Recognize `read -ra foo` as arrays (fixes #1636)

src/ShellCheck/Analytics.hs

@@ -840,6 +840,7 @@ prop_checkArrayWithoutIndex6 = verifyTree checkArrayWithoutIndex "echo $PIPESTAT
 prop_checkArrayWithoutIndex7 = verifyTree checkArrayWithoutIndex "a=(a b); a+=c"
 prop_checkArrayWithoutIndex8 = verifyTree checkArrayWithoutIndex "declare -a foo; foo=bar;"
 prop_checkArrayWithoutIndex9 = verifyTree checkArrayWithoutIndex "read -r -a arr <<< 'foo bar'; echo \"$arr\""
+prop_checkArrayWithoutIndex10= verifyTree checkArrayWithoutIndex "read -ra arr <<< 'foo bar'; echo \"$arr\""
 checkArrayWithoutIndex params _ =
     doVariableFlowAnalysis readF writeF defaultMap (variableFlow params)
   where

src/ShellCheck/AnalyzerLib.hs

@@ -676,9 +676,16 @@ getModifiedVariableCommand base@(T_SimpleCommand _ _ (T_NormalWord _ (T_Literal
         return (base, lastArg, name, DataArray SourceExternal)
 
     -- get all the array variables used in read, e.g. read -a arr
-    getReadArrayVariables args = do
+    getReadArrayVariables args =
         map (getLiteralArray . snd)
-            (filter (\(x,_) -> getLiteralString x == Just "-a") (zip (args) (tail args)))
+            (filter (isArrayFlag . fst) (zip args (tail args)))
+
+    isArrayFlag x = fromMaybe False $ do
+        str <- getLiteralString x
+        return $ case str of
+                    '-':'-':_ -> False
+                    '-':str -> 'a' `elem` str
+                    _ -> False
 
     -- get the FLAGS_ variable created by a shflags DEFINE_ call
     getFlagVariable (n:v:_) = do