FAQ

Why does field order matter for struct size?

Go aligns fields to their natural alignment boundary. If a field with large alignment (e.g. int64, 8 bytes) follows a small field (e.g. bool, 1 byte), the compiler inserts padding bytes between them. Ordering fields by decreasing alignment minimizes this padding.

What's the difference between Size-Optimal and GC-Optimal?

Size-Optimal minimizes total bytes by sorting fields by alignment descending. GC-Optimal minimizes the GC scan range by grouping pointer-containing fields first, which may not always produce the smallest total size.

These goals can conflict — the extension shows both so you can choose.

Does the extension modify my source files?

Only when you explicitly trigger the quick fix (lightbulb or Ctrl+.). The extension is read-only otherwise.

What architectures are supported?

amd64, 386, arm64, and arm. Select via the goStructAnalyzer.architecture setting.

Does this work with generics?

Yes. Generic structs like type Foo[T any] struct are supported.

Are embedded structs supported?

Yes. The extension resolves the real size and alignment of named/embedded struct types defined in the same file. Pointer content from embedded structs is correctly classified.

How accurate are the sizes?

Sizes match Go's unsafe.Sizeof() for all supported types. The extension implements Go's memory layout algorithm and has been validated against the fieldalignment analysis pass.