To help launch the conversation about types, let us take a peek at the types available. Go implements a simple type system that provides programmers direct control over how memory is allocated and laid out. When a program declares a variable, two things must take place:
The variable must receive a type
The variable will also be bound to a value (even when none is assigned)
This allows the type system to allocate the number of bytes necessary to store the declared value. The memory layout for declared variables maps directly to their declared types. There is no type boxing or automatic type conversion that takes place. The space you expect to be allocated is actually what gets reserved in memory.
To demonstrate this fact, the following program uses a special package called unsafe to circumvent the type system and extract memory size information for declared variables. It is important to note that this is purely illustrative as most programs do not commonly make use of the unsafe package...