diff -r a471730347e0 -r 460d743010bc src/HOL/TPTP/TPTP_Interpret_Test.thy
--- a/src/HOL/TPTP/TPTP_Interpret_Test.thy	Mon Oct 26 21:35:39 2020 +0100
+++ b/src/HOL/TPTP/TPTP_Interpret_Test.thy	Tue Oct 27 22:34:37 2020 +0100
@@ -18,7 +18,7 @@
       (TPTP_Interpret.interpret_file
        false
        [Path.explode "$TPTP"]
-       (Path.append tptp_probs_dir (Path.explode "LCL/LCL825-1.p"))
+       (tptp_probs_dir + Path.explode "LCL/LCL825-1.p")
        []
        [])
       @{theory}