godotengine/godot

Using index access on Quaternion type data to get values will result in a parsing error.

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#120,318 opened on Jun 15, 2026

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bugconfirmedgood first issuetopic:gdscript

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Description

Tested versions

  • Reproducible in: 4.7-rc2 and earlier versions.

System information

Godot v4.7.beta (33431363d) - Fedora Linux 44 (Workstation Edition) on Wayland - Wayland display driver, Single-window, 1 monitor - OpenGL 3 (Compatibility) - Mesa Intel(R) HD Graphics 3000 (SNB GT2) - Intel(R) Core(TM) i3-2348M CPU @ 2.30GHz (4 threads) - 15.45 GiB memory - PulseAudio (44100 Hz, Stereo/mono)

Issue description

Using index access on Quaternion data to get values will cause parsing errors; you can't access the x, y, z, w components of a Quaternion through indexing. However, similar types like Basis, Color, Transform2D, and VectorX can be accessed by index without any issues.

Please check the description in the game engine's documentation.

https://docs.godotengine.org/en/latest/classes/class_quaternion.html#class-quaternion-operator-idx-int

Steps to reproduce

Write the following statements in the script:

	var q:Quaternion=Quaternion()
	q[0]

Minimal reproduction project (MRP)

Quaternion.zip

Contributor guide

Research direction
Inspect the C++ implementation of Quaternion's index operator (operator[]) in the Godot engine source code. Compare with similar types like Vector3 or Basis that support index access. Identify where the operator is missing or incorrectly defined and add the appropriate implementation.
Tech stack
cpp
Domain
api
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
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
GDScriptC++
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70