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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2016-06-23 08:47:31 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2016-06-23 09:22:53 +0100 |
| commit | 3e0af469c97d34bea92032d54d155afc65bd4b20 (patch) | |
| tree | 63548506546b50bf1af78d82ba92340d77d42510 /compiler/rename/RnNames.hs | |
| parent | 210a2e122ce3b7c56c780e4541b9f222abe7d2f7 (diff) | |
| download | haskell-3e0af469c97d34bea92032d54d155afc65bd4b20.tar.gz | |
Give lookupGRE_Name a better API
lookupGRE_Name should return either zero or one GREs, never
several. This is a consequence of INVARIANT 1 on GlobalRdrEnv.
So it's better if it returns a Maybe; the panic on multiple results
is put in one place, instead of being scattered or ignored.
Just refactoring, no change in behaviour
Diffstat (limited to 'compiler/rename/RnNames.hs')
| -rw-r--r-- | compiler/rename/RnNames.hs | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/compiler/rename/RnNames.hs b/compiler/rename/RnNames.hs index 2fc62637e8..3803f58da6 100644 --- a/compiler/rename/RnNames.hs +++ b/compiler/rename/RnNames.hs @@ -1973,8 +1973,8 @@ exportClashErr global_env name1 name2 ie1 ie2 -- get_gre finds a GRE for the Name, so that we can show its provenance get_gre name = case lookupGRE_Name global_env name of - (gre:_) -> gre - [] -> pprPanic "exportClashErr" (ppr name) + Just gre -> gre + Nothing -> pprPanic "exportClashErr" (ppr name) get_loc name = greSrcSpan (get_gre name) (name1', ie1', name2', ie2') = if get_loc name1 < get_loc name2 then (name1, ie1, name2, ie2) |