dartium library uses _ as first character in some named argument parameter names

[DartBot]

This issue was originally filed by zundel@google.com

---

Ran into this problem when adding the check specified in spec v 0.10 section 6.2:

"It is a compile-time error if the name of a named optional parameter begins with an character."

ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40520|3|78|Named parameters cannot start with an '_' character
 40519: _F64(buffer, byteOffset, length);
 40520: static _F64(_arg0, [_arg1, _arg2]) native "Float64Array_constructor_Callback";
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[DartBot]

This comment was originally written by zundel@google.com

---

There are multiple methods causing this problem, here is the full output

stderr:
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40513|23|5|Named parameters cannot start with an '_' character
 40512: _F32(buffer, byteOffset, length);
 40513: static _F32(_arg0, [_arg1, arg2]) native "Float32Array_constructor_Callback";
                              ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40513|30|5|Named parameters cannot start with an '' character
 40512: _F32(buffer, byteOffset, length);
 40513: static _F32(_arg0, [_arg1, arg2]) native "Float32Array_constructor_Callback";
                                     ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40520|23|5|Named parameters cannot start with an '' character
 40519: _F64(buffer, byteOffset, length);
 40520: static _F64(_arg0, [_arg1, arg2]) native "Float64Array_constructor_Callback";
                              ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40520|30|5|Named parameters cannot start with an '' character
 40519: _F64(buffer, byteOffset, length);
 40520: static _F64(_arg0, [_arg1, arg2]) native "Float64Array_constructor_Callback";
                                     ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40527|22|5|Named parameters cannot start with an '' character
 40526: _I8(buffer, byteOffset, length);
 40527: static _I8(_arg0, [_arg1, arg2]) native "Int8Array_constructor_Callback";
                             ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40527|29|5|Named parameters cannot start with an '' character
 40526: _I8(buffer, byteOffset, length);
 40527: static _I8(_arg0, [_arg1, arg2]) native "Int8Array_constructor_Callback";
                                    ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40534|23|5|Named parameters cannot start with an '' character
 40533: _I16(buffer, byteOffset, length);
 40534: static _I16(_arg0, [_arg1, arg2]) native "Int16Array_constructor_Callback";
                              ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40534|30|5|Named parameters cannot start with an '' character
 40533: _I16(buffer, byteOffset, length);
 40534: static _I16(_arg0, [_arg1, arg2]) native "Int16Array_constructor_Callback";
                                     ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40541|23|5|Named parameters cannot start with an '' character
 40540: _I32(buffer, byteOffset, length);
 40541: static _I32(_arg0, [_arg1, arg2]) native "Int32Array_constructor_Callback";
                              ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40541|30|5|Named parameters cannot start with an '' character
 40540: _I32(buffer, byteOffset, length);
 40541: static _I32(_arg0, [_arg1, arg2]) native "Int32Array_constructor_Callback";
                                     ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40548|22|5|Named parameters cannot start with an '' character
 40547: _U8(buffer, byteOffset, length);
 40548: static _U8(_arg0, [_arg1, arg2]) native "Uint8Array_constructor_Callback";
                             ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40548|29|5|Named parameters cannot start with an '' character
 40547: _U8(buffer, byteOffset, length);
 40548: static _U8(_arg0, [_arg1, arg2]) native "Uint8Array_constructor_Callback";
                                    ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40555|23|5|Named parameters cannot start with an '' character
 40554: _U16(buffer, byteOffset, length);
 40555: static _U16(_arg0, [_arg1, arg2]) native "Uint16Array_constructor_Callback";
                              ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40555|30|5|Named parameters cannot start with an '' character
 40554: _U16(buffer, byteOffset, length);
 40555: static _U16(_arg0, [_arg1, arg2]) native "Uint16Array_constructor_Callback";
                                     ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40562|23|5|Named parameters cannot start with an '' character
 40561: _U32(buffer, byteOffset, length);
 40562: static _U32(_arg0, [_arg1, arg2]) native "Uint32Array_constructor_Callback";
                              ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40562|30|5|Named parameters cannot start with an '' character
 40561: _U32(buffer, byteOffset, length);
 40562: static _U32(_arg0, [_arg1, arg2]) native "Uint32Array_constructor_Callback";
                                     ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40569|23|5|Named parameters cannot start with an '' character
 40568: _U8C(buffer, byteOffset, length);
 40569: static _U8C(_arg0, [_arg1, arg2]) native "Uint8ClampedArray_constructor_Callback";
                              ~~~~~
ERROR|RESOLVER|NAMED_PARAMETERS_CANNOT_START_WITH_UNDER|dart://html/html_dartium.dart/html_dartium.dart|40569|30|5|Named parameters cannot start with an '' character
 40568: _U8C(buffer, byteOffset, length);
 40569: static _U8C(_arg0, [_arg1, _arg2]) native "Uint8ClampedArray_constructor_Callback";
                                     ~~~~~
Compilation failed with 18 problems.

[vsmenon]

cc @rakudrama.
Removed Area-UI label.
Added Area-DOM label.

[vsmenon]

https://chromiumcodereview.appspot.com/10543115/

---

Set owner to @vsmenon.
Added Started label.

[DartBot]

This comment was originally written by antonm@google.com

---

I believe that was a deliberate decision as we didn't want to expose names of arguments into public API.

And I believe as well that there was a plan to allow _-prefixed named arguments.

Gilad, Kasper, any comments?

---

cc @gbracha.
cc @kasperl.

[gbracha]

The discussion about this has gone back and forth many times. The spec explains the problems allowing this would cause. There is a plan to allow unnamed optional arguments which should mitigate the pain.

[DartBot]

This comment was originally written by antonm@google.com

---

Thanks a lot for clarifications, Gilad. What do you all think, is now the right time to get rid of _ perfices or we'd better wait for unnamed optional arguments?

I think chances are really low that someone will use named argument and we're still in alpha so it's okay to change that at our will, but I'd prefer to have this decided before M1.

[vsmenon]

Anton: in the case Eric reported, the '_' prefixes were only in private static methods, so I went ahead and removed them.

Are we still using this trick to hide params in public APIs?

[gbracha]

The positional optional argument proposal will be decided in a week or two I'm sure. I had suggested to Erik he might want to wait, but he said he'd be ok with fixing all the occurrences right now. If that is not too onerous, that's best. Cases that turn out to be difficult could wait. It will all be done by M1.

[DartBot]

This comment was originally written by antonm@google.com

---

Vijay@, looks like you're right, somehow they have disappeared and I missed that :(

Gilad@, thanks for clarifications.

[vsmenon]

Added Fixed label.