Microsoft/monaco-editor

[Bug] Incorrect Raw String Literals formatting

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#5085 opened on Nov 5, 2025

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Description

Reproducible in vscode.dev or in VS Code Desktop?

  • Not reproducible in vscode.dev or VS Code Desktop

Reproducible in the monaco editor playground?

Monaco Editor Playground Link

This issue is for C#

Raw String Literals do not work on the playground, but Verbatim String Literals do. They should have a similar behavior.

Monaco Editor Playground Code

Console.WriteLine("""
    Prime Numbers :
    sxsxcs
    xsxs 
""");

Reproduction Steps

Actual (Problematic) Behavior

No response

Expected Behavior

No response

Additional Context

No response

Contributor guide

Tech stack
csharptypescript
Domain
frontendtooling
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.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
monaco editor language supportC# string literal syntax
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
The bug is in the C# language tokenizer of monaco editor (likely under src/language/csharp/). Raw string literals are not highlighted similarly to verbatim string literals. Investigate the tokenizer pattern for raw strings and compare it to the verbatim string handling. The fix should add a rule for raw string literals (three double quotes) that colors them as strings. After implementing, verify by running the existing C# tests and manually testing in the playground.