Microsoft/TypeScript

Non-null assertion should work on possibly-uninitialized auto-typed `let` variables

Aperta

#52.439 aperta il 26 gen 2023

 (1 commento) (1 reazione) (0 assegnatari)TypeScript (13.395 fork)batch import
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Descrizione

Bug Report

🔎 Search Terms

non-null postfix bang implicit any

🕗 Version & Regression Information

  • This is the behavior in every version I tried

⏯ Playground Link

This is the link

💻 Code

let foo;
if (Math.random() > 0.5) {
  foo = "hello";
}
// bar: string | undefined, seems fine
let bar = foo;
/* -- pretend I know foo is defined for other reasons -- */
// Error, foo is implicitly any
let baz = foo!;

🙁 Actual behavior

Implicit any on foo!

🙂 Expected behavior

Since the inferred type of foo (as seen in bar) is string | undefined, foo! should trivially have the type string

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