Add test for type refinement with :print in GHCi

testsuite/tests/ghc-regress/ghci.debugger/Test.hs

@@ -33,3 +33,8 @@ instance Show Show1 where
 
 type Just1 = Maybe
 
+
+data Unary = Unary
+
+poly :: a -> ()
+poly x = seq x ()
\ No newline at end of file

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

@@ -16,4 +16,5 @@ test('print014', normal, ghci_script, ['print014.script'])
 
 test('print015', normal, ghci_script, ['print015.script'])
 test('print016', normal, ghci_script, ['print016.script'])
-test('print017', normal, ghci_script, ['print017.script'])
\ No newline at end of file
+test('print017', normal, ghci_script, ['print017.script'])
+test('print018', normal, ghci_script, ['print018.script'])
\ No newline at end of file

testsuite/tests/ghc-regress/ghci.debugger/scripts/print018.script

+-- Test type reconstruction of Constants
+-- Found by Bernie Pope
+
+:set -fglasgow-exts
+:set -fdebugging
+:l ../Test
+
+:break add Test.Test2 40
+poly Unary
+:p x
+:t x
+seq x ()
+:p x
+:t x
+x

testsuite/tests/ghc-regress/ghci.debugger/scripts/print018.stderr

+
+<interactive>:1:0:
+    No instance for (Show Unary)
+      arising from a use of `print' at <interactive>:1:0
+    Possible fix: add an instance declaration for (Show Unary)
+    In the expression: print it
+    In a 'do' expression: print it

testsuite/tests/ghc-regress/ghci.debugger/scripts/print018.stdout

+Breakpoint set at main:Test.Test2:40:9
+Stopped at a breakpoint in ../Test.hs:40. Local bindings in scope:
+  _result :: (), x :: a
+../Test.hs:40:9-16> x = (_t1::a)
+../Test.hs:40:9-16> x :: GHC.Base.Unknown
+../Test.hs:40:9-16> ()
+../Test.hs:40:9-16> x = Unary
+../Test.hs:40:9-16> x :: Unary
+../Test.hs:40:9-16> ../Test.hs:40:9-16> Returning to normal execution...
+()