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| author | Andreas Klebinger <klebinger.andreas@gmx.at> | 2022-04-27 22:01:58 +0200 |
|---|---|---|
| committer | Andreas Klebinger <klebinger.andreas@gmx.at> | 2022-04-30 18:58:00 +0000 |
| commit | edb81f4ed82e6317b03a0c540e1adca194da38d7 (patch) | |
| tree | dabba413bc33b97af10857ca934299dff1cec4ab /compiler/GHC/Core | |
| parent | 5630dde68185f96da026a4e0c722fe6631633299 (diff) | |
| download | haskell-wip/andreask/deadend-fix.tar.gz | |
exprIsDeadEnd: Use isDeadEndAppSig to check if a function appliction is bottoming.wip/andreask/deadend-fix
We used to check the divergence and that the number of arguments > arity.
But arity zero represents unknown arity so this was subtly broken for a long time!
We would check if the saturated function diverges, and if we applied >=arity arguments.
But for unknown arity functions any number of arguments is >=idArity.
This fixes #21440.
Diffstat (limited to 'compiler/GHC/Core')
| -rw-r--r-- | compiler/GHC/Core/Utils.hs | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/compiler/GHC/Core/Utils.hs b/compiler/GHC/Core/Utils.hs index d6653fd387..b7b1c9334b 100644 --- a/compiler/GHC/Core/Utils.hs +++ b/compiler/GHC/Core/Utils.hs @@ -1087,7 +1087,7 @@ exprIsDeadEnd e | otherwise = go 0 e where - go n (Var v) = isDeadEndId v && n >= idArity v + go n (Var v) = isDeadEndAppSig (idDmdSig v) n go n (App e a) | isTypeArg a = go n e | otherwise = go (n+1) e go n (Tick _ e) = go n e |