5 files changed, 45 insertions, 7 deletions
diff --git a/ghc/GHCi/UI.hs b/ghc/GHCi/UI.hs
index ab3992ccd0..31c6db055d 100644
--- a/ghc/GHCi/UI.hs
+++ b/ghc/GHCi/UI.hs
@@ -1543,8 +1543,8 @@ changeDirectory dir = do
   graph <- GHC.getModuleGraph
   when (not (null $ GHC.mgModSummaries graph)) $
         liftIO $ putStrLn "Warning: changing directory causes all loaded modules to be unloaded,\nbecause the search path has changed."
-  GHC.setTargets []
-  _ <- GHC.load LoadAllTargets
+  -- delete targets and all eventually defined breakpoints (#1620)
+  clearAllTargets
   setContextAfterLoad False []
   GHC.workingDirectoryChanged
   dir' <- expandPath dir
@@ -1852,9 +1852,7 @@ loadModule' files = do
 
   -- unload first
   _ <- GHC.abandonAll
-  discardActiveBreakPoints
-  GHC.setTargets []
-  _ <- GHC.load LoadAllTargets
+  clearAllTargets
 
   GHC.setTargets targets
   success <- doLoadAndCollectInfo False LoadAllTargets
@@ -2916,8 +2914,8 @@ newDynFlags interactive_only minus_opts = do
           when (verbosity dflags2 > 0) $
             liftIO . putStrLn $
               "package flags have changed, resetting and loading new packages..."
-          GHC.setTargets []
-          _ <- GHC.load LoadAllTargets
+          -- delete targets and all eventually defined breakpoints. (#1620)
+          clearAllTargets
           liftIO $ linkPackages hsc_env new_pkgs
           -- package flags changed, we can't re-use any of the old context
           setContextAfterLoad False []
@@ -4128,3 +4126,9 @@ wantNameFromInterpretedModule noCanDo str and_then =
                then noCanDo n $ text "module " <> ppr modl <>
                                 text " is not interpreted"
                else and_then n
+
+clearAllTargets :: GhciMonad m => m ()
+clearAllTargets = discardActiveBreakPoints
+                >> GHC.setTargets []
+                >> GHC.load LoadAllTargets
+                >> pure ()
diff --git a/testsuite/tests/ghci.debugger/scripts/T1620.script b/testsuite/tests/ghci.debugger/scripts/T1620.script
new file mode 100644
index 0000000000..17d38d5530
--- /dev/null
+++ b/testsuite/tests/ghci.debugger/scripts/T1620.script
@@ -0,0 +1,18 @@
+-- Test 1: No hanging breakpoints after :cd
+:cd T1620
+:l T1620.hs
+:break 2
+:cd ..
+:break 2
+:show breaks
+:cd T1620
+:l T1620.hs
+:main
+:l T1620.hs
+-- Test 2: Non hanging breakpoints after :set <some-package-flag>
+:break 2
+:set -no-user-package-db
+:show breaks
+:l T1620.hs
+:main
+:l T1620.hs
diff --git a/testsuite/tests/ghci.debugger/scripts/T1620.stdout b/testsuite/tests/ghci.debugger/scripts/T1620.stdout
new file mode 100644
index 0000000000..fc453c2b60
--- /dev/null
+++ b/testsuite/tests/ghci.debugger/scripts/T1620.stdout
@@ -0,0 +1,9 @@
+Breakpoint 0 activated at T1620.hs:2:16-47
+Warning: changing directory causes all loaded modules to be unloaded,
+because the search path has changed.
+No modules are loaded with debugging support.
+No active breakpoints.
+[1,3,4,7,10]
+Breakpoint 1 activated at T1620.hs:2:16-47
+No active breakpoints.
+[1,3,4,7,10]
diff --git a/testsuite/tests/ghci.debugger/scripts/T1620/T1620.hs b/testsuite/tests/ghci.debugger/scripts/T1620/T1620.hs
new file mode 100644
index 0000000000..7c97826676
--- /dev/null
+++ b/testsuite/tests/ghci.debugger/scripts/T1620/T1620.hs
@@ -0,0 +1,5 @@
+qsort [] = []
+qsort (a:as) = qsort left ++ [a] ++ qsort right
+  where (left,right) = (filter (<=a) as, filter (>a) as)
+
+main = print $ qsort [4, 1, 7, 10, 3]
diff --git a/testsuite/tests/ghci.debugger/scripts/all.T b/testsuite/tests/ghci.debugger/scripts/all.T
index bc3d025dcd..8460fbb809 100644
--- a/testsuite/tests/ghci.debugger/scripts/all.T
+++ b/testsuite/tests/ghci.debugger/scripts/all.T
@@ -100,6 +100,8 @@ test('hist001', [extra_files(['../Test3.hs']), extra_run_opts('+RTS -I0')],
 test('hist002', [extra_files(['../Test3.hs']), extra_run_opts('+RTS -I0')],
      ghci_script, ['hist002.script'])
 
+test('T1620', extra_files(['T1620/', 'T1620/T1620.hs']),
+              ghci_script, ['T1620.script'])
 test('T2740', normal, ghci_script, ['T2740.script'])
 
 test('getargs', extra_files(['../getargs.hs']), ghci_script, ['getargs.script'])