From fa5820390033752565320eb096b74129e87ce7aa Mon Sep 17 00:00:00 2001
From: Oliver Charles <ollie@ocharles.org.uk>
Date: Mon, 16 Sep 2019 10:08:22 +0100
Subject: [PATCH] Instances retain everything

---
 src/Weeder.hs                                     |  4 ++--
 tests/Main.hs                                     | 15 ++++++++++-----
 .../Instances retain top level bindings.hs        |  9 +++++++++
 3 files changed, 21 insertions(+), 7 deletions(-)
 create mode 100644 tests/test-cases/Instances retain top level bindings.hs

diff --git a/src/Weeder.hs b/src/Weeder.hs
index c653ccc..7f4d39a 100644
--- a/src/Weeder.hs
+++ b/src/Weeder.hs
@@ -460,9 +460,9 @@ topLevelAnalysis n@Node{ nodeChildren } = do
           [
           --   analyseStandaloneDeriving n
           -- ,
-          analyseBinding n
+            analyseBinding n
           -- , analyseRewriteRule n
-          -- , analyseInstanceDeclaration n
+          , analyseInstanceDeclaration n
           -- , analyseClassDeclaration n
           -- , analyseDataDeclaration n
           ]
diff --git a/tests/Main.hs b/tests/Main.hs
index a1b5c53..60070f7 100644
--- a/tests/Main.hs
+++ b/tests/Main.hs
@@ -108,27 +108,32 @@ fileToTestCase sourceFilePath =
                   analysis =
                     execState ( analyseHieFile hieFile ) emptyAnalysis
 
+                  testModule =
+                    Module
+                      ( DefiniteUnitId ( DefUnitId ( stringToInstalledUnitId "main" ) ) )
+                      testModuleName
+
                   reachableSet =
                     reachable
                       analysis
                       ( Set.singleton
                           Declaration
                             { declModule =
-                                Module
-                                  ( DefiniteUnitId ( DefUnitId ( stringToInstalledUnitId "main" ) ) )
-                                  testModuleName
+                                testModule
                             , declOccName =
                                 mkOccName varName "root"
                             }
                       )
 
                   dead =
-                    allDeclarations analysis Set.\\ reachableSet
+                    Set.filter
+                      ( \d -> declModule d == testModule )
+                      ( allDeclarations analysis Set.\\ reachableSet )
 
                 unless
                   ( Set.null dead )
                   ( for_ dead \d ->
-                      liftIO ( putStrLn ( declarationStableName d <> " is dead, but should be alive" ) )
+                      liftIO ( fail ( declarationStableName d <> " is dead, but should be alive" ) )
                   )
 
 -- | Recursively search for .hie files in given directory
diff --git a/tests/test-cases/Instances retain top level bindings.hs b/tests/test-cases/Instances retain top level bindings.hs
new file mode 100644
index 0000000..3e8126e
--- /dev/null
+++ b/tests/test-cases/Instances retain top level bindings.hs	
@@ -0,0 +1,9 @@
+module Test () where
+
+alive :: String
+alive = "Alive"
+
+data T = T
+
+instance Show T where
+  show T = alive