Package Imports: Get candidate packages also from re-exported modules

Previously we were just looking at the direct imports to try and work
out what a package qualifier could apply to but #22333 pointed out we
also needed to look for reexported modules.

Fixes #22333

16 files changed, 147 insertions, 3 deletions

diff --git a/compiler/GHC/Unit/Finder.hs b/compiler/GHC/Unit/Finder.hs
index 45057d13e2..e722e432af 100644
--- a/compiler/GHC/Unit/Finder.hs
+++ b/compiler/GHC/Unit/Finder.hs
@@ -136,13 +136,13 @@ lookupFileCache (FinderCache _ ref) key = do
 -- that package is searched for the module.
 
 findImportedModule :: HscEnv -> ModuleName -> PkgQual -> IO FindResult
-findImportedModule hsc_env mod fs =
+findImportedModule hsc_env mod pkg_qual =
   let fc        = hsc_FC hsc_env
       mhome_unit = hsc_home_unit_maybe hsc_env
       dflags    = hsc_dflags hsc_env
       fopts     = initFinderOpts dflags
   in do
-    findImportedModuleNoHsc fc fopts (hsc_unit_env hsc_env) mhome_unit mod fs
+    findImportedModuleNoHsc fc fopts (hsc_unit_env hsc_env) mhome_unit mod pkg_qual
 
 findImportedModuleNoHsc
   :: FinderCache
diff --git a/compiler/GHC/Unit/State.hs b/compiler/GHC/Unit/State.hs
index ca361d69d2..8123bbaab6 100644
--- a/compiler/GHC/Unit/State.hs
+++ b/compiler/GHC/Unit/State.hs
@@ -571,13 +571,25 @@ resolvePackageImport unit_st mn pn = do
   -- 1. Find all modules providing the ModuleName (this accounts for visibility/thinning etc)
   providers <- Map.filter originVisible <$> Map.lookup mn (moduleNameProvidersMap unit_st)
   -- 2. Get the UnitIds of the candidates
-  let candidates_uid = map (toUnitId . moduleUnit) $ Map.keys providers
+  let candidates_uid = concatMap to_uid $ Map.assocs providers
   -- 3. Get the package names of the candidates
   let candidates_units = map (\ui -> ((unitPackageName ui), unitId ui))
                               $ mapMaybe (\uid -> Map.lookup uid (unitInfoMap unit_st)) candidates_uid
   -- 4. Check to see if the PackageName helps us disambiguate any candidates.
   lookup pn candidates_units
 
+  where
+
+    -- Get the UnitId from which a visible identifier is from
+    to_uid :: (Module, ModuleOrigin) -> [UnitId]
+    to_uid (mod, ModOrigin mo re_exps _ _) =
+      case mo of
+        -- Available directly, but also potentially from re-exports
+        Just True ->  (toUnitId (moduleUnit mod)) : map unitId re_exps
+        -- Just available from these re-exports
+        _ -> map unitId re_exps
+    to_uid _ = []
+
 -- | Create a Map UnitId UnitInfo
 --
 -- For each instantiated unit, we add two map keys:
diff --git a/testsuite/tests/cabal/t22333/Makefile b/testsuite/tests/cabal/t22333/Makefile
new file mode 100644
index 0000000000..da159a46ae
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/Makefile
@@ -0,0 +1,32 @@
+TOP=../../..
+include $(TOP)/mk/boilerplate.mk
+include $(TOP)/mk/test.mk
+
+SETUP=../Setup -v0
+CONFIGURE=$(SETUP) configure $(CABAL_MINIMAL_BUILD) --with-ghc='$(TEST_HC)' --ghc-options='$(TEST_HC_OPTS)' --package-db=../tmp.d --prefix='$(PWD)/../dist'
+
+T22333: clean
+	$(MAKE) -s --no-print-directory clean
+	'$(GHC_PKG)' init tmp.d
+	'$(TEST_HC)' $(TEST_HC_OPTS) -v0 --make Setup
+	# build b
+	cd my-package-b; $(CONFIGURE) --cid "my-package-b-0.1" my-package-b
+	cd my-package-b; $(SETUP) build
+	cd my-package-b; $(SETUP) copy
+	cd my-package-b; $(SETUP) register
+	# build a
+	cd my-package-a; $(CONFIGURE) --cid "my-package-a-0.1" my-package-a
+	cd my-package-a; $(SETUP) build
+	cd my-package-a; $(SETUP) copy
+	cd my-package-a; $(SETUP) register
+	# build my-exe
+	cd my-exe; $(CONFIGURE) --cid "my-exe-0.1" my-exe
+	cd my-exe; $(SETUP) build
+	cd my-exe; $(SETUP) copy
+	cd my-exe; $(SETUP) register
+ifneq "$(CLEANUP)" ""
+	$(MAKE) -s --no-print-directory clean
+endif
+
+clean :
+	$(RM) -r tmp.d dist Setup$(exeext)
diff --git a/testsuite/tests/cabal/t22333/Setup.hs b/testsuite/tests/cabal/t22333/Setup.hs
new file mode 100644
index 0000000000..9a994af677
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/testsuite/tests/cabal/t22333/all.T b/testsuite/tests/cabal/t22333/all.T
new file mode 100644
index 0000000000..5664400e4a
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/all.T
@@ -0,0 +1,4 @@
+test('T22333',
+     [extra_files(['Setup.hs', 'my-exe', 'my-package-a', 'my-package-b' ])],
+     makefile_test,
+     [])
diff --git a/testsuite/tests/cabal/t22333/my-exe/CHANGELOG.md b/testsuite/tests/cabal/t22333/my-exe/CHANGELOG.md
new file mode 100644
index 0000000000..0313224bbd
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-exe/CHANGELOG.md
@@ -0,0 +1,5 @@
+# Revision history for my-exe
+
+## 0.1.0.0 -- YYYY-mm-dd
+
+* First version. Released on an unsuspecting world.
diff --git a/testsuite/tests/cabal/t22333/my-exe/app/Main.hs b/testsuite/tests/cabal/t22333/my-exe/app/Main.hs
new file mode 100644
index 0000000000..777495202a
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-exe/app/Main.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE PackageImports #-}
+
+module Main (main) where
+
+import "my-package-a" LibB (someFuncB)
+--import LibB (someFuncB)
+
+main :: IO ()
+main = print someFuncB
diff --git a/testsuite/tests/cabal/t22333/my-exe/my-exe.cabal b/testsuite/tests/cabal/t22333/my-exe/my-exe.cabal
new file mode 100644
index 0000000000..1a1c4c60cb
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-exe/my-exe.cabal
@@ -0,0 +1,20 @@
+cabal-version:   3.8
+name:            my-exe
+version:         0.1.0.0
+license:         NONE
+author:          a.pelenitsyn@gmail.com
+maintainer:      Artem Pelenitsyn
+build-type:      Simple
+extra-doc-files: CHANGELOG.md
+
+common warnings
+    ghc-options: -Wall
+
+executable my-exe
+    import:           warnings
+    main-is:          Main.hs
+    build-depends:    base
+                    , my-package-a
+                    , my-package-b
+    hs-source-dirs:   app
+    default-language: Haskell2010
diff --git a/testsuite/tests/cabal/t22333/my-package-a/CHANGELOG.md b/testsuite/tests/cabal/t22333/my-package-a/CHANGELOG.md
new file mode 100644
index 0000000000..7507aa3dab
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-package-a/CHANGELOG.md
@@ -0,0 +1,5 @@
+# Revision history for my-package-a
+
+## 0.1.0.0 -- YYYY-mm-dd
+
+* First version. Released on an unsuspecting world.
diff --git a/testsuite/tests/cabal/t22333/my-package-a/Setup.hs b/testsuite/tests/cabal/t22333/my-package-a/Setup.hs
new file mode 100644
index 0000000000..9a994af677
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-package-a/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/testsuite/tests/cabal/t22333/my-package-a/my-package-a.cabal b/testsuite/tests/cabal/t22333/my-package-a/my-package-a.cabal
new file mode 100644
index 0000000000..bf46792df7
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-package-a/my-package-a.cabal
@@ -0,0 +1,20 @@
+cabal-version:   3.8
+name:            my-package-a
+version:         0.1.0.0
+license:         NONE
+author:          a.pelenitsyn@gmail.com
+maintainer:      Artem Pelenitsyn
+build-type:      Simple
+extra-doc-files: CHANGELOG.md
+
+common warnings
+    ghc-options: -Wall
+
+library
+    import:           warnings
+    exposed-modules:  MyLib
+    build-depends:    base
+                    , my-package-b
+    reexported-modules: LibB
+    hs-source-dirs:   src
+    default-language: Haskell2010
diff --git a/testsuite/tests/cabal/t22333/my-package-a/src/MyLib.hs b/testsuite/tests/cabal/t22333/my-package-a/src/MyLib.hs
new file mode 100644
index 0000000000..e657c4403f
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-package-a/src/MyLib.hs
@@ -0,0 +1,4 @@
+module MyLib (someFunc) where
+
+someFunc :: IO ()
+someFunc = putStrLn "someFunc"
diff --git a/testsuite/tests/cabal/t22333/my-package-b/CHANGELOG.md b/testsuite/tests/cabal/t22333/my-package-b/CHANGELOG.md
new file mode 100644
index 0000000000..b410066be6
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-package-b/CHANGELOG.md
@@ -0,0 +1,5 @@
+# Revision history for my-package-b
+
+## 0.1.0.0 -- YYYY-mm-dd
+
+* First version. Released on an unsuspecting world.
diff --git a/testsuite/tests/cabal/t22333/my-package-b/Setup.hs b/testsuite/tests/cabal/t22333/my-package-b/Setup.hs
new file mode 100644
index 0000000000..9a994af677
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-package-b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/testsuite/tests/cabal/t22333/my-package-b/my-package-b.cabal b/testsuite/tests/cabal/t22333/my-package-b/my-package-b.cabal
new file mode 100644
index 0000000000..7157b9be93
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-package-b/my-package-b.cabal
@@ -0,0 +1,18 @@
+cabal-version:   3.8
+name:            my-package-b
+version:         0.1.0.0
+license:         NONE
+author:          a.pelenitsyn@gmail.com
+maintainer:      Artem Pelenitsyn
+build-type:      Simple
+extra-doc-files: CHANGELOG.md
+
+common warnings
+    ghc-options: -Wall
+
+library
+    import:           warnings
+    exposed-modules:  LibB
+    build-depends:    base 
+    hs-source-dirs:   src
+    default-language: Haskell2010
diff --git a/testsuite/tests/cabal/t22333/my-package-b/src/LibB.hs b/testsuite/tests/cabal/t22333/my-package-b/src/LibB.hs
new file mode 100644
index 0000000000..8e85cdcea3
--- /dev/null
+++ b/testsuite/tests/cabal/t22333/my-package-b/src/LibB.hs
@@ -0,0 +1,4 @@
+module LibB (someFuncB) where
+
+someFuncB :: Int
+someFuncB = 42