TypeScript Version: nightly (2.1.0-dev.20160815)

Code

// NB: non-strict code, valid JavaScript
var dyn = { foo: 'bar' };
with (dyn) {/***/} // ERROR TS2410: All symbols within a 'with' block will be resolved to 'any'

Expected behavior:

Error message that says some thing like "with statement is not supported in TypeScript"

Actual behavior:

The error as shown in the code above. What's confusing is that:

• the error is attributed to the argument of the with statement (not to the statement itself)
• the 'error' is just a message saying that you'll lose typing within the block, which is a consequence of dynamic scoping, but not an error in itself.
• there's no mention of an error or a fix, or that with is not supported in TypeScript.

From this message, I got the impression there was some way of arranging the with statement or its argument to get it to compile. But I think there isn't.

If you are porting code to TypeScript and it contains with statements, the only way you'll ever get an error-free build is when you remove all the with statements. To me that means with statements are not supported in TypeScript, period. I think it would be clearer to just state that in the error message (perhaps with the current message as a secondary explanation).