diff --git a/lldb/source/Host/common/Editline.cpp b/lldb/source/Host/common/Editline.cpp
--- a/lldb/source/Host/common/Editline.cpp
+++ b/lldb/source/Host/common/Editline.cpp
@@ -1006,11 +1006,11 @@
     switch (completion.GetMode()) {
     case CompletionMode::Normal: {
       std::string to_add = completion.GetCompletion();
-      to_add = to_add.substr(request.GetCursorArgumentPrefix().size());
       // Terminate the current argument with a quote if it started with a quote.
       if (!request.GetParsedLine().empty() && request.GetParsedArg().IsQuoted())
         to_add.push_back(request.GetParsedArg().GetQuoteChar());
       to_add.push_back(' ');
+      el_deletestr(m_editline, request.GetCursorArgumentPrefix().size());
       el_insertstr(m_editline, to_add.c_str());
       // Clear all the autosuggestion parts if the only single space can be completed.
       if (to_add == " ")
diff --git a/lldb/test/API/iohandler/completion/Makefile b/lldb/test/API/iohandler/completion/Makefile
new file mode 100644
--- /dev/null
+++ b/lldb/test/API/iohandler/completion/Makefile
@@ -0,0 +1,3 @@
+C_SOURCES := main.c
+
+include Makefile.rules
diff --git a/lldb/test/API/iohandler/completion/TestIOHandlerCompletion.py b/lldb/test/API/iohandler/completion/TestIOHandlerCompletion.py
--- a/lldb/test/API/iohandler/completion/TestIOHandlerCompletion.py
+++ b/lldb/test/API/iohandler/completion/TestIOHandlerCompletion.py
@@ -20,7 +20,8 @@
     @expectedFailureAll(oslist=['freebsd'], bugnumber='llvm.org/pr49408')
     @skipIf(oslist=["linux"], archs=["arm", "aarch64"])
     def test_completion(self):
-        self.launch(dimensions=(100,500))
+        self.build()
+        self.launch(dimensions=(100,500), executable=self.getBuildArtifact("a.out"))
 
         # Start tab completion, go to the next page and then display all with 'a'.
         self.child.send("\t\ta")
@@ -51,6 +52,13 @@
         self.child.send("\n")
         self.expect_prompt()
 
+        # Complete a file path.
+        # FIXME: This should complete to './main.c' and not 'main.c'
+        self.child.send("breakpoint set --file ./main\t")
+        self.child.expect_exact("main.c")
+        self.child.send("\n")
+        self.expect_prompt()
+
         # Start tab completion and abort showing more commands with 'n'.
         self.child.send("\t")
         self.child.expect_exact("More (Y/n/a)")