Set switch statement warnings as errors

Summary:
The warnings lifted to errors should help us track down cases which
haven't been covered in a switch. Obviously, using the default case will
not trigger these errors, so default should only be used when we
actually want to cover more cases.

Reviewers: florijan, dgleich, mferencevic

Reviewed By: dgleich

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D975

CMakeLists.txt

@@ -72,7 +72,7 @@ endif()
 # set(CMAKE_CXX_STANDARD 17)
 # set(CMAKE_CXX_STANDARD_REQUIRED ON)
 # For now, explicitly set -std= flag for C++17.
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++1z -Wall")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++1z -Wall -Werror=switch -Werror=switch-bool")
 
 # Don't omit frame pointer in RelWithDebInfo, for additional callchain debug.
 set(CMAKE_CXX_FLAGS_RELWITHDEBINFO

src/database/indexes/label_property_index.hpp

@@ -466,8 +466,6 @@ class LabelPropertyIndex {
             return lexicographical_compare(ma.begin(), ma.end(), mb.begin(),
                                            mb.end(), cmp);
           }
-          default:
-            LOG(FATAL) << "Unimplemented type operator.";
         }
       }