This is needed for further commit, which supports contracts-based
smartcasts in partial body resolve mode.
NB: Stubs can be built from 3 sources:
- source code (contract presence can be checked by PSI)
- binary data (contract presence can be checked by Kotlin Metadata)
- decompiled sources
The last case is a bit of a headache, because usually bodies are omitted
in decompiled sources. To workaround it, we have to inject stubbed
contract-call in the body.
Fix a problem where deleting last import directive via "optimize imports" could lead to incorrect psi structure resulting in CCE, see EA-64291
New imports are inserted at the head (after package directive if present) of the file (before any comments) if no imports were present
Add test for inserting import to file where a first statement is a comment
Drop code dealing with non-existing import list in ImportInsertHelperImpl
AbstractQuickFixTest: check for unexpected actions before changes to the file are made as it relies on the first line having specific format