unLoc, noLoc, srcLocSpan, SrcSpan )
import BasicTypes ( DeprecTxt )
import DriverPhases ( isHsBoot )
-import Util ( notNull, isSingleton )
+import Util ( notNull, isSingleton, thenCmp )
+import ListSetOps ( equivClasses )
import List ( partition )
import IO ( openFile, IOMode(..) )
\end{code}
Nothing -> imp_mod_name
Just another_name -> another_name
imp_spec = ImportSpec { is_mod = imp_mod_name, is_qual = qual_only,
- is_loc = loc, is_as = qual_mod_name }
+ is_loc = loc, is_as = qual_mod_name, is_explicit = False }
in
-- Get the total imports, and filter them according to the import list
ifaceExportNames filtered_exports `thenM` \ total_avails ->
-- Warns/informs if import spec contains duplicates.
mkGenericRdrEnv imp_spec names
- = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] False }
+ = mkGlobalRdrEnv [ GRE { gre_name = name, gre_prov = Imported [imp_spec] }
| name <- nameSetToList names ]
filterImports iface imp_spec Nothing all_names
; returnM (map (mk_gre loc) names) }
where
mk_gre loc name = GRE { gre_name = name,
- gre_prov = Imported [this_imp_spec loc] (explicit name) }
- this_imp_spec loc = imp_spec { is_loc = loc }
- explicit name = all_explicit || isNothing (nameParent_maybe name)
+ gre_prov = Imported [imp_spec'] }
+ where
+ imp_spec' = imp_spec { is_loc = loc, is_explicit = explicit }
+ explicit = all_explicit || isNothing (nameParent_maybe name)
get_item :: IE RdrName -> RnM [GlobalRdrElt]
-- Empty result for a bad item.
used_names = findUses (tcg_dus tcg_env) emptyNameSet
all_gres = globalRdrEnvElts (tcg_rdr_env tcg_env)
- check hpt pit (GRE {gre_name = name, gre_prov = Imported (imp_spec:_) _})
+ check hpt pit (GRE {gre_name = name, gre_prov = Imported (imp_spec:_)})
| name `elemNameSet` used_names
, Just deprec_txt <- lookupDeprec hpt pit name
= setSrcSpan (is_loc imp_spec) $
= do { warnUnusedTopBinds unused_locals
; warnUnusedModules unused_imp_mods
; warnUnusedImports unused_imports
- ; warnDuplicateImports dup_imps
+ ; warnDuplicateImports defined_and_used
; printMinimalImports minimal_imports }
where
used_names, all_used_names :: NameSet
(defined_and_used, defined_but_not_used)
= partition (gre_is_used all_used_names) defined_names
- -- Find the duplicate imports
- dup_imps = filter is_dup defined_and_used
- is_dup (GRE {gre_prov = Imported imp_spec True}) = not (isSingleton imp_spec)
- is_dup other = False
-
-- Filter out the ones that are
-- (a) defined in this module, and
-- (b) not defined by a 'deriving' clause
unused_imports :: [GlobalRdrElt]
unused_imports = filter unused_imp defined_but_not_used
- unused_imp (GRE {gre_prov = Imported imp_specs True})
+ unused_imp (GRE {gre_prov = Imported imp_specs})
= not (all (module_unused . is_mod) imp_specs)
+ && any is_explicit imp_specs
-- Don't complain about unused imports if we've already said the
-- entire import is unused
unused_imp other = False
-- We've carefully preserved the provenance so that we can
-- construct minimal imports that import the name by (one of)
-- the same route(s) as the programmer originally did.
- add_name (GRE {gre_name = n, gre_prov = Imported imp_specs _}) acc
+ add_name (GRE {gre_name = n, gre_prov = Imported imp_specs}) acc
= addToFM_C plusAvailEnv acc (is_mod (head imp_specs))
(unitAvailEnv (mk_avail n (nameParent_maybe n)))
add_name other acc
---------------------
warnDuplicateImports :: [GlobalRdrElt] -> RnM ()
+-- Given the GREs for names that are used, figure out which imports
+-- could be omitted without changing the top-level environment.
+--
+-- NB: Given import Foo( T )
+-- import qualified Foo
+-- we do not report a duplicate import, even though Foo.T is brought
+-- into scope by both, because there's nothing you can *omit* without
+-- changing the top-level environment. So we complain only if it's
+-- explicitly named in both imports or neither.
+--
+-- Furthermore, we complain about Foo.T only if
+-- there is no complaint about (unqualified) T
+
warnDuplicateImports gres
- = ifOptM Opt_WarnUnusedImports (mapM_ warn gres)
+ = ifOptM Opt_WarnUnusedImports $
+ sequenceM_ [ warn name (head dup_imps)
+ -- The 'head' picks the first offending group
+ -- for this particular name
+ | GRE { gre_name = name, gre_prov = Imported imps } <- gres
+ , let dup_imps = dups imps
+ , not (null dup_imps) ]
where
- warn (GRE { gre_name = name, gre_prov = Imported imps _ })
- = addWarn ((quotes (ppr name) <+> ptext SLIT("is imported more than once:"))
- $$ nest 2 (vcat (map ppr imps)))
- warn gre = panic "warnDuplicateImports"
- -- The GREs should all have Imported provenance
-
-
+ warn name []
+ = panic "warnDuplicateImports" -- equivClasses never returns empty lists
+ warn name dup_imps@(imp1:_)
+ = addWarnAt (is_loc imp1)
+ ((quotes pp_name <+> ptext SLIT("is imported more than once:"))
+ $$ nest 2 (vcat (map ppr dup_imps)))
+ where
+ pp_name | is_qual imp1 = ppr (is_as imp1) <> dot <> ppr occ
+ | otherwise = ppr occ
+ occ = nameOccName name
+
+ dups :: [ImportSpec] -> [[ImportSpec]]
+ dups [imp] = [] -- Very common case
+ dups imps = filter (not . isSingleton) (unqual_dups ++ qual_dups)
+ where
+ unqual_dups = equivClasses cmp_unqual (filter (not . is_qual) imps)
+ qual_dups = equivClasses cmp_qual imps
+
+ cmp_unqual imp1 imp2 -- Make explicit come first
+ = not (is_explicit imp1) `compare` not (is_explicit imp2)
+
+ cmp_qual imp1 imp2 -- Group by explicit-ness, then by module qualifier
+ = (imp1 `cmp_unqual` imp2) `thenCmp`
+ (is_as imp1 `compare` is_as imp2)
+
-- ToDo: deal with original imports with 'qualified' and 'as M' clauses
printMinimalImports :: FiniteMap Module AvailEnv -- Minimal imports
-> RnM ()
projects / ghc-hetmet.git / blobdiff