separate partitioning from asserting no builtins

unison-cli/src/Unison/Codebase/Editor/HandleInput/Merge2.hs

@@ -336,9 +336,12 @@ doMerge info = do
       liftIO (debugFunctions.debugCombinedDiff diff)
 
       -- Partition the combined diff into the conflicted things and the unconflicted things
-      (conflicts, unconflicts) <-
-        Merge.partitionCombinedDiffs (ThreeWay.forgetLca defns3) declNameLookups diff & onLeft \name ->
-          done (Output.MergeConflictInvolvingBuiltin name)
+      (conflicts, unconflicts) <- do
+        let (conflicts0, unconflicts) = Merge.partitionCombinedDiffs (ThreeWay.forgetLca defns3) declNameLookups diff
+        conflicts <-
+          Merge.narrowConflictsToNonBuiltins conflicts0 & onLeft \name ->
+            done (Output.MergeConflictInvolvingBuiltin name)
+        pure (conflicts, unconflicts)
 
       liftIO (debugFunctions.debugPartitionedDiff conflicts unconflicts)
 

unison-cli/src/Unison/Codebase/Editor/Output.hs

@@ -426,7 +426,7 @@ data Output
   | MergeSuccess !MergeSourceAndTarget
   | MergeSuccessFastForward !MergeSourceAndTarget
   | MergeConflictedAliases !MergeSourceOrTarget !(Defn (Name, Name) (Name, Name))
-  | MergeConflictInvolvingBuiltin !Name
+  | MergeConflictInvolvingBuiltin !(Defn Name Name)
   | MergeDefnsInLib !MergeSourceOrTarget
   | InstalledLibdep !(ProjectAndBranch ProjectName ProjectBranchName) !NameSegment
   | NoUpgradeInProgress

unison-cli/src/Unison/CommandLine/OutputMessages.hs

@@ -1368,22 +1368,27 @@ notifyUser dir = \case
         <> P.newline
         <> P.newline
         <> P.wrap "and then try merging again."
-  MergeConflictInvolvingBuiltin name ->
-    pure . P.lines $
-      [ P.wrap "Sorry, I wasn't able to perform the merge:",
-        "",
-        P.wrap
-          ( "There's a merge conflict on"
-              <> P.group (prettyName name <> ",")
-              <> "but it's a builtin on one or both branches. I can't yet handle merge conflicts involving builtins."
-          ),
-        "",
-        P.wrap
-          ( "Please eliminate this conflict by updating one branch or the other, making"
-              <> prettyName name
-              <> "the same on both branches, or making neither of them a builtin, and then try the merge again."
-          )
-      ]
+  MergeConflictInvolvingBuiltin defn ->
+    let (isTerm, name) =
+          case defn of
+            TermDefn n -> (True, n)
+            TypeDefn n -> (False, n)
+     in pure . P.lines $
+          [ P.wrap "Sorry, I wasn't able to perform the merge:",
+            "",
+            P.wrap
+              ( "There's a merge conflict on"
+                  <> (if isTerm then "term" else "type")
+                  <> P.group (prettyName name <> ",")
+                  <> "but it's a builtin on one or both branches. I can't yet handle merge conflicts involving builtins."
+              ),
+            "",
+            P.wrap
+              ( "Please eliminate this conflict by updating one branch or the other, making"
+                  <> prettyName name
+                  <> "the same on both branches, or making neither of them a builtin, and then try the merge again."
+              )
+          ]
   -- Note [DefnsInLibMessage] If you change this, also change the other similar one
   MergeDefnsInLib aliceOrBob ->
     pure . P.lines $

unison-merge/src/Unison/Merge.hs

@@ -22,6 +22,7 @@ module Unison.Merge
     -- * Partitioning combined namespace diffs
     Unconflicts (..),
     partitionCombinedDiffs,
+    narrowConflictsToNonBuiltins,
 
     -- * Merging libdeps
     LibdepDiffOp (..),
@@ -56,7 +57,7 @@ import Unison.Merge.EitherWayI (EitherWayI (..))
 import Unison.Merge.FindConflictedAlias (findConflictedAlias)
 import Unison.Merge.Libdeps (LibdepDiffOp (..), applyLibdepsDiff, diffLibdeps)
 import Unison.Merge.PartialDeclNameLookup (PartialDeclNameLookup (..))
-import Unison.Merge.PartitionCombinedDiffs (partitionCombinedDiffs)
+import Unison.Merge.PartitionCombinedDiffs (narrowConflictsToNonBuiltins, partitionCombinedDiffs)
 import Unison.Merge.Synhashed (Synhashed (..))
 import Unison.Merge.ThreeWay (ThreeWay (..))
 import Unison.Merge.TwoOrThreeWay (TwoOrThreeWay (..))

unison-merge/src/Unison/Merge/PartitionCombinedDiffs.hs

@@ -1,5 +1,6 @@
 module Unison.Merge.PartitionCombinedDiffs
   ( partitionCombinedDiffs,
+    narrowConflictsToNonBuiltins,
   )
 where
 
@@ -27,6 +28,7 @@ import Unison.Referent (Referent)
 import Unison.Referent qualified as Referent
 import Unison.Util.BiMultimap (BiMultimap)
 import Unison.Util.BiMultimap qualified as BiMultimap
+import Unison.Util.Defn (Defn (..))
 import Unison.Util.Defns (Defns (..), DefnsF, DefnsF2, defnsAreEmpty)
 import Unison.Util.Map qualified as Map
 
@@ -35,16 +37,12 @@ partitionCombinedDiffs ::
   TwoWay (Defns (BiMultimap Referent Name) (BiMultimap TypeReference Name)) ->
   TwoWay DeclNameLookup ->
   DefnsF2 (Map Name) CombinedDiffOp Referent TypeReference ->
-  Either
-    Name
-    ( TwoWay (DefnsF (Map Name) TermReferenceId TypeReferenceId),
-      DefnsF Unconflicts Referent TypeReference
-    )
-partitionCombinedDiffs defns declNameLookups diffs = do
-  let conflicts0 = identifyConflicts declNameLookups defns diffs
-  let unconflicts = identifyUnconflicts declNameLookups conflicts0 diffs
-  conflicts <- assertThereAreNoBuiltins conflicts0
-  Right (conflicts, unconflicts)
+  ( TwoWay (DefnsF (Map Name) TermReference TypeReference),
+    DefnsF Unconflicts Referent TypeReference
+  )
+partitionCombinedDiffs defns declNameLookups diffs =
+  let conflicts = identifyConflicts declNameLookups defns diffs
+   in (conflicts, identifyUnconflicts declNameLookups conflicts diffs)
 
 data S = S
   { me :: !(EitherWay ()),
@@ -247,21 +245,20 @@ justTheConflictedNames =
       CombinedDiffOp'Delete _ -> names
       CombinedDiffOp'Update _ -> names
 
-assertThereAreNoBuiltins ::
+narrowConflictsToNonBuiltins ::
   TwoWay (DefnsF (Map Name) TermReference TypeReference) ->
-  Either Name (TwoWay (DefnsF (Map Name) TermReferenceId TypeReferenceId))
-assertThereAreNoBuiltins =
+  Either (Defn Name Name) (TwoWay (DefnsF (Map Name) TermReferenceId TypeReferenceId))
+narrowConflictsToNonBuiltins =
   traverse (bitraverse (Map.traverseWithKey assertTermIsntBuiltin) (Map.traverseWithKey assertTypeIsntBuiltin))
   where
-    assertTermIsntBuiltin :: Name -> TermReference -> Either Name TermReferenceId
+    assertTermIsntBuiltin :: Name -> TermReference -> Either (Defn Name Name) TermReferenceId
     assertTermIsntBuiltin name ref =
       case Reference.toId ref of
-        Nothing -> Left name
+        Nothing -> Left (TermDefn name)
         Just refId -> Right refId
 
-    -- Same body as above, but could be different some day (e.g. return value tells you what namespace)
-    assertTypeIsntBuiltin :: Name -> TypeReference -> Either Name TypeReferenceId
+    assertTypeIsntBuiltin :: Name -> TypeReference -> Either (Defn Name Name) TypeReferenceId
     assertTypeIsntBuiltin name ref =
       case Reference.toId ref of
-        Nothing -> Left name
+        Nothing -> Left (TypeDefn name)
         Just refId -> Right refId