diff --git a/builder/src/Deps/Solver.hs b/builder/src/Deps/Solver.hs
index 52b98815..6ba76521 100644
--- a/builder/src/Deps/Solver.hs
+++ b/builder/src/Deps/Solver.hs
@@ -249,10 +249,15 @@ addVersion reportKey (Goals rootPlatform pending solved) name source =
     if C.goodGren gren
       then
         if Platform.compatible rootPlatform platform
-          then do
-            depsConstraintSources <- Map.traverseWithKey resolveToConstraintSource deps
-            newPending <- foldM (addConstraint name solved) pending (Map.toList depsConstraintSources)
-            return (Goals rootPlatform newPending (Map.insert name source solved))
+          then
+            if any PossibleFilePath.is deps
+              then
+                solverError $
+                  Exit.SolverTransientLocalDep name
+              else do
+                depsConstraintSources <- Map.traverseWithKey resolveToConstraintSource deps
+                newPending <- foldM (addConstraint name solved) pending (Map.toList depsConstraintSources)
+                return (Goals rootPlatform newPending (Map.insert name source solved))
           else
             solverError $
               Exit.SolverIncompatiblePlatforms name rootPlatform platform
diff --git a/builder/src/Reporting/Exit.hs b/builder/src/Reporting/Exit.hs
index a84d8670..c1156f1d 100644
--- a/builder/src/Reporting/Exit.hs
+++ b/builder/src/Reporting/Exit.hs
@@ -1005,6 +1005,7 @@ data Solver
   | SolverBadLocalDepExpectedPkg FilePath Pkg.Name
   | SolverBadLocalDepInvalidGrenJson FilePath Pkg.Name
   | SolverLocalDepNotFound FilePath Pkg.Name
+  | SolverTransientLocalDep Pkg.Name
   | SolverBadGitOperationUnversionedPkg Pkg.Name Git.Error
   | SolverBadGitOperationVersionedPkg Pkg.Name V.Version Git.Error
   | SolverIncompatibleSolvedVersion Pkg.Name Pkg.Name C.Constraint V.Version
@@ -1086,6 +1087,17 @@ toSolverReport problem =
         [ D.reflow
             "Verify that the path is correct."
         ]
+    SolverTransientLocalDep pkgName ->
+      Help.report
+        "PROBLEM SOLVING PACKAGE CONSTRAINTS"
+        Nothing
+        ( Pkg.toChars pkgName
+            ++ " has defined one or more local dependencies."
+        )
+        [ D.reflow
+            "Dependencies are not allowed to define their own local dependencies. Contact the package \
+            \author to resolve this issue."
+        ]
     SolverBadGitOperationUnversionedPkg pkg gitError ->
       toGitErrorReport "PROBLEM SOLVING PACKAGE CONSTRAINTS" gitError $
         "I need the gren.json of "