Adjust display impls to respect lifetime bounds

8 files changed, 164 insertions, 24 deletions

diff --git a/crates/hir-def/src/find_path.rs b/crates/hir-def/src/find_path.rs
index 0cd4a5db8c3..d06fc4df768 100644
--- a/crates/hir-def/src/find_path.rs
+++ b/crates/hir-def/src/find_path.rs
@@ -30,6 +30,8 @@ pub fn find_path(
     find_path_inner(FindPathCtx { db, prefixed: None, prefer_no_std, prefer_prelude }, item, from)
 }
 
+/// Find a path that can be used to refer to a certain item. This can depend on
+/// *from where* you're referring to the item, hence the `from` parameter.
 pub fn find_path_prefixed(
     db: &dyn DefDatabase,
     item: ItemInNs,
@@ -255,7 +257,7 @@ fn find_in_scope(
     item: ItemInNs,
 ) -> Option<Name> {
     def_map.with_ancestor_maps(db, from.local_id, &mut |def_map, local_id| {
-        def_map[local_id].scope.name_of(item).map(|(name, _, _)| name.clone())
+        def_map[local_id].scope.names_of(item, |name, _, _| Some(name.clone()))
     })
 }
 
diff --git a/crates/hir-def/src/generics.rs b/crates/hir-def/src/generics.rs
index 4638b377197..118055b605e 100644
--- a/crates/hir-def/src/generics.rs
+++ b/crates/hir-def/src/generics.rs
@@ -29,6 +29,8 @@ use crate::{
 /// Data about a generic type parameter (to a function, struct, impl, ...).
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub struct TypeParamData {
+    /// [`None`] only if the type ref is an [`TypeRef::ImplTrait`]. FIXME: Might be better to just
+    /// make it always be a value, giving impl trait a special name.
     pub name: Option<Name>,
     pub default: Option<Interned<TypeRef>>,
     pub provenance: TypeParamProvenance,
diff --git a/crates/hir-def/src/item_scope.rs b/crates/hir-def/src/item_scope.rs
index 2b059d1f8dc..a60b9f9f3ab 100644
--- a/crates/hir-def/src/item_scope.rs
+++ b/crates/hir-def/src/item_scope.rs
@@ -277,13 +277,43 @@ impl ItemScope {
             ItemInNs::Types(def) => self.types.iter().find_map(|(name, &(other_def, vis, i))| {
                 (other_def == def).then_some((name, vis, i.is_none()))
             }),
-
             ItemInNs::Values(def) => self.values.iter().find_map(|(name, &(other_def, vis, i))| {
                 (other_def == def).then_some((name, vis, i.is_none()))
             }),
         }
     }
 
+    /// XXX: this is O(N) rather than O(1), try to not introduce new usages.
+    pub(crate) fn names_of<T>(
+        &self,
+        item: ItemInNs,
+        mut cb: impl FnMut(&Name, Visibility, bool) -> Option<T>,
+    ) -> Option<T> {
+        match item {
+            ItemInNs::Macros(def) => self
+                .macros
+                .iter()
+                .filter_map(|(name, &(other_def, vis, i))| {
+                    (other_def == def).then_some((name, vis, i.is_none()))
+                })
+                .find_map(|(a, b, c)| cb(a, b, c)),
+            ItemInNs::Types(def) => self
+                .types
+                .iter()
+                .filter_map(|(name, &(other_def, vis, i))| {
+                    (other_def == def).then_some((name, vis, i.is_none()))
+                })
+                .find_map(|(a, b, c)| cb(a, b, c)),
+            ItemInNs::Values(def) => self
+                .values
+                .iter()
+                .filter_map(|(name, &(other_def, vis, i))| {
+                    (other_def == def).then_some((name, vis, i.is_none()))
+                })
+                .find_map(|(a, b, c)| cb(a, b, c)),
+        }
+    }
+
     pub(crate) fn traits(&self) -> impl Iterator<Item = TraitId> + '_ {
         self.types
             .values()
diff --git a/crates/hir-ty/src/display.rs b/crates/hir-ty/src/display.rs
index 8740ae6797c..eb7f106cdfa 100644
--- a/crates/hir-ty/src/display.rs
+++ b/crates/hir-ty/src/display.rs
@@ -9,6 +9,7 @@ use std::{
 
 use base_db::CrateId;
 use chalk_ir::{BoundVar, Safety, TyKind};
+use either::Either;
 use hir_def::{
     data::adt::VariantData,
     db::DefDatabase,
@@ -1072,6 +1073,7 @@ impl HirDisplay for Ty {
                         write_bounds_like_dyn_trait_with_prefix(
                             f,
                             "impl",
+                            Either::Left(self),
                             bounds.skip_binders(),
                             SizedByDefault::Sized { anchor: krate },
                         )?;
@@ -1087,6 +1089,7 @@ impl HirDisplay for Ty {
                         write_bounds_like_dyn_trait_with_prefix(
                             f,
                             "impl",
+                            Either::Left(self),
                             bounds.skip_binders(),
                             SizedByDefault::Sized { anchor: krate },
                         )?;
@@ -1189,21 +1192,24 @@ impl HirDisplay for Ty {
                                 .generic_predicates(id.parent)
                                 .iter()
                                 .map(|pred| pred.clone().substitute(Interner, &substs))
-                                .filter(|wc| match &wc.skip_binders() {
+                                .filter(|wc| match wc.skip_binders() {
                                     WhereClause::Implemented(tr) => {
-                                        &tr.self_type_parameter(Interner) == self
+                                        tr.self_type_parameter(Interner) == *self
                                     }
                                     WhereClause::AliasEq(AliasEq {
                                         alias: AliasTy::Projection(proj),
                                         ty: _,
-                                    }) => &proj.self_type_parameter(db) == self,
-                                    _ => false,
+                                    }) => proj.self_type_parameter(db) == *self,
+                                    WhereClause::AliasEq(_) => false,
+                                    WhereClause::TypeOutlives(to) => to.ty == *self,
+                                    WhereClause::LifetimeOutlives(_) => false,
                                 })
                                 .collect::<Vec<_>>();
                             let krate = id.parent.module(db.upcast()).krate();
                             write_bounds_like_dyn_trait_with_prefix(
                                 f,
                                 "impl",
+                                Either::Left(self),
                                 &bounds,
                                 SizedByDefault::Sized { anchor: krate },
                             )?;
@@ -1229,6 +1235,7 @@ impl HirDisplay for Ty {
                 write_bounds_like_dyn_trait_with_prefix(
                     f,
                     "dyn",
+                    Either::Left(self),
                     &bounds,
                     SizedByDefault::NotSized,
                 )?;
@@ -1252,6 +1259,7 @@ impl HirDisplay for Ty {
                         write_bounds_like_dyn_trait_with_prefix(
                             f,
                             "impl",
+                            Either::Left(self),
                             bounds.skip_binders(),
                             SizedByDefault::Sized { anchor: krate },
                         )?;
@@ -1266,6 +1274,7 @@ impl HirDisplay for Ty {
                         write_bounds_like_dyn_trait_with_prefix(
                             f,
                             "impl",
+                            Either::Left(self),
                             bounds.skip_binders(),
                             SizedByDefault::Sized { anchor: krate },
                         )?;
@@ -1468,6 +1477,7 @@ impl SizedByDefault {
 pub fn write_bounds_like_dyn_trait_with_prefix(
     f: &mut HirFormatter<'_>,
     prefix: &str,
+    this: Either<&Ty, &Lifetime>,
     predicates: &[QuantifiedWhereClause],
     default_sized: SizedByDefault,
 ) -> Result<(), HirDisplayError> {
@@ -1476,7 +1486,7 @@ pub fn write_bounds_like_dyn_trait_with_prefix(
         || predicates.is_empty() && matches!(default_sized, SizedByDefault::Sized { .. })
     {
         write!(f, " ")?;
-        write_bounds_like_dyn_trait(f, predicates, default_sized)
+        write_bounds_like_dyn_trait(f, this, predicates, default_sized)
     } else {
         Ok(())
     }
@@ -1484,6 +1494,7 @@ pub fn write_bounds_like_dyn_trait_with_prefix(
 
 fn write_bounds_like_dyn_trait(
     f: &mut HirFormatter<'_>,
+    this: Either<&Ty, &Lifetime>,
     predicates: &[QuantifiedWhereClause],
     default_sized: SizedByDefault,
 ) -> Result<(), HirDisplayError> {
@@ -1541,6 +1552,28 @@ fn write_bounds_like_dyn_trait(
                     }
                 }
             }
+            WhereClause::TypeOutlives(to) if Either::Left(&to.ty) == this => {
+                if !is_fn_trait && angle_open {
+                    write!(f, ">")?;
+                    angle_open = false;
+                }
+                if !first {
+                    write!(f, " + ")?;
+                }
+                to.lifetime.hir_fmt(f)?;
+            }
+            WhereClause::TypeOutlives(_) => {}
+            WhereClause::LifetimeOutlives(lo) if Either::Right(&lo.a) == this => {
+                if !is_fn_trait && angle_open {
+                    write!(f, ">")?;
+                    angle_open = false;
+                }
+                if !first {
+                    write!(f, " + ")?;
+                }
+                lo.b.hir_fmt(f)?;
+            }
+            WhereClause::LifetimeOutlives(_) => {}
             WhereClause::AliasEq(alias_eq) if is_fn_trait => {
                 is_fn_trait = false;
                 if !alias_eq.ty.is_unit() {
@@ -1577,10 +1610,6 @@ fn write_bounds_like_dyn_trait(
                 }
                 ty.hir_fmt(f)?;
             }
-
-            // FIXME implement these
-            WhereClause::LifetimeOutlives(_) => {}
-            WhereClause::TypeOutlives(_) => {}
         }
         first = false;
     }
diff --git a/crates/hir-ty/src/tests/traits.rs b/crates/hir-ty/src/tests/traits.rs
index 759af18c98b..fac850eeaf3 100644
--- a/crates/hir-ty/src/tests/traits.rs
+++ b/crates/hir-ty/src/tests/traits.rs
@@ -1612,10 +1612,10 @@ fn test(
 ) {}
 "#,
         expect![[r#"
-            28..29 'a': impl Trait
-            59..60 'b': impl Sized
+            28..29 'a': impl Trait + 'static
+            59..60 'b': impl 'static
             82..83 'c': impl Trait
-            103..104 'd': impl Sized
+            103..104 'd': impl 'static
             128..129 'e': impl ?Sized
             148..149 'f': impl Trait + ?Sized
             173..175 '{}': ()
diff --git a/crates/hir/src/display.rs b/crates/hir/src/display.rs
index 23c6b078b96..84f03d111f2 100644
--- a/crates/hir/src/display.rs
+++ b/crates/hir/src/display.rs
@@ -1,4 +1,5 @@
 //! HirDisplay implementations for various hir types.
+use either::Either;
 use hir_def::{
     data::adt::{StructKind, VariantData},
     generics::{
@@ -13,7 +14,7 @@ use hir_ty::{
         write_bounds_like_dyn_trait_with_prefix, write_visibility, HirDisplay, HirDisplayError,
         HirFormatter, SizedByDefault,
     },
-    Interner, TraitRefExt, WhereClause,
+    AliasEq, AliasTy, Interner, ProjectionTyExt, TraitRefExt, TyKind, WhereClause,
 };
 
 use crate::{
@@ -363,16 +364,52 @@ impl HirDisplay for TypeOrConstParam {
 
 impl HirDisplay for TypeParam {
     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
-        write!(f, "{}", self.name(f.db).display(f.db.upcast()))?;
+        let params = f.db.generic_params(self.id.parent());
+        let param_data = &params.type_or_consts[self.id.local_id()];
+        let substs = TyBuilder::placeholder_subst(f.db, self.id.parent());
+        let krate = self.id.parent().krate(f.db).id;
+        let ty =
+            TyKind::Placeholder(hir_ty::to_placeholder_idx(f.db, self.id.into())).intern(Interner);
+        let predicates = f.db.generic_predicates(self.id.parent());
+        let predicates = predicates
+            .iter()
+            .cloned()
+            .map(|pred| pred.substitute(Interner, &substs))
+            .filter(|wc| match wc.skip_binders() {
+                WhereClause::Implemented(tr) => tr.self_type_parameter(Interner) == ty,
+                WhereClause::AliasEq(AliasEq { alias: AliasTy::Projection(proj), ty: _ }) => {
+                    proj.self_type_parameter(f.db) == ty
+                }
+                WhereClause::AliasEq(_) => false,
+                WhereClause::TypeOutlives(to) => to.ty == ty,
+                WhereClause::LifetimeOutlives(_) => false,
+            })
+            .collect::<Vec<_>>();
+
+        match param_data {
+            TypeOrConstParamData::TypeParamData(p) => match p.provenance {
+                TypeParamProvenance::TypeParamList | TypeParamProvenance::TraitSelf => {
+                    write!(f, "{}", p.name.clone().unwrap().display(f.db.upcast()))?
+                }
+                TypeParamProvenance::ArgumentImplTrait => {
+                    return write_bounds_like_dyn_trait_with_prefix(
+                        f,
+                        "impl",
+                        Either::Left(&ty),
+                        &predicates,
+                        SizedByDefault::Sized { anchor: krate },
+                    );
+                }
+            },
+            TypeOrConstParamData::ConstParamData(p) => {
+                write!(f, "{}", p.name.display(f.db.upcast()))?;
+            }
+        }
+
         if f.omit_verbose_types() {
             return Ok(());
         }
 
-        let bounds = f.db.generic_predicates_for_param(self.id.parent(), self.id.into(), None);
-        let substs = TyBuilder::placeholder_subst(f.db, self.id.parent());
-        let predicates: Vec<_> =
-            bounds.iter().cloned().map(|b| b.substitute(Interner, &substs)).collect();
-        let krate = self.id.parent().krate(f.db).id;
         let sized_trait =
             f.db.lang_item(krate, LangItem::Sized).and_then(|lang_item| lang_item.as_trait());
         let has_only_sized_bound = predicates.iter().all(move |pred| match pred.skip_binders() {
@@ -382,7 +419,16 @@ impl HirDisplay for TypeParam {
         let has_only_not_sized_bound = predicates.is_empty();
         if !has_only_sized_bound || has_only_not_sized_bound {
             let default_sized = SizedByDefault::Sized { anchor: krate };
-            write_bounds_like_dyn_trait_with_prefix(f, ":", &predicates, default_sized)?;
+            write_bounds_like_dyn_trait_with_prefix(
+                f,
+                ":",
+                Either::Left(
+                    &hir_ty::TyKind::Placeholder(hir_ty::to_placeholder_idx(f.db, self.id.into()))
+                        .intern(Interner),
+                ),
+                &predicates,
+                default_sized,
+            )?;
         }
         Ok(())
     }
diff --git a/crates/ide-assists/src/handlers/auto_import.rs b/crates/ide-assists/src/handlers/auto_import.rs
index 62696d1a9a8..5545e41f530 100644
--- a/crates/ide-assists/src/handlers/auto_import.rs
+++ b/crates/ide-assists/src/handlers/auto_import.rs
@@ -1588,4 +1588,36 @@ mod bar {
 "#,
         );
     }
+
+    #[test]
+    fn local_inline_import_has_alias() {
+        // FIXME
+        check_assist_not_applicable(
+            auto_import,
+            r#"
+struct S<T>(T);
+use S as IoResult;
+
+mod foo {
+    pub fn bar() -> S$0<()> {}
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn alias_local() {
+        // FIXME
+        check_assist_not_applicable(
+            auto_import,
+            r#"
+struct S<T>(T);
+use S as IoResult;
+
+mod foo {
+    pub fn bar() -> IoResult$0<()> {}
+}
+"#,
+        );
+    }
 }
diff --git a/crates/ide/src/hover/tests.rs b/crates/ide/src/hover/tests.rs
index 08925fcdff5..d1721f1191a 100644
--- a/crates/ide/src/hover/tests.rs
+++ b/crates/ide/src/hover/tests.rs
@@ -4040,7 +4040,6 @@ impl<T> Foo<T$0> {}
             ```
         "#]],
     );
-    // lifetimes bounds arent being tracked yet
     check(
         r#"
 //- minicore: sized
@@ -4051,7 +4050,7 @@ impl<T: 'static> Foo<T$0> {}
             *T*
 
             ```rust
-            T
+            T: 'static
             ```
         "#]],
     );