[commit: ghc] ghc-8.2: Account for IfUnpackCo in freeNamesIfDecl (1e93425)

[git at git.haskell.org]

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

On branch  : ghc-8.2
Link       : http://ghc.haskell.org/trac/ghc/changeset/1e93425ee78481f10f79cb1d39b6cd4f11f38e5d/ghc

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

commit 1e93425ee78481f10f79cb1d39b6cd4f11f38e5d
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Fri May 19 12:00:26 2017 +0100

    Account for IfUnpackCo in freeNamesIfDecl
    
    We were simply failing to recognise all the free variables of an
    IfaceDecl, notably the ones in the coercion of an IfUnpackCo.
    Result: the dependency analysis got messed up, so that fingerprint
    calculation went wrong.  Trac #13695 showed it up.
    
    A test case is tricky but the fix is a solid one.
    
    (cherry picked from commit 8fe37a0222517c3af5ffbb793fa738ad7f3eac3d)


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

1e93425ee78481f10f79cb1d39b6cd4f11f38e5d
 compiler/iface/IfaceSyn.hs | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/compiler/iface/IfaceSyn.hs b/compiler/iface/IfaceSyn.hs
index 5db8c99..6f8fcf4 100644
--- a/compiler/iface/IfaceSyn.hs
+++ b/compiler/iface/IfaceSyn.hs
@@ -1345,12 +1345,21 @@ freeNamesIfConDecls (IfNewTyCon  c) = freeNamesIfConDecl c
 freeNamesIfConDecls _                   = emptyNameSet
 
 freeNamesIfConDecl :: IfaceConDecl -> NameSet
-freeNamesIfConDecl c
-  = freeNamesIfTyVarBndrs (ifConExTvs c) &&&
-    freeNamesIfContext (ifConCtxt c) &&&
-    fnList freeNamesIfType (ifConArgTys c) &&&
-    mkNameSet (map flSelector (ifConFields c)) &&&
-    fnList freeNamesIfType (map snd (ifConEqSpec c)) -- equality constraints
+freeNamesIfConDecl (IfCon { ifConExTvs   = ex_tvs, ifConCtxt = ctxt
+                          , ifConArgTys  = arg_tys
+                          , ifConFields  = flds
+                          , ifConEqSpec  = eq_spec
+                          , ifConStricts = bangs })
+  = freeNamesIfTyVarBndrs ex_tvs &&&
+    freeNamesIfContext ctxt &&&
+    fnList freeNamesIfType arg_tys &&&
+    mkNameSet (map flSelector flds) &&&
+    fnList freeNamesIfType (map snd eq_spec) &&& -- equality constraints
+    fnList freeNamesIfBang bangs
+
+freeNamesIfBang :: IfaceBang -> NameSet
+freeNamesIfBang (IfUnpackCo co) = freeNamesIfCoercion co
+freeNamesIfBang _               = emptyNameSet
 
 freeNamesIfKind :: IfaceType -> NameSet
 freeNamesIfKind = freeNamesIfType