In checked mode, void should allow any value.

[floitschG]

In checked mode, void should allow any value.

• spec Spec: In checked mode, void should allow any value. #28936
• dart2js dart2js: In checked mode, void should allow any value. #28937
• VM VM: In checked mode, void should allow any value. #28938

[mit-mit]

Punting to 1.24 per dart-leads discussion.

[eernstg]

Punting to 1.25, in agreement with Kasper: The spec part was moved to 1.25 and this meta issue awaits that.

[sgrekhov]

What about analyzer, guys? Now, it doesn't support this feature

void foo() {
  String s = "foo";
  return s;
}

main() {
  foo();
}

In a nostrong mode it produces:
warning - The return type 'String' isn't a 'void', as defined by the method 'foo'
In a strong mode:
error - The return type 'String' isn't a 'void', as defined by the method 'foo'

dartanalyzer version 1.24.0-dev.4.2

[eernstg]

What about analyzer..

The changes to the static analysis related to this issue is issue #28940, part of #28939, and it was landed last week. Here's the 1.24.0-dev.2.0 versus most recent commit behavior:

> dartanalyzer tests/language/void_arrow_return_test.dart
Analyzing tests/language/void_arrow_return_test.dart...
  warning • The return type 'int' isn't a 'void', as defined by the method 'foo' at tests/language/void_arrow_return_test.dart:7:15 • return_of_invalid_type
1 warning found.
> out/ReleaseX64/dart-sdk/bin/dartanalyzer tests/language/void_arrow_return_test.dart
Analyzing tests/language/void_arrow_return_test.dart...
No issues found!
> git sha1
d91f228766a2c1708bec8f62bbe2756e4a529f5e

So the only reason why you don't see it yet is that it is still in the release pipeline.

But there are no plans to allow the example that you gave: It is dynamically allowed to return any value from a void function, but only => functions get a more permissive static analysis.

[eernstg]

All done, closing.