The Compiler Is Your Best Friend, Stop Lying to It

Compilers are powerful tools that developers often underutilize by "lying" through null values, unchecked exceptions, type casts, and untracked side-effects. By making implicit assumptions explicit in the type system—using Option types instead of null, Result types for errors, sealed/union types instead of casts, and separating pure functions from side-effects—developers enable the compiler to catch bugs at compile-time rather than in production. Techniques like typed wrappers for domain concepts, union types for modeling valid states, and encoding guarantees as types transform the compiler from an adversary into a collaborative partner that tracks invariants, guides refactoring, and prevents entire classes of runtime errors.