Revert "Constify SystemTime methods"

This reverts commit 7ce620dd7c6fc3371290b40a1ea28146f0d37031.
The const-hacks introduces bugs, and they make the code harder to maintain.
Let's wait until we can constify these functions without changing their implementation.

1 files changed, 4 insertions, 11 deletions

diff --git a/library/std/src/sys/pal/sgx/time.rs b/library/std/src/sys/pal/sgx/time.rs
index 603dae952ab..db4cf2804bf 100644
--- a/library/std/src/sys/pal/sgx/time.rs
+++ b/library/std/src/sys/pal/sgx/time.rs
@@ -32,22 +32,15 @@ impl SystemTime {
         SystemTime(usercalls::insecure_time())
     }
 
-    #[rustc_const_unstable(feature = "const_system_time", issue = "144517")]
-    pub const fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
-        // FIXME: ok_or_else with const closures
-        match self.0.checked_sub(other.0) {
-            Some(duration) => Ok(duration),
-            None => Err(other.0 - self.0),
-        }
+    pub fn sub_time(&self, other: &SystemTime) -> Result<Duration, Duration> {
+        self.0.checked_sub(other.0).ok_or_else(|| other.0 - self.0)
     }
 
-    #[rustc_const_unstable(feature = "const_system_time", issue = "144517")]
-    pub const fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
+    pub fn checked_add_duration(&self, other: &Duration) -> Option<SystemTime> {
         Some(SystemTime(self.0.checked_add(*other)?))
     }
 
-    #[rustc_const_unstable(feature = "const_system_time", issue = "144517")]
-    pub const fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
+    pub fn checked_sub_duration(&self, other: &Duration) -> Option<SystemTime> {
         Some(SystemTime(self.0.checked_sub(*other)?))
     }
 }