No code completion

[funnym0nk3y]

Hey,

after a few recommendations I started, or better, tried to start using rust-analyzer. Unfortunately in my projects and files (mainly rustlings) I don't get completion of functions and implementations. I already tried reinstalling rust via rustup, but the issue persists.
Would be nice, if I could get some help with figuring this out and diagnosing what's wrong.

funnym0nk3y

[lnicola]

Which editor and extension are you using? And does it also happen on a project created with cargo new?

[funnym0nk3y]

I'm sorry, totally forgot to mention, that I'm using vscode with the rust-analyzer extension on Win10.

This issue still persists with projects created via cargo new.

[lnicola]

There should be a couple of output channels related to Rust Analyzer in the Output pane. What do they say? (Please use a <details> tag if it's a lot of text).

Do you also have the Rust extension installed?

[funnym0nk3y]

This is the output of the Rust Analyzer Client Output:

INFO [23.9.2020, 15:26:41]: Extension version: 0.2.320
INFO [23.9.2020, 15:26:41]: Using configuration {
  lruCapacity: null,
  files: { watcher: 'client', exclude: [] },
  notifications: { cargoTomlNotFound: true },
  cargo: {
    autoreload: true,
    noDefaultFeatures: false,
    allFeatures: true,
    features: [],
    loadOutDirsFromCheck: false,
    target: null
  },
  rustfmt: { extraArgs: [], overrideCommand: null },
  checkOnSave: {
    enable: true,
    extraArgs: [],
    command: 'check',
    overrideCommand: null,
    allTargets: true,
    noDefaultFeatures: null,
    allFeatures: null,
    features: null,
    target: null
  },
  cargoRunner: null,
  runnableEnv: null,
  inlayHints: {
    enable: true,
    typeHints: true,
    chainingHints: true,
    parameterHints: true,
    maxLength: 20
  },
  completion: {
    addCallParenthesis: true,
    addCallArgumentSnippets: true,
    postfix: { enable: true }
  },
  callInfo: { full: true },
  updates: { channel: 'stable', askBeforeDownload: true },
  serverPath: null,
  trace: { server: 'off', extension: false },
  procMacro: { enable: false },
  debug: {
    engine: 'auto',
    sourceFileMap: {
      '/rustc/<id>': '${env:USERPROFILE}/.rustup/toolchains/<toolchain-id>/lib/rustlib/src/rust'
    },
    openDebugPane: false,
    engineSettings: {}
  },
  lens: { enable: true, run: true, debug: true, implementations: true },
  hoverActions: {
    enable: true,
    implementations: true,
    run: true,
    debug: true,
    gotoTypeDef: true
  },
  linkedProjects: null,
  withSysroot: true,
  diagnostics: {
    enable: true,
    enableExperimental: true,
    disabled: [],
    warningsAsInfo: [],
    warningsAsHint: []
  },
  assist: { importMergeBehaviour: 'full' }
}
INFO [23.9.2020, 15:26:41]: PersistentState: {
  lastCheck: undefined,
  releaseId: undefined,
  serverVersion: '0.2.313'
}
INFO [23.9.2020, 15:26:49]: Using server binary at c:\Users\funnym0nk3y\AppData\Roaming\Code\User\globalStorage\matklad.rust-analyzer\rust-analyzer-windows.exe
WARN [23.9.2020, 15:27:04]: LSP request timed out {
  method: 'rust-analyzer/inlayHints',
  param: {
    textDocument: {
      uri: 'file:///c%3A/Users/funnm0nk3y/Software/Rust/rustlings/rustlings/exercises/error_handling/errors1.rs'
    }
  },
  error: [ResponseError: canceled by client
  	at handleResponse (c:\Users\funnym0nk3y\.vscode\extensions\matklad.rust-analyzer-0.2.320\out\src\main.js:3779:48)
  	at processMessageQueue (c:\Users\funnym0nk3y\.vscode\extensions\matklad.rust-analyzer-0.2.320\out\src\main.js:3594:17)
  	at Immediate.<anonymous> (c:\Users\funnym0nk3y\.vscode\extensions\matklad.rust-analyzer-0.2.320\out\src\main.js:3578:13)
  	at processImmediate (internal/timers.js:439:21)] {
    code: -32800,
    data: undefined
  }
}

From the language server trace there is no output. I have the RLS extension installed, but globally deactivated.

[lnicola]

I don't see anything unusual there with the exception of the "LSP request timed out" error.

[Veetaha]

I recommend you to add this to your settings (settings.json) to get more verbose client logs:

{
    "rust-analyzer.trace.extension": true
}

I see the extension is working for you, but there might just be some problem with the particular project.
As I see the rust file for which inlay-hints request failed resides in some non-standard location:

file:///c%3A/Users/funnm0nk3y/Software/Rust/rustlings/rustlings/exercises/error_handling/errors1.rs

By default rust-analyzer expects a layout of a cargo project:

- Cargo.toml
- src
    - main.rs / lib.rs

Could you try to run cargo new, paste the code from errors1.rs file into the lib.rs (or main.rs file, just be sure to have a main() {} function there). It's important to open the exact same folder that contains Cargo.toml and src in vscode.

Anyway, the most helpful input would be a repo with the reproduction of the problem

[funnym0nk3y]

Okay, thanks for your help! The issue was, that rust-analyzer expects a particular folder structure. Following @Veetaha instructions and creating and opening the folder containing Cargo.toml and src solves that issue.

I think this is very inconvenient as there is help from rust-analyzer in just that standard case and not in cases like rustlings, etc. Will there be, let me call it out of tree, completion in the future?

[lnicola]

a particular folder structure

The one used by cargo, specifically. That's why I asked if new projects work.

I think this is very inconvenient as there is help from rust-analyzer in just that standard case and not in cases like rustlings, etc. Will there be, let me call it out of tree, completion in the future?

Maybe, but I feel that rustlings should consider using a more standard structure instead. To paraphrase Tolstoy, all projects with a standard organization are alike, every non-standard one is non-standard in its own way. See LukeMathWalker/build-your-own-jira-with-rust#33 for a similar issue that was impossible to work around in RA, but was fixable in that project.