diff --git a/.github/workflows/implicit.yaml b/.github/workflows/implicit.yaml
index 1b714a1a..d4812e37 100644
--- a/.github/workflows/implicit.yaml
+++ b/.github/workflows/implicit.yaml
@@ -28,9 +28,8 @@ jobs:
         cabal:
           - '3.2'
         ghc:
-          - '8.10.1'
+          - '8.10.4'
           - '8.8.3'
-          - '8.6.5'
 name: Haskell CI
 on:
   - push
diff --git a/implicit.cabal b/implicit.cabal
index 30c381e5..edef6979 100644
--- a/implicit.cabal
+++ b/implicit.cabal
@@ -39,6 +39,10 @@ Common binstuff
                 -optc-O3
                 -- see GHC manual 8.2.1 section 6.5.1.
                 -feager-blackholing
+                -- for weeder
+                -fwrite-ide-info
+                -- for stan
+                -hiedir=.hie
                 -Wall
                 -Wextra
                 -Wcompat
@@ -59,6 +63,10 @@ Common libstuff
                 -optc-O3
                 -- see GHC manual 8.2.1 section 6.5.1.
                 -feager-blackholing
+                -- for weeder
+                -fwrite-ide-info
+                -- for stan
+                -hiedir=.hie
                 -Wall
                 -Wextra
                 -Wcompat
diff --git a/weeder.dhall b/weeder.dhall
new file mode 100644
index 00000000..0e873ea4
--- /dev/null
+++ b/weeder.dhall
@@ -0,0 +1 @@
+{ roots = [ "^Main.main$" ], type-class-roots = True }