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Go Struct Analyzer — v2

Go Struct Analyzer shows memory size and padding information for Go structs, powered by a Go LSP backend (gsa-lsp) for exact fieldalignment parity.

Available for VS Code (extension), Zed (dev extension), Emacs (eglot/lsp-mode), and Neovim (built-in LSP). Works with any LSP-compatible editor via standard LSP protocol.

v2.0.4: Server version compatibility check — extension stops if gsa-lsp major version mismatches. curl installer served from GitHub Pages. v2.0.0: Analysis engine rewritten in Go using go/types. Named interfaces correctly sized at 16B instead of 8B. Matches fieldalignment exactly.

What It Does

  • Hover over any struct field to see size, alignment, offset, and padding
  • Code lens annotations showing struct and field sizes inline
  • Real-time warnings when structs waste memory due to padding
  • GC pressure hints when pointer field reordering would reduce garbage collector scan range
  • One-click quick fix to reorder fields for optimal layout
  • Side panel with current and optimal layouts side by side
  • Architecture-aware calculations (amd64, 386, arm64, arm)

Quick Install

VS Code: VS Code Marketplace

code --install-extension PatricioDiaz.go-struct-analyzer

Zed: See Zed installation guide.

Emacs: See Emacs setup guide — eglot (Emacs 29+) or lsp-mode.

Neovim: See Neovim setup guide — built-in LSP client.

Any LSP editor: Install gsa-lsp with curl -fsSL https://padiazg.github.io/go-struct-analyzer/install.sh | sh, then point your LSP client to it. gsa-lsp speaks standard inlayHint, hover, diagnostics, and codeAction.

Quick Start

Open any Go file in VS Code. Hover over a struct or its fields to see size details. Structs that can be optimized are underlined with a warning — click the lightbulb or press Ctrl+. to reorder fields.

type Event struct {         // ⚠️ 40 bytes (can be 24 bytes)
    A bool
    B int64
    C bool
    D int64
    E int32
    F bool
}

→ Full Quick Start

Configuration

Setting Default Description
goStructAnalyzer.showInlineAnnotations false Show size annotations inline with struct fields
goStructAnalyzer.showPadding true Highlight padding bytes in struct layout
goStructAnalyzer.architecture amd64 Target architecture: amd64, 386, arm64, arm
goStructAnalyzer.enableStructOptimizationWarnings true Show warnings for sub-optimal memory layout
goStructAnalyzer.enableReorderCodeAction true Show quick fix to reorder struct fields
goStructAnalyzer.reorderCodeActionPreferred false Mark reorder as preferred fix for source.fixAll
goStructAnalyzer.enableGCPressureWarnings true Show hints for reducing GC scan range
goStructAnalyzer.gcPressureSeverityWarning false Promote GC hints to warnings (yellow underline)

→ Full Configuration

Resources