ impl DefKind {
             | DefKind::ConstParam
             | DefKind::Static
             | DefKind::Ctor(..)
-            | DefKind::Method
+            | DefKind::AssocFn
             | DefKind::AssocConst => ns == Namespace::ValueNS,
 
             DefKind::Macro(..) => ns == Namespace::MacroNS,
diff --git a/src/librustc_hir/hir.rs b/src/librustc_hir/hir.rs
index f948e22e84b..9993e5c55f6 100644
--- a/src/librustc_hir/hir.rs
+++ b/src/librustc_hir/hir.rs
@@ -609,9 +609,9 @@ pub struct ModuleItems {
 /// The top-level data structure that stores the entire contents of
 /// the crate currently being compiled.
 ///
-/// For more details, see the [rustc guide].
+/// For more details, see the [rustc dev guide].
 ///
-/// [rustc guide]: https://rust-lang.github.io/rustc-guide/hir.html
+/// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
 #[derive(RustcEncodable, RustcDecodable, Debug)]
 pub struct Crate<'hir> {
     pub module: Mod<'hir>,
@@ -1863,8 +1863,8 @@ pub enum TraitMethod<'hir> {
 pub enum TraitItemKind<'hir> {
     /// An associated constant with an optional value (otherwise `impl`s must contain a value).
     Const(&'hir Ty<'hir>, Option<BodyId>),
-    /// A method with an optional body.
-    Method(FnSig<'hir>, TraitMethod<'hir>),
+    /// An associated function with an optional body.
+    Fn(FnSig<'hir>, TraitMethod<'hir>),
     /// An associated type with (possibly empty) bounds and optional concrete
     /// type.
     Type(GenericBounds<'hir>, Option<&'hir Ty<'hir>>),
@@ -2699,7 +2699,7 @@ impl Node<'_> {
 
     pub fn fn_decl(&self) -> Option<&FnDecl<'_>> {
         match self {
-            Node::TraitItem(TraitItem { kind: TraitItemKind::Method(fn_sig, _), .. })
+            Node::TraitItem(TraitItem { kind: TraitItemKind::Fn(fn_sig, _), .. })
             | Node::ImplItem(ImplItem { kind: ImplItemKind::Method(fn_sig, _), .. })
             | Node::Item(Item { kind: ItemKind::Fn(fn_sig, _, _), .. }) => Some(fn_sig.decl),
             Node::ForeignItem(ForeignItem { kind: ForeignItemKind::Fn(fn_decl, _, _), .. }) => {
diff --git a/src/librustc_hir/intravisit.rs b/src/librustc_hir/intravisit.rs
index 45257b04d79..e92192c8b1f 100644
--- a/src/librustc_hir/intravisit.rs
+++ b/src/librustc_hir/intravisit.rs
@@ -911,14 +911,14 @@ pub fn walk_trait_item<'v, V: Visitor<'v>>(visitor: &mut V, trait_item: &'v Trai
             visitor.visit_ty(ty);
             walk_list!(visitor, visit_nested_body, default);
         }
-        TraitItemKind::Method(ref sig, TraitMethod::Required(param_names)) => {
+        TraitItemKind::Fn(ref sig, TraitMethod::Required(param_names)) => {
             visitor.visit_id(trait_item.hir_id);
             visitor.visit_fn_decl(&sig.decl);
             for &param_name in param_names {
                 visitor.visit_ident(param_name);
             }
         }
-        TraitItemKind::Method(ref sig, TraitMethod::Provided(body_id)) => {
+        TraitItemKind::Fn(ref sig, TraitMethod::Provided(body_id)) => {
             visitor.visit_fn(
                 FnKind::Method(trait_item.ident, sig, None, &trait_item.attrs),
                 &sig.decl,
diff --git a/src/librustc_hir/lib.rs b/src/librustc_hir/lib.rs
index d958dfc681b..45f806b53f5 100644
--- a/src/librustc_hir/lib.rs
+++ b/src/librustc_hir/lib.rs
@@ -1,6 +1,6 @@
-//! HIR datatypes. See the [rustc guide] for more info.
+//! HIR datatypes. See the [rustc dev guide] for more info.
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/hir.html
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
 
 #![feature(crate_visibility_modifier)]
 #![feature(const_fn)] // For the unsizing cast on `&[]`
diff --git a/src/librustc_hir/print.rs b/src/librustc_hir/print.rs
index 8cbbef959ce..7eb5cc417b7 100644
--- a/src/librustc_hir/print.rs
+++ b/src/librustc_hir/print.rs
@@ -652,7 +652,7 @@ impl<'a> State<'a> {
                     self.word_nbsp("const");
                 }
 
-                if let hir::ImplPolarity::Negative = polarity {
+                if let hir::ImplPolarity::Negative(_) = polarity {
                     self.s.word("!");
                 }
 
@@ -886,13 +886,13 @@ impl<'a> State<'a> {
                     Spanned { span: rustc_span::DUMMY_SP, node: hir::VisibilityKind::Inherited };
                 self.print_associated_const(ti.ident, &ty, default, &vis);
             }
-            hir::TraitItemKind::Method(ref sig, hir::TraitMethod::Required(ref arg_names)) => {
+            hir::TraitItemKind::Fn(ref sig, hir::TraitMethod::Required(ref arg_names)) => {
                 let vis =
                     Spanned { span: rustc_span::DUMMY_SP, node: hir::VisibilityKind::Inherited };
                 self.print_method_sig(ti.ident, sig, &ti.generics, &vis, arg_names, None);
                 self.s.word(";");
             }
-            hir::TraitItemKind::Method(ref sig, hir::TraitMethod::Provided(body)) => {
+            hir::TraitItemKind::Fn(ref sig, hir::TraitMethod::Provided(body)) => {
                 let vis =
                     Spanned { span: rustc_span::DUMMY_SP, node: hir::VisibilityKind::Inherited };
                 self.head("");
diff --git a/src/librustc_hir/target.rs b/src/librustc_hir/target.rs
index 501976fc3cb..b7bc555d7b4 100644
--- a/src/librustc_hir/target.rs
+++ b/src/librustc_hir/target.rs
@@ -105,10 +105,10 @@ impl Target {
     pub fn from_trait_item(trait_item: &TraitItem<'_>) -> Target {
         match trait_item.kind {
             TraitItemKind::Const(..) => Target::AssocConst,
-            TraitItemKind::Method(_, hir::TraitMethod::Required(_)) => {
+            TraitItemKind::Fn(_, hir::TraitMethod::Required(_)) => {
                 Target::Method(MethodKind::Trait { body: false })
             }
-            TraitItemKind::Method(_, hir::TraitMethod::Provided(_)) => {
+            TraitItemKind::Fn(_, hir::TraitMethod::Provided(_)) => {
                 Target::Method(MethodKind::Trait { body: true })
             }
             TraitItemKind::Type(..) => Target::AssocTy,
diff --git a/src/librustc_incremental/persist/README.md b/src/librustc_incremental/persist/README.md
index 8131d2840b4..b01fe219e1e 100644
--- a/src/librustc_incremental/persist/README.md
+++ b/src/librustc_incremental/persist/README.md
@@ -1,3 +1,3 @@
-For info on how the incremental compilation works, see the [rustc guide].
+For info on how the incremental compilation works, see the [rustc dev guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/query.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/query.html
diff --git a/src/librustc_incremental/persist/dirty_clean.rs b/src/librustc_incremental/persist/dirty_clean.rs
index e212dc81070..54815fe3468 100644
--- a/src/librustc_incremental/persist/dirty_clean.rs
+++ b/src/librustc_incremental/persist/dirty_clean.rs
@@ -328,7 +328,7 @@ impl DirtyCleanVisitor<'tcx> {
                 }
             }
             HirNode::TraitItem(item) => match item.kind {
-                TraitItemKind::Method(..) => ("Node::TraitItem", LABELS_FN_IN_TRAIT),
+                TraitItemKind::Fn(..) => ("Node::TraitItem", LABELS_FN_IN_TRAIT),
                 TraitItemKind::Const(..) => ("NodeTraitConst", LABELS_CONST_IN_TRAIT),
                 TraitItemKind::Type(..) => ("NodeTraitType", LABELS_CONST_IN_TRAIT),
             },
diff --git a/src/librustc_infer/infer/canonical/canonicalizer.rs b/src/librustc_infer/infer/canonical/canonicalizer.rs
index 4d3f25290e1..964e378f7ab 100644
--- a/src/librustc_infer/infer/canonical/canonicalizer.rs
+++ b/src/librustc_infer/infer/canonical/canonicalizer.rs
@@ -1,9 +1,9 @@
 //! This module contains the "canonicalizer" itself.
 //!
 //! For an overview of what canonicalization is and how it fits into
-//! rustc, check out the [chapter in the rustc guide][c].
+//! rustc, check out the [chapter in the rustc dev guide][c].
 //!
-//! [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
+//! [c]: https://rustc-dev-guide.rust-lang.org/traits/canonicalization.html
 
 use crate::infer::canonical::{
     Canonical, CanonicalTyVarKind, CanonicalVarInfo, CanonicalVarKind, Canonicalized,
@@ -33,9 +33,9 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// with a mapping M that maps `'?0` to `'static`.
     ///
     /// To get a good understanding of what is happening here, check
-    /// out the [chapter in the rustc guide][c].
+    /// out the [chapter in the rustc dev guide][c].
     ///
-    /// [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html#canonicalizing-the-query
+    /// [c]: https://rustc-dev-guide.rust-lang.org/traits/canonicalization.html#canonicalizing-the-query
     pub fn canonicalize_query<V>(
         &self,
         value: &V,
@@ -77,9 +77,9 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// reference to `'static` alone.
     ///
     /// To get a good understanding of what is happening here, check
-    /// out the [chapter in the rustc guide][c].
+    /// out the [chapter in the rustc dev guide][c].
     ///
-    /// [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html#canonicalizing-the-query-result
+    /// [c]: https://rustc-dev-guide.rust-lang.org/traits/canonicalization.html#canonicalizing-the-query-result
     pub fn canonicalize_response<V>(&self, value: &V) -> Canonicalized<'tcx, V>
     where
         V: TypeFoldable<'tcx>,
diff --git a/src/librustc_infer/infer/canonical/mod.rs b/src/librustc_infer/infer/canonical/mod.rs
index ba019a8cf03..0e9593e8ea6 100644
--- a/src/librustc_infer/infer/canonical/mod.rs
+++ b/src/librustc_infer/infer/canonical/mod.rs
@@ -17,9 +17,9 @@
 //! `instantiate_query_result` method.
 //!
 //! For a more detailed look at what is happening here, check
-//! out the [chapter in the rustc guide][c].
+//! out the [chapter in the rustc dev guide][c].
 //!
-//! [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
+//! [c]: https://rustc-dev-guide.rust-lang.org/traits/canonicalization.html
 
 use crate::infer::{ConstVariableOrigin, ConstVariableOriginKind};
 use crate::infer::{InferCtxt, RegionVariableOrigin, TypeVariableOrigin, TypeVariableOriginKind};
diff --git a/src/librustc_infer/infer/canonical/query_response.rs b/src/librustc_infer/infer/canonical/query_response.rs
index 966bd997877..b6c0dc3939b 100644
--- a/src/librustc_infer/infer/canonical/query_response.rs
+++ b/src/librustc_infer/infer/canonical/query_response.rs
@@ -3,9 +3,9 @@
 //! encode them therein.
 //!
 //! For an overview of what canonicaliation is and how it fits into
-//! rustc, check out the [chapter in the rustc guide][c].
+//! rustc, check out the [chapter in the rustc dev guide][c].
 //!
-//! [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
+//! [c]: https://rustc-dev-guide.rust-lang.org/traits/canonicalization.html
 
 use crate::infer::canonical::substitute::{substitute_value, CanonicalExt};
 use crate::infer::canonical::{
@@ -196,9 +196,9 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// the query before applying this function.)
     ///
     /// To get a good understanding of what is happening here, check
-    /// out the [chapter in the rustc guide][c].
+    /// out the [chapter in the rustc dev guide][c].
     ///
-    /// [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html#processing-the-canonicalized-query-result
+    /// [c]: https://rustc-dev-guide.rust-lang.org/traits/canonicalization.html#processing-the-canonicalized-query-result
     pub fn instantiate_query_response_and_region_obligations<R>(
         &self,
         cause: &ObligationCause<'tcx>,
diff --git a/src/librustc_infer/infer/canonical/substitute.rs b/src/librustc_infer/infer/canonical/substitute.rs
index 99ddedfe881..afef32c1ffe 100644
--- a/src/librustc_infer/infer/canonical/substitute.rs
+++ b/src/librustc_infer/infer/canonical/substitute.rs
@@ -2,9 +2,9 @@
 //! `Canonical<'tcx, T>`.
 //!
 //! For an overview of what canonicalization is and how it fits into
-//! rustc, check out the [chapter in the rustc guide][c].
+//! rustc, check out the [chapter in the rustc dev guide][c].
 //!
-//! [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
+//! [c]: https://rustc-dev-guide.rust-lang.org/traits/canonicalization.html
 
 use crate::infer::canonical::{Canonical, CanonicalVarValues};
 use rustc::ty::fold::TypeFoldable;
diff --git a/src/librustc_infer/infer/error_reporting/mod.rs b/src/librustc_infer/infer/error_reporting/mod.rs
index 40b493de9f4..7e418898910 100644
--- a/src/librustc_infer/infer/error_reporting/mod.rs
+++ b/src/librustc_infer/infer/error_reporting/mod.rs
@@ -269,7 +269,7 @@ fn item_scope_tag(item: &hir::Item<'_>) -> &'static str {
 
 fn trait_item_scope_tag(item: &hir::TraitItem<'_>) -> &'static str {
     match item.kind {
-        hir::TraitItemKind::Method(..) => "method body",
+        hir::TraitItemKind::Fn(..) => "method body",
         hir::TraitItemKind::Const(..) | hir::TraitItemKind::Type(..) => "associated item",
     }
 }
diff --git a/src/librustc_infer/infer/error_reporting/need_type_info.rs b/src/librustc_infer/infer/error_reporting/need_type_info.rs
index 285f0c9cf51..fe70215dc27 100644
--- a/src/librustc_infer/infer/error_reporting/need_type_info.rs
+++ b/src/librustc_infer/infer/error_reporting/need_type_info.rs
@@ -468,7 +468,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             &segment.args,
         ) {
             let borrow = tables.borrow();
-            if let Some((DefKind::Method, did)) = borrow.type_dependent_def(e.hir_id) {
+            if let Some((DefKind::AssocFn, did)) = borrow.type_dependent_def(e.hir_id) {
                 let generics = self.tcx.generics_of(did);
                 if !generics.params.is_empty() {
                     err.span_suggestion(
diff --git a/src/librustc_infer/infer/error_reporting/nice_region_error/find_anon_type.rs b/src/librustc_infer/infer/error_reporting/nice_region_error/find_anon_type.rs
index 2ae7f4cc04f..7346cb0a033 100644
--- a/src/librustc_infer/infer/error_reporting/nice_region_error/find_anon_type.rs
+++ b/src/librustc_infer/infer/error_reporting/nice_region_error/find_anon_type.rs
@@ -33,7 +33,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
                 let fndecl = match self.tcx().hir().get(hir_id) {
                     Node::Item(&hir::Item { kind: hir::ItemKind::Fn(ref m, ..), .. })
                     | Node::TraitItem(&hir::TraitItem {
-                        kind: hir::TraitItemKind::Method(ref m, ..),
+                        kind: hir::TraitItemKind::Fn(ref m, ..),
                         ..
                     })
                     | Node::ImplItem(&hir::ImplItem {
diff --git a/src/librustc_infer/infer/higher_ranked/README.md b/src/librustc_infer/infer/higher_ranked/README.md
index e7afaa5beb0..533d0ef7e6c 100644
--- a/src/librustc_infer/infer/higher_ranked/README.md
+++ b/src/librustc_infer/infer/higher_ranked/README.md
@@ -1,8 +1,8 @@
 To learn more about how Higher-ranked trait bounds work in the _old_ trait
-solver, see [this chapter][oldhrtb] of the rustc-guide.
+solver, see [this chapter][oldhrtb] of the rustc-dev-guide.
 
 To learn more about how they work in the _new_ trait solver, see [this
 chapter][newhrtb].
 
-[oldhrtb]: https://rust-lang.github.io/rustc-guide/traits/hrtb.html
-[newhrtb]: https://rust-lang.github.io/rustc-guide/borrow_check/region_inference.html#placeholders-and-universes
+[oldhrtb]: https://rustc-dev-guide.rust-lang.org/traits/hrtb.html
+[newhrtb]: https://rustc-dev-guide.rust-lang.org/borrow_check/region_inference.html#placeholders-and-universes
diff --git a/src/librustc_infer/infer/higher_ranked/mod.rs b/src/librustc_infer/infer/higher_ranked/mod.rs
index 33781188a95..105b987f85e 100644
--- a/src/librustc_infer/infer/higher_ranked/mod.rs
+++ b/src/librustc_infer/infer/higher_ranked/mod.rs
@@ -71,9 +71,9 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     /// needed (but is also permitted).
     ///
     /// For more information about how placeholders and HRTBs work, see
-    /// the [rustc guide].
+    /// the [rustc dev guide].
     ///
-    /// [rustc guide]: https://rust-lang.github.io/rustc-guide/traits/hrtb.html
+    /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/hrtb.html
     pub fn replace_bound_vars_with_placeholders<T>(
         &self,
         binder: &ty::Binder<T>,
diff --git a/src/librustc_infer/infer/lexical_region_resolve/README.md b/src/librustc_infer/infer/lexical_region_resolve/README.md
index c26b5625a90..e0b2c0bffee 100644
--- a/src/librustc_infer/infer/lexical_region_resolve/README.md
+++ b/src/librustc_infer/infer/lexical_region_resolve/README.md
@@ -2,6 +2,6 @@
 Lexical Region Resolution was removed in https://github.com/rust-lang/rust/pull/64790.
 
 Rust now uses Non-lexical lifetimes. For more info, please see the [borrowck
-chapter][bc] in the rustc-guide.
+chapter][bc] in the rustc-dev-guide.
 
-[bc]: https://rust-lang.github.io/rustc-guide/borrow_check/region_inference.html
+[bc]: https://rustc-dev-guide.rust-lang.org/borrow_check/region_inference.html
diff --git a/src/librustc_infer/infer/region_constraints/README.md b/src/librustc_infer/infer/region_constraints/README.md
index d789fb0de10..0231dd06677 100644
--- a/src/librustc_infer/infer/region_constraints/README.md
+++ b/src/librustc_infer/infer/region_constraints/README.md
@@ -1,3 +1,3 @@
-For info on how the current borrowck works, see the [rustc guide].
+For info on how the current borrowck works, see the [rustc dev guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/borrow_check.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/borrow_check.html
diff --git a/src/librustc_infer/lib.rs b/src/librustc_infer/lib.rs
index 6c66ef47f33..49e99b574b8 100644
--- a/src/librustc_infer/lib.rs
+++ b/src/librustc_infer/lib.rs
@@ -5,9 +5,9 @@
 //!   this code handles low-level equality and subtyping operations. The
 //!   type check pass in the compiler is found in the `librustc_typeck` crate.
 //!
-//! For more information about how rustc works, see the [rustc guide].
+//! For more information about how rustc works, see the [rustc dev guide].
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/
 //!
 //! # Note
 //!
diff --git a/src/librustc_infer/traits/coherence.rs b/src/librustc_infer/traits/coherence.rs
index 15c5f4d402a..9cf4ed8fe57 100644
--- a/src/librustc_infer/traits/coherence.rs
+++ b/src/librustc_infer/traits/coherence.rs
@@ -1,8 +1,8 @@
-//! See Rustc Guide chapters on [trait-resolution] and [trait-specialization] for more info on how
-//! this works.
+//! See Rustc Dev Guide chapters on [trait-resolution] and [trait-specialization] for more info on
+//! how this works.
 //!
-//! [trait-resolution]: https://rust-lang.github.io/rustc-guide/traits/resolution.html
-//! [trait-specialization]: https://rust-lang.github.io/rustc-guide/traits/specialization.html
+//! [trait-resolution]: https://rustc-dev-guide.rust-lang.org/traits/resolution.html
+//! [trait-specialization]: https://rustc-dev-guide.rust-lang.org/traits/specialization.html
 
 use crate::infer::{CombinedSnapshot, InferOk, TyCtxtInferExt};
 use crate::traits::select::IntercrateAmbiguityCause;
diff --git a/src/librustc_infer/traits/error_reporting/on_unimplemented.rs b/src/librustc_infer/traits/error_reporting/on_unimplemented.rs
index 87c1107bd42..eb34a487596 100644
--- a/src/librustc_infer/traits/error_reporting/on_unimplemented.rs
+++ b/src/librustc_infer/traits/error_reporting/on_unimplemented.rs
@@ -70,7 +70,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 })
             }
             hir::Node::TraitItem(hir::TraitItem {
-                kind: hir::TraitItemKind::Method(_, hir::TraitMethod::Provided(body_id)),
+                kind: hir::TraitItemKind::Fn(_, hir::TraitMethod::Provided(body_id)),
                 ..
             }) => self.describe_generator(*body_id).or_else(|| Some("a trait method")),
             hir::Node::ImplItem(hir::ImplItem {
diff --git a/src/librustc_infer/traits/error_reporting/suggestions.rs b/src/librustc_infer/traits/error_reporting/suggestions.rs
index d05955fb858..228747c3f89 100644
--- a/src/librustc_infer/traits/error_reporting/suggestions.rs
+++ b/src/librustc_infer/traits/error_reporting/suggestions.rs
@@ -62,7 +62,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             match node {
                 hir::Node::TraitItem(hir::TraitItem {
                     generics,
-                    kind: hir::TraitItemKind::Method(..),
+                    kind: hir::TraitItemKind::Fn(..),
                     ..
                 }) if param_ty && self_ty == self.tcx.types.self_param => {
                     // Restricting `Self` for a single method.
@@ -73,7 +73,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, generics, _), .. })
                 | hir::Node::TraitItem(hir::TraitItem {
                     generics,
-                    kind: hir::TraitItemKind::Method(..),
+                    kind: hir::TraitItemKind::Fn(..),
                     ..
                 })
                 | hir::Node::ImplItem(hir::ImplItem {
@@ -803,7 +803,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             })
             | Node::TraitItem(&hir::TraitItem {
                 span,
-                kind: hir::TraitItemKind::Method(ref sig, _),
+                kind: hir::TraitItemKind::Fn(ref sig, _),
                 ..
             }) => (
                 self.tcx.sess.source_map().def_span(span),
diff --git a/src/librustc_infer/traits/mod.rs b/src/librustc_infer/traits/mod.rs
index 800f8e91a78..aa0cfedff9e 100644
--- a/src/librustc_infer/traits/mod.rs
+++ b/src/librustc_infer/traits/mod.rs
@@ -1,6 +1,6 @@
-//! Trait Resolution. See the [rustc guide] for more information on how this works.
+//! Trait Resolution. See the [rustc dev guide] for more information on how this works.
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/traits/resolution.html
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/resolution.html
 
 #[allow(dead_code)]
 pub mod auto_trait;
diff --git a/src/librustc_infer/traits/query/type_op/mod.rs b/src/librustc_infer/traits/query/type_op/mod.rs
index eb4c0a029e1..1644746c16e 100644
--- a/src/librustc_infer/traits/query/type_op/mod.rs
+++ b/src/librustc_infer/traits/query/type_op/mod.rs
@@ -44,7 +44,7 @@ pub trait TypeOp<'tcx>: Sized + fmt::Debug {
 /// first canonicalize the key and then invoke the query on the tcx,
 /// which produces the resulting query region constraints.
 ///
-/// [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
+/// [c]: https://rustc-dev-guide.rust-lang.org/traits/canonicalization.html
 pub trait QueryTypeOp<'tcx>: fmt::Debug + Sized + TypeFoldable<'tcx> + 'tcx {
     type QueryResponse: TypeFoldable<'tcx>;
 
diff --git a/src/librustc_infer/traits/select.rs b/src/librustc_infer/traits/select.rs
index c0d8f3cfd4f..b50f14475fc 100644
--- a/src/librustc_infer/traits/select.rs
+++ b/src/librustc_infer/traits/select.rs
@@ -1,8 +1,8 @@
 // ignore-tidy-filelength
 
-//! Candidate selection. See the [rustc guide] for more information on how this works.
+//! Candidate selection. See the [rustc dev guide] for more information on how this works.
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/traits/resolution.html#selection
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/resolution.html#selection
 
 use self::EvaluationResult::*;
 use self::SelectionCandidate::*;
@@ -931,10 +931,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     //
     // The selection process begins by examining all in-scope impls,
     // caller obligations, and so forth and assembling a list of
-    // candidates. See the [rustc guide] for more details.
+    // candidates. See the [rustc dev guide] for more details.
     //
-    // [rustc guide]:
-    // https://rust-lang.github.io/rustc-guide/traits/resolution.html#candidate-assembly
+    // [rustc dev guide]:
+    // https://rustc-dev-guide.rust-lang.org/traits/resolution.html#candidate-assembly
 
     fn candidate_from_obligation<'o>(
         &mut self,
@@ -2447,10 +2447,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     //
     // Confirmation unifies the output type parameters of the trait
     // with the values found in the obligation, possibly yielding a
-    // type error.  See the [rustc guide] for more details.
+    // type error.  See the [rustc dev guide] for more details.
     //
-    // [rustc guide]:
-    // https://rust-lang.github.io/rustc-guide/traits/resolution.html#confirmation
+    // [rustc dev guide]:
+    // https://rustc-dev-guide.rust-lang.org/traits/resolution.html#confirmation
 
     fn confirm_candidate(
         &mut self,
diff --git a/src/librustc_infer/traits/specialize/mod.rs b/src/librustc_infer/traits/specialize/mod.rs
index ee1c737c208..51da759da99 100644
--- a/src/librustc_infer/traits/specialize/mod.rs
+++ b/src/librustc_infer/traits/specialize/mod.rs
@@ -4,10 +4,10 @@
 //! At the moment, this implementation support only the simple "chain" rule:
 //! If any two impls overlap, one must be a strict subset of the other.
 //!
-//! See the [rustc guide] for a bit more detail on how specialization
+//! See the [rustc dev guide] for a bit more detail on how specialization
 //! fits together with the rest of the trait machinery.
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/traits/specialization.html
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/specialization.html
 
 pub mod specialization_graph;
 use specialization_graph::GraphExt;
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index e1680015bea..249c9af3d48 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -465,7 +465,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc {
 
         let desc = match trait_item.kind {
             hir::TraitItemKind::Const(..) => "an associated constant",
-            hir::TraitItemKind::Method(..) => "a trait method",
+            hir::TraitItemKind::Fn(..) => "a trait method",
             hir::TraitItemKind::Type(..) => "an associated type",
         };
 
diff --git a/src/librustc_lint/nonstandard_style.rs b/src/librustc_lint/nonstandard_style.rs
index b0560dc9fdf..37fefe680d7 100644
--- a/src/librustc_lint/nonstandard_style.rs
+++ b/src/librustc_lint/nonstandard_style.rs
@@ -343,7 +343,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonSnakeCase {
     }
 
     fn check_trait_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::TraitItem<'_>) {
-        if let hir::TraitItemKind::Method(_, hir::TraitMethod::Required(pnames)) = item.kind {
+        if let hir::TraitItemKind::Fn(_, hir::TraitMethod::Required(pnames)) = item.kind {
             self.check_snake_case(cx, "trait method", &item.ident);
             for param_name in pnames {
                 self.check_snake_case(cx, "variable", param_name);
diff --git a/src/librustc_lint/unused.rs b/src/librustc_lint/unused.rs
index 02f04b23459..49d05819c5e 100644
--- a/src/librustc_lint/unused.rs
+++ b/src/librustc_lint/unused.rs
@@ -54,7 +54,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
                 match callee.kind {
                     hir::ExprKind::Path(ref qpath) => {
                         match cx.tables.qpath_res(qpath, callee.hir_id) {
-                            Res::Def(DefKind::Fn, def_id) | Res::Def(DefKind::Method, def_id) => {
+                            Res::Def(DefKind::Fn, def_id) | Res::Def(DefKind::AssocFn, def_id) => {
                                 Some(def_id)
                             }
                             // `Res::Local` if it was a closure, for which we
diff --git a/src/librustc_metadata/rmeta/decoder.rs b/src/librustc_metadata/rmeta/decoder.rs
index f6b914761c2..1d8eb0cde46 100644
--- a/src/librustc_metadata/rmeta/decoder.rs
+++ b/src/librustc_metadata/rmeta/decoder.rs
@@ -505,7 +505,7 @@ impl EntryKind {
             EntryKind::Struct(_, _) => DefKind::Struct,
             EntryKind::Union(_, _) => DefKind::Union,
             EntryKind::Fn(_) | EntryKind::ForeignFn(_) => DefKind::Fn,
-            EntryKind::Method(_) => DefKind::Method,
+            EntryKind::Method(_) => DefKind::AssocFn,
             EntryKind::Type => DefKind::TyAlias,
             EntryKind::TypeParam => DefKind::TyParam,
             EntryKind::ConstParam => DefKind::ConstParam,
diff --git a/src/librustc_metadata/rmeta/encoder.rs b/src/librustc_metadata/rmeta/encoder.rs
index 2b04918296d..ce62f15f85d 100644
--- a/src/librustc_metadata/rmeta/encoder.rs
+++ b/src/librustc_metadata/rmeta/encoder.rs
@@ -805,7 +805,7 @@ impl EncodeContext<'tcx> {
                 )
             }
             ty::AssocKind::Method => {
-                let fn_data = if let hir::TraitItemKind::Method(m_sig, m) = &ast_item.kind {
+                let fn_data = if let hir::TraitItemKind::Fn(m_sig, m) = &ast_item.kind {
                     let param_names = match *m {
                         hir::TraitMethod::Required(ref names) => {
                             self.encode_fn_param_names(names)
diff --git a/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs b/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs
index c6fe0dba80c..5d22ef46c41 100644
--- a/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs
+++ b/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs
@@ -480,7 +480,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         }))
                         | Some(hir::Node::TraitItem(hir::TraitItem {
                             ident,
-                            kind: hir::TraitItemKind::Method(sig, _),
+                            kind: hir::TraitItemKind::Fn(sig, _),
                             ..
                         }))
                         | Some(hir::Node::ImplItem(hir::ImplItem {
@@ -522,7 +522,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 hir::Node::Item(hir::Item { ident, kind: hir::ItemKind::Fn(sig, ..), .. })
                 | hir::Node::TraitItem(hir::TraitItem {
                     ident,
-                    kind: hir::TraitItemKind::Method(sig, _),
+                    kind: hir::TraitItemKind::Fn(sig, _),
                     ..
                 })
                 | hir::Node::ImplItem(hir::ImplItem {
diff --git a/src/librustc_mir/interpret/intrinsics.rs b/src/librustc_mir/interpret/intrinsics.rs
index 1e5ed76c467..869eb1227f2 100644
--- a/src/librustc_mir/interpret/intrinsics.rs
+++ b/src/librustc_mir/interpret/intrinsics.rs
@@ -103,6 +103,10 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 self.write_scalar(location.ptr, dest)?;
             }
 
+            sym::abort => {
+                M::abort(self)?;
+            }
+
             sym::min_align_of
             | sym::pref_align_of
             | sym::needs_drop
diff --git a/src/librustc_mir/interpret/machine.rs b/src/librustc_mir/interpret/machine.rs
index 087517ff4e3..366de6e5561 100644
--- a/src/librustc_mir/interpret/machine.rs
+++ b/src/librustc_mir/interpret/machine.rs
@@ -169,6 +169,11 @@ pub trait Machine<'mir, 'tcx>: Sized {
         unwind: Option<mir::BasicBlock>,
     ) -> InterpResult<'tcx>;
 
+    /// Called to evaluate `Abort` MIR terminator.
+    fn abort(_ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx, !> {
+        throw_unsup_format!("aborting execution is not supported");
+    }
+
     /// Called for all binary operations where the LHS has pointer type.
     ///
     /// Returns a (value, overflowed) pair if the operation succeeded
diff --git a/src/librustc_mir/interpret/terminator.rs b/src/librustc_mir/interpret/terminator.rs
index b5c34daf8a3..473ed9d13ec 100644
--- a/src/librustc_mir/interpret/terminator.rs
+++ b/src/librustc_mir/interpret/terminator.rs
@@ -99,6 +99,10 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 }
             }
 
+            Abort => {
+                M::abort(self)?;
+            }
+
             // When we encounter Resume, we've finished unwinding
             // cleanup for the current stack frame. We pop it in order
             // to continue unwinding the next frame
@@ -114,15 +118,13 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             Unreachable => throw_ub!(Unreachable),
 
             // These should never occur for MIR we actually run.
-            DropAndReplace { .. } | FalseEdges { .. } | FalseUnwind { .. } => {
+            DropAndReplace { .. }
+            | FalseEdges { .. }
+            | FalseUnwind { .. }
+            | Yield { .. }
+            | GeneratorDrop => {
                 bug!("{:#?} should have been eliminated by MIR pass", terminator.kind)
             }
-
-            // These are not (yet) supported. It is unclear if they even can occur in
-            // MIR that we actually run.
-            Yield { .. } | GeneratorDrop | Abort => {
-                throw_unsup_format!("Unsupported terminator kind: {:#?}", terminator.kind)
-            }
         }
 
         Ok(())
diff --git a/src/librustc_mir/util/pretty.rs b/src/librustc_mir/util/pretty.rs
index 416a5bd7d22..e7ca8b0be78 100644
--- a/src/librustc_mir/util/pretty.rs
+++ b/src/librustc_mir/util/pretty.rs
@@ -545,7 +545,7 @@ fn write_mir_sig(
     trace!("write_mir_sig: {:?}", src.instance);
     let kind = tcx.def_kind(src.def_id());
     let is_function = match kind {
-        Some(DefKind::Fn) | Some(DefKind::Method) | Some(DefKind::Ctor(..)) => true,
+        Some(DefKind::Fn) | Some(DefKind::AssocFn) | Some(DefKind::Ctor(..)) => true,
         _ => tcx.is_closure(src.def_id()),
     };
     match (kind, src.promoted) {
diff --git a/src/librustc_mir_build/build/mod.rs b/src/librustc_mir_build/build/mod.rs
index b60a637471e..c6bc8694295 100644
--- a/src/librustc_mir_build/build/mod.rs
+++ b/src/librustc_mir_build/build/mod.rs
@@ -44,7 +44,7 @@ fn mir_build(tcx: TyCtxt<'_>, def_id: DefId) -> BodyAndCache<'_> {
         })
         | Node::TraitItem(hir::TraitItem {
             kind:
-                hir::TraitItemKind::Method(hir::FnSig { decl, .. }, hir::TraitMethod::Provided(body_id)),
+                hir::TraitItemKind::Fn(hir::FnSig { decl, .. }, hir::TraitMethod::Provided(body_id)),
             ..
         }) => (*body_id, decl.output.span()),
         Node::Item(hir::Item { kind: hir::ItemKind::Static(ty, _, body_id), .. })
diff --git a/src/librustc_mir_build/hair/cx/expr.rs b/src/librustc_mir_build/hair/cx/expr.rs
index 46d49b6b493..9f04bc1dc76 100644
--- a/src/librustc_mir_build/hair/cx/expr.rs
+++ b/src/librustc_mir_build/hair/cx/expr.rs
@@ -600,7 +600,7 @@ fn user_substs_applied_to_res<'tcx>(
         // a tuple-struct or tuple-variant. This has the type of a
         // `Fn` but with the user-given substitutions.
         Res::Def(DefKind::Fn, _)
-        | Res::Def(DefKind::Method, _)
+        | Res::Def(DefKind::AssocFn, _)
         | Res::Def(DefKind::Ctor(_, CtorKind::Fn), _)
         | Res::Def(DefKind::Const, _)
         | Res::Def(DefKind::AssocConst, _) => {
@@ -703,7 +703,7 @@ fn convert_path_expr<'a, 'tcx>(
     match res {
         // A regular function, constructor function or a constant.
         Res::Def(DefKind::Fn, _)
-        | Res::Def(DefKind::Method, _)
+        | Res::Def(DefKind::AssocFn, _)
         | Res::Def(DefKind::Ctor(_, CtorKind::Fn), _)
         | Res::SelfCtor(..) => {
             let user_ty = user_substs_applied_to_res(cx, expr.hir_id, res);
diff --git a/src/librustc_parse/parser/item.rs b/src/librustc_parse/parser/item.rs
index 3932bbd7564..513507f9bb8 100644
--- a/src/librustc_parse/parser/item.rs
+++ b/src/librustc_parse/parser/item.rs
@@ -373,6 +373,16 @@ impl<'a> Parser<'a> {
         self.token.is_keyword(kw::Async) && self.is_keyword_ahead(1, &[kw::Fn])
     }
 
+    fn parse_polarity(&mut self) -> ast::ImplPolarity {
+        // Disambiguate `impl !Trait for Type { ... }` and `impl ! { ... }` for the never type.
+        if self.check(&token::Not) && self.look_ahead(1, |t| t.can_begin_type()) {
+            self.bump(); // `!`
+            ast::ImplPolarity::Negative(self.prev_token.span)
+        } else {
+            ast::ImplPolarity::Positive
+        }
+    }
+
     /// Parses an implementation item.
     ///
     /// ```
@@ -411,13 +421,7 @@ impl<'a> Parser<'a> {
             self.sess.gated_spans.gate(sym::const_trait_impl, span);
         }
 
-        // Disambiguate `impl !Trait for Type { ... }` and `impl ! { ... }` for the never type.
-        let polarity = if self.check(&token::Not) && self.look_ahead(1, |t| t.can_begin_type()) {
-            self.bump(); // `!`
-            ast::ImplPolarity::Negative
-        } else {
-            ast::ImplPolarity::Positive
-        };
+        let polarity = self.parse_polarity();
 
         // Parse both types and traits as a type, then reinterpret if necessary.
         let err_path = |span| ast::Path::from_ident(Ident::new(kw::Invalid, span));
diff --git a/src/librustc_passes/dead.rs b/src/librustc_passes/dead.rs
index bcf9fd5a535..4a0ffc23365 100644
--- a/src/librustc_passes/dead.rs
+++ b/src/librustc_passes/dead.rs
@@ -391,7 +391,7 @@ impl<'v, 'k, 'tcx> ItemLikeVisitor<'v> for LifeSeeder<'k, 'tcx> {
                     let trait_item = self.krate.trait_item(trait_item_ref.id);
                     match trait_item.kind {
                         hir::TraitItemKind::Const(_, Some(_))
-                        | hir::TraitItemKind::Method(_, hir::TraitMethod::Provided(_)) => {
+                        | hir::TraitItemKind::Fn(_, hir::TraitMethod::Provided(_)) => {
                             if has_allow_dead_code_or_lang_attr(
                                 self.tcx,
                                 trait_item.hir_id,
@@ -682,11 +682,11 @@ impl Visitor<'tcx> for DeadVisitor<'tcx> {
     fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
         match trait_item.kind {
             hir::TraitItemKind::Const(_, Some(body_id))
-            | hir::TraitItemKind::Method(_, hir::TraitMethod::Provided(body_id)) => {
+            | hir::TraitItemKind::Fn(_, hir::TraitMethod::Provided(body_id)) => {
                 self.visit_nested_body(body_id)
             }
             hir::TraitItemKind::Const(_, None)
-            | hir::TraitItemKind::Method(_, hir::TraitMethod::Required(_))
+            | hir::TraitItemKind::Fn(_, hir::TraitMethod::Required(_))
             | hir::TraitItemKind::Type(..) => {}
         }
     }
diff --git a/src/librustc_passes/reachable.rs b/src/librustc_passes/reachable.rs
index 888f4370dd5..79a9f226030 100644
--- a/src/librustc_passes/reachable.rs
+++ b/src/librustc_passes/reachable.rs
@@ -162,8 +162,8 @@ impl<'a, 'tcx> ReachableContext<'a, 'tcx> {
             },
             Some(Node::TraitItem(trait_method)) => match trait_method.kind {
                 hir::TraitItemKind::Const(_, ref default) => default.is_some(),
-                hir::TraitItemKind::Method(_, hir::TraitMethod::Provided(_)) => true,
-                hir::TraitItemKind::Method(_, hir::TraitMethod::Required(_))
+                hir::TraitItemKind::Fn(_, hir::TraitMethod::Provided(_)) => true,
+                hir::TraitItemKind::Fn(_, hir::TraitMethod::Required(_))
                 | hir::TraitItemKind::Type(..) => false,
             },
             Some(Node::ImplItem(impl_item)) => {
@@ -278,11 +278,11 @@ impl<'a, 'tcx> ReachableContext<'a, 'tcx> {
             Node::TraitItem(trait_method) => {
                 match trait_method.kind {
                     hir::TraitItemKind::Const(_, None)
-                    | hir::TraitItemKind::Method(_, hir::TraitMethod::Required(_)) => {
+                    | hir::TraitItemKind::Fn(_, hir::TraitMethod::Required(_)) => {
                         // Keep going, nothing to get exported
                     }
                     hir::TraitItemKind::Const(_, Some(body_id))
-                    | hir::TraitItemKind::Method(_, hir::TraitMethod::Provided(body_id)) => {
+                    | hir::TraitItemKind::Fn(_, hir::TraitMethod::Provided(body_id)) => {
                         self.visit_nested_body(body_id);
                     }
                     hir::TraitItemKind::Type(..) => {}
diff --git a/src/librustc_passes/region.rs b/src/librustc_passes/region.rs
index 282bd20a9be..908785faff0 100644
--- a/src/librustc_passes/region.rs
+++ b/src/librustc_passes/region.rs
@@ -2,9 +2,9 @@
 //! the parent links in the region hierarchy.
 //!
 //! For more information about how MIR-based region-checking works,
-//! see the [rustc guide].
+//! see the [rustc dev guide].
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/borrow_check.html
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/borrow_check.html
 
 use rustc::hir::map::Map;
 use rustc::middle::region::*;
diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
index 24696b20332..175b2390d30 100644
--- a/src/librustc_privacy/lib.rs
+++ b/src/librustc_privacy/lib.rs
@@ -620,7 +620,7 @@ impl EmbargoVisitor<'tcx> {
             | DefKind::ForeignTy
             | DefKind::Fn
             | DefKind::OpaqueTy
-            | DefKind::Method
+            | DefKind::AssocFn
             | DefKind::Trait
             | DefKind::TyParam
             | DefKind::Variant => (),
@@ -1298,7 +1298,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypePrivacyVisitor<'a, 'tcx> {
             _ => None,
         };
         let def = def.filter(|(kind, _)| match kind {
-            DefKind::Method
+            DefKind::AssocFn
             | DefKind::AssocConst
             | DefKind::AssocTy
             | DefKind::AssocOpaqueTy
diff --git a/src/librustc_resolve/build_reduced_graph.rs b/src/librustc_resolve/build_reduced_graph.rs
index ec5a8c4a0b8..61f511c22e6 100644
--- a/src/librustc_resolve/build_reduced_graph.rs
+++ b/src/librustc_resolve/build_reduced_graph.rs
@@ -874,7 +874,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             | Res::PrimTy(..)
             | Res::ToolMod => self.r.define(parent, ident, TypeNS, (res, vis, span, expansion)),
             Res::Def(DefKind::Fn, _)
-            | Res::Def(DefKind::Method, _)
+            | Res::Def(DefKind::AssocFn, _)
             | Res::Def(DefKind::Static, _)
             | Res::Def(DefKind::Const, _)
             | Res::Def(DefKind::AssocConst, _)
@@ -898,7 +898,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 let field_names = cstore.struct_field_names_untracked(def_id, self.r.session);
                 self.insert_field_names(def_id, field_names);
             }
-            Res::Def(DefKind::Method, def_id) => {
+            Res::Def(DefKind::AssocFn, def_id) => {
                 if cstore.associated_item_cloned_untracked(def_id).method_has_self_argument {
                     self.r.has_self.insert(def_id);
                 }
@@ -1243,7 +1243,7 @@ impl<'a, 'b> Visitor<'b> for BuildReducedGraphVisitor<'a, 'b> {
                 if sig.decl.has_self() {
                     self.r.has_self.insert(item_def_id);
                 }
-                (Res::Def(DefKind::Method, item_def_id), ValueNS)
+                (Res::Def(DefKind::AssocFn, item_def_id), ValueNS)
             }
             AssocItemKind::TyAlias(..) => (Res::Def(DefKind::AssocTy, item_def_id), TypeNS),
             AssocItemKind::Macro(_) => bug!(), // handled above
diff --git a/src/librustc_resolve/late.rs b/src/librustc_resolve/late.rs
index 97d60e1a23d..97f3ad72ee3 100644
--- a/src/librustc_resolve/late.rs
+++ b/src/librustc_resolve/late.rs
@@ -266,7 +266,7 @@ impl<'a> PathSource<'a> {
                 | Res::Def(DefKind::Static, _)
                 | Res::Local(..)
                 | Res::Def(DefKind::Fn, _)
-                | Res::Def(DefKind::Method, _)
+                | Res::Def(DefKind::AssocFn, _)
                 | Res::Def(DefKind::AssocConst, _)
                 | Res::SelfCtor(..)
                 | Res::Def(DefKind::ConstParam, _) => true,
@@ -293,7 +293,7 @@ impl<'a> PathSource<'a> {
                 _ => false,
             },
             PathSource::TraitItem(ns) => match res {
-                Res::Def(DefKind::AssocConst, _) | Res::Def(DefKind::Method, _)
+                Res::Def(DefKind::AssocConst, _) | Res::Def(DefKind::AssocFn, _)
                     if ns == ValueNS =>
                 {
                     true
diff --git a/src/librustc_resolve/late/diagnostics.rs b/src/librustc_resolve/late/diagnostics.rs
index fd62c802934..d1c2c194fca 100644
--- a/src/librustc_resolve/late/diagnostics.rs
+++ b/src/librustc_resolve/late/diagnostics.rs
@@ -124,7 +124,7 @@ impl<'a> LateResolutionVisitor<'a, '_, '_> {
                             .unwrap_or(false)
                     }
                     Res::Def(DefKind::Ctor(..), _)
-                    | Res::Def(DefKind::Method, _)
+                    | Res::Def(DefKind::AssocFn, _)
                     | Res::Def(DefKind::Const, _)
                     | Res::Def(DefKind::AssocConst, _)
                     | Res::SelfCtor(_)
diff --git a/src/librustc_resolve/late/lifetimes.rs b/src/librustc_resolve/late/lifetimes.rs
index d2c20451f36..5c0748797f0 100644
--- a/src/librustc_resolve/late/lifetimes.rs
+++ b/src/librustc_resolve/late/lifetimes.rs
@@ -713,7 +713,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
         use self::hir::TraitItemKind::*;
         self.missing_named_lifetime_spots.push((&trait_item.generics).into());
         match trait_item.kind {
-            Method(ref sig, _) => {
+            Fn(ref sig, _) => {
                 let tcx = self.tcx;
                 self.visit_early_late(
                     Some(tcx.hir().get_parent_item(trait_item.hir_id)),
@@ -1816,8 +1816,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                 match self.tcx.hir().get(fn_id) {
                     Node::Item(&hir::Item { kind: hir::ItemKind::Fn(..), .. })
                     | Node::TraitItem(&hir::TraitItem {
-                        kind: hir::TraitItemKind::Method(..),
-                        ..
+                        kind: hir::TraitItemKind::Fn(..), ..
                     })
                     | Node::ImplItem(&hir::ImplItem {
                         kind: hir::ImplItemKind::Method(..), ..
@@ -2093,9 +2092,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
             // `fn` definitions and methods.
             Node::Item(&hir::Item { kind: hir::ItemKind::Fn(.., body), .. }) => Some(body),
 
-            Node::TraitItem(&hir::TraitItem {
-                kind: hir::TraitItemKind::Method(_, ref m), ..
-            }) => {
+            Node::TraitItem(&hir::TraitItem { kind: hir::TraitItemKind::Fn(_, ref m), .. }) => {
                 if let hir::ItemKind::Trait(.., ref trait_items) =
                     self.tcx.hir().expect_item(self.tcx.hir().get_parent_item(parent)).kind
                 {
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 492ac6ed839..f035df3c34d 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -741,7 +741,7 @@ impl<'a> NameBinding<'a> {
     fn is_importable(&self) -> bool {
         match self.res() {
             Res::Def(DefKind::AssocConst, _)
-            | Res::Def(DefKind::Method, _)
+            | Res::Def(DefKind::AssocFn, _)
             | Res::Def(DefKind::AssocTy, _) => false,
             _ => true,
         }
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index 88bfe7661e2..e4949ea5b4b 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -718,7 +718,7 @@ impl<'l, 'tcx> SaveContext<'l, 'tcx> {
             | Res::Def(HirDefKind::Ctor(..), _) => {
                 Some(Ref { kind: RefKind::Variable, span, ref_id: id_from_def_id(res.def_id()) })
             }
-            Res::Def(HirDefKind::Method, decl_id) => {
+            Res::Def(HirDefKind::AssocFn, decl_id) => {
                 let def_id = if decl_id.is_local() {
                     let ti = self.tcx.associated_item(decl_id);
 
diff --git a/src/librustc_save_analysis/sig.rs b/src/librustc_save_analysis/sig.rs
index 2005366f839..2cffd7f365d 100644
--- a/src/librustc_save_analysis/sig.rs
+++ b/src/librustc_save_analysis/sig.rs
@@ -519,7 +519,7 @@ impl Sig for ast::Item {
                 text.push(' ');
 
                 let trait_sig = if let Some(ref t) = *of_trait {
-                    if polarity == ast::ImplPolarity::Negative {
+                    if let ast::ImplPolarity::Negative(_) = polarity {
                         text.push('!');
                     }
                     let trait_sig = t.path.make(offset + text.len(), id, scx)?;
diff --git a/src/librustc_span/symbol.rs b/src/librustc_span/symbol.rs
index d8ce9bbdfb3..6cb7cbf14fd 100644
--- a/src/librustc_span/symbol.rs
+++ b/src/librustc_span/symbol.rs
@@ -120,6 +120,7 @@ symbols! {
         abi_unadjusted,
         abi_vectorcall,
         abi_x86_interrupt,
+        abort,
         aborts,
         address,
         add_with_overflow,
diff --git a/src/librustc_target/README.md b/src/librustc_target/README.md
index a22000ea9d2..ac1e03385d1 100644
--- a/src/librustc_target/README.md
+++ b/src/librustc_target/README.md
@@ -1,6 +1,6 @@
 `librustc_target` contains some very low-level details that are
 specific to different compilation targets and so forth.
 
-For more information about how rustc works, see the [rustc guide].
+For more information about how rustc works, see the [rustc dev guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/
diff --git a/src/librustc_traits/lowering/environment.rs b/src/librustc_traits/lowering/environment.rs
index 0e26e9461f4..db392ede432 100644
--- a/src/librustc_traits/lowering/environment.rs
+++ b/src/librustc_traits/lowering/environment.rs
@@ -185,7 +185,7 @@ crate fn environment(tcx: TyCtxt<'_>, def_id: DefId) -> Environment<'_> {
 
     let node_kind = match node {
         Node::TraitItem(item) => match item.kind {
-            TraitItemKind::Method(..) => NodeKind::Fn,
+            TraitItemKind::Fn(..) => NodeKind::Fn,
             _ => NodeKind::Other,
         },
 
diff --git a/src/librustc_traits/lowering/mod.rs b/src/librustc_traits/lowering/mod.rs
index 97b81c224d5..9b48cf489ba 100644
--- a/src/librustc_traits/lowering/mod.rs
+++ b/src/librustc_traits/lowering/mod.rs
@@ -108,13 +108,13 @@ impl<'tcx> Lower<PolyDomainGoal<'tcx>> for ty::Predicate<'tcx> {
     }
 }
 
-/// Used for implied bounds related rules (see rustc guide).
+/// Used for implied bounds related rules (see rustc dev guide).
 trait IntoFromEnvGoal {
     /// Transforms an existing goal into a `FromEnv` goal.
     fn into_from_env_goal(self) -> Self;
 }
 
-/// Used for well-formedness related rules (see rustc guide).
+/// Used for well-formedness related rules (see rustc dev guide).
 trait IntoWellFormedGoal {
     /// Transforms an existing goal into a `WellFormed` goal.
     fn into_well_formed_goal(self) -> Self;
@@ -178,7 +178,7 @@ crate fn program_clauses_for(tcx: TyCtxt<'_>, def_id: DefId) -> Clauses<'_> {
 fn program_clauses_for_trait(tcx: TyCtxt<'_>, def_id: DefId) -> Clauses<'_> {
     // `trait Trait<P1..Pn> where WC { .. } // P0 == Self`
 
-    // Rule Implemented-From-Env (see rustc guide)
+    // Rule Implemented-From-Env (see rustc dev guide)
     //
     // ```
     // forall<Self, P1..Pn> {
@@ -282,7 +282,7 @@ fn program_clauses_for_impl(tcx: TyCtxt<'tcx>, def_id: DefId) -> Clauses<'tcx> {
         return List::empty();
     }
 
-    // Rule Implemented-From-Impl (see rustc guide)
+    // Rule Implemented-From-Impl (see rustc dev guide)
     //
     // `impl<P0..Pn> Trait<A1..An> for A0 where WC { .. }`
     //
@@ -501,7 +501,7 @@ pub fn program_clauses_for_associated_type_def(tcx: TyCtxt<'_>, item_id: DefId)
 }
 
 pub fn program_clauses_for_associated_type_value(tcx: TyCtxt<'_>, item_id: DefId) -> Clauses<'_> {
-    // Rule Normalize-From-Impl (see rustc guide)
+    // Rule Normalize-From-Impl (see rustc dev guide)
     //
     // ```
     // impl<P0..Pn> Trait<A1..An> for A0 {
diff --git a/src/librustc_typeck/README.md b/src/librustc_typeck/README.md
index fdcbd935524..b61dbd8c964 100644
--- a/src/librustc_typeck/README.md
+++ b/src/librustc_typeck/README.md
@@ -1,5 +1,5 @@
 For high-level intro to how type checking works in rustc, see the
-[type checking] chapter of the [rustc guide].
+[type checking] chapter of the [rustc dev guide].
 
-[type checking]: https://rust-lang.github.io/rustc-guide/type-checking.html
-[rustc guide]: https://rust-lang.github.io/rustc-guide/
+[type checking]: https://rustc-dev-guide.rust-lang.org/type-checking.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index c3cf0cdc61d..36461f2400c 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -2588,7 +2588,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             }
 
             // Case 4. Reference to a method or associated const.
-            DefKind::Method | DefKind::AssocConst => {
+            DefKind::AssocFn | DefKind::AssocConst => {
                 if segments.len() >= 2 {
                     let generics = tcx.generics_of(def_id);
                     path_segs.push(PathSeg(generics.parent.unwrap(), last - 1));
diff --git a/src/librustc_typeck/check/compare_method.rs b/src/librustc_typeck/check/compare_method.rs
index 8b54b534375..0c8dec8f8d4 100644
--- a/src/librustc_typeck/check/compare_method.rs
+++ b/src/librustc_typeck/check/compare_method.rs
@@ -412,8 +412,8 @@ fn extract_spans_for_error_reporting<'a, 'tcx>(
         TypeError::Mutability => {
             if let Some(trait_m_hir_id) = tcx.hir().as_local_hir_id(trait_m.def_id) {
                 let trait_m_iter = match tcx.hir().expect_trait_item(trait_m_hir_id).kind {
-                    TraitItemKind::Method(ref trait_m_sig, _) => trait_m_sig.decl.inputs.iter(),
-                    _ => bug!("{:?} is not a TraitItemKind::Method", trait_m),
+                    TraitItemKind::Fn(ref trait_m_sig, _) => trait_m_sig.decl.inputs.iter(),
+                    _ => bug!("{:?} is not a TraitItemKind::Fn", trait_m),
                 };
 
                 impl_m_iter
@@ -440,10 +440,10 @@ fn extract_spans_for_error_reporting<'a, 'tcx>(
             if let Some(trait_m_hir_id) = tcx.hir().as_local_hir_id(trait_m.def_id) {
                 let (trait_m_output, trait_m_iter) =
                     match tcx.hir().expect_trait_item(trait_m_hir_id).kind {
-                        TraitItemKind::Method(ref trait_m_sig, _) => {
+                        TraitItemKind::Fn(ref trait_m_sig, _) => {
                             (&trait_m_sig.decl.output, trait_m_sig.decl.inputs.iter())
                         }
-                        _ => bug!("{:?} is not a TraitItemKind::Method", trait_m),
+                        _ => bug!("{:?} is not a TraitItemKind::Fn", trait_m),
                     };
 
                 let impl_iter = impl_sig.inputs().iter();
@@ -708,7 +708,7 @@ fn compare_number_of_method_arguments<'tcx>(
         let trait_m_hir_id = tcx.hir().as_local_hir_id(trait_m.def_id);
         let trait_span = if let Some(trait_id) = trait_m_hir_id {
             match tcx.hir().expect_trait_item(trait_id).kind {
-                TraitItemKind::Method(ref trait_m_sig, _) => {
+                TraitItemKind::Fn(ref trait_m_sig, _) => {
                     let pos = if trait_number_args > 0 { trait_number_args - 1 } else { 0 };
                     if let Some(arg) = trait_m_sig.decl.inputs.get(pos) {
                         Some(if pos == 0 {
diff --git a/src/librustc_typeck/check/generator_interior.rs b/src/librustc_typeck/check/generator_interior.rs
index 50692e0f104..7e526573773 100644
--- a/src/librustc_typeck/check/generator_interior.rs
+++ b/src/librustc_typeck/check/generator_interior.rs
@@ -237,7 +237,7 @@ impl<'a, 'tcx> Visitor<'tcx> for InteriorVisitor<'a, 'tcx> {
                         // ZST in a temporary, so skip its type, just in case it
                         // can significantly complicate the generator type.
                         Res::Def(DefKind::Fn, _)
-                        | Res::Def(DefKind::Method, _)
+                        | Res::Def(DefKind::AssocFn, _)
                         | Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) => {
                             // NOTE(eddyb) this assumes a path expression has
                             // no nested expressions to keep track of.
diff --git a/src/librustc_typeck/check/method/mod.rs b/src/librustc_typeck/check/method/mod.rs
index 542a1ac4536..189b05a819b 100644
--- a/src/librustc_typeck/check/method/mod.rs
+++ b/src/librustc_typeck/check/method/mod.rs
@@ -1,6 +1,6 @@
-//! Method lookup: the secret sauce of Rust. See the [rustc guide] for more information.
+//! Method lookup: the secret sauce of Rust. See the [rustc dev guide] for more information.
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/method-lookup.html
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/method-lookup.html
 
 mod confirm;
 pub mod probe;
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index 084601fbde1..654ec372ded 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.rs
@@ -933,7 +933,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             if let ty::AssocKind::Method = item.kind {
                                 let id = self.tcx.hir().as_local_hir_id(item.def_id);
                                 if let Some(hir::Node::TraitItem(hir::TraitItem {
-                                    kind: hir::TraitItemKind::Method(fn_sig, method),
+                                    kind: hir::TraitItemKind::Fn(fn_sig, method),
                                     ..
                                 })) = id.map(|id| self.tcx.hir().get(id))
                                 {
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index b34c6ddab39..f1f505e1859 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -811,7 +811,7 @@ fn primary_body_of(
         },
         Node::TraitItem(item) => match item.kind {
             hir::TraitItemKind::Const(ref ty, Some(body)) => Some((body, Some(ty), None, None)),
-            hir::TraitItemKind::Method(ref sig, hir::TraitMethod::Provided(body)) => {
+            hir::TraitItemKind::Fn(ref sig, hir::TraitMethod::Provided(body)) => {
                 Some((body, None, Some(&sig.header), Some(&sig.decl)))
             }
             _ => None,
@@ -1733,7 +1733,7 @@ pub fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, it: &'tcx hir::Item<'tcx>) {
 
             for item in items.iter() {
                 let item = tcx.hir().trait_item(item.id);
-                if let hir::TraitItemKind::Method(sig, _) = &item.kind {
+                if let hir::TraitItemKind::Fn(sig, _) = &item.kind {
                     let abi = sig.header.abi;
                     fn_maybe_err(tcx, item.ident.span, abi);
                 }
@@ -2976,7 +2976,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
     pub fn write_method_call(&self, hir_id: hir::HirId, method: MethodCallee<'tcx>) {
         debug!("write_method_call(hir_id={:?}, method={:?})", hir_id, method);
-        self.write_resolution(hir_id, Ok((DefKind::Method, method.def_id)));
+        self.write_resolution(hir_id, Ok((DefKind::AssocFn, method.def_id)));
         self.write_substs(hir_id, method.substs);
 
         // When the method is confirmed, the `method.substs` includes
@@ -4769,7 +4769,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
             Node::TraitItem(&hir::TraitItem {
                 ident,
-                kind: hir::TraitItemKind::Method(ref sig, ..),
+                kind: hir::TraitItemKind::Fn(ref sig, ..),
                 ..
             }) => Some((&sig.decl, ident, true)),
             Node::ImplItem(&hir::ImplItem {
@@ -4863,7 +4863,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     ..
                 }))
                 | Some(Node::TraitItem(hir::TraitItem {
-                    kind: hir::TraitItemKind::Method(.., hir::TraitMethod::Provided(body_id)),
+                    kind: hir::TraitItemKind::Fn(.., hir::TraitMethod::Provided(body_id)),
                     ..
                 })) => {
                     let body = hir.body(*body_id);
@@ -4934,7 +4934,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         .join(", ")
                 }
                 Some(Node::TraitItem(hir::TraitItem {
-                    kind: hir::TraitItemKind::Method(.., hir::TraitMethod::Required(idents)),
+                    kind: hir::TraitItemKind::Fn(.., hir::TraitMethod::Required(idents)),
                     ..
                 })) => {
                     sugg_call = idents
@@ -5364,7 +5364,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     is_alias_variant_ctor = true;
                 }
             }
-            Res::Def(DefKind::Method, def_id) | Res::Def(DefKind::AssocConst, def_id) => {
+            Res::Def(DefKind::AssocFn, def_id) | Res::Def(DefKind::AssocConst, def_id) => {
                 let container = tcx.associated_item(def_id).container;
                 debug!("instantiate_value_path: def_id={:?} container={:?}", def_id, container);
                 match container {
diff --git a/src/librustc_typeck/check/pat.rs b/src/librustc_typeck/check/pat.rs
index 84854dff851..70b39a62cd7 100644
--- a/src/librustc_typeck/check/pat.rs
+++ b/src/librustc_typeck/check/pat.rs
@@ -707,7 +707,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.set_tainted_by_errors();
                 return tcx.types.err;
             }
-            Res::Def(DefKind::Method, _)
+            Res::Def(DefKind::AssocFn, _)
             | Res::Def(DefKind::Ctor(_, CtorKind::Fictive), _)
             | Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) => {
                 report_unexpected_variant_res(tcx, res, pat.span, qpath);
@@ -793,7 +793,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             );
             let mut err = struct_span_err!(tcx.sess, pat.span, E0164, "{}", msg);
             match (res, &pat.kind) {
-                (Res::Def(DefKind::Fn, _), _) | (Res::Def(DefKind::Method, _), _) => {
+                (Res::Def(DefKind::Fn, _), _) | (Res::Def(DefKind::AssocFn, _), _) => {
                     err.span_label(pat.span, "`fn` calls are not allowed in patterns");
                     err.help(
                         "for more information, visit \
@@ -830,7 +830,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 on_error();
                 return tcx.types.err;
             }
-            Res::Def(DefKind::AssocConst, _) | Res::Def(DefKind::Method, _) => {
+            Res::Def(DefKind::AssocConst, _) | Res::Def(DefKind::AssocFn, _) => {
                 report_unexpected_res(res);
                 return tcx.types.err;
             }
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index e8e34a4e8f0..335b4a28501 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -173,7 +173,7 @@ pub fn check_trait_item(tcx: TyCtxt<'_>, def_id: DefId) {
     let trait_item = tcx.hir().expect_trait_item(hir_id);
 
     let method_sig = match trait_item.kind {
-        hir::TraitItemKind::Method(ref sig, _) => Some(sig),
+        hir::TraitItemKind::Fn(ref sig, _) => Some(sig),
         _ => None,
     };
     check_object_unsafe_self_trait_by_name(tcx, &trait_item);
@@ -207,7 +207,7 @@ fn check_object_unsafe_self_trait_by_name(tcx: TyCtxt<'_>, item: &hir::TraitItem
         {
             trait_should_be_self.push(ty.span)
         }
-        hir::TraitItemKind::Method(sig, _) => {
+        hir::TraitItemKind::Fn(sig, _) => {
             for ty in sig.decl.inputs {
                 if could_be_self(trait_def_id, ty) {
                     trait_should_be_self.push(ty.span);
diff --git a/src/librustc_typeck/coherence/unsafety.rs b/src/librustc_typeck/coherence/unsafety.rs
index a6044217403..3b25f67aacc 100644
--- a/src/librustc_typeck/coherence/unsafety.rs
+++ b/src/librustc_typeck/coherence/unsafety.rs
@@ -69,11 +69,11 @@ impl UnsafetyChecker<'tcx> {
                     .emit();
                 }
 
-                (_, _, Unsafety::Unsafe, hir::ImplPolarity::Negative) => {
+                (_, _, Unsafety::Unsafe, hir::ImplPolarity::Negative(_)) => {
                     // Reported in AST validation
                     self.tcx.sess.delay_span_bug(item.span, "unsafe negative impl");
                 }
-                (_, _, Unsafety::Normal, hir::ImplPolarity::Negative)
+                (_, _, Unsafety::Normal, hir::ImplPolarity::Negative(_))
                 | (Unsafety::Unsafe, _, Unsafety::Unsafe, hir::ImplPolarity::Positive)
                 | (Unsafety::Normal, Some(_), Unsafety::Unsafe, hir::ImplPolarity::Positive)
                 | (Unsafety::Normal, None, Unsafety::Normal, _) => {
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 08028a580d9..cd63dacdcda 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -715,7 +715,7 @@ fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::HirId) {
     tcx.generics_of(def_id);
 
     match trait_item.kind {
-        hir::TraitItemKind::Method(..) => {
+        hir::TraitItemKind::Fn(..) => {
             tcx.type_of(def_id);
             tcx.fn_sig(def_id);
         }
@@ -1121,7 +1121,7 @@ fn has_late_bound_regions<'tcx>(tcx: TyCtxt<'tcx>, node: Node<'tcx>) -> Option<S
 
     match node {
         Node::TraitItem(item) => match item.kind {
-            hir::TraitItemKind::Method(ref sig, _) => {
+            hir::TraitItemKind::Fn(ref sig, _) => {
                 has_late_bound_regions(tcx, &item.generics, &sig.decl)
             }
             _ => None,
@@ -1437,7 +1437,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
 
     match tcx.hir().get(hir_id) {
         TraitItem(hir::TraitItem {
-            kind: TraitItemKind::Method(sig, TraitMethod::Provided(_)),
+            kind: TraitItemKind::Fn(sig, TraitMethod::Provided(_)),
             ident,
             generics,
             ..
@@ -1474,7 +1474,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
         }
 
         TraitItem(hir::TraitItem {
-            kind: TraitItemKind::Method(FnSig { header, decl }, _),
+            kind: TraitItemKind::Fn(FnSig { header, decl }, _),
             ident,
             generics,
             ..
@@ -1548,7 +1548,7 @@ fn impl_polarity(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ImplPolarity {
     let is_rustc_reservation = tcx.has_attr(def_id, sym::rustc_reservation_impl);
     let item = tcx.hir().expect_item(hir_id);
     match &item.kind {
-        hir::ItemKind::Impl { polarity: hir::ImplPolarity::Negative, .. } => {
+        hir::ItemKind::Impl { polarity: hir::ImplPolarity::Negative(_), .. } => {
             if is_rustc_reservation {
                 tcx.sess.span_err(item.span, "reservation impls can't be negative");
             }
diff --git a/src/librustc_typeck/collect/type_of.rs b/src/librustc_typeck/collect/type_of.rs
index ec87112b7a8..815235adc71 100644
--- a/src/librustc_typeck/collect/type_of.rs
+++ b/src/librustc_typeck/collect/type_of.rs
@@ -27,7 +27,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
 
     match tcx.hir().get(hir_id) {
         Node::TraitItem(item) => match item.kind {
-            TraitItemKind::Method(..) => {
+            TraitItemKind::Fn(..) => {
                 let substs = InternalSubsts::identity_for_item(tcx, def_id);
                 tcx.mk_fn_def(def_id, substs)
             }
diff --git a/src/librustc_typeck/constrained_generic_params.rs b/src/librustc_typeck/constrained_generic_params.rs
index 9b187d461cd..aff3768e35c 100644
--- a/src/librustc_typeck/constrained_generic_params.rs
+++ b/src/librustc_typeck/constrained_generic_params.rs
@@ -36,7 +36,7 @@ pub fn parameters_for_impl<'tcx>(
     vec.into_iter().collect()
 }
 
-/// If `include_projections` is false, returns the list of parameters that are
+/// If `include_nonconstraining` is false, returns the list of parameters that are
 /// constrained by `t` - i.e., the value of each parameter in the list is
 /// uniquely determined by `t` (see RFC 447). If it is true, return the list
 /// of parameters whose values are needed in order to constrain `ty` - these
diff --git a/src/librustc_typeck/mem_categorization.rs b/src/librustc_typeck/mem_categorization.rs
index a4569a14756..8e06948a109 100644
--- a/src/librustc_typeck/mem_categorization.rs
+++ b/src/librustc_typeck/mem_categorization.rs
@@ -425,7 +425,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
             | Res::Def(DefKind::ConstParam, _)
             | Res::Def(DefKind::AssocConst, _)
             | Res::Def(DefKind::Fn, _)
-            | Res::Def(DefKind::Method, _)
+            | Res::Def(DefKind::AssocFn, _)
             | Res::SelfCtor(..) => Ok(self.cat_rvalue(hir_id, span, expr_ty)),
 
             Res::Def(DefKind::Static, _) => Ok(Place {
diff --git a/src/librustc_typeck/variance/constraints.rs b/src/librustc_typeck/variance/constraints.rs
index 6f5caea250b..fc3b7201a1e 100644
--- a/src/librustc_typeck/variance/constraints.rs
+++ b/src/librustc_typeck/variance/constraints.rs
@@ -105,7 +105,7 @@ impl<'a, 'tcx, 'v> ItemLikeVisitor<'v> for ConstraintContext<'a, 'tcx> {
     }
 
     fn visit_trait_item(&mut self, trait_item: &hir::TraitItem<'_>) {
-        if let hir::TraitItemKind::Method(..) = trait_item.kind {
+        if let hir::TraitItemKind::Fn(..) = trait_item.kind {
             self.visit_node_helper(trait_item.hir_id);
         }
     }
diff --git a/src/librustc_typeck/variance/mod.rs b/src/librustc_typeck/variance/mod.rs
index ddde11b3844..b1fcc3d3fe8 100644
--- a/src/librustc_typeck/variance/mod.rs
+++ b/src/librustc_typeck/variance/mod.rs
@@ -1,7 +1,7 @@
-//! Module for inferring the variance of type and lifetime parameters. See the [rustc guide]
+//! Module for inferring the variance of type and lifetime parameters. See the [rustc dev guide]
 //! chapter for more info.
 //!
-//! [rustc guide]: https://rust-lang.github.io/rustc-guide/variance.html
+//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/variance.html
 
 use hir::Node;
 use rustc::ty::query::Providers;
@@ -54,7 +54,7 @@ fn variances_of(tcx: TyCtxt<'_>, item_def_id: DefId) -> &[ty::Variance] {
         },
 
         Node::TraitItem(item) => match item.kind {
-            hir::TraitItemKind::Method(..) => {}
+            hir::TraitItemKind::Fn(..) => {}
 
             _ => unsupported(),
         },
diff --git a/src/librustc_typeck/variance/terms.rs b/src/librustc_typeck/variance/terms.rs
index dd593a6abb4..bd44a3eda98 100644
--- a/src/librustc_typeck/variance/terms.rs
+++ b/src/librustc_typeck/variance/terms.rs
@@ -77,8 +77,8 @@ pub fn determine_parameters_to_be_inferred<'a, 'tcx>(
 
     // See the following for a discussion on dep-graph management.
     //
-    // - https://rust-lang.github.io/rustc-guide/query.html
-    // - https://rust-lang.github.io/rustc-guide/variance.html
+    // - https://rustc-dev-guide.rust-lang.org/query.html
+    // - https://rustc-dev-guide.rust-lang.org/variance.html
     tcx.hir().krate().visit_all_item_likes(&mut terms_cx);
 
     terms_cx
@@ -164,7 +164,7 @@ impl<'a, 'tcx, 'v> ItemLikeVisitor<'v> for TermsContext<'a, 'tcx> {
     }
 
     fn visit_trait_item(&mut self, trait_item: &hir::TraitItem<'_>) {
-        if let hir::TraitItemKind::Method(..) = trait_item.kind {
+        if let hir::TraitItemKind::Fn(..) = trait_item.kind {
             self.add_inferreds_for_item(trait_item.hir_id);
         }
     }
diff --git a/src/librustdoc/README.md b/src/librustdoc/README.md
index e4f7bc30e3f..5a5f547068d 100644
--- a/src/librustdoc/README.md
+++ b/src/librustdoc/README.md
@@ -1,3 +1,3 @@
-For more information about how `librustdoc` works, see the [rustc guide].
+For more information about how `librustdoc` works, see the [rustc dev guide].
 
-[rustc guide]: https://rust-lang.github.io/rustc-guide/rustdoc.html
+[rustc dev guide]: https://rustc-dev-guide.rust-lang.org/rustdoc.html
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 7cb870ae702..f600b3308e8 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -12,7 +12,6 @@ use rustc_hir::Mutability;
 use rustc_metadata::creader::LoadedMacro;
 use rustc_mir::const_eval::is_min_const_fn;
 use rustc_span::hygiene::MacroKind;
-use rustc_span::symbol::sym;
 use rustc_span::Span;
 
 use crate::clean::{self, GetDefId, ToSource, TypeKind};
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index b28f1899925..661666b6637 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1082,10 +1082,10 @@ impl Clean<Item> for hir::TraitItem<'_> {
             hir::TraitItemKind::Const(ref ty, default) => {
                 AssocConstItem(ty.clean(cx), default.map(|e| print_const_expr(cx, e)))
             }
-            hir::TraitItemKind::Method(ref sig, hir::TraitMethod::Provided(body)) => {
+            hir::TraitItemKind::Fn(ref sig, hir::TraitMethod::Provided(body)) => {
                 MethodItem((sig, &self.generics, body, None).clean(cx))
             }
-            hir::TraitItemKind::Method(ref sig, hir::TraitMethod::Required(ref names)) => {
+            hir::TraitItemKind::Fn(ref sig, hir::TraitMethod::Required(ref names)) => {
                 let (generics, decl) = enter_impl_trait(cx, || {
                     (self.generics.clean(cx), (&*sig.decl, &names[..]).clean(cx))
                 });
diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index 7aa90d66781..75355b84fee 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -149,7 +149,7 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
                 // In case this is a trait item, skip the
                 // early return and try looking for the trait.
                 let value = match res {
-                    Res::Def(DefKind::Method, _) | Res::Def(DefKind::AssocConst, _) => true,
+                    Res::Def(DefKind::AssocFn, _) | Res::Def(DefKind::AssocConst, _) => true,
                     Res::Def(DefKind::AssocTy, _) => false,
                     Res::Def(DefKind::Variant, _) => {
                         return handle_variant(cx, res, extra_fragment);
@@ -813,7 +813,7 @@ fn ambiguity_error(
 
                     for (res, ns) in candidates {
                         let (action, mut suggestion) = match res {
-                            Res::Def(DefKind::Method, _) | Res::Def(DefKind::Fn, _) => {
+                            Res::Def(DefKind::AssocFn, _) | Res::Def(DefKind::Fn, _) => {
                                 ("add parentheses", format!("{}()", path_str))
                             }
                             Res::Def(DefKind::Macro(..), _) => {
diff --git a/src/libstd/error.rs b/src/libstd/error.rs
index 3f6501bc7b4..2a370f19296 100644
--- a/src/libstd/error.rs
+++ b/src/libstd/error.rs
@@ -552,6 +552,9 @@ impl Error for char::ParseCharError {
     }
 }
 
+#[unstable(feature = "try_reserve", reason = "new API", issue = "48043")]
+impl Error for alloc::collections::TryReserveError {}
+
 // Copied from `any.rs`.
 impl dyn Error + 'static {
     /// Returns `true` if the boxed type is the same as `T`
diff --git a/src/test/COMPILER_TESTS.md b/src/test/COMPILER_TESTS.md
index 3f47ca834cd..ea540bd0b18 100644
--- a/src/test/COMPILER_TESTS.md
+++ b/src/test/COMPILER_TESTS.md
@@ -1,4 +1,4 @@
 # Compiler Test Documentation
 
 Documentation for the compiler testing framework can be found in
-[the rustc guide](https://rust-lang.github.io/rustc-guide/tests/intro.html).
+[the rustc dev guide](https://rustc-dev-guide.rust-lang.org/tests/intro.html).
diff --git a/src/test/ui/async-await/no-const-async.stderr b/src/test/ui/async-await/no-const-async.stderr
index 07559cd240b..4e59bb50767 100644
--- a/src/test/ui/async-await/no-const-async.stderr
+++ b/src/test/ui/async-await/no-const-async.stderr
@@ -1,8 +1,8 @@
 error: functions cannot be both `const` and `async`
-  --> $DIR/no-const-async.rs:4:1
+  --> $DIR/no-const-async.rs:4:5
    |
 LL | pub const async fn x() {}
-   | ^^^^-----^-----^^^^^^^^^^
+   | ----^^^^^-^^^^^----------
    |     |     |
    |     |     `async` because of this
    |     `const` because of this
diff --git a/src/test/ui/auto-trait-validation.stderr b/src/test/ui/auto-trait-validation.stderr
index 51422fab81f..4040e66c6af 100644
--- a/src/test/ui/auto-trait-validation.stderr
+++ b/src/test/ui/auto-trait-validation.stderr
@@ -1,20 +1,26 @@
 error[E0567]: auto traits cannot have generic parameters
-  --> $DIR/auto-trait-validation.rs:3:1
+  --> $DIR/auto-trait-validation.rs:3:19
    |
 LL | auto trait Generic<T> {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -------^^^ help: remove the parameters
+   |            |
+   |            auto trait cannot have generic parameters
 
 error[E0568]: auto traits cannot have super traits
-  --> $DIR/auto-trait-validation.rs:5:1
+  --> $DIR/auto-trait-validation.rs:5:20
    |
 LL | auto trait Bound : Copy {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -----   ^^^^ help: remove the super traits
+   |            |
+   |            auto trait cannot have super traits
 
 error[E0380]: auto traits cannot have methods or associated items
-  --> $DIR/auto-trait-validation.rs:7:1
+  --> $DIR/auto-trait-validation.rs:7:25
    |
 LL | auto trait MyTrait { fn foo() {} }
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -------      ^^^
+   |            |
+   |            auto trait cannot have items
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/coherence/coherence-negative-impls-safe.stderr b/src/test/ui/coherence/coherence-negative-impls-safe.stderr
index 4db66af6783..1bd37f39590 100644
--- a/src/test/ui/coherence/coherence-negative-impls-safe.stderr
+++ b/src/test/ui/coherence/coherence-negative-impls-safe.stderr
@@ -1,9 +1,10 @@
 error[E0198]: negative impls cannot be unsafe
-  --> $DIR/coherence-negative-impls-safe.rs:7:1
+  --> $DIR/coherence-negative-impls-safe.rs:7:13
    |
 LL | unsafe impl !Send for TestType {}
-   | ------^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   | |
+   | ------      -^^^^
+   | |           |
+   | |           negative because of this
    | unsafe because of this
 
 error: aborting due to previous error
diff --git a/src/test/ui/error-codes/E0197.stderr b/src/test/ui/error-codes/E0197.stderr
index 51ed9c83bc9..35e1042649e 100644
--- a/src/test/ui/error-codes/E0197.stderr
+++ b/src/test/ui/error-codes/E0197.stderr
@@ -1,8 +1,8 @@
 error[E0197]: inherent impls cannot be unsafe
-  --> $DIR/E0197.rs:3:1
+  --> $DIR/E0197.rs:3:13
    |
 LL | unsafe impl Foo { }
-   | ------^^^^^^^^^^^^^
+   | ------      ^^^ inherent impl for this type
    | |
    | unsafe because of this
 
diff --git a/src/test/ui/error-codes/E0198.stderr b/src/test/ui/error-codes/E0198.stderr
index 90e8b4abd12..bb2efefb427 100644
--- a/src/test/ui/error-codes/E0198.stderr
+++ b/src/test/ui/error-codes/E0198.stderr
@@ -1,9 +1,10 @@
 error[E0198]: negative impls cannot be unsafe
-  --> $DIR/E0198.rs:5:1
+  --> $DIR/E0198.rs:5:13
    |
 LL | unsafe impl !Send for Foo { }
-   | ------^^^^^^^^^^^^^^^^^^^^^^^
-   | |
+   | ------      -^^^^
+   | |           |
+   | |           negative because of this
    | unsafe because of this
 
 error: aborting due to previous error
diff --git a/src/test/ui/feature-gates/feature-gate-optin-builtin-traits.stderr b/src/test/ui/feature-gates/feature-gate-optin-builtin-traits.stderr
index d29c373a33c..490d29ad8a3 100644
--- a/src/test/ui/feature-gates/feature-gate-optin-builtin-traits.stderr
+++ b/src/test/ui/feature-gates/feature-gate-optin-builtin-traits.stderr
@@ -8,10 +8,10 @@ LL | auto trait AutoDummyTrait {}
    = help: add `#![feature(optin_builtin_traits)]` to the crate attributes to enable
 
 error[E0658]: negative trait bounds are not yet fully implemented; use marker types for now
-  --> $DIR/feature-gate-optin-builtin-traits.rs:9:1
+  --> $DIR/feature-gate-optin-builtin-traits.rs:9:6
    |
 LL | impl !AutoDummyTrait for DummyStruct {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |      ^^^^^^^^^^^^^^^
    |
    = note: see issue #13231 <https://github.com/rust-lang/rust/issues/13231> for more information
    = help: add `#![feature(optin_builtin_traits)]` to the crate attributes to enable
diff --git a/src/test/ui/issues/issue-23080-2.rs b/src/test/ui/issues/issue-23080-2.rs
index 319aa2a5cce..d20bb4bd907 100644
--- a/src/test/ui/issues/issue-23080-2.rs
+++ b/src/test/ui/issues/issue-23080-2.rs
@@ -3,8 +3,7 @@
 #![feature(optin_builtin_traits)]
 
 unsafe auto trait Trait {
-//~^ ERROR E0380
-    type Output;
+    type Output; //~ ERROR E0380
 }
 
 fn call_method<T: Trait>(x: T) {}
diff --git a/src/test/ui/issues/issue-23080-2.stderr b/src/test/ui/issues/issue-23080-2.stderr
index 1103de0d910..fcd1ecfa982 100644
--- a/src/test/ui/issues/issue-23080-2.stderr
+++ b/src/test/ui/issues/issue-23080-2.stderr
@@ -1,11 +1,10 @@
 error[E0380]: auto traits cannot have methods or associated items
-  --> $DIR/issue-23080-2.rs:5:1
+  --> $DIR/issue-23080-2.rs:6:10
    |
-LL | / unsafe auto trait Trait {
-LL | |
-LL | |     type Output;
-LL | | }
-   | |_^
+LL | unsafe auto trait Trait {
+   |                   ----- auto trait cannot have items
+LL |     type Output;
+   |          ^^^^^^
 
 error[E0275]: overflow evaluating the requirement `<() as Trait>::Output`
    |
diff --git a/src/test/ui/issues/issue-23080.rs b/src/test/ui/issues/issue-23080.rs
index fdfee698144..fa5c35316bc 100644
--- a/src/test/ui/issues/issue-23080.rs
+++ b/src/test/ui/issues/issue-23080.rs
@@ -1,8 +1,7 @@
 #![feature(optin_builtin_traits)]
 
 unsafe auto trait Trait {
-//~^ ERROR E0380
-    fn method(&self) {
+    fn method(&self) { //~ ERROR E0380
         println!("Hello");
     }
 }
diff --git a/src/test/ui/issues/issue-23080.stderr b/src/test/ui/issues/issue-23080.stderr
index 91c27217324..dbb9861b578 100644
--- a/src/test/ui/issues/issue-23080.stderr
+++ b/src/test/ui/issues/issue-23080.stderr
@@ -1,13 +1,10 @@
 error[E0380]: auto traits cannot have methods or associated items
-  --> $DIR/issue-23080.rs:3:1
+  --> $DIR/issue-23080.rs:4:8
    |
-LL | / unsafe auto trait Trait {
-LL | |
-LL | |     fn method(&self) {
-LL | |         println!("Hello");
-LL | |     }
-LL | | }
-   | |_^
+LL | unsafe auto trait Trait {
+   |                   ----- auto trait cannot have items
+LL |     fn method(&self) {
+   |        ^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/fn-header-semantic-fail.stderr b/src/test/ui/parser/fn-header-semantic-fail.stderr
index 1142cee9851..d6b36fbb714 100644
--- a/src/test/ui/parser/fn-header-semantic-fail.stderr
+++ b/src/test/ui/parser/fn-header-semantic-fail.stderr
@@ -2,7 +2,7 @@ error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:13:5
    |
 LL |     const async unsafe extern "C" fn ff5() {} // OK.
-   |     -----^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^-^^^^^------------------------------
    |     |     |
    |     |     `async` because of this
    |     `const` because of this
@@ -45,7 +45,7 @@ error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:21:9
    |
 LL |         const async unsafe extern "C" fn ft5();
-   |         -----^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^-^^^^^----------------------------
    |         |     |
    |         |     `async` because of this
    |         `const` because of this
@@ -88,7 +88,7 @@ error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:34:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}
-   |         -----^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^-^^^^^------------------------------
    |         |     |
    |         |     `async` because of this
    |         `const` because of this
@@ -97,7 +97,7 @@ error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:46:9
    |
 LL |         const async unsafe extern "C" fn fi5() {}
-   |         -----^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^-^^^^^------------------------------
    |         |     |
    |         |     `async` because of this
    |         `const` because of this
@@ -160,7 +160,7 @@ error: functions cannot be both `const` and `async`
   --> $DIR/fn-header-semantic-fail.rs:55:9
    |
 LL |         const async unsafe extern "C" fn fe5();
-   |         -----^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^-^^^^^----------------------------
    |         |     |
    |         |     `async` because of this
    |         `const` because of this
diff --git a/src/test/ui/rfc-2632-const-trait-impl/inherent-impl.stderr b/src/test/ui/rfc-2632-const-trait-impl/inherent-impl.stderr
index 3ea58a3728a..834f6a409f5 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/inherent-impl.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/inherent-impl.stderr
@@ -1,18 +1,18 @@
 error: inherent impls cannot be `const`
-  --> $DIR/inherent-impl.rs:9:1
+  --> $DIR/inherent-impl.rs:9:12
    |
 LL | impl const S {}
-   | ^^^^^-----^^^^^
+   |      ----- ^ inherent impl for this type
    |      |
    |      `const` because of this
    |
    = note: only trait implementations may be annotated with `const`
 
 error: inherent impls cannot be `const`
-  --> $DIR/inherent-impl.rs:12:1
+  --> $DIR/inherent-impl.rs:12:12
    |
 LL | impl const T {}
-   | ^^^^^-----^^^^^
+   |      ----- ^ inherent impl for this type
    |      |
    |      `const` because of this
    |
diff --git a/src/test/ui/specialization/defaultimpl/validation.stderr b/src/test/ui/specialization/defaultimpl/validation.stderr
index 03b1ef69ca0..6e19d79e48f 100644
--- a/src/test/ui/specialization/defaultimpl/validation.stderr
+++ b/src/test/ui/specialization/defaultimpl/validation.stderr
@@ -1,8 +1,8 @@
 error: inherent impls cannot be `default`
-  --> $DIR/validation.rs:7:1
+  --> $DIR/validation.rs:7:14
    |
 LL | default impl S {}
-   | -------^^^^^^^
+   | -------      ^ inherent impl for this type
    | |
    | `default` because of this
    |
diff --git a/src/test/ui/syntax-trait-polarity-feature-gate.stderr b/src/test/ui/syntax-trait-polarity-feature-gate.stderr
index ed76377278b..5d4c1b354f7 100644
--- a/src/test/ui/syntax-trait-polarity-feature-gate.stderr
+++ b/src/test/ui/syntax-trait-polarity-feature-gate.stderr
@@ -1,8 +1,8 @@
 error[E0658]: negative trait bounds are not yet fully implemented; use marker types for now
-  --> $DIR/syntax-trait-polarity-feature-gate.rs:7:1
+  --> $DIR/syntax-trait-polarity-feature-gate.rs:7:6
    |
 LL | impl !Send for TestType {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |      ^^^^^
    |
    = note: see issue #13231 <https://github.com/rust-lang/rust/issues/13231> for more information
    = help: add `#![feature(optin_builtin_traits)]` to the crate attributes to enable
diff --git a/src/test/ui/syntax-trait-polarity.stderr b/src/test/ui/syntax-trait-polarity.stderr
index fef3a650888..5777e0ade90 100644
--- a/src/test/ui/syntax-trait-polarity.stderr
+++ b/src/test/ui/syntax-trait-polarity.stderr
@@ -1,29 +1,35 @@
 error: inherent impls cannot be negative
-  --> $DIR/syntax-trait-polarity.rs:7:1
+  --> $DIR/syntax-trait-polarity.rs:7:7
    |
 LL | impl !TestType {}
-   | ^^^^^^^^^^^^^^^^^
+   |      -^^^^^^^^ inherent impl for this type
+   |      |
+   |      negative because of this
 
 error[E0198]: negative impls cannot be unsafe
-  --> $DIR/syntax-trait-polarity.rs:12:1
+  --> $DIR/syntax-trait-polarity.rs:12:13
    |
 LL | unsafe impl !Send for TestType {}
-   | ------^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   | |
+   | ------      -^^^^
+   | |           |
+   | |           negative because of this
    | unsafe because of this
 
 error: inherent impls cannot be negative
-  --> $DIR/syntax-trait-polarity.rs:19:1
+  --> $DIR/syntax-trait-polarity.rs:19:10
    |
 LL | impl<T> !TestType2<T> {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^
+   |         -^^^^^^^^^^^^ inherent impl for this type
+   |         |
+   |         negative because of this
 
 error[E0198]: negative impls cannot be unsafe
-  --> $DIR/syntax-trait-polarity.rs:22:1
+  --> $DIR/syntax-trait-polarity.rs:22:16
    |
 LL | unsafe impl<T> !Send for TestType2<T> {}
-   | ------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   | |
+   | ------         -^^^^
+   | |              |
+   | |              negative because of this
    | unsafe because of this
 
 error[E0192]: negative impls are only allowed for auto traits (e.g., `Send` and `Sync`)
diff --git a/src/test/ui/traits/trait-safety-inherent-impl.stderr b/src/test/ui/traits/trait-safety-inherent-impl.stderr
index c398785d394..0738d2973e2 100644
--- a/src/test/ui/traits/trait-safety-inherent-impl.stderr
+++ b/src/test/ui/traits/trait-safety-inherent-impl.stderr
@@ -1,14 +1,10 @@
 error[E0197]: inherent impls cannot be unsafe
-  --> $DIR/trait-safety-inherent-impl.rs:5:1
+  --> $DIR/trait-safety-inherent-impl.rs:5:13
    |
-LL |   unsafe impl SomeStruct {
-   |   ^-----
-   |   |
-   |  _unsafe because of this
+LL | unsafe impl SomeStruct {
+   | ------      ^^^^^^^^^^ inherent impl for this type
    | |
-LL | |     fn foo(self) { }
-LL | | }
-   | |_^
+   | unsafe because of this
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/traits/traits-inductive-overflow-supertrait-oibit.stderr b/src/test/ui/traits/traits-inductive-overflow-supertrait-oibit.stderr
index 63182a6bd95..a83ff370151 100644
--- a/src/test/ui/traits/traits-inductive-overflow-supertrait-oibit.stderr
+++ b/src/test/ui/traits/traits-inductive-overflow-supertrait-oibit.stderr
@@ -1,8 +1,10 @@
 error[E0568]: auto traits cannot have super traits
-  --> $DIR/traits-inductive-overflow-supertrait-oibit.rs:7:1
+  --> $DIR/traits-inductive-overflow-supertrait-oibit.rs:7:19
    |
 LL | auto trait Magic: Copy {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -----  ^^^^ help: remove the super traits
+   |            |
+   |            auto trait cannot have super traits
 
 error[E0277]: the trait bound `NoClone: std::marker::Copy` is not satisfied
   --> $DIR/traits-inductive-overflow-supertrait-oibit.rs:15:23
diff --git a/src/test/ui/typeck/typeck-auto-trait-no-supertraits-2.stderr b/src/test/ui/typeck/typeck-auto-trait-no-supertraits-2.stderr
index 8755bcded9d..e3976293277 100644
--- a/src/test/ui/typeck/typeck-auto-trait-no-supertraits-2.stderr
+++ b/src/test/ui/typeck/typeck-auto-trait-no-supertraits-2.stderr
@@ -1,8 +1,10 @@
 error[E0568]: auto traits cannot have super traits
-  --> $DIR/typeck-auto-trait-no-supertraits-2.rs:3:1
+  --> $DIR/typeck-auto-trait-no-supertraits-2.rs:3:20
    |
 LL | auto trait Magic : Sized where Option<Self> : Magic {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -----   ^^^^^ help: remove the super traits
+   |            |
+   |            auto trait cannot have super traits
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/typeck/typeck-auto-trait-no-supertraits.stderr b/src/test/ui/typeck/typeck-auto-trait-no-supertraits.stderr
index 5a388834909..b1602e3642e 100644
--- a/src/test/ui/typeck/typeck-auto-trait-no-supertraits.stderr
+++ b/src/test/ui/typeck/typeck-auto-trait-no-supertraits.stderr
@@ -1,8 +1,10 @@
 error[E0568]: auto traits cannot have super traits
-  --> $DIR/typeck-auto-trait-no-supertraits.rs:27:1
+  --> $DIR/typeck-auto-trait-no-supertraits.rs:27:19
    |
 LL | auto trait Magic: Copy {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            -----  ^^^^ help: remove the super traits
+   |            |
+   |            auto trait cannot have super traits
 
 error: aborting due to previous error
 
diff --git a/src/tools/publish_toolstate.py b/src/tools/publish_toolstate.py
index 5fbb986286a..b389cd0373c 100755
--- a/src/tools/publish_toolstate.py
+++ b/src/tools/publish_toolstate.py
@@ -1,11 +1,10 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
-# This script publishes the new "current" toolstate in the toolstate repo (not to be
-# confused with publishing the test results, which happens in
-# `src/ci/docker/x86_64-gnu-tools/checktools.sh`).
-# It is set as callback for `src/ci/docker/x86_64-gnu-tools/repo.sh` by the CI scripts
-# when a new commit lands on `master` (i.e., after it passed all checks on `auto`).
+# This script computes the new "current" toolstate for the toolstate repo (not to be
+# confused with publishing the test results, which happens in `src/bootstrap/toolstate.rs`).
+# It gets called from `src/ci/publish_toolstate.sh` when a new commit lands on `master`
+# (i.e., after it passed all checks on `auto`).
 
 from __future__ import print_function
 
diff --git a/triagebot.toml b/triagebot.toml
index a174dd1e7f3..13777d7a6c4 100644
--- a/triagebot.toml
+++ b/triagebot.toml
@@ -17,7 +17,7 @@ Hey LLVM ICE-breakers! This bug has been identified as a good
 [instructions] for tackling these sorts of bugs. Maybe take a look?
 Thanks! <3
 
-[instructions]: https://rust-lang.github.io/rustc-guide/ice-breaker/llvm.html
+[instructions]: https://rustc-dev-guide.rust-lang.org/ice-breaker/llvm.html
 """
 label = "ICEBreaker-LLVM"
 
@@ -28,6 +28,6 @@ Hey Cleanup Crew ICE-breakers! This bug has been identified as a good
 [instructions] for tackling these sorts of bugs. Maybe take a look?
 Thanks! <3
 
-[instructions]: https://rust-lang.github.io/rustc-guide/ice-breaker/cleanup-crew.html
+[instructions]: https://rustc-dev-guide.rust-lang.org/ice-breaker/cleanup-crew.html
 """
 label = "ICEBreaker-Cleanup-Crew"