…r=Centril

Deny the `overflowing_literals` lint for all editions

The `overflowing_literals` was made deny by default for the 2018 edition by rust-lang#54507, however I'm not aware of any reason it can't be made deny by default for the 2015 edition as well.

…on, r=oli-obk

Reduce Miri Code Repetition like `(n << amt) >> amt`

This Pull Request fixes a part of [rust-lang#49937](rust-lang#49937).

…ri-related, r=oli-obk

Reduce a Code Repetition like `(n << amt) >> amt`

Fixes a part of [rust-lang#49937](rust-lang#49937).

…ths, r=oli-obk

librustc_codegen_llvm: #![deny(elided_lifetimes_in_paths)]

As part of the Rust 2018 transition, remove `#![allow(elided_lifetimes_in_paths)]` from `librustc_codegen_llvm`.

r? @oli-obk

…ths-librustc_codegen_ssa, r=oli-obk

librustc_codegen_ssa: #![deny(elided_lifetimes_in_paths)]

As part of the Rust 2018 transition, remove `#![allow(elided_lifetimes_in_paths)]` from `librustc_codegen_ssa`.

r? @oli-obk

…ths-librustc_typeck, r=oli-obk

librustc_typeck: deny(elided_lifetimes_in_paths)

As part of the Rust 2018 transition, remove `#![allow(elided_lifetimes_in_paths)]` from `librustc_typeck`.

r? @oli-obk

…ths-librustc, r=oli-obk

librustc: deny(elided_lifetimes_in_paths)

As part of the Rust 2018 transition, remove `#![allow(elided_lifetimes_in_paths)]` from `librustc`.

r? @oli-obk