Skip command argument when checking trap signal specs (#946)

ShellCheck/ASTLib.hs

@@ -119,6 +119,11 @@ getLeadingFlags = getFlagsUntil (\x -> x == "--" || (not $ "-" `isPrefixOf` x))
 -- Check if a command has a flag.
 hasFlag cmd str = str `elem` (map snd $ getAllFlags cmd)
 
+-- Is this token a word that starts with a dash?
+isFlag token =
+    case getWordParts token of
+        T_Literal _ ('-':_) : _ -> True
+        _ -> False
 
 -- Given a T_DollarBraced, return a simplified version of the string contents.
 bracedString (T_DollarBraced _ l) = concat $ oversimplify l

ShellCheck/Checks/Commands.hs

@@ -415,9 +415,13 @@ prop_checkNonportableSignals3 = verifyNot checkNonportableSignals "trap f 14"
 prop_checkNonportableSignals4 = verify checkNonportableSignals "trap f SIGKILL"
 prop_checkNonportableSignals5 = verify checkNonportableSignals "trap f 9"
 prop_checkNonportableSignals6 = verify checkNonportableSignals "trap f stop"
+prop_checkNonportableSignals7 = verifyNot checkNonportableSignals "trap 'stop' int"
 checkNonportableSignals = CommandCheck (Exactly "trap") (f . arguments)
   where
-    f = mapM_ check
+    f args = case args of
+        first:rest -> unless (isFlag first) $ mapM_ check rest
+        _ -> return ()
+
     check param = potentially $ do
         str <- getLiteralString param
         let id = getId param