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Remove expression statement restriction from dot shorthands spec #4745

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Remove expression statement restriction from dot shorthands spec #4745

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21 changes: 8 additions & 13 deletions accepted/3.10/dot-shorthands/feature-specification.md
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ Author: lrn@google.com

Status: Accepted

Version: 1.4.1 (2025-04-02)
Version: 1.4.2 (2026-08-11)

Experiment Flag: dot-shorthands

Expand Down Expand Up @@ -54,11 +54,6 @@ We introduce grammar productions of the form:
| 'const' '.' (<identifier> | 'new') <arguments> -- shorthand for constant object creation
```

We also add `.` to the tokens that an expression statement cannot start with. This doesn't
affect starting with a double literal like `.42`, since that's a different token than a single `.`.
_(Not sure this is *necessary*, but it will possibly make parser recovery easier/
So mainly disallow this as an abundance of caution.)_

That means you can write things like the following (with the intended meaning as
comments, specification to achieve that below):

Expand Down Expand Up @@ -92,6 +87,9 @@ Future futures = .wait<int>([.value(1), .value(2)]);

// -> Future<List<String>>.wait([lazyString(), lazyString()]).then<String>((list) => list.join())
Future<String> futures = .wait([lazyString(), lazyString()]).then((list) => list.join());

// -> bool.parse(userInput) || (throw Exception('Not true!'));
.parse(userInput) || (throw Exception('Not true!'));
```

This is a simple grammatical change. It allows new constructs in any place where
Expand Down Expand Up @@ -122,13 +120,6 @@ new rules are needed.

Therefore the new productions introduces no new grammatical ambiguities.

We prevent expression statements from starting with `.` mainly out of caution.
_(It's an unlikely expression that can start with a static member, it requires something
that adds a context type on the left, `.parse(userInput) || (throw "Not true!")`
or similar, which isn't particularly *useful*._
_If we ever allow metadata on statements, we don’t want `@foo . bar(4);`
to be ambiguous. If we ever allow metadata on expressions, we have bigger issues.)_

A postfix expression expression *can* follow a `?` in a conditional expression, as in
`{e1 ? . id : e2}`. This is not ambiguous with `e1?.id` since we parse `?.` as a
single token, and will keep doing so. It does mean that `{e1?.id:e2}` and
Expand Down Expand Up @@ -717,6 +708,10 @@ not members of `Future`. Primarily to allow people to return values from

## Versions

1.4.2 (2026-08-11): Remove the restriction preventing a static member shorthand
from beginning an expression statement, matching the existing implementations
([dart-lang/sdk#64009](https://github.com/dart-lang/sdk/issues/64009)).

1.4.1 (2025-04-02): Fix phrasing to avoid using "raw type" where it means
"uninstantiated type declaration reference".

Expand Down