6ce8d74761
Serializing Let.fileOffset supports positions in stacktraces resulting from null aware expressions, like `if (o?.foo) ...` when `o` is `null`. Adding Function.futureValueType supports the proper backend implementation for the fix in https://dart-review.googlesource.com/c/sdk/+/181303 Closes #44654 TEST=existing Change-Id: Ie5939a248d3d8bf41388e8f435e4ba4195afeabd Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/182269 Commit-Queue: Johnni Winther <johnniwinther@google.com> Reviewed-by: Jens Johansen <jensj@google.com>