Version 1.45.2 (2020-08-03)

Version 1.45.1 (2020-07-30)

Out of range float to int conversions using as has been defined as a saturating conversion. This was previously undefined behaviour, but you can use the {f64, f32}::to_int_unchecked methods to continue using the current behaviour, which may be desirable in rare performance sensitive situations.
mem::Discriminant<T> now uses T's discriminant type instead of always using u64.
Function like procedural macros can now be used in expression, pattern, and statement positions. This means you can now use a function-like procedural macro anywhere you can use a declarative (macro_rules!) macro.

* Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support.

#![allow(unused)]
fn main() {
for ch in 'a'..='z' {
    print!("{}", ch);
}
println!();
// Prints "abcdefghijklmnopqrstuvwxyz"
}

Trying to self initialize a static value (that is creating a value using itself) is unsound and now causes a compile error.
{f32, f64}::powi now returns a slightly different value on Windows. This is due to changes in LLVM's intrinsics which {f32, f64}::powi uses.
Rustdoc's CLI's extra error exit codes have been removed. These were previously undocumented and not intended for public use. Rustdoc still provides a non-zero exit code on errors.
Rustc's lto flag is incompatible with the new embed-bitcode=no. This may cause issues if LTO is enabled through RUSTFLAGS or cargo rustc flags while cargo is adding embed-bitcode itself. The recommended way to control LTO is with Cargo profiles, either in Cargo.toml or .cargo/config, or by setting CARGO_PROFILE_<name>_LTO in the environment.