Report error on duplicate supertypes

Report error on duplicate supertypes

Report error if the same type appears more than once in the implements
or extends list.
Committed: https://code.google.com/p/dart/source/detail?r=3403

[hausner, 2012-01-18 01:06:16]

Thanks!

http://codereview.chromium.org/9252001/diff/1/runtime/vm/parser.cc
File runtime/vm/parser.cc (right):

http://codereview.chromium.org/9252001/diff/1/runtime/vm/parser.cc#newcode2995
runtime/vm/parser.cc:2995: if (interface_name.Equals(other_name)) {
I tried to use Equals on the type object directly, but ran into asserts because
the types may be not finalized when we run this code. Any better idea to check
whether two types are identical?

[regis, 2012-01-18 01:29:40]

http://codereview.chromium.org/9252001/diff/1/runtime/vm/parser.cc
File runtime/vm/parser.cc (right):

http://codereview.chromium.org/9252001/diff/1/runtime/vm/parser.cc#newcode2995
runtime/vm/parser.cc:2995: if (interface_name.Equals(other_name)) {
On 2012/01/18 01:06:16, hausner wrote:
> I tried to use Equals on the type object directly, but ran into asserts
because
> the types may be not finalized when we run this code. Any better idea to check
> whether two types are identical?

Using the name seems brittle. How about using AbstractType::Equals() in the
class finalizer? See the code finalizing interfaces around line 1030 in
class_finalizer.cc.

[hausner, 2012-01-18 17:44:00]

Given the discussion we had, can you bless this CL?

http://codereview.chromium.org/9252001/diff/1/runtime/vm/parser.cc
File runtime/vm/parser.cc (right):

http://codereview.chromium.org/9252001/diff/1/runtime/vm/parser.cc#newcode2995
runtime/vm/parser.cc:2995: if (interface_name.Equals(other_name)) {
On 2012/01/18 01:29:40, regis wrote:
> On 2012/01/18 01:06:16, hausner wrote:
> > I tried to use Equals on the type object directly, but ran into asserts
> because
> > the types may be not finalized when we run this code. Any better idea to
check
> > whether two types are identical?
> 
> Using the name seems brittle. How about using AbstractType::Equals() in the
> class finalizer? See the code finalizing interfaces around line 1030 in
> class_finalizer.cc.
>  

As discussed in person: doing the check in the finalizer does not work, since
the implements lists of the whole class hierarchy is flattened into one list.
However, we only need to find duplicate interfaces per implements clause.

I think we can get away with comparing type names for this, at least as long as
we don't have arbitrary type aliases.

[regis, 2012-01-18 17:44:42]

LGTM