immutable-and-constant

Detects state variables that should be declared constant or immutable in Solidity contracts. Constant for compile-time-known values (inlined by compiler, zero runtime cost), immutable for constructor-set-once values (baked into bytecode, ~3 gas per read vs 2100 gas cold SLOAD). Covers IC-001 (constant for literal assignments), IC-002 (immutable for constructor-set values), IC-003 (immutable for frequently-read address variables). Use when writing constructors or reviewing state variable declarations in Foundry-based Solidity projects.