golang/go

x/tools/gopls/internal/analysis: analyzer for slice aliasing mistakes

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#73,830 opened on May 22, 2025

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Description

In a discussion about slice aliasing bugs, @randall77 suggested an analyzer that detects "aliasing of two slice variables, where the capacity of the slice is unknown (due to append starting from nil, say), and then an append on each of the aliased slices". We should prototype a simple analyzer to detect this pattern and see what turns up.

Contributor guide

Research direction
Understand the slice aliasing pattern: when two slice variables share the same underlying array and both are appended, it can lead to data corruption. Prototype an analyzer using the go/analysis package. Write test cases first (e.g., cases where aliasing occurs and where it doesn't), then implement the analysis logic to detect such patterns. Check for cases where slices are obtained from the same source (e.g., slicing the same array or starting from nil and then copying). Use go/ast and go/types to inspect variable assignments and append calls.
Tech stack
go
Domain
tooling
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Go
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60