This would close#2761. I figured that if you're supplying your own custom message, you probably don't mind the stringification of the condition to not be in the message.
My goal is to explain the underlying concepts first (destructors and then ownership) with plenty of step-by-step examples, so that thoroughly explaining the semantics of mutability, boxes, moves, etc. is a breeze. I'm trying to avoid the comparisons with C++ that were done before, because this should be approachable for people coming from any language. C++ programmers already know these concepts so they aren't the audience that needs to be catered to. Comparisons with other languages can be done in separate documents (like [this one](https://github.com/mozilla/rust/wiki/Rust-for-CXX-programmers)).
This still needs examples for ownership (inherited mutability), owned boxes and managed boxes.
So this is a partial fix for #3469. Partial because it only works for simple constant expressions like `32/2` and `2+2` and not for any actual constants.
For example:
```
const FOO: uint = 2+2;
let v: [int * FOO];
```
results in:
```
error: expected constant expr for vector length: Non-constant path in constant expr
```
This seems to be because at the point of error (`typeck::astconv`) the def_map doesn't contain the constant and thus it can't lookup the actual expression (`2+2` in this case).
So, feedback on what I have so far and suggestions for how to address the constant issue?
All current meta items types (word, name-value, list) are now
properly parsed by rustc --cfg command line. Fixes#2399
Signed-off-by: Luca Bruno <lucab@debian.org>
librustc: Make the compiler ignore purity. …
For bootstrapping purposes, this commit does not remove all uses of
the keyword "pure" -- doing so would cause the compiler to no longer
bootstrap due to some syntax extensions ("deriving" in particular).
Instead, it makes the compiler ignore "pure". Post-snapshot, we can
remove "pure" from the language.
There are quite a few (~100) borrow check errors that were essentially
all the result of mutable fields or partial borrows of `@mut`. Per
discussions with Niko I think we want to allow partial borrows of
`@mut` but detect obvious footguns. We should also improve the error
message when `@mut` is erroneously reborrowed.
r? @nikomatsakis
For bootstrapping purposes, this commit does not remove all uses of
the keyword "pure" -- doing so would cause the compiler to no longer
bootstrap due to some syntax extensions ("deriving" in particular).
Instead, it makes the compiler ignore "pure". Post-snapshot, we can
remove "pure" from the language.
There are quite a few (~100) borrow check errors that were essentially
all the result of mutable fields or partial borrows of `@mut`. Per
discussions with Niko I think we want to allow partial borrows of
`@mut` but detect obvious footguns. We should also improve the error
message when `@mut` is erroneously reborrowed.
