diff --git a/src/libstd/sys/cloudabi/shims/process.rs b/src/libstd/sys/cloudabi/shims/process.rs
index e719b362cbf55..03a59d6d7c832 100644
--- a/src/libstd/sys/cloudabi/shims/process.rs
+++ b/src/libstd/sys/cloudabi/shims/process.rs
@@ -4,14 +4,16 @@ use crate::io;
 use crate::sys::fs::File;
 use crate::sys::pipe::AnonPipe;
 use crate::sys::{unsupported, Void};
-use crate::sys_common::process::{CommandEnv, DefaultEnvKey};
+use crate::sys_common::process::CommandEnv;
+
+pub use crate::ffi::OsString as EnvKey;
 
 ////////////////////////////////////////////////////////////////////////////////
 // Command
 ////////////////////////////////////////////////////////////////////////////////
 
 pub struct Command {
-    env: CommandEnv<DefaultEnvKey>,
+    env: CommandEnv,
 }
 
 // passed back to std::process with the pipes connected to the child, if any
@@ -37,7 +39,7 @@ impl Command {
 
     pub fn arg(&mut self, _arg: &OsStr) {}
 
-    pub fn env_mut(&mut self) -> &mut CommandEnv<DefaultEnvKey> {
+    pub fn env_mut(&mut self) -> &mut CommandEnv {
         &mut self.env
     }
 
diff --git a/src/libstd/sys/sgx/process.rs b/src/libstd/sys/sgx/process.rs
index a02e009d95356..edf933d10e074 100644
--- a/src/libstd/sys/sgx/process.rs
+++ b/src/libstd/sys/sgx/process.rs
@@ -4,14 +4,16 @@ use crate::io;
 use crate::sys::fs::File;
 use crate::sys::pipe::AnonPipe;
 use crate::sys::{unsupported, Void};
-use crate::sys_common::process::{CommandEnv, DefaultEnvKey};
+use crate::sys_common::process::CommandEnv;
+
+pub use crate::ffi::OsString as EnvKey;
 
 ////////////////////////////////////////////////////////////////////////////////
 // Command
 ////////////////////////////////////////////////////////////////////////////////
 
 pub struct Command {
-    env: CommandEnv<DefaultEnvKey>
+    env: CommandEnv,
 }
 
 // passed back to std::process with the pipes connected to the child, if any
@@ -38,7 +40,7 @@ impl Command {
     pub fn arg(&mut self, _arg: &OsStr) {
     }
 
-    pub fn env_mut(&mut self) -> &mut CommandEnv<DefaultEnvKey> {
+    pub fn env_mut(&mut self) -> &mut CommandEnv {
         &mut self.env
     }
 
diff --git a/src/libstd/sys/unix/process/mod.rs b/src/libstd/sys/unix/process/mod.rs
index bba4b21c46232..056a20345f404 100644
--- a/src/libstd/sys/unix/process/mod.rs
+++ b/src/libstd/sys/unix/process/mod.rs
@@ -1,5 +1,6 @@
 pub use self::process_common::{Command, ExitStatus, ExitCode, Stdio, StdioPipes};
 pub use self::process_inner::Process;
+pub use crate::ffi::OsString as EnvKey;
 
 mod process_common;
 #[cfg(not(target_os = "fuchsia"))]
diff --git a/src/libstd/sys/unix/process/process_common.rs b/src/libstd/sys/unix/process/process_common.rs
index 21fca23a8fe9e..72e66cc8e7240 100644
--- a/src/libstd/sys/unix/process/process_common.rs
+++ b/src/libstd/sys/unix/process/process_common.rs
@@ -7,7 +7,7 @@ use crate::ptr;
 use crate::sys::fd::FileDesc;
 use crate::sys::fs::{File, OpenOptions};
 use crate::sys::pipe::{self, AnonPipe};
-use crate::sys_common::process::{CommandEnv, DefaultEnvKey};
+use crate::sys_common::process::CommandEnv;
 use crate::collections::BTreeMap;
 
 use libc::{c_int, gid_t, uid_t, c_char, EXIT_SUCCESS, EXIT_FAILURE};
@@ -69,7 +69,7 @@ pub struct Command {
     program: CString,
     args: Vec<CString>,
     argv: Argv,
-    env: CommandEnv<DefaultEnvKey>,
+    env: CommandEnv,
 
     cwd: Option<CString>,
     uid: Option<uid_t>,
@@ -201,7 +201,7 @@ impl Command {
         self.stderr = Some(stderr);
     }
 
-    pub fn env_mut(&mut self) -> &mut CommandEnv<DefaultEnvKey> {
+    pub fn env_mut(&mut self) -> &mut CommandEnv {
         &mut self.env
     }
 
@@ -271,7 +271,7 @@ impl CStringArray {
     }
 }
 
-fn construct_envp(env: BTreeMap<DefaultEnvKey, OsString>, saw_nul: &mut bool) -> CStringArray {
+fn construct_envp(env: BTreeMap<OsString, OsString>, saw_nul: &mut bool) -> CStringArray {
     let mut result = CStringArray::with_capacity(env.len());
     for (k, v) in env {
         let mut k: OsString = k.into();
diff --git a/src/libstd/sys/vxworks/process/process_common.rs b/src/libstd/sys/vxworks/process/process_common.rs
index ba797354a7380..509140229fd3a 100644
--- a/src/libstd/sys/vxworks/process/process_common.rs
+++ b/src/libstd/sys/vxworks/process/process_common.rs
@@ -7,11 +7,13 @@ use crate::ptr;
 use crate::sys::fd::FileDesc;
 use crate::sys::fs::{File, OpenOptions};
 use crate::sys::pipe::{self, AnonPipe};
-use crate::sys_common::process::{CommandEnv, DefaultEnvKey};
+use crate::sys_common::process::CommandEnv;
 use crate::collections::BTreeMap;
 
 use libc::{c_int, gid_t, uid_t, c_char, EXIT_SUCCESS, EXIT_FAILURE};
 
+pub use crate::ffi::OsString as EnvKey;
+
 ////////////////////////////////////////////////////////////////////////////////
 // Command
 ////////////////////////////////////////////////////////////////////////////////
@@ -37,7 +39,7 @@ pub struct Command {
     program: CString,
     args: Vec<CString>,
     argv: Argv,
-    env: CommandEnv<DefaultEnvKey>,
+    env: CommandEnv,
 
     cwd: Option<CString>,
     uid: Option<uid_t>,
@@ -170,7 +172,7 @@ impl Command {
         self.stderr = Some(stderr);
     }
 
-    pub fn env_mut(&mut self) -> &mut CommandEnv<DefaultEnvKey> {
+    pub fn env_mut(&mut self) -> &mut CommandEnv {
         &mut self.env
     }
 
@@ -240,7 +242,7 @@ impl CStringArray {
     }
 }
 
-fn construct_envp(env: BTreeMap<DefaultEnvKey, OsString>, saw_nul: &mut bool) -> CStringArray {
+fn construct_envp(env: BTreeMap<OsString, OsString>, saw_nul: &mut bool) -> CStringArray {
     let mut result = CStringArray::with_capacity(env.len());
     for (k, v) in env {
         let mut k: OsString = k.into();
diff --git a/src/libstd/sys/wasi/process.rs b/src/libstd/sys/wasi/process.rs
index 788b829f4bac9..1c4d028b7618b 100644
--- a/src/libstd/sys/wasi/process.rs
+++ b/src/libstd/sys/wasi/process.rs
@@ -4,14 +4,16 @@ use crate::io;
 use crate::sys::fs::File;
 use crate::sys::pipe::AnonPipe;
 use crate::sys::{unsupported, Void};
-use crate::sys_common::process::{CommandEnv, DefaultEnvKey};
+use crate::sys_common::process::CommandEnv;
+
+pub use crate::ffi::OsString as EnvKey;
 
 ////////////////////////////////////////////////////////////////////////////////
 // Command
 ////////////////////////////////////////////////////////////////////////////////
 
 pub struct Command {
-    env: CommandEnv<DefaultEnvKey>
+    env: CommandEnv
 }
 
 // passed back to std::process with the pipes connected to the child, if any
@@ -38,7 +40,7 @@ impl Command {
     pub fn arg(&mut self, _arg: &OsStr) {
     }
 
-    pub fn env_mut(&mut self) -> &mut CommandEnv<DefaultEnvKey> {
+    pub fn env_mut(&mut self) -> &mut CommandEnv {
         &mut self.env
     }
 
diff --git a/src/libstd/sys/wasm/process.rs b/src/libstd/sys/wasm/process.rs
index a02e009d95356..edf933d10e074 100644
--- a/src/libstd/sys/wasm/process.rs
+++ b/src/libstd/sys/wasm/process.rs
@@ -4,14 +4,16 @@ use crate::io;
 use crate::sys::fs::File;
 use crate::sys::pipe::AnonPipe;
 use crate::sys::{unsupported, Void};
-use crate::sys_common::process::{CommandEnv, DefaultEnvKey};
+use crate::sys_common::process::CommandEnv;
+
+pub use crate::ffi::OsString as EnvKey;
 
 ////////////////////////////////////////////////////////////////////////////////
 // Command
 ////////////////////////////////////////////////////////////////////////////////
 
 pub struct Command {
-    env: CommandEnv<DefaultEnvKey>
+    env: CommandEnv,
 }
 
 // passed back to std::process with the pipes connected to the child, if any
@@ -38,7 +40,7 @@ impl Command {
     pub fn arg(&mut self, _arg: &OsStr) {
     }
 
-    pub fn env_mut(&mut self) -> &mut CommandEnv<DefaultEnvKey> {
+    pub fn env_mut(&mut self) -> &mut CommandEnv {
         &mut self.env
     }
 
diff --git a/src/libstd/sys/windows/process.rs b/src/libstd/sys/windows/process.rs
index 05e0ca6706453..8658deb854635 100644
--- a/src/libstd/sys/windows/process.rs
+++ b/src/libstd/sys/windows/process.rs
@@ -19,7 +19,7 @@ use crate::sys::pipe::{self, AnonPipe};
 use crate::sys::stdio;
 use crate::sys::cvt;
 use crate::sys_common::{AsInner, FromInner, IntoInner};
-use crate::sys_common::process::{CommandEnv, EnvKey};
+use crate::sys_common::process::CommandEnv;
 use crate::borrow::Borrow;
 
 use libc::{c_void, EXIT_SUCCESS, EXIT_FAILURE};
@@ -30,30 +30,28 @@ use libc::{c_void, EXIT_SUCCESS, EXIT_FAILURE};
 
 #[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
 #[doc(hidden)]
-pub struct WindowsEnvKey(OsString);
+pub struct EnvKey(OsString);
 
-impl From<OsString> for WindowsEnvKey {
+impl From<OsString> for EnvKey {
     fn from(k: OsString) -> Self {
         let mut buf = k.into_inner().into_inner();
         buf.make_ascii_uppercase();
-        WindowsEnvKey(FromInner::from_inner(FromInner::from_inner(buf)))
+        EnvKey(FromInner::from_inner(FromInner::from_inner(buf)))
     }
 }
 
-impl From<WindowsEnvKey> for OsString {
-    fn from(k: WindowsEnvKey) -> Self { k.0 }
+impl From<EnvKey> for OsString {
+    fn from(k: EnvKey) -> Self { k.0 }
 }
 
-impl Borrow<OsStr> for WindowsEnvKey {
+impl Borrow<OsStr> for EnvKey {
     fn borrow(&self) -> &OsStr { &self.0 }
 }
 
-impl AsRef<OsStr> for WindowsEnvKey {
+impl AsRef<OsStr> for EnvKey {
     fn as_ref(&self) -> &OsStr { &self.0 }
 }
 
-impl EnvKey for WindowsEnvKey {}
-
 
 fn ensure_no_nuls<T: AsRef<OsStr>>(str: T) -> io::Result<T> {
     if str.as_ref().encode_wide().any(|b| b == 0) {
@@ -66,7 +64,7 @@ fn ensure_no_nuls<T: AsRef<OsStr>>(str: T) -> io::Result<T> {
 pub struct Command {
     program: OsString,
     args: Vec<OsString>,
-    env: CommandEnv<WindowsEnvKey>,
+    env: CommandEnv,
     cwd: Option<OsString>,
     flags: u32,
     detach: bool, // not currently exposed in std::process
@@ -110,7 +108,7 @@ impl Command {
     pub fn arg(&mut self, arg: &OsStr) {
         self.args.push(arg.to_os_string())
     }
-    pub fn env_mut(&mut self) -> &mut CommandEnv<WindowsEnvKey> {
+    pub fn env_mut(&mut self) -> &mut CommandEnv {
         &mut self.env
     }
     pub fn cwd(&mut self, dir: &OsStr) {
@@ -498,7 +496,7 @@ fn make_command_line(prog: &OsStr, args: &[OsString]) -> io::Result<Vec<u16>> {
     }
 }
 
-fn make_envp(maybe_env: Option<BTreeMap<WindowsEnvKey, OsString>>)
+fn make_envp(maybe_env: Option<BTreeMap<EnvKey, OsString>>)
              -> io::Result<(*mut c_void, Vec<u16>)> {
     // On Windows we pass an "environment block" which is not a char**, but
     // rather a concatenation of null-terminated k=v\0 sequences, with a final
diff --git a/src/libstd/sys_common/process.rs b/src/libstd/sys_common/process.rs
index 4d40dec97245a..bdf66fca35970 100644
--- a/src/libstd/sys_common/process.rs
+++ b/src/libstd/sys_common/process.rs
@@ -1,47 +1,20 @@
 #![allow(dead_code)]
 #![unstable(feature = "process_internals", issue = "0")]
 
-use crate::ffi::{OsStr, OsString};
-use crate::env;
 use crate::collections::BTreeMap;
-use crate::borrow::Borrow;
-
-pub trait EnvKey:
-    From<OsString> + Into<OsString> +
-    Borrow<OsStr> + Borrow<Self> + AsRef<OsStr> +
-    Ord + Clone {}
-
-// Implement a case-sensitive environment variable key
-#[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
-pub struct DefaultEnvKey(OsString);
-
-impl From<OsString> for DefaultEnvKey {
-    fn from(k: OsString) -> Self { DefaultEnvKey(k) }
-}
-
-impl From<DefaultEnvKey> for OsString {
-    fn from(k: DefaultEnvKey) -> Self { k.0 }
-}
-
-impl Borrow<OsStr> for DefaultEnvKey {
-    fn borrow(&self) -> &OsStr { &self.0 }
-}
-
-impl AsRef<OsStr> for DefaultEnvKey {
-    fn as_ref(&self) -> &OsStr { &self.0 }
-}
-
-impl EnvKey for DefaultEnvKey {}
+use crate::env;
+use crate::ffi::{OsStr, OsString};
+use crate::sys::process::EnvKey;
 
 // Stores a set of changes to an environment
 #[derive(Clone, Debug)]
-pub struct CommandEnv<K> {
+pub struct CommandEnv {
     clear: bool,
     saw_path: bool,
-    vars: BTreeMap<K, Option<OsString>>
+    vars: BTreeMap<EnvKey, Option<OsString>>
 }
 
-impl<K: EnvKey> Default for CommandEnv<K> {
+impl Default for CommandEnv {
     fn default() -> Self {
         CommandEnv {
             clear: false,
@@ -51,10 +24,10 @@ impl<K: EnvKey> Default for CommandEnv<K> {
     }
 }
 
-impl<K: EnvKey> CommandEnv<K> {
+impl CommandEnv {
     // Capture the current environment with these changes applied
-    pub fn capture(&self) -> BTreeMap<K, OsString> {
-        let mut result = BTreeMap::<K, OsString>::new();
+    pub fn capture(&self) -> BTreeMap<EnvKey, OsString> {
+        let mut result = BTreeMap::<EnvKey, OsString>::new();
         if !self.clear {
             for (k, v) in env::vars_os() {
                 result.insert(k.into(), v);
@@ -90,7 +63,7 @@ impl<K: EnvKey> CommandEnv<K> {
         !self.clear && self.vars.is_empty()
     }
 
-    pub fn capture_if_changed(&self) -> Option<BTreeMap<K, OsString>> {
+    pub fn capture_if_changed(&self) -> Option<BTreeMap<EnvKey, OsString>> {
         if self.is_unchanged() {
             None
         } else {
@@ -103,6 +76,7 @@ impl<K: EnvKey> CommandEnv<K> {
         self.maybe_saw_path(&key);
         self.vars.insert(key.to_owned().into(), Some(value.to_owned()));
     }
+
     pub fn remove(&mut self, key: &OsStr) {
         self.maybe_saw_path(&key);
         if self.clear {
@@ -111,13 +85,16 @@ impl<K: EnvKey> CommandEnv<K> {
             self.vars.insert(key.to_owned().into(), None);
         }
     }
+
     pub fn clear(&mut self) {
         self.clear = true;
         self.vars.clear();
     }
+
     pub fn have_changed_path(&self) -> bool {
         self.saw_path || self.clear
     }
+
     fn maybe_saw_path(&mut self, key: &OsStr) {
         if !self.saw_path && key == "PATH" {
             self.saw_path = true;