From d17c5416af3d90b4c827224d4cd73366fa5a294b Mon Sep 17 00:00:00 2001 From: Florian Diebold Date: Fri, 6 Mar 2020 18:08:10 +0100 Subject: Resolve `Self::AssocTy` in impls To do this we need to carry around the original resolution a bit, because `Self` gets resolved to the actual type immediately, but you're not allowed to write the equivalent type in a projection. (I tried just comparing the projection base type with the impl self type, but that seemed too dirty.) This is basically how rustc does it as well. Fixes #3249. --- crates/ra_hir_ty/src/infer/path.rs | 4 +- crates/ra_hir_ty/src/lower.rs | 86 +++++++++++++++++++++--------------- crates/ra_hir_ty/src/tests/traits.rs | 41 +++++++++++++++++ 3 files changed, 93 insertions(+), 38 deletions(-) (limited to 'crates/ra_hir_ty/src') diff --git a/crates/ra_hir_ty/src/infer/path.rs b/crates/ra_hir_ty/src/infer/path.rs index 471d60342..c733b9e1d 100644 --- a/crates/ra_hir_ty/src/infer/path.rs +++ b/crates/ra_hir_ty/src/infer/path.rs @@ -40,7 +40,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> { let ty = self.make_ty(type_ref); let remaining_segments_for_ty = path.segments().take(path.segments().len() - 1); let ctx = crate::lower::TyLoweringContext::new(self.db, &resolver); - let ty = Ty::from_type_relative_path(&ctx, ty, remaining_segments_for_ty); + let (ty, _) = Ty::from_type_relative_path(&ctx, ty, None, remaining_segments_for_ty); self.resolve_ty_assoc_item( ty, &path.segments().last().expect("path had at least one segment").name, @@ -115,7 +115,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> { let remaining_segments_for_ty = remaining_segments.take(remaining_segments.len() - 1); let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver); - let ty = Ty::from_partly_resolved_hir_path( + let (ty, _) = Ty::from_partly_resolved_hir_path( &ctx, def, resolved_segment, diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs index 092977e93..b96dc126c 100644 --- a/crates/ra_hir_ty/src/lower.rs +++ b/crates/ra_hir_ty/src/lower.rs @@ -91,7 +91,14 @@ pub enum TypeParamLoweringMode { impl Ty { pub fn from_hir(ctx: &TyLoweringContext<'_, impl HirDatabase>, type_ref: &TypeRef) -> Self { - match type_ref { + Ty::from_hir_ext(ctx, type_ref).0 + } + pub fn from_hir_ext( + ctx: &TyLoweringContext<'_, impl HirDatabase>, + type_ref: &TypeRef, + ) -> (Self, Option) { + let mut res = None; + let ty = match type_ref { TypeRef::Never => Ty::simple(TypeCtor::Never), TypeRef::Tuple(inner) => { let inner_tys: Arc<[Ty]> = inner.iter().map(|tr| Ty::from_hir(ctx, tr)).collect(); @@ -100,7 +107,11 @@ impl Ty { Substs(inner_tys), ) } - TypeRef::Path(path) => Ty::from_hir_path(ctx, path), + TypeRef::Path(path) => { + let (ty, res_) = Ty::from_hir_path(ctx, path); + res = res_; + ty + } TypeRef::RawPtr(inner, mutability) => { let inner_ty = Ty::from_hir(ctx, inner); Ty::apply_one(TypeCtor::RawPtr(*mutability), inner_ty) @@ -183,7 +194,8 @@ impl Ty { } } TypeRef::Error => Ty::Unknown, - } + }; + (ty, res) } /// This is only for `generic_predicates_for_param`, where we can't just @@ -217,17 +229,19 @@ impl Ty { pub(crate) fn from_type_relative_path( ctx: &TyLoweringContext<'_, impl HirDatabase>, ty: Ty, + // We need the original resolution to lower `Self::AssocTy` correctly + res: Option, remaining_segments: PathSegments<'_>, - ) -> Ty { + ) -> (Ty, Option) { if remaining_segments.len() == 1 { // resolve unselected assoc types let segment = remaining_segments.first().unwrap(); - Ty::select_associated_type(ctx, ty, segment) + (Ty::select_associated_type(ctx, ty, res, segment), None) } else if remaining_segments.len() > 1 { // FIXME report error (ambiguous associated type) - Ty::Unknown + (Ty::Unknown, None) } else { - ty + (ty, res) } } @@ -236,14 +250,14 @@ impl Ty { resolution: TypeNs, resolved_segment: PathSegment<'_>, remaining_segments: PathSegments<'_>, - ) -> Ty { + ) -> (Ty, Option) { let ty = match resolution { TypeNs::TraitId(trait_) => { // if this is a bare dyn Trait, we'll directly put the required ^0 for the self type in there let self_ty = if remaining_segments.len() == 0 { Some(Ty::Bound(0)) } else { None }; let trait_ref = TraitRef::from_resolved_path(ctx, trait_, resolved_segment, self_ty); - return if remaining_segments.len() == 1 { + let ty = if remaining_segments.len() == 1 { let segment = remaining_segments.first().unwrap(); let associated_ty = associated_type_by_name_including_super_traits( ctx.db, @@ -269,6 +283,7 @@ impl Ty { } else { Ty::Dyn(Arc::new([GenericPredicate::Implemented(trait_ref)])) }; + return (ty, None); } TypeNs::GenericParam(param_id) => { let generics = @@ -306,22 +321,25 @@ impl Ty { TypeNs::BuiltinType(it) => Ty::from_hir_path_inner(ctx, resolved_segment, it.into()), TypeNs::TypeAliasId(it) => Ty::from_hir_path_inner(ctx, resolved_segment, it.into()), // FIXME: report error - TypeNs::EnumVariantId(_) => return Ty::Unknown, + TypeNs::EnumVariantId(_) => return (Ty::Unknown, None), }; - Ty::from_type_relative_path(ctx, ty, remaining_segments) + Ty::from_type_relative_path(ctx, ty, Some(resolution), remaining_segments) } - pub(crate) fn from_hir_path(ctx: &TyLoweringContext<'_, impl HirDatabase>, path: &Path) -> Ty { + pub(crate) fn from_hir_path( + ctx: &TyLoweringContext<'_, impl HirDatabase>, + path: &Path, + ) -> (Ty, Option) { // Resolve the path (in type namespace) if let Some(type_ref) = path.type_anchor() { - let ty = Ty::from_hir(ctx, &type_ref); - return Ty::from_type_relative_path(ctx, ty, path.segments()); + let (ty, res) = Ty::from_hir_ext(ctx, &type_ref); + return Ty::from_type_relative_path(ctx, ty, res, path.segments()); } let (resolution, remaining_index) = match ctx.resolver.resolve_path_in_type_ns(ctx.db, path.mod_path()) { Some(it) => it, - None => return Ty::Unknown, + None => return (Ty::Unknown, None), }; let (resolved_segment, remaining_segments) = match remaining_index { None => ( @@ -336,31 +354,27 @@ impl Ty { fn select_associated_type( ctx: &TyLoweringContext<'_, impl HirDatabase>, self_ty: Ty, + res: Option, segment: PathSegment<'_>, ) -> Ty { - let def = match ctx.resolver.generic_def() { - Some(def) => def, - None => return Ty::Unknown, // this can't actually happen - }; - let param_id = match self_ty { - Ty::Placeholder(id) if ctx.type_param_mode == TypeParamLoweringMode::Placeholder => id, - Ty::Bound(idx) if ctx.type_param_mode == TypeParamLoweringMode::Variable => { - let generics = generics(ctx.db, def); - let param_id = if let Some((id, _)) = generics.iter().nth(idx as usize) { - id - } else { - return Ty::Unknown; - }; - param_id + let traits_from_env: Vec<_> = match res { + Some(TypeNs::SelfType(impl_id)) => match ctx.db.impl_trait(impl_id) { + None => return Ty::Unknown, + Some(trait_ref) => vec![trait_ref.value.trait_], + }, + Some(TypeNs::GenericParam(param_id)) => { + let predicates = ctx.db.generic_predicates_for_param(param_id); + predicates + .iter() + .filter_map(|pred| match &pred.value { + GenericPredicate::Implemented(tr) => Some(tr.trait_), + _ => None, + }) + .collect() } - _ => return Ty::Unknown, // Error: Ambiguous associated type + _ => return Ty::Unknown, }; - let predicates = ctx.db.generic_predicates_for_param(param_id); - let traits_from_env = predicates.iter().filter_map(|pred| match &pred.value { - GenericPredicate::Implemented(tr) => Some(tr.trait_), - _ => None, - }); - let traits = traits_from_env.flat_map(|t| all_super_traits(ctx.db, t)); + let traits = traits_from_env.into_iter().flat_map(|t| all_super_traits(ctx.db, t)); for t in traits { if let Some(associated_ty) = ctx.db.trait_data(t).associated_type_by_name(&segment.name) { diff --git a/crates/ra_hir_ty/src/tests/traits.rs b/crates/ra_hir_ty/src/tests/traits.rs index 547010b35..f009a708c 100644 --- a/crates/ra_hir_ty/src/tests/traits.rs +++ b/crates/ra_hir_ty/src/tests/traits.rs @@ -1802,6 +1802,47 @@ fn test() where T::Item: Trait2, T: Trait, U: Trait<()> { assert_eq!(t, "u32"); } +#[test] +fn unselected_projection_on_trait_self() { + assert_snapshot!(infer( + r#" +//- /main.rs +trait Trait { + type Item; + + fn f(&self, x: Self::Item); +} + +struct S; + +impl Trait for S { + type Item = u32; + fn f(&self, x: Self::Item) { let y = x; } +} + +struct S2; + +impl Trait for S2 { + type Item = i32; + fn f(&self, x: ::Item) { let y = x; } +} +"#, + ), @r###" + [54; 58) 'self': &Self + [60; 61) 'x': {unknown} + [140; 144) 'self': &S + [146; 147) 'x': u32 + [161; 175) '{ let y = x; }': () + [167; 168) 'y': u32 + [171; 172) 'x': u32 + [242; 246) 'self': &S2 + [248; 249) 'x': i32 + [265; 279) '{ let y = x; }': () + [271; 272) 'y': i32 + [275; 276) 'x': i32 + "###); +} + #[test] fn trait_impl_self_ty() { let t = type_at( -- cgit v1.2.3