convert caseSensitiveMatchName to a plain function

Signed-off-by: Raphael Silva <[email protected]>

confmap/confmap.go

@@ -161,7 +161,7 @@ func decodeConfig(m *Conf, result interface{}, errorUnused bool) error {
 		Result:           result,
 		TagName:          "mapstructure",
 		WeaklyTypedInput: true,
-		MatchName:        caseSensitiveMatchName(),
+		MatchName:        caseSensitiveMatchName,
 		DecodeHook: mapstructure.ComposeDecodeHookFunc(
 			expandNilStructPointersHookFunc(),
 			mapstructure.StringToSliceHookFunc(","),
@@ -193,8 +193,8 @@ func encoderConfig(rawVal interface{}) *encoder.EncoderConfig {
 // case-sensitive version of the callback to be used in the MatchName property
 // of the DecoderConfig. The default for MatchEqual is to use strings.EqualFold,
 // which is case-insensitive.
-func caseSensitiveMatchName() func(a, b string) bool {
-	return func(a, b string) bool { return a == b }
+func caseSensitiveMatchName(a, b string) bool {
+	return a == b
 }
 
 // In cases where a config has a mapping of something to a struct pointers