Typing

1. Abstract Types

int[]

• Typecheck at Flattening time

• Only type names and structure

• LSP Into & suggestions

• trait bounds

1. Concrete Types

int[256]

• Typecheck at Instantiation time

• Type names and concrete values

• Actually defines wires

In Sus, variables never appear within types, which affects how dependent types work. You can see this in the compiler by hovering over a value—this reveals its abstract type.

For example, in a recursive module like three_add, initially instantiated with size 255, the compiler splits it repeatedly (e.g., 255 → 127 → 63, etc.), showing the concrete types of each instantiation.