This makes error messages about (e.g.) `#[deriving(Clone)] struct Foo {
x: Type }` point at `x: Type` rather than `Clone` in the header (while
still referring to the `#[deriving(Clone)]` in the expansion info).
ToStr, Encodable and Decodable are not marked as such, since they're
already expensive, and lead to large methods, so inlining will bloat the
metadata & the binaries.
This means that something like
#[deriving(Eq)]
struct A { x: int }
creates an instance like
#[doc = "Automatically derived."]
impl ::std::cmp::Eq for A {
#[inline]
fn eq(&self, __arg_0: &A) -> ::bool {
match *__arg_0 {
A{x: ref __self_1_0} =>
match *self {
A{x: ref __self_0_0} => true && __self_0_0.eq(__self_1_0)
}
}
}
#[inline]
fn ne(&self, __arg_0: &A) -> ::bool {
match *__arg_0 {
A{x: ref __self_1_0} =>
match *self {
A{x: ref __self_0_0} => false || __self_0_0.ne(__self_1_0)
}
}
}
}
(The change being the `#[inline]` attributes.)
This rearranges the deriving code so that #[deriving] a trait on a field
that doesn't implement that trait will point to the field in question,
e.g.
struct NotEq; // doesn't implement Eq
#[deriving(Eq)]
struct Foo {
ok: int,
also_ok: ~str,
bad: NotEq // error points here.
}
Unfortunately, this means the error is disconnected from the `deriving`
itself but there's no current way to pass that information through to
rustc except via the spans, at the moment.
Fixes#7724.
This does a number of things, but especially dramatically reduce the
number of allocations performed for operations involving attributes/
meta items:
- Converts ast::meta_item & ast::attribute and other associated enums
to CamelCase.
- Converts several standalone functions in syntax::attr into methods,
defined on two traits AttrMetaMethods & AttributeMethods. The former
is common to both MetaItem and Attribute since the latter is a thin
wrapper around the former.
- Deletes functions that are unnecessary due to iterators.
- Converts other standalone functions to use iterators and the generic
AttrMetaMethods rather than allocating a lot of new vectors (e.g. the
old code would have to allocate a new vector to use functions that
operated on &[meta_item] on &[attribute].)
- Moves the core algorithm of the #[cfg] matching to syntax::attr,
similar to find_inline_attr and find_linkage_metas.
This doesn't have much of an effect on the speed of #[cfg] stripping,
despite hugely reducing the number of allocations performed; presumably
most of the time is spent in the ast folder rather than doing attribute
checks.
Also fixes the Eq instance of MetaItem_ to correctly ignore spaces, so
that `rustc --cfg 'foo(bar)'` now works.
I removed the `static-method-test.rs` test because it was heavily based
on `BaseIter` and there are plenty of other more complex uses of static
methods anyway.
Pulls out many of the common patterns from the Eq and Clone deriving code (and
invents a few of its own), so that deriving instances are very easy to write
for a certain class of traits. (Basically, those which don't have parameters
and where all methods only take arguments of type `&Self` and return either
`Self` or types with no parameters.)
