Specify FutureOr.

Specify FutureOr.

R=eernst@google.com, floitsch@google.com

Committed: https://github.com/dart-lang/sdk/commit/c41ae1571338e331e04f652bab45cf66c58700db

[Lasse Reichstein Nielsen, 2017-01-31 18:38:03]

lrn@google.com changed reviewers:
+ eernst@google.com, floitsch@google.com

[floitsch, 2017-01-31 18:49:16]

LGTM!!

[eernst, 2017-02-01 16:54:30]

LGTM, with just a small remark about the treatment of entities of kind `* -> *`
(first-order type level functions) as opposed to kind `*` (types).

https://codereview.chromium.org/2664263002/diff/1/docs/language/dartLangSpec.tex
File docs/language/dartLangSpec.tex (right):

https://codereview.chromium.org/2664263002/diff/1/docs/language/dartLangSpec....
docs/language/dartLangSpec.tex:30: % - Specified the FutureOf type.
`FutureOr`. Also, it seems to be the standard style to use double quotes around
literal source code, which makes it `"FutureOr"`.

https://codereview.chromium.org/2664263002/diff/1/docs/language/dartLangSpec....
docs/language/dartLangSpec.tex:7667: The name \code{FutureOr} denotes the same
\cd{Type} object as \DYNAMIC{}.
This raises the question: So what's the semantics of applying `\code{FutureOr}`
to a list of type arguments? I'd say that we always do this (either the
arguments are provide explicitly, or the compiler adds them), and the type
arguments are ignored (it's like the constant type level function (x) =>
dynamic). With that, `\code{FutureOr<T>}` evaluated as an expression denotes the
same type object as `\DYNAMIC{}` for all `T`.

Or do we want to make it a semantic primitive that a generic class can be
evaluated to a type "when needed", without passing any arguments? I think that
would be more confusing and more complex to handle.

[Lasse Reichstein Nielsen, 2017-02-02 06:45:47]

https://codereview.chromium.org/2664263002/diff/1/docs/language/dartLangSpec.tex
File docs/language/dartLangSpec.tex (right):

https://codereview.chromium.org/2664263002/diff/1/docs/language/dartLangSpec....
docs/language/dartLangSpec.tex:7667: The name \code{FutureOr} denotes the same
\cd{Type} object as \DYNAMIC{}.
I'm not sure what this is suggesting.
You can't evaluate `FutureOr<T>` as an expression, type literals don't take type
parameters at all.

[Lasse Reichstein Nielsen, 2017-02-03 07:02:50]

Description was changed from

==========
Specify FutureOr.
==========

to

==========
Specify FutureOr.

R=eernst@google.com, floitsch@google.com

Committed:
https://github.com/dart-lang/sdk/commit/c41ae1571338e331e04f652bab45cf66c58700db
==========

[Lasse Reichstein Nielsen, 2017-02-03 07:02:51]

Committed patchset #1 (id:1) manually as
c41ae1571338e331e04f652bab45cf66c58700db (presubmit successful).