Unclear error message for function getting wrong arguments

[DartBot]

This issue was originally filed by [email protected]

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Hello,

I tried out code like this, where "view.on.click" takes a function responding to mouse click events:

view.on.click = function() {
  print('clicked');
};

The above is wrong, it has to be, for example:

view.on.click = function(var event) {
  print('clicked');
};

Dartium gives the following error message:

Exception: Closure argument mismatch

It would be nice if it would say something more helpful, like "Wrong function signature, one argument of type ..... required".

[DartBot]

This comment was originally written by [email protected]

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Lode, have you tried to run this code in checked mode (http://www.dartlang.org/articles/optional-types/) ?

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[DartBot]

This comment was originally written by [email protected]

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The error is better in checked mode:

 type '() => Dynamic' is not a subtype of type '(Event) => void' of 'handler'.

So I guess we have to learn to recognize different error messages in checked and non checked mode? :)

[sethladd]

Added Usability, Triaged labels.

[iposva-google]

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[iposva-google]

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[iposva-google]

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[larsbak]

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[iposva-google]

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[iposva-google]

Removed this from the M5 milestone.

[DartBot]

This comment was originally written by @mhausner

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I think this is no longer accurate. In a similar situation calling a closure with wrong number of arguments) we now get this info in production mode (i.e. not checked mode):

NoSuchMethodError: incorrect number of arguments passed to method named 'main.<anonymous closure>'
Receiver: Closure: () => dynamic
Tried calling: main.<anonymous closure>("hello")
Found: main.<anonymous closure>()

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Added AssumedStale label.