rust-lang / book

Hi,

I am currently studying rust and here in the screenshot below:

It says that the sample closures are all valid but when I tried it in actual. The rust compiler reports an error.

This closure definition syntax is valid if you call the closure so that Rust can infer the types involved. This is mentioned in this part of the text:

book/src/ch13-01-closures.md

Lines 135 to 137 in 71352de

    
           valid definitions that will produce the same behavior when they’re called. The 
        
           `add_one_v3` and `add_one_v4` lines require the closures to be evaluated to be 
        
           able to compile because the types will be inferred from their usage. This is

Additionally, please follow the issue template next time: if you had searched for add_one_v3, you would have found this duplicate issue that points to the text added that addresses this point explicitly.

	valid definitions that will produce the same behavior when they’re called. The
	`add_one_v3` and `add_one_v4` lines require the closures to be evaluated to be
	able to compile because the types will be inferred from their usage. This is

Chapter 13 closure examples tells that all the sample closures scenario are valid but in actual rust compiler reports an error.