previous compilation file was not self-contained.

[timsneath]

Launching lib/main.dart on iPhone Xs in debug mode...

Compiler message:

Warning: Tried to initialize from a previous compilation (build/app.dill.track.dill), 
but the file was not self-contained. This might be a bug.

The Dart team would greatly appreciate it if you would take a moment to report 
this problem at http://dartbug.com/new.

If you are comfortable with it, it would improve the chances of fixing any bug 
if you included the file 
/var/folders/31/vhvrysrx1h17pvzhwxsywpn400gq16/T/initialize_from.dill42b4BC/initialize_from.dill.gz 
in your error report, but be aware that this file includes your source code.
Either way, you should probably delete the file so it doesn't use unnecessary 
disk space.

File: initialize_from.dill.gz

Another instance of #36032, perhaps?

[a-siva]

This appears to be a duplicate of #37043

[jensjoha]

Yes, it's #36032.
With a new sdk (one with 5eff2a0) we'll issue a "CanonicalNameSdkError" and not issue the warning in the incremental compiler.

The underlying issue is - again - a changed sdk (missing root::dart:ui::Rect::@getters::left because left became a field instead of a getter).