Various E0308/E0107 errors in rustc code

[RalfJung]

RA recently started showing type errors in well-typed Rust code in the Rust compiler:

• This triggers E0308 expected &IndexSlice<{unknown}, Operand<'_>>, found &IndexVec<{unknown}, Operand<'_>>
• This triggers E0107 expected 1 argument, found 0
• This (and similar code later that file) triggers E0308 expected &LayoutError<'_>, found LayoutError<'_>

rust-analyzer version: rust-analyzer version: 0.3.1599-standalone

rustc version: rustc bootstrap

relevant settings:

    // user settings
    "rust-analyzer.lens.enable": false,
    "rust-analyzer.cachePriming.enable": false,
    "rust-analyzer.cargo.buildScripts.useRustcWrapper": false,
    "rust-analyzer.diagnostics.disabled": [
        "unlinked-file", // I guess for "normal" projects unlinked files are strange, for me they are common
        "unresolved-module", // https://github.com/rust-lang/rust-analyzer/issues/9173
        "type-mismatch", // https://github.com/rust-lang/rust-analyzer/issues/1109
    ],
    // workspace settings
    "rust-analyzer.rustc.source": "./Cargo.toml",
    "rust-analyzer.linkedProjects": [
        "./Cargo.toml",
        "./src/bootstrap/Cargo.toml"
    ],
    "rust-analyzer.checkOnSave.overrideCommand": [
        "./x.sh",
        "check",
        "--json-output",
        "library/std",
        "compiler/rustc",
        //"compiler/rustc_codegen_cranelift",
        "src/tools/miri",
    ],
    "rust-analyzer.rustfmt.overrideCommand": [
        "./build/host/rustfmt/bin/rustfmt",
        "--edition=2021",
    ],
    // These just make everything way too slow.
    "rust-analyzer.cargo.buildScripts.overrideCommand": ["false"],
    "rust-analyzer.cargo.buildScripts.enable": false,
    "rust-analyzer.procMacro.enable": false,

[Veykril]

• This triggers E0308 expected &IndexSlice<{unknown}, Operand<'_>>, found &IndexVec<{unknown}, Operand<'_>>

This I can't reproduce

• This triggers E0107 expected 1 argument, found 0

We resolve position to Iterator::position here, we resolve it correctly if decoder is a &D instead of a &mut D, so it seems like our autoderef is failing here maybe?

• This (and similar code later that file) triggers E0308 expected &LayoutError<'_>, found LayoutError<'_>

This I can't reproduce

[RalfJung]

Hm, is my RA outdated or so? I am still seeing both of the E0308 with current rustc master. I am using vscodium but I doubt that should make a difference. Enabling build scripts and proc macros made no difference.

[Veykril]

Ah, nevermind I can reproduce those two if I disable proc-macro expansion. (So I suppose something else with proc-macros fails for you when you enable them).

For the issue in layout this makes sense, since the scrutinee of the match expression no longer resolves so the patterns infer by value instead. The step.rs one fails since the FieldIdx in the type no longer exists, so the coercion fails.

[RalfJung]

Ah right, when I enable proc macros and build scripts, there is some "failed to build proc macro" popup for about 0.5s but it disappears too quickly to read the message.

[lowr]

Rather than the concrete errors, I'm wondering why rust-analyzer even shows type-mismatches when "type-mismatch" is set in "rust-analyzer.diagnostics.disabled". Has #14990 changed the way it works?

[RalfJung]

I now have to add E0308 and E0107 to diagnostics.disabled to hide these.

[Veykril]

I'll close this, only one of these remains and that one is a chalk bug (don't recall which there are too many)