no-unnecessary-type-assertion always errors

[noseglid]

It seems like this rule (when enabled) always errors for any type assertion. Unnecessary or not:

This is not a problem when running tslint from terminal - which is odd because I can't see that anything special is med on a per-rule basis in this package.

[Xapphire13]

Does it occur when you have "use local TSLint" turned on (assuming you have TSLint installed locally)? Or, what version of TSLint are you using on the command line?

[noseglid]

I have Try using the local tslint package (if exists) enabled.
TSlint on command line:

./node_modules/.bin/tslint --version
5.7.0

(installed via yarn add tslint).

[Xapphire13]

The version of TSLint shipped with linter-tslint is currently 5.5.0 if i recall correctly. Could you downgrade to that and run again in command line?

[noseglid]

The command line don't complain with 5.5.0, but this plugin does.

I removed a semicolon too to make sure that the file was linted properly, and it was.

I'm invoking tslint as ./node_modules/.bin/tslint --project tsconfig.json

where tsconfig.json:

{
  "compileOnSave": true,
  "compilerOptions": {
    "module": "es6",
    "target": "es2017",
    "moduleResolution": "node",
    "allowSyntheticDefaultImports": true,
    "baseUrl": "src",
    "sourceMap": true,
    "outDir": "ts-build",
    "jsx": "preserve",
    "strict": true,
    "noImplicitAny": true,
    "noImplicitThis": true,
    "noUnusedLocals": false,
    "noUnusedParameters": false,
    "allowJs": true
  },
  "include": [
    "src/**/*"
  ],
  "exclude": [
    "node_modules"
  ],
  "files": [
    "./node_modules/@types/node/index.d.ts"
  ]
}

[noseglid]

I've done some more digging here. I've verified that:

• the error actually do come from the linter.
• It is using the correct linter (e.g. the one in my node_modules).

I've written a small testscript to lint my files with the library rather than the cli:

"use strict";
var { Linter, Configuration } = require("tslint");

const program = Linter.createProgram("tsconfig.json");
const files = Linter.getFileNames(program);

const results = files.map(file => {
  console.log("Linting", file);
  const fileContents = program.getSourceFile(file).getFullText();
  const configuration = Configuration.findConfiguration("tslint.json", "./src").results;
  var options = {
      fix: false,
      formatter: "json"
  };
  const linter = new Linter(options, program);
  linter.lint(file, fileContents, configuration);
  return linter.getResult();
});


console.log(results.filter(r => r.errorCount > 0));

Which works correctly (it does not complain about the type assertion, but do complain if I put in a legitimate lint error; a missing semicolon). Any idea on how I can continue debug this?

[Xapphire13]

Are you saying that the bug does reproduce with the script you posted?

the error actually do come from the linter.

What steps did you take to verify this?

[noseglid]

Sorry for being unclear. My script does not give the no-unnecessary-type-assertion. I did this to rule out the chance that there might be a discrepancy between using the CLI and using the library.

I can see lintResult includes the error.

Another thing I noticed is that I get the following error once for each Atom window:

I have strict enabled in my tsconfig.json which implies strictNullChecks.

[Arcanemagus]

Fixed by #202 (see #202 (comment)).