[MLton] front-end functor bug
Fri, 6 Feb 2004 19:12:59 -0800
> I've encountered a front-end bug with the Moby sources; unfortunately I
> can't boil it down to a smaller example
Here's a small example that shows the problem.
functor F () =
val A = 0
structure S =
datatype z = A
structure F = F ()
> a) a functor RegisterAllocator includes the following declarations in
> its body:
> val SPILL_COALESCING = 0wx100
> val SPILL_COLORING = 0wx200
> Now, when compiling the program, I get errors like:
> Error: z.sml 18294.7: pattern and expression disagree
> pattern: [raPhase]
> expression: [mode]
> in: SPILL_COLORING = 0wx200
> which appears to indicate that SPILL_COLORING is being granted
> constructor status, despite the fact that this declaration corresponds
> to (a).
Yep, that's the problem. There was a bug in the implementation of
functor closures that forgot to "zero out" the constructors before
re-elaborating the functor body. You would only ever see it if the
constructor was not in scope at the functor definition.
I've checked in a fix.