Tracking issue for RFC 2438, "Deny the `overflowing_literals` lint for the 2018 edition"

[Centril]

This is a tracking issue for the RFC "Deny the overflowing_literals lint for the 2018 edition" (rust-lang/rfcs#2438).

Steps:

• Implement the RFC (cc @rust-lang/compiler -- can anyone write up mentoring instructions?)
• Adjust documentation (see instructions on forge)

Unresolved questions:

None

[Centril]

Marked as P-high for T-compiler due to edition 2018.

[eddyb]

@nikomatsakis Do we have a mechanism for per-edition default lint levels?

[varkor]

Do we have a mechanism for per-edition default lint levels?

Yes we do. We should just be able to replace:
https://github.com/rust-lang/rust/blob/f0bae412e97db7ef26e24546bce5199c6a086152/src/librustc_lint/types.rs#L38-L42
with:

declare_lint! {
    OVERFLOWING_LITERALS,
    Warn,
    "literal out of range for its type",
    Edition::Edition2018 => Deny
}

[ollie27]

Is there any reason it can't be made deny by default in the 2015 edition as well?