gifnksm/power-assert-rs

Power Assert in Rust. Provides better assertion message.

power-assert-rs

Power Assert in Rust. Provides better assertion message like this:

$ cargo run --example normal
     Running `target/debug/examples/normal`
thread '<main>' panicked at 'assertion failed: bar.val == bar.foo.val
power_assert!(bar.val == bar.foo.val)
              |   |   |  |   |   |
              |   3   |  |   |   2
              |       |  |   Foo { val: 2 }
              |       |  Bar { val: 3, foo: Foo { val: 2 } }
              |       false
              Bar { val: 3, foo: Foo { val: 2 } }
', examples/normal.rs:26
An unknown error occurred

To learn more, run the command again with --verbose.

How to use

Add this to your Cargo.toml:

[dependencies]
power-assert = "*"

and add this to your lib.rs or main.rs:

#![feature(plugin)]
#![plugin(power_assert)]

Now, you can use power_assert!() and power_assert_eq!().

If you want to override builtin assert!() and assert_eq!(), change your lib.rs or main.rs as follows.

#![feature(plugin)]
#![plugin(power_assert(override_builtins))]

power-assert-rs's Issues

power_assert! does not behave like assert! with deref coercion

This program:

#![feature(plugin)]
#![plugin(power_assert)]

pub fn check(s: &str) -> Result<(), ()> {
    Ok(())
}

#[test]
fn test() {
    let s = "hello".to_owned();
    //assert!(check(&s) == Ok(()));
    power_assert!(check(&s) == Ok(()));
}

outputs:

# cargo test
   Compiling power-assert-deref v0.1.0 (file:///x/power-assert-deref)
src/lib.rs:12:23: 12:24 error: mismatched types:
 expected `str`,
    found `collections::string::String`
(expected str,
    found struct `collections::string::String`) [E0308]
src/lib.rs:12   power_assert!(check(&s) == Ok(()));
                                     ^
src/lib.rs:12:2: 12:37 note: in this expansion of power_assert! (defined in src/lib.rs)
src/lib.rs:12:23: 12:24 help: run `rustc --explain E0308` to see a detailed explanation
error: aborting due to previous error
Could not compile `power-assert-deref`.

To learn more, run the command again with --verbose.

while the assert! works as expected.

I have put this in the repo https://github.com/ivan/power-assert-deref which can be tested with cargo test.

# rustc --version
rustc 1.6.0-nightly (2e07996a9 2015-10-29)

expand.rs: error: mismatched types

With a recent Rust nightly:

# rustc --version
rustc 1.7.0-dev (64a8ffeff 2016-01-07)

I see:

/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:22:13: 22:18 error: mismatched types:
 expected `bool`,
    found `core::result::Result<_, _>`
(expected bool,
    found enum `core::result::Result`) [E0308]
/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:22             Ok(e) => e,
                                                                                                              ^~~~~
/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:134:22: 134:65 note: in this expansion of panictry! (defined in /home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs)
/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:22:13: 22:18 help: run `rustc --explain E0308` to see a detailed explanation
/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:23:13: 23:23 error: mismatched types:
 expected `bool`,
    found `core::result::Result<_, _>`
(expected bool,
    found enum `core::result::Result`) [E0308]
/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:23             Err(mut e) => {
                                                                                                              ^~~~~~~~~~
/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:134:22: 134:65 note: in this expansion of panictry! (defined in /home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs)
/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:23:13: 23:23 help: run `rustc --explain E0308` to see a detailed explanation
/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:24:17: 24:25 error: the type of this value must be known in this context
/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:24                 e.emit();
                                                                                                                  ^~~~~~~~
/home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs:134:22: 134:65 note: in this expansion of panictry! (defined in /home/rustdev/.cargo/registry/src/github.com-88ac128001ac3a9a/power-assert-0.3.7/src/expand.rs)
error: aborting due to 3 previous errors

Rewrite using proc-macro-hack

Hey,

It's now possible to create functionlike!() proc macros on stable rust using proc-macro-hack.

I'm going to try rewriting power-assert-rs using it.

power_assert! has problems with types that implement Drop

struct A {
    v: Vec<i32>,
}
impl Drop for A {
    fn drop(&mut self) { unimplemented!() }
}
fn bla(a: &mut A) {
    power_assert!(a.v.is_empty()); // cannot move out of type `A`, which defines the `Drop` trait [E0509]
}

Build fails on Rust nightly

# cargo run
    Updating registry `https://github.com/rust-lang/crates.io-index`
 Downloading power-assert v0.3.0
   Compiling power-assert v0.3.0
/home/at/.cargo/registry/src/github.com-0a35038f75765ae4/power-assert-0.3.0/src/convert.rs:104:17: 104:35 error: this pattern has 3 fields, but the corresponding variant has 2 fields [E0023]
/home/at/.cargo/registry/src/github.com-0a35038f75765ae4/power-assert-0.3.0/src/convert.rs:104                 ExprMatch(_, _, _) => {
                                                                                                               ^~~~~~~~~~~~~~~~~~
/home/at/.cargo/registry/src/github.com-0a35038f75765ae4/power-assert-0.3.0/src/convert.rs:104:17: 104:35 help: run `rustc --explain E0023` to see a detailed explanation
error: aborting due to previous error
Could not compile `power-assert`.

To learn more, run the command again with --verbose.

# rustc --version
rustc 1.6.0-nightly (2e07996a9 2015-10-29)

Typo in readme

The readme suggests adding #![plugin(power-assert)]rather than #![plugin(power_assert)].

power_assert_eq! causes internal compiler error: unexpected panic

Building this program:

#![feature(plugin)]
#![plugin(power_assert)]

#[test]
fn test_get_concealment_size() {
        power_assert_eq!(2*2, 4);
}

Results in:

# cargo build
   Compiling power-assert-crash v0.1.0 (file:///x/power-assert-crash)
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'assertion failed: `(left == right)` (left: `1`, right: `2`)', /home/at/.cargo/registry/src/github.com-0a35038f75765ae4/power-assert-0.3.1/src/convert.rs:15

Could not compile `power-assert-crash`.

To learn more, run the command again with --verbose.

That assert_eq! panic is coming from

power-assert-rs/src/convert.rs

Line 15 in fce93a0

assert_eq!(e.get(), &pp_pos);

# rustc --version
rustc 1.6.0-nightly (2e07996a9 2015-10-29)

Broken on the latest nightly

The latest nightly(rustc 1.13.0-nightly (e07dd59ea 2016-08-25)) seems to break power-assert pretty badly. It looks like there has been some changes in syntax::ast.

Full error message:

    Updating registry `https://github.com/rust-lang/crates.io-index`
   Compiling power-assert v0.3.9
error[E0432]: unresolved import `syntax::ast::TokenTree`
 --> /home/giodamelio//.cargo/registry/src/github.com-1ecc6299db9ec823/power-assert-0.3.9/src/expand.rs:3:32
  |
3 | use syntax::ast::{Expr, Ident, TokenTree, Stmt};
  |                                ^^^^^^^^^ no `TokenTree` in `syntax::ast`

error[E0432]: unresolved import `syntax::ast::TokenTree`
 --> /home/giodamelio//.cargo/registry/src/github.com-1ecc6299db9ec823/power-assert-0.3.9/src/convert.rs:3:32
  |
3 | use syntax::ast::{Expr, Ident, TokenTree};
  |                                ^^^^^^^^^ no `TokenTree` in `syntax::ast`

error: the type of this value must be known in this context
  --> /home/giodamelio//.cargo/registry/src/github.com-1ecc6299db9ec823/power-assert-0.3.9/src/expand.rs:33:32
   |
33 |        .filter(|tt| span.lo <= tt.get_span().lo && tt.get_span().hi <= span.hi)
   |                                ^^^^^^^^^^^^^

error: the type of this value must be known in this context
   --> /home/giodamelio//.cargo/registry/src/github.com-1ecc6299db9ec823/power-assert-0.3.9/src/expand.rs:132:31
    |
132 |     let cond_expr = panictry!(parser.parse_expr());
    |                     ----------^^^^^^^^^^^^^^^^^^^-
    |                     |
    |                     in this macro invocation

error: the type of this value must be known in this context
   --> /home/giodamelio//.cargo/registry/src/github.com-1ecc6299db9ec823/power-assert-0.3.9/src/expand.rs:177:25
    |
177 |     let lhs = panictry!(parser.parse_expr());
    |               ----------^^^^^^^^^^^^^^^^^^^-
    |               |
    |               in this macro invocation

error: the type of this value must be known in this context
  --> /home/giodamelio//.cargo/registry/src/github.com-1ecc6299db9ec823/power-assert-0.3.9/src/convert.rs:28:41
   |
28 |     register_pos(map, tt.get_span().lo, line.lines[0].start_col.0 as i32);
   |                                         ^^^^^^^^^^

error[E0061]: this function takes 3 parameters but 2 parameters were supplied
  --> /home/giodamelio//.cargo/registry/src/github.com-1ecc6299db9ec823/power-assert-0.3.9/src/convert.rs:41:27
   |
41 |     let filemap = codemap.new_filemap("".to_string(), ppstr);
   |                           ^^^^^^^^^^^ expected 3 parameters
   |
   = note: the following parameter types were expected: std::string::String, std::option::Option<std::string::String>, std::string::String

error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements
   --> /home/giodamelio//.cargo/registry/src/github.com-1ecc6299db9ec823/power-assert-0.3.9/src/convert.rs:247:22
    |
247 |     let mut folder = AssertFolder {
    |                      ^^^^^^^^^^^^
    |
help: consider using an explicit lifetime parameter as shown: fn convert_expr<'a>(cx: &'a mut ExtCtxt<'a>, expr: P<Expr>, ident: Ident,
                    tts: &[TokenTree]) -> (P<Expr>, bool)
   --> /home/giodamelio//.cargo/registry/src/github.com-1ecc6299db9ec823/power-assert-0.3.9/src/convert.rs:234:1
    |
234 | pub fn convert_expr(cx: &mut ExtCtxt,
    | ^

error: aborting due to 6 previous errors

error: Could not compile `power-assert`.

To learn more, run the command again with --verbose.