upsuper / assert-impl

Macro for static assert that types implement a trait or not.

Macro for static assert that types implement a trait or not.

Note: this macro can only be used inside function body due to restriction of Rust.

Example

Assuming you have the following definitions:

struct C;
struct Java;
struct JavaScript;
struct Python;
struct Rust;

trait StaticTyping {}
impl StaticTyping for C {}
impl StaticTyping for Java {}
impl StaticTyping for Rust {}

This should build:

assert_impl!(StaticTyping: C, Java, Rust);
assert_impl!(StaticTyping: C, Java, Rust, );
assert_impl!(!StaticTyping: JavaScript, Python);
assert_impl!(!StaticTyping: JavaScript, Python, );

But this should fail to build:

assert_impl!(StaticTyping: JavaScript);
assert_impl!(!StaticTyping: Rust);

assert-impl's Issues

Need to support generic types

There are usecases for types like Foo<'a>, Bar<T: Clone> things like that. We should add support for that.

Syntax can be something like

assert_impl!(FancyTrait: for<'a> Foo<'a>, for<T: Clone> Bar<T>);

Add more extensive tests

Currently we rely on using doc test to ensure that violation of the assertion would correctly trigger compile failure. But doc test isn't really scalable, and with adding more complicated stuff (e.g. #1), we need a better way to do testing.

There is a wonderful crate compiletest_rs, but unfortunately it doesn't currently work on stable (see Manishearth/compiletest-rs#124), so we probably cannot use it for now...