diff --git a/src/libstd/sys/unix/process/process_fuchsia.rs b/src/libstd/sys/unix/process/process_fuchsia.rs
index f0bd1cdfed52..6daf2885baed 100644
--- a/src/libstd/sys/unix/process/process_fuchsia.rs
+++ b/src/libstd/sys/unix/process/process_fuchsia.rs
@@ -246,6 +246,7 @@ impl ExitStatus {
     }
 }
 
+/// Converts a raw `c_int` to a type-safe `ExitStatus` by wrapping it without copying.
 impl From<c_int> for ExitStatus {
     fn from(a: c_int) -> ExitStatus {
         ExitStatus(a as i64)
diff --git a/src/libstd/sys/unix/process/process_unix.rs b/src/libstd/sys/unix/process/process_unix.rs
index de35fe0521d0..371291b9f76a 100644
--- a/src/libstd/sys/unix/process/process_unix.rs
+++ b/src/libstd/sys/unix/process/process_unix.rs
@@ -479,6 +479,7 @@ impl ExitStatus {
     }
 }
 
+/// Converts a raw `c_int` to a type-safe `ExitStatus` by wrapping it without copying.
 impl From<c_int> for ExitStatus {
     fn from(a: c_int) -> ExitStatus {
         ExitStatus(a)
diff --git a/src/libstd/sys/vxworks/process/process_common.rs b/src/libstd/sys/vxworks/process/process_common.rs
index 78b6e9a4db78..bbbd5eda7731 100644
--- a/src/libstd/sys/vxworks/process/process_common.rs
+++ b/src/libstd/sys/vxworks/process/process_common.rs
@@ -376,6 +376,7 @@ impl ExitStatus {
     }
 }
 
+/// Converts a raw `c_int` to a type-safe `ExitStatus` by wrapping it without copying.
 impl From<c_int> for ExitStatus {
     fn from(a: c_int) -> ExitStatus {
         ExitStatus(a)
diff --git a/src/libstd/sys/windows/process.rs b/src/libstd/sys/windows/process.rs
index 77f9a5c9dc7b..7d6d4775eec8 100644
--- a/src/libstd/sys/windows/process.rs
+++ b/src/libstd/sys/windows/process.rs
@@ -378,6 +378,7 @@ impl ExitStatus {
     }
 }
 
+/// Converts a raw `c::DWORD` to a type-safe `ExitStatus` by wrapping it without copying.
 impl From<c::DWORD> for ExitStatus {
     fn from(u: c::DWORD) -> ExitStatus {
         ExitStatus(u)