Cursor 3 hangs on certain Golang syntax in plan.md

[Nicholas_Kwan]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Cursor 3 hangs on certain Golang syntax in plan.md or chat markdown, likely related to interaction of “interface{}” and field tags.

Performance issue reproduced on Mac and Windows, the cursor IDE would hang indefinitely until force closed.

Steps to Reproduce

Enable plan mode, prompt: Create a Golang file containing this

type Sample struct {
	Params map[string]interface{} `json:"params,omitempty" yaml:"params,omitempty"`
}

Expected Behavior

Cursor should not hang.

Screenshots / Screen Recordings

Operating System

Windows 10/11
MacOS

Version Information

Version: 3.0.9 (system setup)
VSCode Version: 1.105.1
Commit: 93e276db8a03af947eafb2d10241e2de17806c20
Date: 2026-04-03T02:06:46.446Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Windows_NT x64 10.0.26200

Does this stop you from using Cursor

Yes - Cursor is unusable

[deanrie]

Hey, thanks for the report. This is a known bug. The combination of interface{} (curly braces) plus backtick struct tags with spaces can trigger a hang when rendering markdown.

The same issue is already documented here: Markdown Preview causes "Cursor Helper (Renderer)" to spike to 100% CPU and crash

The team is aware, but there’s no ETA yet. Your report helps with prioritization.

For now, the workaround is to use any instead of interface{} in Go code. Without the curly braces, it doesn’t crash, so this should unblock you.

Let me know if you run into anything else.