Test for Trac #1913

testsuite/tests/ghc-regress/deriving/should_fail/all.T

@@ -13,3 +13,4 @@ test('drvfail011', normal, compile_fail, [''])
 test('drvfail012', normal, compile_fail, [''])
 test('drvfail013', normal, compile_fail, [''])
 test('drvfail014', normal, compile_fail, [''])
+test('drvfail015', normal, compile_fail, [''])

testsuite/tests/ghc-regress/deriving/should_fail/drvfail015.hs

+{-# OPTIONS_GHC -XStandaloneDeriving #-}
+
+module ShouldFail where
+
+import System.IO( Handle )
+
+
+-- T is a synonym
+type T = Int
+deriving instance Eq T
+
+-- Handle is abstract
+deriving instance Eq Handle

testsuite/tests/ghc-regress/deriving/should_fail/drvfail015.stderr

+
+drvfail015.hs:10:0:
+    Illegal instance declaration for `Eq T'
+        (All instance types must be of the form (T t1 ... tn)
+         where T is not a synonym.
+         Use -XTypeSynonymInstances if you want to disable this.)
+    In the stand-alone deriving instance for `Eq T'
+
+drvfail015.hs:13:0:
+    The data constructors of `Handle' are not all in scope
+      so you cannot derive an instance for it
+    In the stand-alone deriving instance for `Eq Handle'