Added 'ConstraintScope' to PackageConstraint.

I also removed 'unqualified' from PackagePath.hs and replaced all
uses of it with 'scopeToplevel'. The meaning is identical,
however 'scopeToplevel' is a less confusing name.

cabal-install/Distribution/Client/Configure.hs

@@ -336,7 +336,7 @@ planLocalPackage verbosity comp platform configFlags configExFlags
         . addConstraints
             -- package flags from the config file or command line
             [ let pc = PackageConstraint
-                       (unqualified $ packageName pkg)
+                       (scopeToplevel $ packageName pkg)
                        (PackagePropertyFlags $ configConfigurationsFlags configFlags)
               in LabeledPackageConstraint pc ConstraintSourceConfigFlagOrTarget
             ]
@@ -344,7 +344,7 @@ planLocalPackage verbosity comp platform configFlags configExFlags
         . addConstraints
             -- '--enable-tests' and '--enable-benchmarks' constraints from
             -- the config file or command line
-            [ let pc = PackageConstraint (unqualified $ packageName pkg) .
+            [ let pc = PackageConstraint (scopeToplevel $ packageName pkg) .
                        PackagePropertyStanzas $
                        [ TestStanzas  | testsEnabled ] ++
                        [ BenchStanzas | benchmarksEnabled ]

cabal-install/Distribution/Client/Dependency.hs

@@ -25,7 +25,7 @@ module Distribution.Client.Dependency (
     -- * Constructing resolver policies
     PackageProperty(..),
     PackageConstraint(..),
-    unqualified,
+    scopeToplevel,
     PackagesPreferenceDefault(..),
     PackagePreference(..),
 
@@ -361,7 +361,7 @@ dontUpgradeNonUpgradeablePackages params =
   where
     extraConstraints =
       [ LabeledPackageConstraint
-        (PackageConstraint (unqualified pkgname) PackagePropertyInstalled)
+        (PackageConstraint (scopeToplevel pkgname) PackagePropertyInstalled)
         ConstraintSourceNonUpgradeablePackage
       | Set.notMember (mkPackageName "base") (depResolverTargets params)
       -- If you change this enumeration, make sure to update the list in
@@ -492,7 +492,7 @@ addSetupCabalMinVersionConstraint :: Version
 addSetupCabalMinVersionConstraint minVersion =
     addConstraints
       [ LabeledPackageConstraint
-          (PackageConstraint (unqualified cabalPkgname)
+          (PackageConstraint (scopeToplevel cabalPkgname)
                              (PackagePropertyVersion $ orLaterVersion minVersion))
           ConstraintSetupCabalMinVersion
       ]
@@ -600,7 +600,7 @@ applySandboxInstallPolicy
 
   . addConstraints
       [ let pc = PackageConstraint
-                 (unqualified $ packageName pkg)
+                 (scopeToplevel $ packageName pkg)
                  (PackagePropertyVersion $ thisVersion (packageVersion pkg))
         in LabeledPackageConstraint pc ConstraintSourceModifiedAddSourceDep
       | pkg <- modifiedDeps ]
@@ -946,9 +946,9 @@ resolveWithoutDependencies (DepResolverParams targets constraints
       Map.findWithDefault anyVersion pkgname packageVersionConstraintMap
     packageVersionConstraintMap =
       let pcs = map unlabelPackageConstraint constraints
-      in Map.fromList [ (name, range)
+      in Map.fromList [ (scopeToPackageName scope, range)
                       | PackageConstraint
-                          (Q _ name) (PackagePropertyVersion range) <- pcs ]
+                          scope (PackagePropertyVersion range) <- pcs ]
 
     packagePreferences :: PackageName -> PackagePreferences
     packagePreferences = interpretPackagesPreference targets defpref prefs

cabal-install/Distribution/Client/Freeze.hs

@@ -183,7 +183,7 @@ planPackages verbosity comp platform mSandboxPkgInfo freezeFlags
 
       . addConstraints
           [ let pkg = pkgSpecifierTarget pkgSpecifier
-                pc = PackageConstraint (unqualified pkg)
+                pc = PackageConstraint (scopeToplevel pkg)
                                        (PackagePropertyStanzas stanzas)
             in LabeledPackageConstraint pc ConstraintSourceFreeze
           | pkgSpecifier <- pkgSpecifiers ]

cabal-install/Distribution/Client/Install.hs

@@ -410,7 +410,7 @@ planPackages comp platform mSandboxPkgInfo solver
           --FIXME: this just applies all flags to all targets which
           -- is silly. We should check if the flags are appropriate
           [ let pc = PackageConstraint
-                     (unqualified $ pkgSpecifierTarget pkgSpecifier)
+                     (scopeToplevel $ pkgSpecifierTarget pkgSpecifier)
                      (PackagePropertyFlags flags)
             in LabeledPackageConstraint pc ConstraintSourceConfigFlagOrTarget
           | let flags = configConfigurationsFlags configFlags
@@ -419,7 +419,7 @@ planPackages comp platform mSandboxPkgInfo solver
 
       . addConstraints
           [ let pc = PackageConstraint
-                     (unqualified $ pkgSpecifierTarget pkgSpecifier)
+                     (scopeToplevel $ pkgSpecifierTarget pkgSpecifier)
                      (PackagePropertyStanzas stanzas)
             in LabeledPackageConstraint pc ConstraintSourceConfigFlagOrTarget
           | pkgSpecifier <- pkgSpecifiers ]

cabal-install/Distribution/Client/ProjectPlanning.hs

@@ -985,7 +985,7 @@ planPackages comp platform solver SolverSettings{..}
       . addConstraints
           -- enable stanza constraints where the user asked to enable
           [ LabeledPackageConstraint
-              (PackageConstraint (unqualified pkgname)
+              (PackageConstraint (scopeToplevel pkgname)
                                  (PackagePropertyStanzas stanzas))
               ConstraintSourceConfigFlagOrTarget
           | pkg <- localPackages
@@ -1000,7 +1000,7 @@ planPackages comp platform solver SolverSettings{..}
           --TODO: [nice to have] should have checked at some point that the
           -- package in question actually has these flags.
           [ LabeledPackageConstraint
-              (PackageConstraint (unqualified pkgname)
+              (PackageConstraint (scopeToplevel pkgname)
                                  (PackagePropertyFlags flags))
               ConstraintSourceConfigFlagOrTarget
           | (pkgname, flags) <- Map.toList solverSettingFlagAssignments ]
@@ -1011,7 +1011,7 @@ planPackages comp platform solver SolverSettings{..}
           -- former we just apply all these flags to all local targets which
           -- is silly. We should check if the flags are appropriate.
           [ LabeledPackageConstraint
-              (PackageConstraint (unqualified pkgname) 
+              (PackageConstraint (scopeToplevel pkgname) 
                                  (PackagePropertyFlags flags))
               ConstraintSourceConfigFlagOrTarget
           | let flags = solverSettingFlagAssignment

cabal-install/Distribution/Client/Targets.hs

@@ -201,13 +201,13 @@ pkgSpecifierConstraints :: Package pkg
 pkgSpecifierConstraints (NamedPackage name props) = map toLpc props
   where
     toLpc prop = LabeledPackageConstraint
-                 (PackageConstraint (unqualified name) prop)
+                 (PackageConstraint (scopeToplevel name) prop)
                  ConstraintSourceUserTarget
 pkgSpecifierConstraints (SpecificSourcePackage pkg)  =
     [LabeledPackageConstraint pc ConstraintSourceUserTarget]
   where
     pc = PackageConstraint
-         (unqualified $ packageName pkg)
+         (scopeToplevel $ packageName pkg)
          (PackagePropertyVersion $ thisVersion (packageVersion pkg))
 
 -- ------------------------------------------------------------
@@ -718,7 +718,7 @@ userConstraintPackageName (UserConstraint _ name _) = name
 
 userToPackageConstraint :: UserConstraint -> PackageConstraint
 userToPackageConstraint (UserConstraint qual name prop) =
-  PackageConstraint (Q path name) prop
+  PackageConstraint (ScopeQualified $ Q path name) prop
   where
     path = PackagePath DefaultNamespace (fromUserQualifier qual)
 

cabal-install/Distribution/Solver/Modular.hs

@@ -31,7 +31,6 @@ import Distribution.Solver.Modular.Solver
          ( SolverConfig(..), solve )
 import Distribution.Solver.Types.LabeledPackageConstraint
 import Distribution.Solver.Types.PackageConstraint
-import Distribution.Solver.Types.PackagePath
 import Distribution.Solver.Types.DependencyResolver
 import Distribution.System
          ( Platform(..) )
@@ -60,4 +59,4 @@ modularResolver sc (Platform arch os) cinfo iidx sidx pkgConfigDB pprefs pcs pns
 
       -- Helper function to extract the PN from a constraint.
       pcName :: PackageConstraint -> PN
-      pcName (PackageConstraint (Q _ pn) _) = pn
+      pcName (PackageConstraint scope _) = scopeToPackageName scope

cabal-install/Distribution/Solver/Types/PackageConstraint.hs

@@ -6,6 +6,9 @@
 -- range or inconsistent flag assignment).
 --
 module Distribution.Solver.Types.PackageConstraint (
+    ConstraintScope(..),
+    scopeToplevel,
+    scopeToPackageName,
     PackageProperty(..),
     dispPackageProperty,
     PackageConstraint(..),
@@ -13,11 +16,13 @@ module Distribution.Solver.Types.PackageConstraint (
     showPackageConstraint,
   ) where
 
+import Distribution.Package (PackageName)
 import Distribution.Version (VersionRange, simplifyVersionRange)
 import Distribution.PackageDescription (FlagAssignment, dispFlagAssignment)
 import Distribution.Solver.Types.OptionalStanza
-import Distribution.Solver.Types.PackagePath (QPN, dispQPN)
+import Distribution.Solver.Types.PackagePath
 
+import Distribution.Client.Compat.Prelude ((<<>>))
 import GHC.Generics (Generic)
 import Distribution.Compat.Binary (Binary)
 
@@ -25,6 +30,34 @@ import Distribution.Text (disp, flatStyle)
 import qualified Text.PrettyPrint as Disp
 import Text.PrettyPrint ((<+>))
 
+-- | Determines to what packages and in what contexts a
+-- constraint applies.
+data ConstraintScope
+     -- | The package with the specified qualified name.
+   = ScopeQualified QPN
+     -- | The package with the specified name regardless of
+     -- qualifier.
+   | ScopeAnyQualifier PackageName
+  deriving (Eq, Show, Generic)
+
+instance Binary ConstraintScope
+
+-- | Constructor for a common use case: the constraint applies to
+-- the package with the specified name when that package is a
+-- top-level dependency in the default namespace.
+scopeToplevel :: PackageName -> ConstraintScope
+scopeToplevel = ScopeQualified . Q (PackagePath DefaultNamespace Unqualified)
+
+-- | Returns the package name associated with a constraint scope.
+scopeToPackageName :: ConstraintScope -> PackageName
+scopeToPackageName (ScopeQualified (Q _ pn)) = pn
+scopeToPackageName (ScopeAnyQualifier pn) = pn
+
+-- | Pretty-prints a constraint scope.
+dispConstraintScope :: ConstraintScope -> Disp.Doc
+dispConstraintScope (ScopeQualified qpn) = dispQPN qpn
+dispConstraintScope (ScopeAnyQualifier pn) = Disp.text "any." <<>> disp pn
+
 -- | A package property is a logical predicate on packages.
 data PackageProperty
    = PackagePropertyVersion   VersionRange
@@ -45,29 +78,29 @@ dispPackageProperty (PackagePropertyFlags flags) = dispFlagAssignment flags
 dispPackageProperty (PackagePropertyStanzas stanzas) =
   Disp.hsep $ map (Disp.text . showStanza) stanzas
 
--- | A package constraint consists of a package plus a property
--- that must hold for that package.
-data PackageConstraint = PackageConstraint QPN PackageProperty
+-- | A package constraint consists of a scope plus a property
+-- that must hold for all packages within that scope.
+data PackageConstraint = PackageConstraint ConstraintScope PackageProperty
   deriving (Eq, Show, Generic)
 
 instance Binary PackageConstraint
 
 -- | Pretty-prints a package constraint.
 dispPackageConstraint :: PackageConstraint -> Disp.Doc
-dispPackageConstraint (PackageConstraint qpn prop) =
-  dispQPN qpn <+> dispPackageProperty prop
+dispPackageConstraint (PackageConstraint scope prop) =
+  dispConstraintScope scope <+> dispPackageProperty prop
 
 -- | Alternative textual representation of a package constraint
 -- for debugging purposes (slightly more verbose than that
 -- produced by 'dispPackageConstraint').
 --
 showPackageConstraint :: PackageConstraint -> String
-showPackageConstraint pc@(PackageConstraint qpn prop) =
+showPackageConstraint pc@(PackageConstraint scope prop) =
   Disp.renderStyle flatStyle . postprocess $ dispPackageConstraint pc2
   where
     pc2 = case prop of
       PackagePropertyVersion vr ->
-        PackageConstraint qpn $ PackagePropertyVersion (simplifyVersionRange vr)
+        PackageConstraint scope $ PackagePropertyVersion (simplifyVersionRange vr)
       _ -> pc
     postprocess = case prop of
       PackagePropertyFlags _ -> (Disp.text "flags" <+>)

cabal-install/Distribution/Solver/Types/PackagePath.hs

@@ -5,7 +5,6 @@ module Distribution.Solver.Types.PackagePath
     , Qualifier(..)
     , dispQualifier
     , Qualified(..)
-    , unqualified
     , QPN
     , dispQPN
     , showQPN
@@ -102,10 +101,6 @@ data Qualified a = Q PackagePath a
            
 instance Binary a => Binary (Qualified a)
 
--- | Marks the entity as a top-level dependency in the default namespace.
-unqualified :: a -> Qualified a
-unqualified = Q (PackagePath DefaultNamespace Unqualified)
-
 -- | Qualified package name.
 type QPN = Qualified PackageName
 

cabal-install/tests/UnitTests/Distribution/Solver/Modular/DSL.hs

@@ -545,7 +545,7 @@ exResolve db exts langs pkgConfigDb targets solver mbj indepGoals reorder
                      }
     enableTests
         | asBool enableAllTests = fmap (\p -> PackageConstraint
-                                              (unqualified (C.mkPackageName p))
+                                              (scopeToplevel (C.mkPackageName p))
                                               (PackagePropertyStanzas [TestStanzas]))
                                        (exDbPkgs db)
         | otherwise             = []