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

3 files changed, 11 insertions, 1 deletions

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