diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 6847ed7..b5b851d 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -104,7 +104,14 @@ jobs:
 
   android:
     runs-on: ubuntu-latest
-    timeout-minutes: 45
+    # 70 rather than 45: a ghc-options change invalidates every
+    # Haskell derivation, and this job only READS nix-cache.jappie.me
+    # (extra-substituters; nothing here pushes to it), so each run of
+    # such a change builds cold until the cache is populated
+    # externally, and the budget must fit a full cold build; run
+    # 29340371964 timed out at exactly 45 minutes mid emulator test
+    # on such a build. Warm runs take ~25 minutes.
+    timeout-minutes: 70
     steps:
     - name: Free disk space
       run: |
@@ -157,7 +164,14 @@ jobs:
 
   ios:
     runs-on: macos-latest
-    timeout-minutes: 45
+    # 70 rather than 45: like the android job, this only READS
+    # nix-cache.jappie.me, so a ghc-options change builds cold until
+    # the cache is fed externally, and the leftover budget must still
+    # fit the simulator test (which is also the #235 flake). The
+    # cutoff has eaten the simulator test after a successful build
+    # twice (run 29281533228 on #239, run 29344658446 on #244) and
+    # once mid-compile before that (9dcf105).
+    timeout-minutes: 70
     steps:
     - uses: actions/checkout@v4
     - uses: cachix/install-nix-action@v31
diff --git a/Changelog.md b/Changelog.md
index 7d4671a..e97aeaf 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -4,6 +4,13 @@
 
 ### Changed
 
+- Missing fields in record construction are compile errors now
+  (`-Werror=missing-fields`): the default-on warning was overlooked
+  during the #243 migration and surfaced as a runtime crash in the
+  test suite, and the same flag immediately caught three long-standing
+  incomplete `UserState` constructions in the tests. A missing field
+  is always a latent runtime crash, so the build refuses it outright.
+
 - BREAKING: text color moved from `WidgetStyle` into the text-bearing
   configs (`tcTextColor` / `bcTextColor` / `tiTextColor`, next to the
   font override), following the `tcFontConfig` precedent. A text
diff --git a/hatter.cabal b/hatter.cabal
index a781c20..09fe483 100644
--- a/hatter.cabal
+++ b/hatter.cabal
@@ -76,6 +76,7 @@ common common-options
     -O2 -Wall -split-sections -Wincomplete-uni-patterns
     -Wincomplete-record-updates -Widentities -Wredundant-constraints
     -Wcpp-undef -fwarn-tabs -Wpartial-fields
+    -Werror=missing-fields
     -fdefer-diagnostics -Wunused-packages
     -fenable-th-splice-warnings
     -fno-omit-yields
diff --git a/test/Test/AppContextTests.hs b/test/Test/AppContextTests.hs
index 45edf6d..3e78073 100644
--- a/test/Test/AppContextTests.hs
+++ b/test/Test/AppContextTests.hs
@@ -32,6 +32,7 @@ import Hatter.Lifecycle
   )
 import Hatter.Widget (ButtonConfig(..), TextConfig(..), Widget(..))
 import Hatter.Permission (newPermissionState)
+import Hatter.PlatformSignIn (newPlatformSignInState)
 import Hatter.SecureStorage (newSecureStorageState)
 import Hatter.Ble (newBleState)
 import Hatter.Dialog (newDialogState)
@@ -76,6 +77,7 @@ registrationTests = testGroup "Registration"
       dummyHttpState <- newHttpState
       dummyNetworkStatusState <- newNetworkStatusState
       dummyAnimationState <- newAnimationState
+      dummyPlatformSignInState <- newPlatformSignInState
       let dummyUserState = UserState
             { userPermissionState    = dummyPermState
             , userSecureStorageState = dummySecureStorageState
@@ -88,6 +90,8 @@ registrationTests = testGroup "Registration"
             , userHttpState          = dummyHttpState
             , userNetworkStatusState = dummyNetworkStatusState
             , userAnimationState     = dummyAnimationState
+            , userPlatformSignInState = dummyPlatformSignInState
+            , userRequestRedraw      = pure ()
             }
       viewFn <- readIORef (acViewFunction appCtx)
       widget <- viewFn dummyUserState
@@ -124,6 +128,7 @@ registrationTests = testGroup "Registration"
       dummyHttpState <- newHttpState
       dummyNetworkStatusState <- newNetworkStatusState
       dummyAnimationState <- newAnimationState
+      dummyPlatformSignInState <- newPlatformSignInState
       let dummyUserState = UserState
             { userPermissionState    = dummyPermState
             , userSecureStorageState = dummySecureStorageState
@@ -136,6 +141,8 @@ registrationTests = testGroup "Registration"
             , userHttpState          = dummyHttpState
             , userNetworkStatusState = dummyNetworkStatusState
             , userAnimationState     = dummyAnimationState
+            , userPlatformSignInState = dummyPlatformSignInState
+            , userRequestRedraw      = pure ()
             }
       viewFnA <- readIORef (acViewFunction appCtxA)
       viewFnB <- readIORef (acViewFunction appCtxB)
diff --git a/test/Test/WidgetTests.hs b/test/Test/WidgetTests.hs
index b5cf06b..a00a6f8 100644
--- a/test/Test/WidgetTests.hs
+++ b/test/Test/WidgetTests.hs
@@ -56,6 +56,7 @@ import Hatter.Widget
   )
 import Hatter.Render (RenderState(..), RenderedNode(..), renderWidget, dispatchEvent, dispatchTextEvent)
 import Hatter.Permission (newPermissionState)
+import Hatter.PlatformSignIn (newPlatformSignInState)
 import Hatter.SecureStorage (newSecureStorageState)
 import Hatter.Ble (newBleState)
 import Hatter.Dialog (newDialogState)
@@ -160,6 +161,7 @@ uiTests = testGroup "UI"
       dummyHttpState <- newHttpState
       dummyNetworkStatusState <- newNetworkStatusState
       dummyAnimationState <- newAnimationState
+      dummyPlatformSignInState <- newPlatformSignInState
       let dummyUserState = UserState
             { userPermissionState    = dummyPermState
             , userSecureStorageState = dummySecureStorageState
@@ -172,6 +174,8 @@ uiTests = testGroup "UI"
             , userHttpState          = dummyHttpState
             , userNetworkStatusState = dummyNetworkStatusState
             , userAnimationState     = dummyAnimationState
+            , userPlatformSignInState = dummyPlatformSignInState
+            , userRequestRedraw      = pure ()
             }
       app <- testApp
       widget <- maView app dummyUserState