`Insert imports on paste` causes IDE freezes

[Undin]

Environment

• IntelliJ Rust plugin version: 0.4.182.4966-222-nightly
• Rust toolchain version: 1.67.0-nightly (77e57db38 2022-10-30) x86_64-apple-darwin
• IDE name and version: IntelliJ IDEA 2022.2 Ultimate Edition (IU-222.3345.118)
• Operating system: macOS 12.5.1
• Macro expansion: enabled
• Additional experimental features: org.rust.cargo.features.settings.gutter, org.rust.cargo.emulate.terminal, org.rust.macros.proc

Problem description

Insert imports on paste feature (Preferences | Editor | General | Auto Import | Rust settings) introduced in #7597 leads to execution of resolve-related code in EDT. As a result, if a user pastes large fragment of code, IDE may freeze.

• https://youtrack.jetbrains.com/issue/VIM-2769
• https://github.com/intellij-rust/intellij-rust/issues/9610

Not to affect users, the option is disabled by default now but it would be nice to fix it by moving execution of name resolution into background thread

Large file for testing: https://github.com/apache/arrow-rs/blob/master/arrow-cast/src/cast.rs

[dima74]

So the plan is:

• [x] Fix visitors - now we can process the same PsiElement multiple times
• [ ] Make paste phase asynchronous
• [ ] ? Investigate why we use auto-import when all pasted references are resolved (e.g. when pasting whole file content with imports)