From 8a0fca09565df99474568888253415f9bbe0fb68 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=96mer=20Sinan=20A=C4=9Facan?= <omeragacan@gmail.com>
Date: Mon, 24 Dec 2018 15:02:27 +0300
Subject: Simplify Core output with -dsuppress-type-signatures

Currently we duplicate top-level binder ids for no reason:

    $fEqHsExpr_$c/=
    $fEqHsExpr_$c/=
      = \ @ id_a27U $dEq_a27V eta_B2 eta1_B1 ->
          case $fEqHsExpr_$c== $dEq_a27V eta_B2 eta1_B1 of {
            False -> True;
            True -> False
          }

with this patch we drop the first line when type signatures are not
printed (-dsuppress-type-signatures, which is implied by -dsuppress-all)

Reviewers: simonpj, bgamari

Reviewed By: simonpj

Subscribers: rwbarton, carter

Differential Revision: https://phabricator.haskell.org/D5472
---
 compiler/coreSyn/PprCore.hs                                   | 8 +++++++-
 testsuite/tests/simplCore/should_compile/T16038/T16038.stdout | 3 ---
 testsuite/tests/simplCore/should_compile/T5996.stdout         | 1 -
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/compiler/coreSyn/PprCore.hs b/compiler/coreSyn/PprCore.hs
index f22d803cb1..5fe033b862 100644
--- a/compiler/coreSyn/PprCore.hs
+++ b/compiler/coreSyn/PprCore.hs
@@ -115,7 +115,13 @@ ppr_bind ann (Rec binds)           = vcat (map pp binds)
 
 ppr_binding :: OutputableBndr b => Annotation b -> (b, Expr b) -> SDoc
 ppr_binding ann (val_bdr, expr)
-  = ann expr $$ pprBndr LetBind val_bdr $$ pp_bind
+  = sdocWithDynFlags $ \dflags ->
+      vcat [ ann expr
+           , if gopt Opt_SuppressTypeSignatures dflags
+               then empty
+               else pprBndr LetBind val_bdr
+           , pp_bind
+           ]
   where
     pp_bind = case bndrIsJoin_maybe val_bdr of
                 Nothing -> pp_normal_bind
diff --git a/testsuite/tests/simplCore/should_compile/T16038/T16038.stdout b/testsuite/tests/simplCore/should_compile/T16038/T16038.stdout
index f52fd1b79c..eec60ece9c 100644
--- a/testsuite/tests/simplCore/should_compile/T16038/T16038.stdout
+++ b/testsuite/tests/simplCore/should_compile/T16038/T16038.stdout
@@ -1,8 +1,5 @@
 Rec {
 $fEqHsExpr_$c/=
-$fEqHsExpr_$c/=
-$fEqHsExpr
 $fEqHsExpr
 $fEqHsExpr_$c==
-$fEqHsExpr_$c==
 end Rec }
diff --git a/testsuite/tests/simplCore/should_compile/T5996.stdout b/testsuite/tests/simplCore/should_compile/T5996.stdout
index b8a3398c16..e56cd1f491 100644
--- a/testsuite/tests/simplCore/should_compile/T5996.stdout
+++ b/testsuite/tests/simplCore/should_compile/T5996.stdout
@@ -1,2 +1 @@
-y2
 y2 = x2
-- 
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