Extract-method with namespace declaration results in invalid code

[ghost]

TypeScript Version: nightly (2.6.0-dev.20170916)

See test extract-method-empty-namespace.ts.

Code

function f() {
    namespace N {}
}

Extract "namespace N" out to a global function.

Expected behavior:

function f() {
    newFunction();
}
function newFunction() {
    namespace N { }
}

Actual behavior:

function f() {
    newFunction(N);
}
function newFunction(N: any) {
    namespace N { }
}

[amcasey]

I'm curious about why it's doing that but, unless I'm mistaken, that's not even legal code. Generally speaking, I don't think we make many guarantees about the behavior of refactorings and code fixes on non-compiling code.

[amcasey]

If you do it with a class instead (also illegal), you get newFunction(C: typeof C). 😄

[amcasey]

The same thing happens for a nested function, which is legal. I believe the issue is that rangeContainsRange is comparing the selection range to the full range of the declaration. Since the selection does not contain the full range, we assume that it was declared elsewhere and try to pass it along.

[ghost]

Actually, namespaces are legal to appear anywhere a declaration would be. In that case they create a local variable, not a global variable.

[amcasey]

@andy-ms, that seems reasonable. Is there a switch or something I have to set to suppress/disable TS1235 (a namespace declaration is only allowed in a namespace or module)?

[ghost]

That is strange, I was seeing no error yesterday. Probably my services were failing but vscode doesn't tell me. I wonder why we have this restriction, since namespaces are legal inside of a module (not global) and the emit for a namespace inside a function looks fine.
Classes are legal though.