[commit: ghc] master: StgLint: Allow join point bindings of unlifted type (9afaebe)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/9afaebefe5e59c8e9632f381bee14aa84b44c955/ghc

>---------------------------------------------------------------

commit 9afaebefe5e59c8e9632f381bee14aa84b44c955
Author: Ben Gamari <bgamari.foss at gmail.com>
Date:   Tue Aug 22 08:44:47 2017 -0400

    StgLint: Allow join point bindings of unlifted type
    
    As described in `Note [CoreSyn let/app invariant]` this is allowed.
    
    Fixes #14117.
    
    Test Plan: Build GHC with BuildFlavour=devel2 with -dstg-lint
    
    Reviewers: austin, simonpj
    
    Reviewed By: simonpj
    
    Subscribers: rwbarton, thomie
    
    GHC Trac Issues: #14117
    
    Differential Revision: https://phabricator.haskell.org/D3857


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9afaebefe5e59c8e9632f381bee14aa84b44c955
 compiler/stgSyn/StgLint.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/compiler/stgSyn/StgLint.hs b/compiler/stgSyn/StgLint.hs
index cbfd11b..ad7b142 100644
--- a/compiler/stgSyn/StgLint.hs
+++ b/compiler/stgSyn/StgLint.hs
@@ -11,7 +11,7 @@ module StgLint ( lintStgTopBindings ) where
 import StgSyn
 
 import Bag              ( Bag, emptyBag, isEmptyBag, snocBag, bagToList )
-import Id               ( Id, idType, isLocalId )
+import Id               ( Id, idType, isLocalId, isJoinId )
 import VarSet
 import DataCon
 import CoreSyn          ( AltCon(..) )
@@ -108,7 +108,7 @@ lint_binds_help (binder, rhs)
         _maybe_rhs_ty <- lintStgRhs rhs
 
         -- Check binder doesn't have unlifted type
-        checkL (not (isUnliftedType binder_ty))
+        checkL (isJoinId binder || not (isUnliftedType binder_ty))
                (mkUnliftedTyMsg binder rhs)
 
         -- Check match to RHS type