Rust 1.37.0 - Hackdot

Re:Rust 1.37.0 by oconnor663 on Thursday August 15, 2019 @02:30PM (#20708193)

The hack that I've seen people use the most is to write a line like this:

    () = foo;

Then rustc will print out an error that includes the type of `foo`.

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Re:Rust 1.37.0 by danbolt on Thursday August 15, 2019 @02:48PM (#20708347)

Scott Meyers also suggests the same sort of thing in Effective Modern C++ when not using an IDE.

Personally, I use the technique a lot for debugging template errors in the language.

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Re:Rust 1.37.0 by stochastic_monk on Thursday August 15, 2019 @03:06PM (#20708549)

Specifically:

template<typename T> struct TD;

Instantiate this as ‘TD<decltype(foo)>’ to get the full name of the type.

Rust’s does seem more concise.

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Re:Rust 1.37.0 by edflsafoiewq on Thursday August 15, 2019 @04:45PM (#20709470)

Note that you don't get the full name of the type with a bad assignment in Rust, you only get the part of the type that was deduced before type checking failed. A generic type might have undeduced blanks, eg. Vec<_>. A side-effect of type inference.

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Re:Rust 1.37.0 by hathawsh on Thursday August 15, 2019 @02:33PM (#20708216)

Nice, thanks!

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