import {-# SOURCE #-} RnExpr( rnLExpr )
import HsSyn
-import RdrName ( RdrName, isRdrDataCon, elemLocalRdrEnv )
+import RdrName ( RdrName, isRdrDataCon, elemLocalRdrEnv, globalRdrEnvElts,
+ GlobalRdrElt(..), isLocalGRE )
import RdrHsSyn ( extractGenericPatTyVars, extractHsRhoRdrTyVars )
import RnHsSyn
import RnTypes ( rnLHsType, rnLHsTypes, rnHsSigType, rnHsTypeFVs, rnContext )
import Name ( Name, nameOccName )
import NameSet
import NameEnv
+import OccName ( occEnvElts )
import Outputable
import SrcLoc ( Located(..), unLoc, getLoc, noLoc )
import DynFlags ( DynFlag(..) )
%* *
%*********************************************************
+Note [Splices]
+~~~~~~~~~~~~~~
+Consider
+ f = ...
+ h = ...$(thing "f")...
+
+The splice can expand into literally anything, so when we do dependency
+analysis we must assume that it might mention 'f'. So we simply treat
+all locally-defined names as mentioned by any splice. This is terribly
+brutal, but I don't see what else to do. For example, it'll mean
+that every locally-defined thing will appear to be used, so no unused-binding
+warnings. But if we miss the dependency, then we might typecheck 'h' before 'f',
+and that will crash the type checker because 'f' isn't in scope.
+
+Currently, I'm not treating a splice as also mentioning every import,
+which is a bit inconsistent -- but there are a lot of them. We might
+thereby get some bogus unused-import warnings, but we won't crash the
+type checker. Not very satisfactory really.
+
\begin{code}
rnSplice :: HsSplice RdrName -> RnM (HsSplice Name, FreeVars)
rnSplice (HsSplice n expr)
- = checkTH expr "splice" `thenM_`
- getSrcSpanM `thenM` \ loc ->
- newLocalsRn [L loc n] `thenM` \ [n'] ->
- rnLExpr expr `thenM` \ (expr', fvs) ->
- returnM (HsSplice n' expr', fvs)
+ = do { checkTH expr "splice"
+ ; loc <- getSrcSpanM
+ ; [n'] <- newLocalsRn [L loc n]
+ ; (expr', fvs) <- rnLExpr expr
+
+ -- Ugh! See Note [Splices] above
+ ; lcl_rdr <- getLocalRdrEnv
+ ; gbl_rdr <- getGlobalRdrEnv
+ ; let gbl_names = mkNameSet [gre_name gre | gre <- globalRdrEnvElts gbl_rdr,
+ isLocalGRE gre]
+ lcl_names = mkNameSet (occEnvElts lcl_rdr)
+
+ ; return (HsSplice n' expr', fvs `plusFV` lcl_names `plusFV` gbl_names) }
#ifdef GHCI
checkTH e what = returnM () -- OK