blob: 4193e7db4cc430b4566e107ec034583baa2e4f6e (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
|
-- Test #3118
-- The test is quite delicate. It aims to get 'f' to look like
-- f y = case x of
-- Red -> (y, y)
-- _ -> let v = case x of
-- Green -> 2
-- Blue -> 3
-- in (v, 5)
--
-- And now float the inner case to top level
-- so that it's not so obvious that the Red case
-- cannot occur. This crashed GHC 6.10.
--
-- It's delicate to make the bug show up
-- (a) because it relies on not "seeing" that
-- x = Red until later.
-- (b) because dropping the Red case must happen
-- before float-out, which itself happens v early
-- In the original report, the x=Red was concealed by profiling
module T3118 where
data Colour = Red | Green | Blue
{-# NOINLINE [0] f #-}
g x = Red
x = g True
f :: Int -> (Int,Int)
f y = case x of
Red -> (y, y)
xx -> let v = case xx of
Red -> 1
Green -> 2
Blue -> 3
in (v, 5)
|
