Code folding is broken for single-line varconst declarations

[dunric]

environment: Vim 9.0, Linux x86_64

description: In case of single-line declarations of var or const blocks, invocation of code folding improperly swallows unrelated following lines, usually all, to the end of file. Declarations may be empty, non-empty, with a comment - it does not matter.

expected behavior: single-line declarations are unaffected with code folding and definitely should not fold unrelated lines which follow

how to replicate the issue:

• insert single-line declaration of constants or variables

  const ()

• insert some code after above declaration

  func main() {
      fmt.Println("Hello, world!")
  }

• invoke code folding in that buffer (zM)