[ fix ] consider nest when guessing scrutinee (#3070)

src/Idris/Elab/Implementation.idr

@@ -128,9 +128,7 @@ elabImplementation : {vars : _} ->
 elabImplementation {vars} ifc vis opts_in pass env nest is cons iname ps named impName_in nusing mbody
     = do -- let impName_in = maybe (mkImplName fc iname ps) id impln
          -- If we're in a nested block, update the name
-         let impName_nest = case lookup impName_in (names nest) of
-                                 Just (Just n', _) => n'
-                                 _ => impName_in
+         let impName_nest = mapNestedName nest impName_in
          impName <- inCurrentNS impName_nest
          -- The interface name might be qualified, so check if it's an
          -- alias for something

src/TTImp/Elab/App.idr

@@ -836,9 +836,7 @@ checkApp rig elabinfo nest env fc (IVar fc' n) expargs autoargs namedargs exp
                           " to " ++ show expargs ++ "\n\tFunction type " ++
                           (show !(toFullNames fnty)) ++ "\n\tExpected app type "
                                 ++ show exptyt))
-        let fn = case lookup n (names nest) of
-                      Just (Just n', _) => n'
-                      _ => n
+        let fn = mapNestedName nest n
         normalisePrims prims env
            !(checkAppWith rig elabinfo nest env fc ntm nty (Just fn, arglen) expargs autoargs namedargs False exp)
   where

src/TTImp/Elab/Case.idr

@@ -13,6 +13,7 @@ import Core.Value
 import Idris.Syntax
 import Idris.REPL.Opts
 
+import TTImp.Elab.App
 import TTImp.Elab.Check
 import TTImp.Elab.Delayed
 import TTImp.Elab.ImplicitBind
@@ -460,7 +461,7 @@ checkCase rig elabinfo nest env fc opts scr scrty_in alts exp
         = case getFn x of
                IVar _ n =>
                   do defs <- get Ctxt
-                     [(n', (_, ty))] <- lookupTyName n (gamma defs)
+                     [(_, (_, ty))] <- lookupTyName (mapNestedName nest n) (gamma defs)
                          | _ => guessScrType xs
                      Just (tyn, tyty) <- getRetTy defs !(nf defs [] ty)
                          | _ => guessScrType xs

src/TTImp/Elab/Local.idr

@@ -103,44 +103,38 @@ localHelper {vars} nest env nestdecls_in func
     -- Update the names in the declarations to the new 'nested' names.
     -- When we encounter the names in elaboration, we'll update to an
     -- application of the nested name.
-    newName : NestedNames vars -> Name -> Name
-    newName nest n
-        = case lookup n (names nest) of
-               Just (Just n', _) => n'
-               _ => n
-
     updateTyName : NestedNames vars -> ImpTy -> ImpTy
     updateTyName nest (MkImpTy loc' nameLoc n ty)
-        = MkImpTy loc' nameLoc (newName nest n) ty
+        = MkImpTy loc' nameLoc (mapNestedName nest n) ty
 
     updateDataName : NestedNames vars -> ImpData -> ImpData
     updateDataName nest (MkImpData loc' n tycons dopts dcons)
-        = MkImpData loc' (newName nest n) tycons dopts
+        = MkImpData loc' (mapNestedName nest n) tycons dopts
                          (map (updateTyName nest) dcons)
     updateDataName nest (MkImpLater loc' n tycons)
-        = MkImpLater loc' (newName nest n) tycons
+        = MkImpLater loc' (mapNestedName nest n) tycons
 
     updateFieldName : NestedNames vars -> IField -> IField
     updateFieldName nest (MkIField fc rigc piinfo n rawimp)
-        = MkIField fc rigc piinfo (newName nest n) rawimp
+        = MkIField fc rigc piinfo (mapNestedName nest n) rawimp
 
     updateRecordName : NestedNames vars -> ImpRecord -> ImpRecord
     updateRecordName nest (MkImpRecord fc n params opts conName fields)
-        = MkImpRecord fc (newName nest n)
+        = MkImpRecord fc (mapNestedName nest n)
                          params
                          opts
-                         (newName nest conName)
+                         (mapNestedName nest conName)
                          (map (updateFieldName nest) fields)
 
     updateRecordNS : NestedNames vars -> Maybe String -> Maybe String
     updateRecordNS _    Nothing   = Nothing
-    updateRecordNS nest (Just ns) = Just $ show $ newName nest (UN $ mkUserName ns)
+    updateRecordNS nest (Just ns) = Just $ show $ mapNestedName nest (UN $ mkUserName ns)
 
     updateName : NestedNames vars -> ImpDecl -> ImpDecl
     updateName nest (IClaim loc' r vis fnopts ty)
          = IClaim loc' r vis fnopts (updateTyName nest ty)
     updateName nest (IDef loc' n cs)
-         = IDef loc' (newName nest n) cs
+         = IDef loc' (mapNestedName nest n) cs
     updateName nest (IData loc' vis mbt d)
          = IData loc' vis mbt (updateDataName nest d)
     updateName nest (IRecord loc' ns vis mbt imprecord)

src/TTImp/TTImp.idr

@@ -38,6 +38,13 @@ Weaken NestedNames where
       wknName (n, (mn, vars, rep))
           = (n, (mn, map weaken vars, \fc, nt => weaken (rep fc nt)))
 
+-- replace nested name with full name
+export
+mapNestedName : NestedNames vars -> Name -> Name
+mapNestedName nest n = case lookup n (names nest) of
+                               (Just (Just n', _)) => n'
+                               _ => n
+
 -- Unchecked terms, with implicit arguments
 -- This is the raw, elaboratable form.
 -- Higher level expressions (e.g. case, pattern matching let, where blocks,

tests/idris2/basic/case002/WhereData.idr

@@ -0,0 +1,11 @@
+module Main
+
+foo : Int -> Int
+foo x = case isLT of
+            Yes => x*2
+            No => x*4
+   where
+      data MyLT = Yes | No
+
+      isLT : MyLT
+      isLT = if x < 20 then Yes else No

tests/idris2/basic/case002/expected

@@ -0,0 +1 @@
+1/1: Building WhereData (WhereData.idr)

tests/idris2/basic/case002/run

@@ -0,0 +1,3 @@
+rm -rf build
+
+$1 --no-color --console-width 0 --no-banner --check WhereData.idr