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| author | Bartosz Nitka <niteria@gmail.com> | 2016-05-24 02:56:59 -0700 |
|---|---|---|
| committer | Bartosz Nitka <niteria@gmail.com> | 2016-05-24 04:33:21 -0700 |
| commit | 4c6e69d58a300d6ef440d326a3fd29b58b284fa1 (patch) | |
| tree | 6653f56c150c3aa988a96c50359d53f27f2edb01 /compiler/specialise/Rules.hs | |
| parent | 8f7d01632cd79957fe42ea37103ca9b91a1c54f5 (diff) | |
| download | haskell-4c6e69d58a300d6ef440d326a3fd29b58b284fa1.tar.gz | |
Document some benign nondeterminism
I've changed the functions to their nonDet equivalents and explained
why they're OK there. This allowed me to remove foldNameSet,
foldVarEnv, foldVarEnv_Directly, foldVarSet and foldUFM_Directly.
Test Plan: ./validate, there should be no change in behavior
Reviewers: simonpj, simonmar, austin, goldfire, bgamari
Reviewed By: bgamari
Subscribers: thomie
Differential Revision: https://phabricator.haskell.org/D2244
GHC Trac Issues: #4012
Diffstat (limited to 'compiler/specialise/Rules.hs')
| -rw-r--r-- | compiler/specialise/Rules.hs | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/compiler/specialise/Rules.hs b/compiler/specialise/Rules.hs index aebfbc744e..e11de97902 100644 --- a/compiler/specialise/Rules.hs +++ b/compiler/specialise/Rules.hs @@ -568,7 +568,9 @@ matchN (in_scope, id_unf) rule_name tmpl_vars tmpl_es target_es kind = Type.substTy (mkTCvSubst in_scope (tv_subst, cv_subst)) (tyVarKind tmpl_var) - to_co_env env = foldVarEnv_Directly to_co emptyVarEnv env + to_co_env env = nonDetFoldUFM_Directly to_co emptyVarEnv env + -- It's OK to use nonDetFoldUFM_Directly because we forget the + -- order immediately by creating a new env to_co uniq expr env | Just co <- exprToCoercion_maybe expr = extendVarEnv_Directly env uniq co |