CFA not work in function · Issue #13142 · microsoft/TypeScript (original) (raw)

TypeScript Version: 2.1.1 / nightly (2.2.0-dev.201xxxxx)
2.1.4

Code

let f:string | null = 'xx'; let v:string; if(f){ [].forEach(item=>{ v = f; }) }

Expected behavior:
Compile successfully

Actual behavior:

test.ts(5,9): error TS2322: Type 'string | null' is not assignable to type 'string'.
Type 'null' is not assignable to type 'string'.