Partial matching of parameters is confusing

In Quarto 1.4.451, create the following dashboard with parameters:

---
title: "Sample dashboard"
format: dashboard
engine: knitr
params:
  hello: 1
  mello: "a character"
---

This should print out the value of `params$hello`: `{r} params$hello`.

This should print out the value of `params$mello`: `{r} params$mello`.

This shouldn't work because it's looking for a parameter that doesn't exist, `params$jello`: `{r} params$jello`.

This also shouldn't work because it's looking for a parameter that doesn't exist, `params$m`, but it does partial matching to `params$mello`, and the document renders: `{r} params$m`

It works, but I think it would be better if partial matching wasn't enabled by default for parameters.

Then add the following and re-render:

This doesn't work because it's doing partial matching and then failing when adding a number to a character `params$m + 2`: `{r} params$m + 2`.

You get the following error:

Quitting from lines 2-18 (untitled.qmd)
Error in `params$m + 2`:
! non-numeric argument to binary operator
Backtrace:
 1. .QuartoInlineRender(params$m + 2)
                                                                                          
Execution halted

It makes sense why this happens, but again, not doing partial matching by default would be less confusing.

Additionally, if I set partial matching to warn in the YAML of my document, e.g.,

knitr:
    opts_chunk:
      R.options:
        warnPartialMatchDollar: true

the first example with partial matching still runs, which was even more surprising to me.