Inconsistency in getDocumentHighlights for import aliases

[leeavital]

For the file:

import fs = require('fs');
import ws = fs.writeStream;

getDocumentHighlights will not find that the fs on line 1 is the same as the one on line 2.

But for the file:

import fs = require('fs');
var ws = fs.writeStream;

---

I wrote a small program to demonstrate the problem.

var ts = require('typescript');
var fs = require('fs');

var source = fs.readFileSync('test.ts').toString();
var sourceFile = ts.createSourceFile('test.ts', source, 1, false);

var host = {
  getCompilationSettings: function() {
      return {
          noResolve: true,
          target: ts.ScriptTarget.ES5
      };
  },
  getCurrentDirectory: function() {
    return '';
  },
  getDefaultLibFileName: function() {
    return "lib.d.ts"
  },
  getScriptFileNames: function() {
    return ['test.ts'];
  },
  getScriptIsOpen: function() {
    return true
  },
  getScriptVersion: function() {
    return "1"
  },
  getScriptSnapshot: function() {
    return {
      getLength: function() {
        return source.length;
      },
      getLineStartPositions: function () {
        return ts.computeLineStarts(source);
      },
      getText: function(start, end) {
        return source.substring(start, end);
      }
    };
  }
};

var documentRegistry = ts.createDocumentRegistry();
var languageServices = ts.createLanguageService(host, documentRegistry);

var importFS  = sourceFile.statements[0];
var highlights = languageServices.getDocumentHighlights('test.ts', importFS.name.pos + 1, ['test.ts']);
console.log(highlights[0].highlightSpans.length);

When test.ts contains the first example, it outputs 1. When test.ts contains the second example, it outputs 2.

[DanielRosenwasser]

I assume this also means find-references and rename is also not working in this scenario.

[jkillian]

There seem to be some related funny issues going on. When calling getDocumentHighlights on the position of the hello variable declaration in the following code snippet:

// Incorrect case:

class HelloWorld {
    constructor(public name: string) { }
    sayHello() {
        return `Hello, ${this.name}!`;
    }
};

let hello = new HelloWorld("TSLint");
hello.sayHello();

only the declaration is returned and not the usage on the next line. However, in the following code snippet, both uses are returned, correctly:

// Correct case:

class HelloWorld {
    constructor(public name: string) { }
    sayHello() {
        return `Hello, ${this.name}!`;
    }
};

if (true) {
    let hello = new HelloWorld("TSLint");
    hello.sayHello();
}

Also strangely, Sublime will correctly show both references in both cases.

I've been trying to figure out the root cause but haven't been able to yet. I did notice that in the getReferencesInNode function the array of possible positions contains exactly the two actual positions in both the incorrect and correct case. However, there is a difference when finding the relatedSymbol:

var referenceSymbol = typeChecker.getSymbolAtLocation(referenceLocation);
if (referenceSymbol) {
    var referenceSymbolDeclaration = referenceSymbol.valueDeclaration;
    var shorthandValueSymbol = typeChecker.getShorthandAssignmentValueSymbol(referenceSymbolDeclaration);
    var relatedSymbol = getRelatedSymbol(searchSymbols, referenceSymbol, referenceLocation);
    // NOTE (added for the Github issue):
    // relatedSymbol is undefined here in incorrect case, defined in the correct case
    if (relatedSymbol) {
        var referencedSymbol = getReferencedSymbol(relatedSymbol);
        referencedSymbol.references.push(getReferenceEntryFromNode(referenceLocation));
    }
    else if (!(referenceSymbol.flags & 67108864 /* Transient */) && searchSymbols.indexOf(shorthandValueSymbol) >= 0) {
        var referencedSymbol = getReferencedSymbol(shorthandValueSymbol);
        referencedSymbol.references.push(getReferenceEntryFromNode(referenceSymbolDeclaration.name));
    }
}

(Related to palantir/tslint#570)

[DanielRosenwasser]

@jkillian I'm not able to reproduce the error:

it's likely unrelated to the issue filed here, so if you're still seeing it, can you file a separate bug?

[jkillian]

@DanielRosenwasser Created a new issue from my previous comment with a few details added: #4560

[jkillian]

@leeavital The issue comes from this code:

getScriptSnapshot: function() {
    return {
      getLength: function() {
        return source.length;
      },
      getLineStartPositions: function () {
        return ts.computeLineStarts(source);
      },
      getText: function(start, end) {
        return source.substring(start, end);
      }
    };
  }

getScriptSnapshot can request snapshots for files other than source, so only returning code form source causes things to happen incorrectly.