diff --git a/src/cli.rs b/src/cli.rs
index 163fbd993d..7ac235724c 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -4,7 +4,7 @@ pub mod log;
 pub mod common;
 mod download_tracker;
 pub mod errors;
-pub mod help;
+mod help;
 mod job;
 mod markdown;
 pub mod proxy_mode;
diff --git a/src/config.rs b/src/config.rs
index b91b94d21e..ab38e037fc 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -86,7 +86,7 @@ impl<T: Into<String>> From<T> for OverrideFile {
 }
 
 #[derive(Debug)]
-pub enum OverrideReason {
+pub(crate) enum OverrideReason {
     Environment,
     CommandLine,
     OverrideDB(PathBuf),
@@ -170,7 +170,7 @@ pub enum PgpPublicKey {
 
 impl PgpPublicKey {
     /// Retrieve the key.
-    pub fn key(&self) -> &SignedPublicKey {
+    pub(crate) fn key(&self) -> &SignedPublicKey {
         match self {
             Self::Builtin => &*BUILTIN_PGP_KEY,
             Self::FromEnvironment(_, k) => k,
@@ -179,7 +179,7 @@ impl PgpPublicKey {
     }
 
     /// Display the key in detail for the user
-    pub fn show_key(&self) -> Result<Vec<String>> {
+    pub(crate) fn show_key(&self) -> Result<Vec<String>> {
         fn format_hex(bytes: &[u8], separator: &str, every: usize) -> Result<String> {
             use std::fmt::Write;
             let mut ret = String::new();
@@ -226,7 +226,7 @@ impl Display for PgpPublicKey {
     }
 }
 
-pub const UNIX_FALLBACK_SETTINGS: &str = "/etc/rustup/settings.toml";
+pub(crate) const UNIX_FALLBACK_SETTINGS: &str = "/etc/rustup/settings.toml";
 
 pub struct Cfg {
     profile_override: Option<dist::Profile>,
@@ -241,7 +241,6 @@ pub struct Cfg {
     pub toolchain_override: Option<String>,
     pub env_override: Option<String>,
     pub dist_root_url: String,
-    pub dist_root_server: String,
     pub notify_handler: Arc<dyn Fn(Notification<'_>)>,
 }
 
@@ -330,7 +329,7 @@ impl Cfg {
             dist_root_server.as_str(),
             Box::new(move |n| (notify_clone)(n.into())),
         );
-        let dist_root = dist_root_server.clone() + "/dist";
+        let dist_root = dist_root_server + "/dist";
 
         let cfg = Self {
             profile_override: None,
@@ -346,7 +345,6 @@ impl Cfg {
             toolchain_override: None,
             env_override,
             dist_root_url: dist_root,
-            dist_root_server,
         };
 
         // Run some basic checks against the constructed configuration
@@ -372,7 +370,7 @@ impl Cfg {
         }
     }
 
-    pub fn get_pgp_keys(&self) -> &[PgpPublicKey] {
+    pub(crate) fn get_pgp_keys(&self) -> &[PgpPublicKey] {
         &self.pgp_keys
     }
 
@@ -380,7 +378,7 @@ impl Cfg {
         self.profile_override = Some(profile);
     }
 
-    pub fn set_default(&self, toolchain: &str) -> Result<()> {
+    pub(crate) fn set_default(&self, toolchain: &str) -> Result<()> {
         self.settings_file.with_mut(|s| {
             s.default_toolchain = Some(toolchain.to_owned());
             Ok(())
@@ -389,7 +387,7 @@ impl Cfg {
         Ok(())
     }
 
-    pub fn set_profile(&mut self, profile: &str) -> Result<()> {
+    pub(crate) fn set_profile(&mut self, profile: &str) -> Result<()> {
         match Profile::from_str(profile) {
             Ok(p) => {
                 self.profile_override = None;
@@ -404,7 +402,7 @@ impl Cfg {
         }
     }
 
-    pub fn set_auto_self_update(&mut self, mode: &str) -> Result<()> {
+    pub(crate) fn set_auto_self_update(&mut self, mode: &str) -> Result<()> {
         match SelfUpdateMode::from_str(mode) {
             Ok(update_mode) => {
                 self.settings_file.with_mut(|s| {
@@ -418,7 +416,7 @@ impl Cfg {
         }
     }
 
-    pub fn set_toolchain_override(&mut self, toolchain_override: &str) {
+    pub(crate) fn set_toolchain_override(&mut self, toolchain_override: &str) {
         self.toolchain_override = Some(toolchain_override.to_owned());
     }
 
@@ -442,7 +440,7 @@ impl Cfg {
         })
     }
 
-    pub fn get_self_update_mode(&self) -> Result<SelfUpdateMode> {
+    pub(crate) fn get_self_update_mode(&self) -> Result<SelfUpdateMode> {
         self.settings_file.with(|s| {
             let mode = match &s.auto_self_update {
                 Some(mode) => mode.clone(),
@@ -452,7 +450,7 @@ impl Cfg {
         })
     }
 
-    pub fn get_toolchain(&self, name: &str, create_parent: bool) -> Result<Toolchain<'_>> {
+    pub(crate) fn get_toolchain(&self, name: &str, create_parent: bool) -> Result<Toolchain<'_>> {
         if create_parent {
             utils::ensure_dir_exists("toolchains", &self.toolchains_dir, &|n| {
                 (self.notify_handler)(n)
@@ -462,7 +460,7 @@ impl Cfg {
         Toolchain::from(self, name)
     }
 
-    pub fn get_hash_file(&self, toolchain: &str, create_parent: bool) -> Result<PathBuf> {
+    pub(crate) fn get_hash_file(&self, toolchain: &str, create_parent: bool) -> Result<PathBuf> {
         if create_parent {
             utils::ensure_dir_exists(
                 "update-hash",
@@ -474,7 +472,7 @@ impl Cfg {
         Ok(self.update_hash_dir.join(toolchain))
     }
 
-    pub fn which_binary_by_toolchain(
+    pub(crate) fn which_binary_by_toolchain(
         &self,
         toolchain: &str,
         binary: &str,
@@ -487,12 +485,12 @@ impl Cfg {
         }
     }
 
-    pub fn which_binary(&self, path: &Path, binary: &str) -> Result<Option<PathBuf>> {
+    pub(crate) fn which_binary(&self, path: &Path, binary: &str) -> Result<Option<PathBuf>> {
         let (toolchain, _) = self.find_or_install_override_toolchain_or_default(path)?;
         Ok(Some(toolchain.binary_file(binary)))
     }
 
-    pub fn upgrade_data(&self) -> Result<()> {
+    pub(crate) fn upgrade_data(&self) -> Result<()> {
         let current_version = self.settings_file.with(|s| Ok(s.version.clone()))?;
 
         if current_version == DEFAULT_METADATA_VERSION {
@@ -532,7 +530,7 @@ impl Cfg {
         }
     }
 
-    pub fn find_default(&self) -> Result<Option<Toolchain<'_>>> {
+    pub(crate) fn find_default(&self) -> Result<Option<Toolchain<'_>>> {
         let opt_name = self.get_default()?;
 
         if let Some(name) = opt_name {
@@ -543,7 +541,10 @@ impl Cfg {
         }
     }
 
-    pub fn find_override(&self, path: &Path) -> Result<Option<(Toolchain<'_>, OverrideReason)>> {
+    pub(crate) fn find_override(
+        &self,
+        path: &Path,
+    ) -> Result<Option<(Toolchain<'_>, OverrideReason)>> {
         self.find_override_config(path).map(|opt| {
             opt.and_then(|(override_cfg, reason)| {
                 override_cfg.toolchain.map(|toolchain| (toolchain, reason))
@@ -722,7 +723,7 @@ impl Cfg {
         }
     }
 
-    pub fn find_or_install_override_toolchain_or_default(
+    pub(crate) fn find_or_install_override_toolchain_or_default(
         &self,
         path: &Path,
     ) -> Result<(Toolchain<'_>, Option<OverrideReason>)> {
@@ -819,7 +820,7 @@ impl Cfg {
         }
     }
 
-    pub fn get_default(&self) -> Result<Option<String>> {
+    pub(crate) fn get_default(&self) -> Result<Option<String>> {
         let user_opt = self.settings_file.with(|s| Ok(s.default_toolchain.clone()));
         if let Some(fallback_settings) = &self.fallback_settings {
             match user_opt {
@@ -830,7 +831,7 @@ impl Cfg {
         user_opt
     }
 
-    pub fn list_toolchains(&self) -> Result<Vec<String>> {
+    pub(crate) fn list_toolchains(&self) -> Result<Vec<String>> {
         if utils::is_directory(&self.toolchains_dir) {
             let mut toolchains: Vec<_> = utils::read_dir("toolchains", &self.toolchains_dir)?
                 .filter_map(io::Result::ok)
@@ -846,7 +847,7 @@ impl Cfg {
         }
     }
 
-    pub fn list_channels(&self) -> Result<Vec<(String, Result<Toolchain<'_>>)>> {
+    pub(crate) fn list_channels(&self) -> Result<Vec<(String, Result<Toolchain<'_>>)>> {
         let toolchains = self.list_toolchains()?;
 
         // Convert the toolchain strings to Toolchain values
@@ -859,7 +860,7 @@ impl Cfg {
             .collect())
     }
 
-    pub fn update_all_channels(
+    pub(crate) fn update_all_channels(
         &self,
         force_update: bool,
     ) -> Result<Vec<(String, Result<UpdateStatus>)>> {
@@ -883,7 +884,7 @@ impl Cfg {
         Ok(channels.collect())
     }
 
-    pub fn check_metadata_version(&self) -> Result<()> {
+    pub(crate) fn check_metadata_version(&self) -> Result<()> {
         utils::assert_is_directory(&self.rustup_dir)?;
 
         self.settings_file.with(|s| {
@@ -898,14 +899,14 @@ impl Cfg {
         })
     }
 
-    pub fn toolchain_for_dir(
+    pub(crate) fn toolchain_for_dir(
         &self,
         path: &Path,
     ) -> Result<(Toolchain<'_>, Option<OverrideReason>)> {
         self.find_or_install_override_toolchain_or_default(path)
     }
 
-    pub fn create_command_for_dir(&self, path: &Path, binary: &str) -> Result<Command> {
+    pub(crate) fn create_command_for_dir(&self, path: &Path, binary: &str) -> Result<Command> {
         let (ref toolchain, _) = self.toolchain_for_dir(path)?;
 
         if let Some(cmd) = self.maybe_do_cargo_fallback(toolchain, binary)? {
@@ -918,7 +919,7 @@ impl Cfg {
         }
     }
 
-    pub fn create_command_for_toolchain(
+    pub(crate) fn create_command_for_toolchain(
         &self,
         toolchain: &str,
         install_if_missing: bool,
@@ -974,7 +975,7 @@ impl Cfg {
         Ok(None)
     }
 
-    pub fn set_default_host_triple(&self, host_triple: &str) -> Result<()> {
+    pub(crate) fn set_default_host_triple(&self, host_triple: &str) -> Result<()> {
         // Ensure that the provided host_triple is capable of resolving
         // against the 'stable' toolchain.  This provides early errors
         // if the supplied triple is insufficient / bad.
@@ -997,7 +998,7 @@ impl Cfg {
             .unwrap_or_else(dist::TargetTriple::from_host_or_build))
     }
 
-    pub fn resolve_toolchain(&self, name: &str) -> Result<String> {
+    pub(crate) fn resolve_toolchain(&self, name: &str) -> Result<String> {
         if let Ok(desc) = dist::PartialToolchainDesc::from_str(name) {
             let host = self.get_default_host_triple()?;
             Ok(desc.resolve(&host)?.to_string())
diff --git a/src/currentprocess.rs b/src/currentprocess.rs
index c286f9a5df..6e53145435 100644
--- a/src/currentprocess.rs
+++ b/src/currentprocess.rs
@@ -191,13 +191,13 @@ impl ProcessSource for OSProcess {
 
 #[derive(Clone, Debug, Default)]
 pub struct TestProcess {
-    pub(crate) cwd: PathBuf,
-    pub(crate) args: Vec<String>,
-    pub(crate) vars: HashMap<String, String>,
-    pub(crate) id: u64,
-    pub(crate) stdin: TestStdinInner,
-    pub(crate) stdout: TestWriterInner,
-    pub(crate) stderr: TestWriterInner,
+    pub cwd: PathBuf,
+    pub args: Vec<String>,
+    pub vars: HashMap<String, String>,
+    pub id: u64,
+    pub stdin: TestStdinInner,
+    pub stdout: TestWriterInner,
+    pub stderr: TestWriterInner,
 }
 
 impl TestProcess {
diff --git a/src/env_var.rs b/src/env_var.rs
index ebc7d81bc5..ae9670ae4b 100644
--- a/src/env_var.rs
+++ b/src/env_var.rs
@@ -7,7 +7,7 @@ use crate::process;
 pub const RUST_RECURSION_COUNT_MAX: u32 = 20;
 
 #[allow(unused)]
-pub fn append_path(name: &str, value: Vec<PathBuf>, cmd: &mut Command) {
+fn append_path(name: &str, value: Vec<PathBuf>, cmd: &mut Command) {
     let old_value = process().var_os(name);
     let mut parts: Vec<PathBuf>;
     if let Some(ref v) = old_value {
@@ -21,7 +21,7 @@ pub fn append_path(name: &str, value: Vec<PathBuf>, cmd: &mut Command) {
     }
 }
 
-pub fn prepend_path(name: &str, value: Vec<PathBuf>, cmd: &mut Command) {
+pub(crate) fn prepend_path(name: &str, value: Vec<PathBuf>, cmd: &mut Command) {
     let old_value = process().var_os(name);
     let mut parts: Vec<PathBuf>;
     if let Some(ref v) = old_value {
@@ -36,7 +36,7 @@ pub fn prepend_path(name: &str, value: Vec<PathBuf>, cmd: &mut Command) {
     }
 }
 
-pub fn inc(name: &str, cmd: &mut Command) {
+pub(crate) fn inc(name: &str, cmd: &mut Command) {
     let old_value = process()
         .var(name)
         .ok()
diff --git a/src/errors.rs b/src/errors.rs
index 5b20ddd722..3e190ff2b2 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -10,7 +10,7 @@ use url::Url;
 
 use crate::dist::manifest::{Component, Manifest};
 
-pub const TOOLSTATE_MSG: &str =
+const TOOLSTATE_MSG: &str =
     "If you require these components, please install and use the latest successful build version,\n\
      which you can find at <https://rust-lang.github.io/rustup-components-history>.\n\nAfter determining \
      the correct date, install it with a command such as:\n\n    \
diff --git a/src/fallback_settings.rs b/src/fallback_settings.rs
index 54ca0bf568..9a07055b9b 100644
--- a/src/fallback_settings.rs
+++ b/src/fallback_settings.rs
@@ -20,7 +20,7 @@ impl Default for FallbackSettings {
 }
 
 impl FallbackSettings {
-    pub fn new<P: AsRef<Path>>(path: P) -> Result<Option<Self>> {
+    pub(crate) fn new<P: AsRef<Path>>(path: P) -> Result<Option<Self>> {
         // Users cannot fix issues with missing/unreadable/invalid centralised files, but logging isn't setup early so
         // we can't simply trap all errors and log diagnostics. Ideally we would, and then separate these into different
         // sorts of issues, logging messages about errors that should be fixed. Instead we trap some conservative errors
diff --git a/src/install.rs b/src/install.rs
index 4f4958985e..6cc9345208 100644
--- a/src/install.rs
+++ b/src/install.rs
@@ -10,11 +10,11 @@ use crate::dist::prefix::InstallPrefix;
 use crate::dist::Notification;
 use crate::errors::RustupError;
 use crate::notifications::Notification as RootNotification;
-use crate::toolchain::{CustomToolchain, DistributableToolchain, Toolchain, UpdateStatus};
+use crate::toolchain::{CustomToolchain, Toolchain, UpdateStatus};
 use crate::utils::utils;
 
 #[derive(Copy, Clone)]
-pub enum InstallMethod<'a> {
+pub(crate) enum InstallMethod<'a> {
     Copy(&'a Path, &'a CustomToolchain<'a>),
     Link(&'a Path, &'a CustomToolchain<'a>),
     // bool is whether to force an update
@@ -35,13 +35,12 @@ pub enum InstallMethod<'a> {
         components: &'a [&'a str],
         // Extra targets to install from dist
         targets: &'a [&'a str],
-        distributable: &'a DistributableToolchain<'a>,
     },
 }
 
 impl<'a> InstallMethod<'a> {
     // Install a toolchain
-    pub fn install(&self, toolchain: &Toolchain<'a>) -> Result<UpdateStatus> {
+    pub(crate) fn install(&self, toolchain: &Toolchain<'a>) -> Result<UpdateStatus> {
         let previous_version = if toolchain.exists() {
             Some(toolchain.rustc_version())
         } else {
diff --git a/src/lib.rs b/src/lib.rs
index aa47f6b80d..ee03f79584 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -8,11 +8,10 @@
 #![recursion_limit = "1024"]
 
 pub use crate::config::*;
-pub use crate::currentprocess::varsource::*;
-pub use crate::currentprocess::*;
+use crate::currentprocess::*;
 pub use crate::errors::*;
 pub use crate::notifications::*;
-pub use crate::toolchain::*;
+use crate::toolchain::*;
 pub(crate) use crate::utils::toml_utils;
 
 #[macro_use]
@@ -60,17 +59,17 @@ fn component_for_bin(binary: &str) -> Option<&'static str> {
 
 #[macro_use]
 pub mod cli;
-pub mod command;
+mod command;
 mod config;
 pub mod currentprocess;
-pub mod diskio;
+mod diskio;
 pub mod dist;
 pub mod env_var;
 pub mod errors;
-pub mod fallback_settings;
+mod fallback_settings;
 mod install;
-mod notifications;
-pub mod settings;
+pub mod notifications;
+mod settings;
 pub mod test;
-pub mod toolchain;
+mod toolchain;
 pub mod utils;
diff --git a/src/settings.rs b/src/settings.rs
index c0197fee51..af70d21396 100644
--- a/src/settings.rs
+++ b/src/settings.rs
@@ -12,8 +12,8 @@ use crate::notifications::*;
 use crate::toml_utils::*;
 use crate::utils::utils;
 
-pub const SUPPORTED_METADATA_VERSIONS: [&str; 2] = ["2", "12"];
-pub const DEFAULT_METADATA_VERSION: &str = "12";
+pub(crate) const SUPPORTED_METADATA_VERSIONS: [&str; 2] = ["2", "12"];
+pub(crate) const DEFAULT_METADATA_VERSION: &str = "12";
 
 #[derive(Clone, Debug, PartialEq)]
 pub struct SettingsFile {
@@ -22,7 +22,7 @@ pub struct SettingsFile {
 }
 
 impl SettingsFile {
-    pub fn new(path: PathBuf) -> Self {
+    pub(crate) fn new(path: PathBuf) -> Self {
         Self {
             path,
             cache: RefCell::new(None),
@@ -55,14 +55,14 @@ impl SettingsFile {
         Ok(())
     }
 
-    pub fn with<T, F: FnOnce(&Settings) -> Result<T>>(&self, f: F) -> Result<T> {
+    pub(crate) fn with<T, F: FnOnce(&Settings) -> Result<T>>(&self, f: F) -> Result<T> {
         self.read_settings()?;
 
         // Settings can no longer be None so it's OK to unwrap
         f(self.cache.borrow().as_ref().unwrap())
     }
 
-    pub fn with_mut<T, F: FnOnce(&mut Settings) -> Result<T>>(&self, f: F) -> Result<T> {
+    pub(crate) fn with_mut<T, F: FnOnce(&mut Settings) -> Result<T>>(&self, f: F) -> Result<T> {
         self.read_settings()?;
 
         // Settings can no longer be None so it's OK to unwrap
@@ -137,16 +137,16 @@ impl Settings {
         self.overrides.get(&key).cloned()
     }
 
-    pub fn parse(data: &str) -> Result<Self> {
+    pub(crate) fn parse(data: &str) -> Result<Self> {
         let value = toml::from_str(data).context("error parsing settings")?;
         Self::from_toml(value, "")
     }
 
-    pub fn stringify(self) -> String {
+    pub(crate) fn stringify(self) -> String {
         toml::Value::Table(self.into_toml()).to_string()
     }
 
-    pub fn from_toml(mut table: toml::value::Table, path: &str) -> Result<Self> {
+    pub(crate) fn from_toml(mut table: toml::value::Table, path: &str) -> Result<Self> {
         let version = get_string(&mut table, "version", path)?;
         if !SUPPORTED_METADATA_VERSIONS.contains(&&*version) {
             return Err(RustupError::UnknownMetadataVersion(version).into());
@@ -165,7 +165,7 @@ impl Settings {
             auto_self_update,
         })
     }
-    pub fn into_toml(self) -> toml::value::Table {
+    pub(crate) fn into_toml(self) -> toml::value::Table {
         let mut result = toml::value::Table::new();
 
         result.insert("version".to_owned(), toml::Value::String(self.version));
diff --git a/src/test.rs b/src/test.rs
index 219b4dcb9f..dcd8b8850d 100644
--- a/src/test.rs
+++ b/src/test.rs
@@ -8,6 +8,7 @@ use std::io;
 use std::path::{Path, PathBuf};
 use std::process::Command;
 
+#[cfg(test)]
 use anyhow::Result;
 
 pub use crate::cli::self_update::test::{get_path, with_saved_path};
@@ -168,7 +169,8 @@ impl fmt::Display for RustupHome {
 
 /// Create an isolated rustup home with no content, then call f with it, and
 /// delete it afterwards.
-pub fn with_rustup_home<F>(f: F) -> Result<()>
+#[cfg(test)]
+pub(crate) fn with_rustup_home<F>(f: F) -> Result<()>
 where
     F: FnOnce(&RustupHome) -> Result<()>,
 {
diff --git a/src/toolchain.rs b/src/toolchain.rs
index a9963a83b6..b76a3cd22d 100644
--- a/src/toolchain.rs
+++ b/src/toolchain.rs
@@ -67,7 +67,7 @@ pub enum UpdateStatus {
 static V1_COMMON_COMPONENT_LIST: &[&str] = &["cargo", "rustc", "rust-docs"];
 
 impl<'a> Toolchain<'a> {
-    pub fn from(cfg: &'a Cfg, name: &str) -> Result<Self> {
+    pub(crate) fn from(cfg: &'a Cfg, name: &str) -> Result<Self> {
         let resolved_name = cfg.resolve_toolchain(name)?;
         let path = cfg.toolchains_dir.join(&resolved_name);
         Ok(Toolchain {
@@ -78,7 +78,7 @@ impl<'a> Toolchain<'a> {
         })
     }
 
-    pub fn from_path(
+    pub(crate) fn from_path(
         cfg: &'a Cfg,
         cfg_file: Option<impl AsRef<Path>>,
         path: impl AsRef<Path>,
@@ -127,7 +127,7 @@ impl<'a> Toolchain<'a> {
             Ok(Box::new(toolchain) as Box<dyn InstalledToolchain<'a>>)
         }
     }
-    pub fn cfg(&self) -> &Cfg {
+    pub(crate) fn cfg(&self) -> &Cfg {
         self.cfg
     }
     pub fn name(&self) -> &str {
@@ -774,7 +774,6 @@ impl<'a> DistributableToolchain<'a> {
             old_date: old_date.as_deref(),
             components,
             targets,
-            distributable: self,
         }
         .install(self.0)
     }
@@ -795,7 +794,6 @@ impl<'a> DistributableToolchain<'a> {
                 old_date: None,
                 components: &[],
                 targets: &[],
-                distributable: self,
             }
             .install(self.0)?)
         } else {