Comment by ash_gti

The haskell source has `let channel = "11"` vs `let channel = 11`. The example from the post is an example that looks like it should be pretty straight forward but the swift compiler falls over when you try it.

Trying it locally for example:

  # Original example
  $ time swiftc -typecheck - <<-HERE
  let address = "127.0.0.1"
  let username = "steve"
  let password = "1234"
  let channel = 11
  
  let url = "http://" + username
              + ":" + password
              + "@" + address
              + "/api/" + channel        
              + "/picture"
  
  print(url)
  
  HERE
  <stdin>:6:5: error: the compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions
   4 | let channel = 11
   5 | 
   6 | let url = "http://" + username 
     |     `- error: the compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions
   7 |             + ":" + password 
   8 |             + "@" + address 
  swiftc -typecheck - <<<''  36.38s user 1.40s system 96% cpu 39.154 total
  
  # Adding a type to one of the expression values
  $ time swiftc -typecheck - <<-HERE
  let address = "127.0.0.1"
  let username = "steve"
  let password = "1234"
  let channel = 11
  
  let url = "http://" + username
              + ":" + password
              + "@" + address
              + "/api/" + String(channel)
              + "/picture"

  print(url)
  
  HERE
  swiftc -typecheck - <<<''  0.11s user 0.03s system 74% cpu 0.192 total

Which is roughly the in line with the numbers in the original post.