[Git][ghc/ghc][master] Enforce that bindings of implicit parameters are lifted

[Marge Bot (@marge-bot)]

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC


Commits:
685b467c by Krzysztof Gogolewski at 2023-12-29T15:37:06-05:00
Enforce that bindings of implicit parameters are lifted

Fixes #24298

- - - - -


4 changed files:

- compiler/GHC/Tc/Gen/Bind.hs
- + testsuite/tests/typecheck/should_fail/T24298.hs
- + testsuite/tests/typecheck/should_fail/T24298.stderr
- testsuite/tests/typecheck/should_fail/all.T


Changes:

=====================================
compiler/GHC/Tc/Gen/Bind.hs
=====================================
@@ -291,7 +291,7 @@ tcLocalBinds (HsIPBinds x (IPBinds _ ip_binds)) thing_inside
         --              ?y = ?x + 1
     tc_ip_bind :: Class -> IPBind GhcRn -> TcM (DictId, IPBind GhcTc)
     tc_ip_bind ipClass (IPBind _ l_name@(L _ ip) expr)
-       = do { ty <- newOpenFlexiTyVarTy
+       = do { ty <- newFlexiTyVarTy liftedTypeKind  -- see #24298
             ; let p = mkStrLitTy $ hsIPNameFS ip
             ; ip_id <- newDict ipClass [ p, ty ]
             ; expr' <- tcCheckMonoExpr expr ty


=====================================
testsuite/tests/typecheck/should_fail/T24298.hs
=====================================
@@ -0,0 +1,4 @@
+{-# LANGUAGE ImplicitParams, MagicHash #-}
+module T24298 where
+
+f = let ?foo = 4# in True


=====================================
testsuite/tests/typecheck/should_fail/T24298.stderr
=====================================
@@ -0,0 +1,9 @@
+
+T24298.hs:4:16: error: [GHC-18872]
+    • Couldn't match a lifted type with an unlifted type
+      When matching types
+        t0 :: *
+        GHC.Prim.Int# :: TYPE GHC.Types.IntRep
+    • In the expression: 4#
+      In the expression: let ?foo = 4# in True
+      In an equation for ‘f’: f = let ?foo = 4# in True


=====================================
testsuite/tests/typecheck/should_fail/all.T
=====================================
@@ -710,3 +710,4 @@ test('T23776', normal, compile_fail, ['']) # error due to -Werror=compat, schedu
 test('T17940', normal, compile_fail, [''])
 test('ErrorIndexLinks', normal, compile_fail, ['-fprint-error-index-links=always'])
 test('T24064', normal, compile_fail, [''])
+test('T24298', normal, compile_fail, [''])



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/685b467c690a79598526d904b599c183993b2d30

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/685b467c690a79598526d904b599c183993b2d30
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