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| author | Seraphime Kirkovski <kirkseraph@gmail.com> | 2016-07-20 09:47:23 +0200 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2016-07-20 15:17:50 +0200 |
| commit | 8de6e13f9ef784750e502955fcb38d4a7e179727 (patch) | |
| tree | 5c4755be247b3d6ec2f5b83374b7993628851a67 /compiler/ghci/ByteCodeGen.hs | |
| parent | 908f8e234fdbf951e763e0c47b018c6f74ae952c (diff) | |
| download | haskell-8de6e13f9ef784750e502955fcb38d4a7e179727.tar.gz | |
Fix bytecode generator panic
This fixes #12128.
The bug was introduced in 1c9fd3f1c5522372fcaf250c805b959e8090a62c.
Test Plan: ./validate
Reviewers: simonmar, austin, hvr, simonpj, bgamari
Reviewed By: bgamari
Subscribers: simonpj, thomie
Differential Revision: https://phabricator.haskell.org/D2374
GHC Trac Issues: #12128
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)) |