type_coerce not working with _make_proxy

[Mike Bayer]

this affects 0.8 and 0.7, but for the moment I'd like to keep this in 0.8 only. I don't think type_coerce() is in widespread use yet.

class MyType(TypeDecorator):
    impl = Integer

stmt = select([MyType).label('foo')](type_coerce(column('x'),))
stmt2 = stmt.select()
assert isinstance(stmt._raw_columns[0](0).type, MyType)
assert isinstance(stmt.c.foo.type, MyType)
assert isinstance(stmt2.c.foo.type, MyType)

[Mike Bayer]

this is in 6397a4ff4bce537487a3b30552622544868da9a0. the forced type change in Label is a little dramatic, should be OK though.

[Mike Bayer]

Removing milestone: 0.8.0final (automated comment)