diff --git a/lldb/source/Host/common/Editline.cpp b/lldb/source/Host/common/Editline.cpp
index 45d3db24bbc6..b29c218f0369 100644
--- a/lldb/source/Host/common/Editline.cpp
+++ b/lldb/source/Host/common/Editline.cpp
@@ -120,6 +120,7 @@ static int GetOperation(HistoryOperation op) {
     case HistoryOperation::Newest:
       return H_LAST;
   }
+  llvm_unreachable("Fully covered switch!");
 }