Comments not formatted properly into multiple lines when there is an expression in a line before a comment when a line length including comments exceeds the maximum line width value

[lulunac27a]

When I enter an expression in a line that has a comment after an expression when the line length exceeds the maximum line width value, it doesn't formatted into multiple lines. Instead, it formatted into a single line.
For example:

0 ## here is a long long long long long long long long long long long long long long long long long long long long comment

Actual formatted output:

## here is a long long long long long long long long long long long
## long long long long long long long long long comment

Another example:

0 ## here is a long long long long long long long long long long long long long long long long long long long long comment

Actual formatted output:

0  ## here is a long long long long long long long long long long long long long long long long long long long long comment

Expected formatted output:

0 ## here is a long long long long long long long long long long long
## long long long long long long long long long comment

---

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[lulunac27a]

Another example that fails to parse the code but the code is correct with no syntax errors:

c(a,#a
b#b
)

Expected formatted output:

c(a,  # a
    b  # b
)

Error message:

Error in base::parse(text = code, keep.source = keep.source) : 
  <text>:1:9: unexpected SPECIAL

[lulunac27a]

Another formatting error:

a(#a
)

Actual output:

Error in base::parse(text = code, keep.source = keep.source) : 
  <text>:1:5: unexpected SPECIAL
1: a ( %

Expected formatted output:

a(  #a
)

[yihui]

For the first problem, formatR is not intelligent enough to move an inline comment to a block comment. You have to use a block comment in the original source.

For the second and third problems, that's a known limitation: https://yihui.org/formatr/#6-further-notes