Impls can implement either zero or one traits; this has been true
more or less since we removed classes. So I got rid of the comments
saying "we should support multiple traits" and changed the code to
make it clear that we don't. This is just cleanup, and doesn't break
any existing tests.
fail!() used to require owned strings but can handle static strings
now. Also, it can pass its arguments to fmt!() on its own, no need for
the caller to call fmt!() itself.
&str can be turned into @~str on demand, using to_owned(), so for
strings, we can create a specialized interner that accepts &str for
intern() and find() but stores and returns @~str.
I've added trt_field_vtable, trt_field_box, and trt_field_tydesc, and
inserted them in place of the "magic numbers" used to access trait
object fields through GEPi().
- In a TraitRef, use the self type consistently to refer to the Self type:
- trait ref in `impl Trait<A,B,C> for S` has a self type of `S`.
- trait ref in `A:Trait` has the self type `A`
- trait ref associated with a trait decl has self type `Self`
- trait ref associated with a supertype has self type `Self`
- trait ref in an object type `@Trait` has no self type
- Rewrite `each_bound_traits_and_supertraits` to perform
substitutions as it goes, and thus yield a series of trait refs
that are always in the same 'namespace' as the type parameter
bound given as input. Before, we left this to the caller, but
this doesn't work because the caller lacks adequare information
to perform the type substitutions correctly.
- For provided methods, substitute the generics involved in the provided
method correctly.
- Introduce TypeParameterDef, which tracks the bounds declared on a type
parameter and brings them together with the def_id and (in the future)
other information (maybe even the parameter's name!).
- Introduce Subst trait, which helps to cleanup a lot of the
repetitive code involved with doing type substitution.
- Introduce Repr trait, which makes debug printouts far more convenient.
Fixes#4183. Needed for #5656.
bare function store (which is not in fact a kind of value) but rather
ty::TraitRef. Removes many uses of fail!() and other telltale signs of
type-semantic mismatch.
cc #4183 (not a fix, but related)
and from typeck, which is verboten. We are supposed to write inference results
into the FnCtxt and then these get copied over in writeback. Add assertions
that no inference by-products are added to this table.
Fixes#3888Fixes#4036Fixes#4492
Major changes are:
- replace ~[ty_param] with Generics structure, which includes
both OptVec<TyParam> and OptVec<Lifetime>;
- the use of syntax::opt_vec to avoid allocation for empty lists;
cc #4846
