src/Pure/PIDE/prover.scala

--- a/src/Pure/PIDE/prover.scala	Sun May 16 13:14:16 2021 +0200
+++ b/src/Pure/PIDE/prover.scala	Sun May 16 13:34:27 2021 +0200
@@ -140,7 +140,7 @@
           }
           catch { case _: IOException => finished = Some(false) }
         }
-        Time.seconds(0.05).sleep
+        Time.seconds(0.05).sleep()
       }
       (finished.isEmpty || !finished.get, result.toString.trim)
     }
@@ -181,7 +181,7 @@
 
     var count = 10
     while (!process_result.is_finished && count > 0) {
-      Time.seconds(0.1).sleep
+      Time.seconds(0.1).sleep()
       count -= 1
     }
     if (!process_result.is_finished) terminate_process()