From 8262c954ac3084f0dfcb6d5fa6e6172afd22eae7 Mon Sep 17 00:00:00 2001
From: Thomas Miedema <thomasmiedema@gmail.com>
Date: Sun, 8 Nov 2015 00:20:15 +0100
Subject: [PATCH] Parser: allow empty multi-line deprecation warnings

This should work,

    {-# DEPRECATED someFunction [] #-}

Test Plan: parser/should_compile/T3303

Reviewers: bgamari, austin

Reviewed By: austin

Subscribers: mpickering

Differential Revision: https://phabricator.haskell.org/D1433

GHC Trac Issues: #11044
---
 compiler/parser/Parser.y                           | 1 +
 testsuite/tests/parser/should_compile/T3303.hs     | 2 ++
 testsuite/tests/parser/should_compile/T3303.stderr | 5 ++++-
 testsuite/tests/parser/should_compile/T3303A.hs    | 5 +++++
 4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/compiler/parser/Parser.y b/compiler/parser/Parser.y
index 62d1114ae4..d72f50d871 100644
--- a/compiler/parser/Parser.y
+++ b/compiler/parser/Parser.y
@@ -1422,6 +1422,7 @@ stringlist :: { Located (OrdList (Located StringLiteral)) }
                                return (sLL $1 $> (unLoc $1 `snocOL`
                                                   (L (gl $3) (getStringLiteral $3)))) }
     | STRING                { sLL $1 $> (unitOL (L (gl $1) (getStringLiteral $1))) }
+    | {- empty -}           { noLoc nilOL }
 
 -----------------------------------------------------------------------------
 -- Annotations
diff --git a/testsuite/tests/parser/should_compile/T3303.hs b/testsuite/tests/parser/should_compile/T3303.hs
index 08de52e6cd..7d9bfbd640 100644
--- a/testsuite/tests/parser/should_compile/T3303.hs
+++ b/testsuite/tests/parser/should_compile/T3303.hs
@@ -6,3 +6,5 @@ import T3303A
 bar :: Int
 bar = foo
 
+bar2 :: Int
+bar2 = foo2
diff --git a/testsuite/tests/parser/should_compile/T3303.stderr b/testsuite/tests/parser/should_compile/T3303.stderr
index df227f47ef..a8d2f631cf 100644
--- a/testsuite/tests/parser/should_compile/T3303.stderr
+++ b/testsuite/tests/parser/should_compile/T3303.stderr
@@ -1,6 +1,9 @@
 
-T3303.hs:7:7: Warning:
+T3303.hs:7:7: warning:
     In the use of ‘foo’ (imported from T3303A):
     Deprecated: "This is a multi-line
                  deprecation message
                  for foo"
+
+T3303.hs:10:8: warning:
+    In the use of ‘foo2’ (imported from T3303A): Deprecated: ""
diff --git a/testsuite/tests/parser/should_compile/T3303A.hs b/testsuite/tests/parser/should_compile/T3303A.hs
index daa4bfb91d..07a2eb8503 100644
--- a/testsuite/tests/parser/should_compile/T3303A.hs
+++ b/testsuite/tests/parser/should_compile/T3303A.hs
@@ -8,3 +8,8 @@ module T3303A where
 foo :: Int
 foo = 4
 
+-- Empty list should work too (#11044).
+{-# DEPRECATED foo2 [] #-}
+
+foo2 :: Int
+foo2 = 4
-- 
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