language-servers/rust-analyzer
1
0
Fork 0
mirror of https://github.com/rust-lang/rust-analyzer.git synced 2025-10-01 06:11:35 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 3

Implement return position impl trait / opaque type support

Browse source 
This is working, but I'm not that happy with how the lowering works. We might
need an additional representation between `TypeRef` and `Ty` where names are
resolved and `impl Trait` bounds are separated out, but things like inference
variables don't exist and `impl Trait` is always represented the same
way.

Also note that this doesn't implement correct handling of RPIT *inside* the
function (which involves turning the `impl Trait`s into variables and creating
obligations for them). That intermediate representation might help there as
well.
This commit is contained in:
Florian Diebold 2020-03-04 23:00:44 +01:00 • committed by Florian Diebold
parent 9c52f527a1
commit 02962b374e
10 changed files with 403 additions and 85 deletions
Download patch file Download diff file Expand all files Collapse all files

37
crates/ra_hir_ty/src/display.rs
View file

@ -359,6 +359,21 @@ impl HirDisplay for ApplicationTy {
write!(f, ">")?;
}
}
TypeCtor::OpaqueType(opaque_ty_id) => {
let bounds = match opaque_ty_id {
crate::OpaqueTyId::ReturnTypeImplTrait(func, idx) => {
let datas =
f.db.return_type_impl_traits(func).expect("impl trait id without data");
let data = (*datas)
.as_ref()
.map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
data.clone().subst(&self.parameters)
}
};
write!(f, "impl ")?;
write_bounds_like_dyn_trait(&bounds.value, f)?;
// FIXME: it would maybe be good to distinguish this from the alias type (when debug printing), and to show the substitution
}
TypeCtor::Closure { .. } => {
let sig = self.parameters[0].callable_sig(f.db);
if let Some(sig) = sig {
@ -427,14 +442,24 @@ impl HirDisplay for Ty {
}
}
Ty::Bound(idx) => write!(f, "?{}.{}", idx.debruijn.depth(), idx.index)?,
Ty::Dyn(predicates) | Ty::Opaque(predicates) => {
match self {
Ty::Dyn(_) => write!(f, "dyn ")?,
Ty::Opaque(_) => write!(f, "impl ")?,
_ => unreachable!(),
};
Ty::Dyn(predicates) => {
write!(f, "dyn ")?;
write_bounds_like_dyn_trait(predicates, f)?;
}
Ty::Opaque(opaque_ty) => {
let bounds = match opaque_ty.opaque_ty_id {
crate::OpaqueTyId::ReturnTypeImplTrait(func, idx) => {
let datas =
f.db.return_type_impl_traits(func).expect("impl trait id without data");
let data = (*datas)
.as_ref()
.map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
data.clone().subst(&opaque_ty.parameters)
}
};
write!(f, "impl ")?;
write_bounds_like_dyn_trait(&bounds.value, f)?;
}
Ty::Unknown => write!(f, "{{unknown}}")?,
Ty::Infer(..) => write!(f, "_")?,
}