Test for Trac #1581

testsuite/tests/ghc-regress/ghci/scripts/all.T

@@ -26,4 +26,5 @@ test('ghci015', ignore_output, ghci_script, ['ghci015.script'])
 test('ghci016', expect_broken(552), ghci_script, ['ghci016.script'])
 test('ghci017', extra_run_opts('-hide-package haskell98'), ghci_script, ['ghci017.script'])
 test('ghci018', expect_broken(1201), ghci_script, ['ghci018.script'])
+test('ghci019', normal, ghci_script, ['ghci019.script'])
 

testsuite/tests/ghc-regress/ghci/scripts/ghci019.hs

+-- Trac #1581
+-- Even though Eq is not in scope unqualified, we want to 
+-- see the Eq instance of Foo when we say :i Foo
+
+module Foo where
+import qualified Prelude
+
+data Foo = Foo
+instance Prelude.Eq Foo

testsuite/tests/ghc-regress/ghci/scripts/ghci019.script

+:l ghci019
+:i Foo

testsuite/tests/ghc-regress/ghci/scripts/ghci019.stdout

+data Foo = Foo 	-- Defined at ghci019.hs:4:5-7
+instance Prelude.Eq Foo -- Defined at ghci019.hs:5:0-22