If you have a RED MSP432 LaunchPad then please install and use the "Energia MSP432 EMT RED boards" package using the board manager.
If you have a BLACK MSP432 LaunchPad then edit the file C:\Users\<user name\AppData\Local\Energia15\packages\energia\hardware\msp432\3.8.0\platform.txt
On line 20 change:
I will have an update for this package later this week that fixes this issue.
The issue is that the Energia always picks the latest compiler if a compiler version is not explicitly called for in platform.txt. The current msp432 (BLACK) core is not compatible with the latest compiler installed by other boards (e.g. MSP432 RED core).