Collapsing R functions within code chunks is impossible

Bug description

In .Rmd files (R Markdown language mode selected), I can fold (i.e. collapse) R multi-line functions/lists that are defined within ```{r} ... ``` chunks.

This behavior is (more or less) identical to .R files:

With a .qmd file, (Quarto language mode selected), the folding arrows are not there and folding is not possible.

Am I missing something obvious here? Shouldn't I be able to fold my function definition in R chunks in .qmd files?

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Steps to reproduce

• Disable all extensions
• Enable Quarto
• Enable R
• Create a .qmd document and write an ```{r} ... ``` chunk with a multi-line, indented list/function/....

My settings:

My extensions:

Expected behavior

Functions and multi-line lists should be foldable.

Actual behavior

The folding arrows are not there and folding is not possible.

Your environment

IDE: VSCode 1.78.2
OS: MacOS 12.5.1
Quarto extension 1.87.3
R extension v2.8.1

Quarto check output

[✓] Checking Quarto installation......OK
      Version: 1.1.189
      Path: /Applications/RStudio.app/Contents/MacOS/quarto/bin

[✓] Checking basic markdown render....OK

[✓] Checking Python 3 installation....OK
      Version: 3.10.8
      Path: /Library/Frameworks/Python.framework/Versions/3.10/bin/python3
      Jupyter: 5.3.0
      Kernels: python3

[✓] Checking Jupyter engine render....OK

(/) Checking R installation...........R version 4.3.0 (2023-04-21) -- Already Tomorrow
[✓] Checking R installation...........OK
      Version: 4.3.0
      Path: /Library/Frameworks/R.framework/Versions/4.3-arm64/Resources
      LibPaths:
        - /Users/jacques/Library/R/arm64/4.3/library
        - /Library/Frameworks/R.framework/Versions/4.3-arm64/Resources/library
      rmarkdown: 2.20

[✓] Checking Knitr engine render......OK

Start by reproducing the difference between .Rmd and .qmd files with the Quarto and R language modes enabled, using an R chunk containing a multi-line function or list. Compare folding behavior in .R and .Rmd files; done means folding arrows appear for R functions and multi-line lists inside .qmd R chunks.