Go

What make and new are in Go, why memory allocation is needed, how they are used, their differences, and their implementation details.

What reflection is, how Go implements reflection through interfaces, and the relationship between Type and Value.

The distinction between exception and error in Go, how errors are used and handled, their implementation, and practical patterns.

Empty and non-empty interfaces, how interfaces are used, type conversion and assertions, iface/eface internals, nil comparison, and interface conversion.

What functions are in Go, variadic parameters, multiple return values, named returns, closures, init functions, methods, stacks, and common functions.

Character sets and Unicode, basic Go string usage, string/[]byte conversion, StringHeader, and string immutability.

What a map is, how hash buckets work, collision handling, expansion, and the historical Go map implementation.

Pointer types in Go, why pointers are needed, the unsafe pointer type, examples, and the underlying APIs.

What panic and recover are, why they are needed, how to use them, and the runtime calls behind them.

Built-in and custom Go types, type metadata, _type, extra metadata for built-in types, and uncommontype metadata for custom types.