id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
3738	Typechecker floats stuff out of INLINE right hand sides	rl	igloo	"Small program:
{{{
foo :: Num a => [a] -> a
{-# INLINE foo #-}
foo = go 0
  where
    go m (n:ns) = m `seq` go (m+n) ns
    go m []     = m

bar :: [Int] -> Int
{-# INLINE bar #-}
bar = foo
}}}
Here is what `bar` looks like in the interface file:
{{{
a6de4c46e53e565ed25ab5a38910e9cb
  $wgo :: GHC.Prim.Int# -> [GHC.Types.Int] -> GHC.Prim.Int#
    {- Arity: 2, HasNoCafRefs, Strictness: LS -}
6838e3faa095285614477ebc92f54987
  bar :: [GHC.Types.Int] -> GHC.Types.Int
    {- Arity: 1, HasNoCafRefs, Strictness: Sm, Inline: INLINE,
       Unfolding: InlineRule: (arity 0 False) (Foo.bar_foo) -}
5d06906ae99b9aefa1c6d251c3f2fc46
  bar_foo :: [GHC.Types.Int] -> GHC.Types.Int
    {- Arity: 1, HasNoCafRefs, Strictness: Sm,
       Unfolding: InlineRule: (arity 0 True) (\ w :: [GHC.Types.Int] ->
                                              case @ GHC.Types.Int Foo.$wgo 0 w of ww { DEFAULT ->
                                              GHC.Types.I# ww }) -}
}}}
Note that the loop has disappeared from `bar`'s unfolding. Also, `bar_foo` doesn't have an INLINE pragma.

Incidentally, GHC specialises `foo` here and the specialisation doesn't get an INLINE pragma, either:
{{{
  foo :: forall a. GHC.Num.Num a => [a] -> a
    {- Arity: 1, HasNoCafRefs, Strictness: L, Inline: INLINE,
       Unfolding: InlineRule: (arity 1 False) ... -}

 foo_$sfoo :: [GHC.Types.Int] -> GHC.Types.Int
    {- Arity: 1, HasNoCafRefs, Strictness: Sm,
       Unfolding: InlineRule: (arity 0 False) ... -}

""SPEC Foo.foo [GHC.Types.Int]"" ALWAYS forall $dNum :: GHC.Num.Num GHC.Types.Int
  Foo.foo @ GHC.Types.Int $dNum = Foo.foo_$sfoo
}}}
"	bug	closed	normal	7.0.1	Compiler	6.13	fixed			Unknown/Multiple	Unknown/Multiple	Runtime performance bug		T3738