From 76b798394f18307677b44e231d6922db251955be Mon Sep 17 00:00:00 2001
From: "Joseph C. Sible" <josephcsible@users.noreply.github.com>
Date: Sat, 1 Feb 2020 23:07:16 -0500
Subject: [PATCH] Use case matching instead of null

Using null followed by a head, tail, or a partial pattern match is
an anti-pattern. Use case matching instead.
---
 src/ShellCheck/Parser.hs | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/ShellCheck/Parser.hs b/src/ShellCheck/Parser.hs
index 727572d..025fa98 100644
--- a/src/ShellCheck/Parser.hs
+++ b/src/ShellCheck/Parser.hs
@@ -329,12 +329,11 @@ getCurrentContexts = Ms.gets contextStack
 
 popContext = do
     v <- getCurrentContexts
-    if not $ null v
-        then do
-            let (a:r) = v
+    case v of
+        (a:r) -> do
             setCurrentContexts r
             return $ Just a
-        else
+        [] ->
             return Nothing
 
 pushContext c = do