diff --git a/src/ShellCheck/Parser.hs b/src/ShellCheck/Parser.hs
index 17107ba..d884a7b 100644
--- a/src/ShellCheck/Parser.hs
+++ b/src/ShellCheck/Parser.hs
@@ -70,8 +70,10 @@ variableChars = upper <|> lower <|> digit <|> oneOf "_"
 functionStartChars = variableChars <|> oneOf ":+?-./^@,"
 -- Chars to allow inside function names
 functionChars = variableChars <|> oneOf "#:+?-./^@,"
+-- Chars to allow function names to start with, using the 'function' keyword
+extendedFunctionStartChars = functionStartChars <|> oneOf "[]*=!"
 -- Chars to allow in functions using the 'function' keyword
-extendedFunctionChars = functionChars <|> oneOf "[]*=!"
+extendedFunctionChars = extendedFunctionStartChars <|> oneOf "[]*=!"
 specialVariable = oneOf (concat specialVariables)
 paramSubSpecialChars = oneOf "/:+-=%"
 quotableChars = "|&;<>()\\ '\t\n\r\xA0" ++ doubleQuotableChars
@@ -2770,7 +2772,7 @@ readFunctionDefinition = called "function" $ do
                 string "function"
                 whitespace
             spacing
-            name <- (:) <$> functionStartChars <*> many extendedFunctionChars
+            name <- (:) <$> extendedFunctionStartChars <*> many extendedFunctionChars
             spaces <- spacing
             hasParens <- wasIncluded readParens
             when (not hasParens && null spaces) $