Problem with type inference. Caching?

[d0ruk]

Hello,

When I start a new .ts file and do;

var name:string;
name = "foo";

It compiles as expected.

Then I change name's type;

var name:string[];
name = ["foo","bar","baz"];

Compiler complains thus;

test.ts(1,5): error TS2403: Subsequent variable declarations must have the same type. Variable 'name' must be of type 'string', but here has type 'string[]'.
test.ts(2,1): error TS2322: Type 'string[]' is not assignable to type 'string'.

This stops when I change the name to something else;

var spam:string[];
name = ["foo","bar","baz"];

When I try to reproduce it with different names other than name, problem seems to go away. I think this is either related to the var name (reserved word?) or some caching.

-d

[RyanCavanaugh]

The global name is exposed in TypeScript.

https://developer.mozilla.org/en-US/docs/Web/API/Window/name

When you write var name at top-level, that doesn't create a new variable:

var name: string;
console.log(name); // Expected: undefined, actual: "" (depending)

We don't let you write var name: string[] because that identifier already has a meaning at global scope.

[mhegazy]

This has been a common source if confusion. issue #1351 is tracking removing the definition of "name" and "length" from the library to avoid these issues.