let
imp_mod = mi_module iface
deprecs = mi_deprecs iface
- is_orph = mi_orphan iface
+ orph_iface = mi_orphan iface
has_finsts = mi_finsts iface
deps = mi_deps iface
let
-- Compute new transitive dependencies
- orphans | is_orph = ASSERT( not (imp_mod `elem` dep_orphs deps) )
- imp_mod : dep_orphs deps
- | otherwise = dep_orphs deps
+ orphans | orph_iface = ASSERT( not (imp_mod `elem` dep_orphs deps) )
+ imp_mod : dep_orphs deps
+ | otherwise = dep_orphs deps
finsts | has_finsts = ASSERT( not (imp_mod `elem` dep_finsts deps) )
imp_mod : dep_finsts deps
case gre_par gre of
ParentIs p -> mi_dep_fn iface p -- its parent*, is deprec'd
NoParent -> Nothing
- Nothing
- | isWiredInName name -> Nothing
- -- We have not necessarily loaded the .hi file for a
- -- wired-in name (yet), although we *could*.
- -- And we never deprecate them
-
- | otherwise -> pprPanic "lookupDeprec" (ppr name)
- -- By now all the interfaces should have been loaded
+
+ Nothing -> Nothing -- See Note [Used names with interface not loaded]
where
name = gre_name gre
\end{code}
+Note [Used names with interface not loaded]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+By now all the interfaces should have been loaded,
+because reportDeprecations happens after typechecking.
+However, it's still (just) possible to to find a used
+Name whose interface hasn't been loaded:
+
+a) It might be a WiredInName; in that case we may not load
+ its interface (although we could).
+
+b) It might be GHC.Real.fromRational, or GHC.Num.fromInteger
+ These are seen as "used" by the renamer (if -fno-implicit-prelude)
+ is on), but the typechecker may discard their uses
+ if in fact the in-scope fromRational is GHC.Read.fromRational,
+ (see tcPat.tcOverloadedLit), and the typechecker sees that the type
+ is fixed, say, to GHC.Base.Float (see Inst.lookupSimpleInst).
+ In that obscure case it won't force the interface in.
+
+In both cases we simply don't permit deprecations;
+this is, after all, wired-in stuff.
+
+
%*********************************************************
%* *
Unused names