Add rough reason context to DetailsHandEditedDependencies

builder/src/Elm/Details.hs

@@ -253,6 +253,8 @@ verifyApp env time outline@(Outline.AppOutline elmVersion srcDirs direct _ _ _)
         if Map.size stated == Map.size actual
           then verifyDependencies env time (ValidApp srcDirs) actual direct
           else Task.throw $ Exit.DetailsHandEditedDependencies
+            $ "The stated and actual dependencies do not match.\n\n"
+            ++ "Stated: " ++ show stated ++ "\n\nActual: " ++ show actual
   else
     Task.throw $ Exit.DetailsBadElmInAppOutline elmVersion
 
@@ -289,14 +291,17 @@ union tieBreaker deps1 deps2 =
 
 noDups :: k -> v -> v -> Task v
 noDups _ _ _ =
-  Task.throw Exit.DetailsHandEditedDependencies
+  Task.throw $ Exit.DetailsHandEditedDependencies
+    "The same dependency is listed in multiple places in your elm.json file."
 
 
-allowEqualDups :: (Eq v) => k -> v -> v -> Task v
+allowEqualDups :: (Eq v, Show v) => k -> v -> v -> Task v
 allowEqualDups _ v1 v2 =
   if v1 == v2
   then return v1
-  else Task.throw Exit.DetailsHandEditedDependencies
+  else Task.throw $ Exit.DetailsHandEditedDependencies
+    $ "The same dependency is listed in multiple places in your elm.json file, but with different constraints.\n\n"
+    ++ "Dep 1: " ++ show v1 ++ "\n\nDep 2: " ++ show v2
 
 
 

builder/src/Reporting/Exit.hs

@@ -1281,6 +1281,7 @@ data Details
   | DetailsBadElmInPkg C.Constraint
   | DetailsBadElmInAppOutline V.Version
   | DetailsHandEditedDependencies
+      String -- @LAMDERA addition: reason
   | DetailsBadOutline Outline
   | DetailsCannotGetRegistry RegistryProblem
   | DetailsBadDeps FilePath [DetailsBadDep]
@@ -1356,11 +1357,13 @@ toDetailsReport details =
         , D.reflow $ "Lamdera hint: modify your elm.json to \"elm-version\": \"0.19.1\"."
         ]
 
-    DetailsHandEditedDependencies ->
+    DetailsHandEditedDependencies reason ->
       Help.report "ERROR IN DEPENDENCIES" (Just "elm.json")
         "It looks like the dependencies elm.json in were edited by hand (or by a 3rd\
         \ party tool) leaving them in an invalid state."
-        [ D.fillSep
+        [ D.reflow $
+            "Reason: " ++ reason
+        , D.fillSep
             ["Try","to","change","them","back","to","what","they","were","before!"
             ,"It","is","much","more","reliable","to","add","dependencies","with",D.green "lamdera install" <> "."
             ]