Test proxy-polymorphic sameNat and sameSymbol

testsuite/tests/lib/base/T17310.hs

+{-# LANGUAGE DataKinds      #-}
+{-# LANGUAGE GADTs          #-}
+{-# LANGUAGE KindSignatures #-}
+
+module Lib where
+
+import Data.Type.Equality
+import GHC.TypeLits
+import GHC.TypeNats
+
+data A (t :: Nat)    = A
+data B (t :: Nat)    = B
+data C (t :: Symbol) = C
+data D (t :: Symbol) = D
+
+cmpNats :: (KnownNat n, KnownNat m) => A n -> B m -> Bool
+cmpNats a b = case a `sameNat` b of
+  Nothing   -> False
+  Just Refl -> True
+
+cmpSymbols :: (KnownSymbol n, KnownSymbol m) => C n -> D m -> Bool
+cmpSymbols c d = case c `sameSymbol` d of
+  Nothing   -> False
+  Just Refl -> True

testsuite/tests/lib/base/all.T

 test('T16586', normal, compile_and_run, ['-O2'])
 # Event-manager not supported on Windows
 test('T16916', when(opsys('mingw32'), skip), compile_and_run, ['-O2 -threaded'])
+test('T17310', normal, compile, [''])