Go Data Structures: Interfaces

Deep explanation of interface representation, dynamic type/value pairs, and nil behavior.

• Author: Russ Cox
• Authority: primary
• Kind: article
• URL: https://research.swtch.com/interfaces

What it covers

• interface runtime representation
• typed nil behavior
• interface assignment semantics

Why authoritative

Seminal technical write-up by Russ Cox on Go interface internals.

Use when

• why is this interface value not nil
• how are Go interfaces represented
• why does a typed nil behave this way in Go

Keywords

• interfaces, typed nil, interface internals, dynamic type, nil interface

Used by

• interface-design
• nil-interfaces
• type-assertions
• interface-types-and-method-sets
• errors-as-language-semantics