Add a changelog entry for the function-type syntax.
Fixes #27527
BUG= http://dartbug.com/27527
R=leafp@google.com
Review-Url: https://codereview.chromium.org/2906453002 .
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8031041..7b8a311 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,30 @@
type `void` now allows the returned expression to have any type. For example,
assuming the declaration `int x;`, it is now type correct to have
`void f() => ++x;`.
+* A new function-type syntax has been added to the language.
+ Intuitively, the type of a function can be constructed by textually replacing
+ the function's name with `Function` in its declaration. For instance, the
+ type of `void foo() {}` would be `void Function()`. The new syntax may be used
+ wherever a type can be written. It is thus now possible to declare fields
+ containing functions without needing to write typedefs: `void Function() x;`.
+ The new function type has one restriction: it may not contain the old-style
+ function-type syntax for its parameters. The following is thus
+ illegal: `void Function(int f())`.
+ `typedefs` have been updated to support this new syntax.
+ Examples:
+ ```
+ typedef F = void Function(); // F is the name for a `void` callback.
+ int Function(int) f; // A field `f` that contains an int->int function.
+
+ class A<T> {
+ // The parameter `callback` is a function that takes a `T` and returns
+ // `void`.
+ void forEach(void Function(T) callback);
+ }
+
+ // The new function type supports generic arguments.
+ typedef Invoker = T Function<T>(T Function() callback);
+ ```
#### Strong Mode
@@ -24,6 +48,7 @@
* The following is also a change in strong mode: During static analysis, a
function or setter declared using `=>` with return type `void` now allows the
returned expression to have any type.
+* The new function-type syntax is also supported by strong mode.
### Core library changes
