Quick info on 'new' keyword should be the same as that of resolved expression

[DanielRosenwasser]

class C {
    /**
     * NOTE: this constructor is private! Please use the factory function
     */
    private constructor() { }
    static makeC() { new C(); }
}

new C();

Expected: Quick info on C and new in new C() should be the same.
Actual: no quick info on new

Why it matters

It'd be nice if hovering over the error at any point could also give you better quick info.

[DanielRosenwasser]

(Courtesy of @jonathandturner)

[rpgeeganage]

@DanielRosenwasser ,
May I work on this please?

[DanielRosenwasser]

Yes you certainly may! This one will be in the language service. Start here in getQuickInfoAtPosition.

Tests can be found in tests/cases/fourslash. I'd make a quickInfoOnNewKeyword01.ts file there.

[rpgeeganage]

@DanielRosenwasser
Thanks a lot. I’ll start working on this.

[rpgeeganage]

I have started working on this. Will open a PR as soon as I finished it.
Thanks.

[rpgeeganage]

@DanielRosenwasser ,
Can you please help me on viewing the quick info?
I started with a test case. I added new file quickInfoOnNewKeyword01.ts in tests/cases/fourslash.
The content of the test file is as follows.

/// <reference path='fourslash.ts' />

////class C {
/////**
//// * NOTE: this constructor is private! Please use the factory function
//// */
////private constructor() { }
////static makeC() { new C(); }
////}
////
////new C();

debug.printCurrentQuickInfo();

After that I ran the test as gulp runtests --tests=quickInfoOnNewKeyword01.
The only output was:
Quick Info: class C
How can I print the entire quick info ?

[DanielRosenwasser]

I'm not sure since it's been a while and I don't develop in the codebase as much anymore - but you'll have to look for where quick info is resolved for overloads (e.g. what code path is it taking for when you hover on the identifier?). Then, when the quick info target is a NewKeyword, find a way to dispatch the same logic.

[rpgeeganage]

@DanielRosenwasser ,
Thanks a lot. I'll look into it.

[rpgeeganage]

@sandersn ,
Can you please give me a small help on this please?
I have to debug till this line.
My test case:

////class Cat {
////  /**
////   * NOTE: this constructor is private! Please use the factory function
////   */
////  private constructor() { }
////
////  static makeCat() { new Cat(); }
////}

////ne/*1*/w C/*2*/at();

goTo.marker('2');
debug.printCurrentQuickInfo();
debug.printErrorList();

goTo.marker('1');
debug.printCurrentQuickInfo();
debug.printErrorList();

for the marker 2,
expression in below line evaluate as false
https://github.com/Microsoft/TypeScript/blob/master/src/services/services.ts#L1472
so,
symbol value is not null, so it goes to the following function.
https://github.com/Microsoft/TypeScript/blob/master/src/services/services.ts#L1484

const { symbolKind, displayParts, documentation, tags } = typeChecker.runWithCancellationToken(cancellationToken, typeChecker =>
  SymbolDisplay.getSymbolDisplayPartsDocumentationAndSymbolKind(typeChecker, symbol, sourceFile, getContainerNode(node), node)
);

but for the marker 1, symbol is undefined so, it doesn't go through the above function.
as a result, documentation is not properly generated.