ConstructorNamedTest fails on dartc: should have run-time error

[DartBot]

This issue was originally filed by zundel@google.com

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Currently, dartc treats this problem as a warning:

class X {
  X([a='arg1',b='arg2']) { }
}

main() {
  var x = new X('foo', a: 'bar');
}

WARNING:STATIC_TYPE:DUPLICATE_NAMED_ARGUMENT:file:/tmp/t.dart/t.dart:7:24:8: Named parameter argument already provided as positional argument
     6: main() {
     7: var x = new X('foo', a: 'bar');

10.13.2 has non-normative text about the issue saying it 'may not repeat' arguments.

[DartBot]

This comment was originally written by zundel@google.com

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After discussing with Gilad today, I think the 'warning' in the case of dartc is
correct (section 10.14.1: the declaration signature is not a supertype of function type formed by the invocation parameters.)

The error specified by 10.13.2 is a run-time error, not a compile-time error, so the static checker wouldn't catch it.

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Changed the title to: "ConstructorNamedTest fails on dartc: should have run-time error".

[DartBot]

This comment was originally written by zundel@google.com

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https://chromiumcodereview.appspot.com/9477013/

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Set owner to zundel@google.com.

[DartBot]

This comment was originally written by zundel@google.com

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Added Fixed label.