diff --git a/src/bootstrap/Cargo.toml b/src/bootstrap/Cargo.toml
index 3e91c2b3e86c8..0f7b6c22e1cc5 100644
--- a/src/bootstrap/Cargo.toml
+++ b/src/bootstrap/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "bootstrap"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "bootstrap"
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 32f3e573d6845..26760a6edc907 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -21,20 +21,20 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::time::{Duration, Instant};
 
-use cache::{Cache, Interned, INTERNER};
-use check;
-use compile;
-use dist;
-use doc;
-use flags::Subcommand;
-use install;
-use native;
-use test;
-use tool;
-use util::{add_lib_path, exe, libdir};
-use {Build, DocTests, Mode, GitRepo};
-
-pub use Compiler;
+use crate::cache::{Cache, Interned, INTERNER};
+use crate::check;
+use crate::compile;
+use crate::dist;
+use crate::doc;
+use crate::flags::Subcommand;
+use crate::install;
+use crate::native;
+use crate::test;
+use crate::tool;
+use crate::util::{add_lib_path, exe, libdir};
+use crate::{Build, DocTests, Mode, GitRepo};
+
+pub use crate::Compiler;
 
 use petgraph::graph::NodeIndex;
 use petgraph::Graph;
@@ -1251,7 +1251,7 @@ impl<'a> Builder<'a> {
 #[cfg(test)]
 mod __test {
     use super::*;
-    use config::Config;
+    use crate::config::Config;
     use std::thread;
 
     fn configure(host: &[&str], target: &[&str]) -> Config {
diff --git a/src/bootstrap/cache.rs b/src/bootstrap/cache.rs
index 0b561a3523f2b..165cffa4587d3 100644
--- a/src/bootstrap/cache.rs
+++ b/src/bootstrap/cache.rs
@@ -23,7 +23,7 @@ use std::path::{Path, PathBuf};
 use std::sync::Mutex;
 use std::cmp::{PartialOrd, Ord, Ordering};
 
-use builder::Step;
+use crate::builder::Step;
 
 pub struct Interned<T>(usize, PhantomData<*const T>);
 
diff --git a/src/bootstrap/cc_detect.rs b/src/bootstrap/cc_detect.rs
index d5da0cabec84a..3d2b3a2c9de49 100644
--- a/src/bootstrap/cc_detect.rs
+++ b/src/bootstrap/cc_detect.rs
@@ -39,9 +39,9 @@ use std::process::Command;
 use build_helper::output;
 use cc;
 
-use {Build, GitRepo};
-use config::Target;
-use cache::Interned;
+use crate::{Build, GitRepo};
+use crate::config::Target;
+use crate::cache::Interned;
 
 // The `cc` crate doesn't provide a way to obtain a path to the detected archiver,
 // so use some simplified logic here. First we respect the environment variable `AR`, then
diff --git a/src/bootstrap/channel.rs b/src/bootstrap/channel.rs
index 88b6925b2b1e7..61ddc8aa9498b 100644
--- a/src/bootstrap/channel.rs
+++ b/src/bootstrap/channel.rs
@@ -20,8 +20,8 @@ use std::process::Command;
 
 use build_helper::output;
 
-use Build;
-use config::Config;
+use crate::Build;
+use crate::config::Config;
 
 // The version number
 pub const CFG_RELEASE_NUM: &str = "1.32.0";
diff --git a/src/bootstrap/check.rs b/src/bootstrap/check.rs
index 0c6dbb06bb882..84e7c40e4559e 100644
--- a/src/bootstrap/check.rs
+++ b/src/bootstrap/check.rs
@@ -10,11 +10,12 @@
 
 //! Implementation of compiling the compiler and standard library, in "check" mode.
 
-use compile::{run_cargo, std_cargo, test_cargo, rustc_cargo, rustc_cargo_env, add_to_sysroot};
-use builder::{RunConfig, Builder, ShouldRun, Step};
-use tool::{prepare_tool_cargo, SourceType};
-use {Compiler, Mode};
-use cache::{INTERNER, Interned};
+use crate::compile::{run_cargo, std_cargo, test_cargo, rustc_cargo, rustc_cargo_env,
+                     add_to_sysroot};
+use crate::builder::{RunConfig, Builder, ShouldRun, Step};
+use crate::tool::{prepare_tool_cargo, SourceType};
+use crate::{Compiler, Mode};
+use crate::cache::{INTERNER, Interned};
 use std::path::PathBuf;
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
diff --git a/src/bootstrap/clean.rs b/src/bootstrap/clean.rs
index 87f194fb7d2f8..dc42159d068b1 100644
--- a/src/bootstrap/clean.rs
+++ b/src/bootstrap/clean.rs
@@ -19,7 +19,7 @@ use std::fs;
 use std::io::{self, ErrorKind};
 use std::path::Path;
 
-use Build;
+use crate::Build;
 
 pub fn clean(build: &Build, all: bool) {
     rm_rf("tmp".as_ref());
diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index c84abe42a6372..db5d8645e3323 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -29,12 +29,12 @@ use build_helper::{output, mtime, up_to_date};
 use filetime::FileTime;
 use serde_json;
 
-use util::{exe, libdir, is_dylib};
-use {Compiler, Mode, GitRepo};
-use native;
+use crate::util::{exe, libdir, is_dylib};
+use crate::{Compiler, Mode, GitRepo};
+use crate::native;
 
-use cache::{INTERNER, Interned};
-use builder::{Step, RunConfig, ShouldRun, Builder};
+use crate::cache::{INTERNER, Interned};
+use crate::builder::{Step, RunConfig, ShouldRun, Builder};
 
 #[derive(Debug, PartialOrd, Ord, Copy, Clone, PartialEq, Eq, Hash)]
 pub struct Std {
diff --git a/src/bootstrap/config.rs b/src/bootstrap/config.rs
index 1dafbe148afda..2ae9da9c085d4 100644
--- a/src/bootstrap/config.rs
+++ b/src/bootstrap/config.rs
@@ -22,9 +22,9 @@ use std::cmp;
 
 use num_cpus;
 use toml;
-use cache::{INTERNER, Interned};
-use flags::Flags;
-pub use flags::Subcommand;
+use crate::cache::{INTERNER, Interned};
+use crate::flags::Flags;
+pub use crate::flags::Subcommand;
 
 /// Global configuration for the entire build and/or bootstrap.
 ///
diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index f03eefb7a129b..927f9bf8ddbca 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -26,13 +26,13 @@ use std::process::{Command, Stdio};
 
 use build_helper::output;
 
-use {Compiler, Mode, LLVM_TOOLS};
-use channel;
-use util::{libdir, is_dylib, exe};
-use builder::{Builder, RunConfig, ShouldRun, Step};
-use compile;
-use tool::{self, Tool};
-use cache::{INTERNER, Interned};
+use crate::{Compiler, Mode, LLVM_TOOLS};
+use crate::channel;
+use crate::util::{libdir, is_dylib, exe};
+use crate::builder::{Builder, RunConfig, ShouldRun, Step};
+use crate::compile;
+use crate::tool::{self, Tool};
+use crate::cache::{INTERNER, Interned};
 use time;
 
 pub fn pkgname(builder: &Builder, component: &str) -> String {
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index 2d0625b26dbe3..217328adfbf66 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -22,15 +22,15 @@ use std::fs;
 use std::io;
 use std::path::{PathBuf, Path};
 
-use Mode;
+use crate::Mode;
 use build_helper::up_to_date;
 
-use util::symlink_dir;
-use builder::{Builder, Compiler, RunConfig, ShouldRun, Step};
-use tool::{self, prepare_tool_cargo, Tool, SourceType};
-use compile;
-use cache::{INTERNER, Interned};
-use config::Config;
+use crate::util::symlink_dir;
+use crate::builder::{Builder, Compiler, RunConfig, ShouldRun, Step};
+use crate::tool::{self, prepare_tool_cargo, Tool, SourceType};
+use crate::compile;
+use crate::cache::{INTERNER, Interned};
+use crate::config::Config;
 
 macro_rules! book {
     ($($name:ident, $path:expr, $book_name:expr;)+) => {
diff --git a/src/bootstrap/flags.rs b/src/bootstrap/flags.rs
index c49da8fc73489..14e2f69432dac 100644
--- a/src/bootstrap/flags.rs
+++ b/src/bootstrap/flags.rs
@@ -19,12 +19,12 @@ use std::process;
 
 use getopts::Options;
 
-use builder::Builder;
-use config::Config;
-use metadata;
-use {Build, DocTests};
+use crate::builder::Builder;
+use crate::config::Config;
+use crate::metadata;
+use crate::{Build, DocTests};
 
-use cache::{Interned, INTERNER};
+use crate::cache::{Interned, INTERNER};
 
 /// Deserialized version of all flags for this compile.
 pub struct Flags {
diff --git a/src/bootstrap/install.rs b/src/bootstrap/install.rs
index cb28698aa3d6d..aebcfb4519543 100644
--- a/src/bootstrap/install.rs
+++ b/src/bootstrap/install.rs
@@ -18,11 +18,11 @@ use std::fs;
 use std::path::{Path, PathBuf, Component};
 use std::process::Command;
 
-use dist::{self, pkgname, sanitize_sh, tmpdir};
+use crate::dist::{self, pkgname, sanitize_sh, tmpdir};
 
-use builder::{Builder, RunConfig, ShouldRun, Step};
-use cache::Interned;
-use config::Config;
+use crate::builder::{Builder, RunConfig, ShouldRun, Step};
+use crate::cache::Interned;
+use crate::config::Config;
 
 pub fn install_docs(builder: &Builder, stage: u32, host: Interned<String>) {
     install_sh(builder, "docs", "rust-docs", stage, Some(host));
diff --git a/src/bootstrap/job.rs b/src/bootstrap/job.rs
index f7b1c50f0fd67..a9da2c491da53 100644
--- a/src/bootstrap/job.rs
+++ b/src/bootstrap/job.rs
@@ -42,7 +42,7 @@
 use std::env;
 use std::io;
 use std::mem;
-use Build;
+use crate::Build;
 
 type HANDLE = *mut u8;
 type BOOL = i32;
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index c8792918db2e2..c5b8f19eee6fb 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -159,7 +159,7 @@ use std::os::windows::fs::symlink_file;
 use build_helper::{run_silent, run_suppressed, try_run_silent, try_run_suppressed, output, mtime};
 use filetime::FileTime;
 
-use util::{exe, libdir, OutputFolder, CiEnv};
+use crate::util::{exe, libdir, OutputFolder, CiEnv};
 
 mod cc_detect;
 mod channel;
@@ -188,7 +188,7 @@ mod job;
 mod job {
     use libc;
 
-    pub unsafe fn setup(build: &mut ::Build) {
+    pub unsafe fn setup(build: &mut crate::Build) {
         if build.config.low_priority {
             libc::setpriority(libc::PRIO_PGRP as _, 0, 10);
         }
@@ -197,14 +197,14 @@ mod job {
 
 #[cfg(any(target_os = "haiku", not(any(unix, windows))))]
 mod job {
-    pub unsafe fn setup(_build: &mut ::Build) {
+    pub unsafe fn setup(_build: &mut crate::Build) {
     }
 }
 
-pub use config::Config;
-use flags::Subcommand;
-use cache::{Interned, INTERNER};
-use toolstate::ToolState;
+pub use crate::config::Config;
+use crate::flags::Subcommand;
+use crate::cache::{Interned, INTERNER};
+use crate::toolstate::ToolState;
 
 const LLVM_TOOLS: &[&str] = &[
     "llvm-nm", // used to inspect binaries; it shows symbol names, their sizes and visibility
diff --git a/src/bootstrap/metadata.rs b/src/bootstrap/metadata.rs
index fa0b1983510b9..bb503e8b8d3d1 100644
--- a/src/bootstrap/metadata.rs
+++ b/src/bootstrap/metadata.rs
@@ -16,8 +16,8 @@ use std::collections::HashSet;
 use build_helper::output;
 use serde_json;
 
-use {Build, Crate};
-use cache::INTERNER;
+use crate::{Build, Crate};
+use crate::cache::INTERNER;
 
 #[derive(Deserialize)]
 struct Output {
diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index 8ff175b018756..2da800f19c07b 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -28,11 +28,11 @@ use build_helper::output;
 use cmake;
 use cc;
 
-use util::{self, exe};
+use crate::util::{self, exe};
 use build_helper::up_to_date;
-use builder::{Builder, RunConfig, ShouldRun, Step};
-use cache::Interned;
-use GitRepo;
+use crate::builder::{Builder, RunConfig, ShouldRun, Step};
+use crate::cache::Interned;
+use crate::GitRepo;
 
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct Llvm {
diff --git a/src/bootstrap/sanity.rs b/src/bootstrap/sanity.rs
index 7a9e6d4fd387b..f585495b0aa94 100644
--- a/src/bootstrap/sanity.rs
+++ b/src/bootstrap/sanity.rs
@@ -27,7 +27,7 @@ use std::process::Command;
 
 use build_helper::output;
 
-use Build;
+use crate::Build;
 
 struct Finder {
     cache: HashMap<OsString, Option<PathBuf>>,
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index dc061fe5099a5..174f2d537cda5 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -23,17 +23,17 @@ use std::process::Command;
 
 use build_helper::{self, output};
 
-use builder::{Builder, Compiler, Kind, RunConfig, ShouldRun, Step};
-use cache::{Interned, INTERNER};
-use compile;
-use dist;
-use flags::Subcommand;
-use native;
-use tool::{self, Tool, SourceType};
-use toolstate::ToolState;
-use util::{self, dylib_path, dylib_path_var};
-use Crate as CargoCrate;
-use {DocTests, Mode, GitRepo};
+use crate::builder::{Builder, Compiler, Kind, RunConfig, ShouldRun, Step};
+use crate::cache::{Interned, INTERNER};
+use crate::compile;
+use crate::dist;
+use crate::flags::Subcommand;
+use crate::native;
+use crate::tool::{self, Tool, SourceType};
+use crate::toolstate::ToolState;
+use crate::util::{self, dylib_path, dylib_path_var};
+use crate::Crate as CargoCrate;
+use crate::{DocTests, Mode, GitRepo};
 
 const ADB_TEST_DIR: &str = "/data/tmp/work";
 
@@ -577,7 +577,7 @@ impl Step for RustdocJS {
         if let Some(ref nodejs) = builder.config.nodejs {
             let mut command = Command::new(nodejs);
             command.args(&["src/tools/rustdoc-js/tester.js", &*self.host]);
-            builder.ensure(::doc::Std {
+            builder.ensure(crate::doc::Std {
                 target: self.target,
                 stage: builder.top_stage,
             });
diff --git a/src/bootstrap/tool.rs b/src/bootstrap/tool.rs
index 1bd4403a66ffa..4335359e11589 100644
--- a/src/bootstrap/tool.rs
+++ b/src/bootstrap/tool.rs
@@ -15,16 +15,16 @@ use std::path::PathBuf;
 use std::process::{Command, exit};
 use std::collections::HashSet;
 
-use Mode;
-use Compiler;
-use builder::{Step, RunConfig, ShouldRun, Builder};
-use util::{exe, add_lib_path};
-use compile;
-use native;
-use channel::GitInfo;
-use channel;
-use cache::Interned;
-use toolstate::ToolState;
+use crate::Mode;
+use crate::Compiler;
+use crate::builder::{Step, RunConfig, ShouldRun, Builder};
+use crate::util::{exe, add_lib_path};
+use crate::compile;
+use crate::native;
+use crate::channel::GitInfo;
+use crate::channel;
+use crate::cache::Interned;
+use crate::toolstate::ToolState;
 
 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
 pub enum SourceType {
diff --git a/src/bootstrap/util.rs b/src/bootstrap/util.rs
index be24ae0ce6648..b18e38e471eff 100644
--- a/src/bootstrap/util.rs
+++ b/src/bootstrap/util.rs
@@ -21,8 +21,8 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::time::{SystemTime, Instant};
 
-use config::Config;
-use builder::Builder;
+use crate::config::Config;
+use crate::builder::Builder;
 
 /// Returns the `name` as the filename of a static library for `target`.
 pub fn staticlib(name: &str, target: &str) -> String {