VM fails language/prefix_core_test

[peter-ahe-google]

The VM fails this test:

import('dart:core', prefix:'core');

class Object {
}

main() => core.print(new Object());

[DartBot]

This comment was originally written by @mhausner

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The test is meaningless with the new scoping rules for imported names. The local definition for Object is shadowing the one in the core library.

Also, print is not defined in dart:core but in dart:builtin.

Removed the test.

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Set owner to @mhausner.
Added Fixed label.

[peter-ahe-google]

I wouldn't say the test is meaningless. The VM fails the test, but dart2js passes. So we have a problem.

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Added label.

[DartBot]

This comment was originally written by @mhausner

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The problem seems to be that the VM and dart2js have a different set of library names. The VM defines print() in a library called dart:builtin. If the names of the libraries must match, then this should be specified in the spec.

[peter-ahe-google]

It is already specified by the specification. See section "13.2 Imports":

"The dart core library dart:core is implicitly imported into every dart library other than itself via an import clause of the form

  import ‘dart:core’;

unless the importing library explicitly imports dart:core."

This means that dart:core is implicitly imported. Since the specification doesn't say that other libraries are imported implicitly, it means that dart:core is also the only library to be imported implicitly.

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Added Triaged label.

[iposva-google]

As comment 2 points out there is a mismatch between whether print is considered part of the core library or not. I do not recall any definite decision on this matter. I have filed issue #4806 to resolve this matter. One could argue that dart2js is the one at fault to a similar degree.

As far as I understand prefixing core for functions and classes actually defined in dart:core works.

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Added Fixed label.

[peter-ahe-google]

Please restore the test until this is resolved.

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Added Triaged label.

[andersjohnsen]

This code is now working. Should we close?

[peter-ahe-google]

We can close this issue if the test has been restored.

[iposva-google]

The original cannot be restored as it is incorrect. When implementing the latest language semantics we added language/import_core_prefix_test which is essentially the equivalent, but correct test according to the language spec.

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Added AssumedStale label.

[peter-ahe-google]

The tests are not equivalent, and there is nothing wrong with the original test (except that it uses the old library syntax which language/import_core_prefix_test also does).

In particular, language/import_core_prefix_test does not test what happens when you make a conflict with a core class, also, language/import_core_prefix_test does not test that print is available in the core library.

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Added Triaged label.

[DartBot]

This comment was originally written by @mhausner

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Updated language/import_core_prefix.dart with the test cases of the original test.
r14719.

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Added Fixed label.