Check in initial diff engine and semantic analysis #5

Job	Run time
Security Audit	5m 10s
Test Suite (windows-latest, beta)	30s
Test Suite (ubuntu-latest, stable)	18s
Test Suite (ubuntu-latest, beta)	32s
Test Suite (macos-latest, stable)	21s
Test Suite (macos-latest, beta)	30s
Test Suite (windows-latest, stable)	5s
Build Release	0s
	7m 26s

Provide feedback