Fix parsing of [[ a =~ {$var} ]]

ShellCheck/Analytics.hs

@@ -2057,6 +2057,7 @@ prop_checkUnused29= verifyNotTree checkUnusedAssignments "var=(a b); declare -p
 prop_checkUnused30= verifyTree checkUnusedAssignments "let a=1"
 prop_checkUnused31= verifyTree checkUnusedAssignments "let 'a=1'"
 prop_checkUnused32= verifyTree checkUnusedAssignments "let a=b=c; echo $a"
+prop_checkUnused33= verifyNotTree checkUnusedAssignments "a=foo; [[ foo =~ ^{$a}$ ]]"
 checkUnusedAssignments params t = execWriter (mapM_ warnFor unused)
   where
     flow = variableFlow params

ShellCheck/Parser.hs

@@ -586,8 +586,8 @@ readConditionContents single =
       where
         readGlobLiteral = do
             id <- getNextId
-            s <- many1 (extglobStart <|> oneOf "{}[]$")
-            return $ T_Literal id s
+            s <- extglobStart <|> oneOf "{}[]$"
+            return $ T_Literal id [s]
         readGroup = called "regex grouping" $ do
             id <- getNextId
             char '('