diff options
Diffstat (limited to 'compiler/ghci/ByteCodeGen.hs')
| -rw-r--r-- | compiler/ghci/ByteCodeGen.hs | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/compiler/ghci/ByteCodeGen.hs b/compiler/ghci/ByteCodeGen.hs index 0d4c64b4d1..8839ffa544 100644 --- a/compiler/ghci/ByteCodeGen.hs +++ b/compiler/ghci/ByteCodeGen.hs @@ -1327,6 +1327,12 @@ pushAtom d p e pushAtom _ _ (AnnCoercion {}) -- Coercions are zero-width things, = return (nilOL, 0) -- treated just like a variable V +-- See Note [Empty case alternatives] in coreSyn/CoreSyn.hs +-- and Note [Bottoming expressions] in coreSyn/CoreUtils.hs: +-- The scrutinee of an empty case evaluates to bottom +pushAtom d p (AnnCase (_, a) _ _ []) -- trac #12128 + = pushAtom d p a + pushAtom d p (AnnVar v) | UnaryRep rep_ty <- repType (idType v) , V <- typeArgRep rep_ty @@ -1627,6 +1633,11 @@ atomPrimRep :: AnnExpr' Id ann -> PrimRep atomPrimRep e | Just e' <- bcView e = atomPrimRep e' atomPrimRep (AnnVar v) = bcIdPrimRep v atomPrimRep (AnnLit l) = typePrimRep (literalType l) + +-- Trac #12128: +-- A case expresssion can be an atom because empty cases evaluate to bottom. +-- See Note [Empty case alternatives] in coreSyn/CoreSyn.hs +atomPrimRep (AnnCase _ _ ty _) = ASSERT(typePrimRep ty == PtrRep) PtrRep atomPrimRep (AnnCoercion {}) = VoidRep atomPrimRep other = pprPanic "atomPrimRep" (ppr (deAnnotate' other)) |