Circular associated types using Self: "index out of bounds: the len is 1 but the index is 1"

[weswigham]

#10286 has been closed, but a somewhat similar issue is happening to me. Here's as small as I could make my repro: https://github.com/weswigham/rust-analyzer-crash

Here's what it reports in the output log in vscode:

[Error - 4:51:45 AM] Request textDocument/hover failed.
  Message: server panicked: index out of bounds: the len is 1 but the index is 1
  Code: -32603 
Panic context:
> 
version: 04f03a360 2021-11-02 nightly
request: textDocument/codeAction CodeActionParams {
    text_document: TextDocumentIdentifier {
        uri: Url {
            scheme: "file",
            cannot_be_a_base: false,
            username: "",
            password: None,
            host: None,
            port: None,
            path: "/d%3A/Github/test_rust/src/main.rs",
            query: None,
            fragment: None,
        },
    },
    range: Range {
        start: Position {
            line: 35,
            character: 85,
        },
        end: Position {
            line: 35,
            character: 92,
        },
    },
    context: CodeActionContext {
        diagnostics: [],
        only: None,
    },
    work_done_progress_params: WorkDoneProgressParams {
        work_done_token: None,
    },
    partial_result_params: PartialResultParams {
        partial_result_token: None,
    },
}

thread '<unnamed>' panicked at 'index out of bounds: the len is 1 but the index is 1', C:\Users\runneradmin\.cargo\registry\src\gb.xjqchip.workers.dev-1ecc6299db9ec823\chalk-ir-0.72.0\src\lib.rs:2753:10
stack backtrace:
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at 'index out of bounds: the len is 1 but the index is 1', C:\Users\runneradmin\.cargo\registry\src\gb.xjqchip.workers.dev-1ecc6299db9ec823\chalk-ir-0.72.0\src\lib.rs:2753:10
stack backtrace:
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at 'index out of bounds: the len is 1 but the index is 1', C:\Users\runneradmin\.cargo\registry\src\gb.xjqchip.workers.dev-1ecc6299db9ec823\chalk-ir-0.72.0\src\lib.rs:2753:10
stack backtrace:
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
Panic context:
> 
version: 04f03a360 2021-11-02 nightly
request: rust-analyzer/inlayHints InlayHintsParams {
    text_document: TextDocumentIdentifier {
        uri: Url {
            scheme: "file",
            cannot_be_a_base: false,
            username: "",
            password: None,
            host: None,
            port: None,
            path: "/d%3A/Github/test_rust/src/main.rs",
            query: None,
            fragment: None,
        },
    },
}

thread '<unnamed>' panicked at 'index out of bounds: the len is 1 but the index is 1', C:\Users\runneradmin\.cargo\registry\src\gb.xjqchip.workers.dev-1ecc6299db9ec823\chalk-ir-0.72.0\src\lib.rs:2753:10
stack backtrace:
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

It seems to need both the circularly referential associated types (as shown by the GetOnChangeSystem and OnChangeEvent traits), and a generic usage of those traits (as in the write method of the Command impl. If either are removed, rust-analyzer stops crashing.

[lnicola]

@weswigham can you still reproduce this? I can't using your sample code.

[Veykril]

Assuming this is fixed then