windows bump to 0.52

compiler/rustc_errors/src/lock.rs

@@ -27,7 +27,8 @@ pub fn acquire_global_lock(name: &str) -> Box<dyn Any> {
     impl Drop for Handle {
         fn drop(&mut self) {
             unsafe {
-                CloseHandle(self.0);
+                // FIXME can panic here
+                CloseHandle(self.0).unwrap();
             }
         }
     }
@@ -37,7 +38,8 @@ pub fn acquire_global_lock(name: &str) -> Box<dyn Any> {
     impl Drop for Guard {
         fn drop(&mut self) {
             unsafe {
-                ReleaseMutex((self.0).0);
+                // FIXME can panic here
+                ReleaseMutex((self.0).0).unwrap();
             }
         }
     }