Hello,

After I've upgraded fsharp to 1.1.13.8 version. I tried to compile old sources I had written previously and ended up with an error message that lead me to "wrong behavior" for the first time (it's the time when you don't think, you just follows...).

Here's example:

---test_0.fs file (original code)---

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

#light

type integer =
   {
   mutable number : int 
   }
with
   static member create () =
       {
       number = 42
       }
end

let _ = 
   let f = 2.72
   let i = integer.create ()
   printf "%.2f\t%i\n" f i.number

---snip---

I've run compiler on this: (fscp10.exe test.fs) and got this error:

1
2
3
4
5

$ fscp10.exe test.fs 

test_0.fs(16,4): error: syntax error.

test_0.fs(15,4): error: no matching 'in' found for this 'let'.

This confused me since I'm using #light so I shouldn't get this type of errors. But I got this error... Ok what to do next? Well, let's do what error message says - so I simply added in keywords at the end of lines 15 and 16.

---test_1.fs file---

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

#light

type integer =
   {
   mutable number : int 
   }
with
   static member create () =
       {
       number = 42
       }
end

let _ = 
   let f = 2.72 in
   let i = integer.create () in
   printf "%.2f\t%i\n" f i.number

---snip---

This "solved" the problem, no error, program compiles and runs fine. But I didn't like this solution... I knew this is something related to #light option - also release notes for 1.1.13.8 version mention this - so I started to think harder... and voila, here's the running code:

---test_2.fs file---

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

#light

type integer =
   {
   mutable number : int 
   }
   with
   static member create () =
       {
       number = 42
       }
   end

let _ = 
   let f = 2.72
   let i = integer.create ()
   printf "%.2f\t%i\n" f i.number

---snip---

The difference? See lines 7 and 12, the with and end keywords are pushed by 3 spaces to right. Now we don't need any ins at the end of respective let keywords.

So. Finaly I have some questions:

1. Is it possible to show the culprit of the problem mentioned above in error message? I.e. let message to show a problem on line 7 (and 12)?
2. Is it ok that #light option allows error-free compilation after the "hack" in test_1.fs was applied?

Cheers,
Juraj