I've been wondering for some time about the details of how GHC uses syntax with inlining, and how other transformations come into play in the process (I recently asked a question on SO if anyone wants some karma: http://stackoverflow.com/q/11690146/176841). I know this is a big topic and there's probably a lot more out there I should read. In particular I don't fully understand why these sorts of contortions... http://hackage.haskell.org/packages/archive/base/latest/doc/html/src/GHC-Lis... ...are required. It seems like a programmer has to throw "equational reasoning", separation of concerns, and all the little elegant bits about the language out the window just to indicate something boring to the compiler. Disclaimer: The following is less a proposal meant to be taken seriously, and more me trying to better understand things. Could the following be used as syntax for indicating inlining? Rather than relying on the syntactic LHS, instead let that be specified in the type signature... foldl :: (a -> b -> a) -> a -> [b] -> {-# INLINE #-} a foldl f z [] = z foldl f z (x:xs) = foldl f (f z x) xs ...indicating, in this case, that foldl should be inlined when "fully-applied" means its first three arguments (I guess that's the intent of the original version linked above?). Then (waves hands) the compiler could do the necessary transformations that the programmer had to do to foldl above. Maybe what I'm proposing is actually a separate NORECURSIVE_TRANSFORM pragma or something. An alternative if including the pragma in the type sig. isn't sound, is to allow it in the function definition left-hand side, after the bindings we would like applied before inlining. Brandon