Add a regression test for #11822wip/pmcheck-t11822

The particular test is already fixed, but the issue seems to have
multiple different test cases lumped together.

1 files changed, 42 insertions, 0 deletions

diff --git a/testsuite/tests/pmcheck/should_compile/T11822.hs b/testsuite/tests/pmcheck/should_compile/T11822.hs
new file mode 100644
index 0000000000..01afdf46c3
--- /dev/null
+++ b/testsuite/tests/pmcheck/should_compile/T11822.hs
@@ -0,0 +1,42 @@
+{-# OPTIONS_GHC -Wincomplete-patterns -fforce-recomp #-}
+{-# LANGUAGE OverloadedLists #-}
+{-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE GeneralisedNewtypeDeriving #-}
+
+module T11822 where
+
+import Data.Sequence (Seq, pattern (:<|))
+import Data.Set (Set)
+
+newtype SiblingDependencies = SiblingDependencies Int
+  deriving (Eq, Ord, Enum, Integral, Real, Num)
+
+newtype Depth = Depth Int
+  deriving (Eq, Ord, Enum, Integral, Real, Num)
+
+data TreeNode prefix
+  = OnlyChild prefix
+  | LeafLast prefix
+  | LeafMid prefix
+  | NodeLast prefix
+  | NodeMid prefix
+  | PrefixedLast prefix (Seq SiblingDependencies) (Set prefix) Depth
+  | PrefixedMid prefix (Seq SiblingDependencies) (Set prefix) Depth
+
+mkTreeNode
+  :: Ord prefix
+  => prefix
+  -> Seq SiblingDependencies
+  -> Set prefix
+  -> Depth
+  -> TreeNode prefix
+mkTreeNode t     []      _   _   = OnlyChild t
+mkTreeNode t     [0]    []   _   = LeafLast t
+mkTreeNode t     [_]    []   _   = LeafMid t
+mkTreeNode t     [0]     _   0   = LeafLast t
+mkTreeNode t     [_]     _   0   = LeafMid t
+mkTreeNode t     [0]     _   _   = NodeLast t
+mkTreeNode t     [_]     _   _   = NodeMid t
+mkTreeNode t (0 :<| ns) ds depth = PrefixedLast t ns ds depth
+mkTreeNode t (_ :<| ns) ds depth = PrefixedMid t ns ds depth
+