4 files changed, 172 insertions, 15 deletions

diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index ccc4348f4..daea02f88 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -808,15 +808,13 @@ impl Ty {
         }
     }
 
-    /// If this is an `impl Trait` or `dyn Trait`, returns that trait.
-    pub fn inherent_trait(&self) -> Option<TraitId> {
+    /// If this is a `dyn Trait`, returns that trait.
+    pub fn dyn_trait(&self) -> Option<TraitId> {
         match self {
-            Ty::Dyn(predicates) | Ty::Opaque(predicates) => {
-                predicates.iter().find_map(|pred| match pred {
-                    GenericPredicate::Implemented(tr) => Some(tr.trait_),
-                    _ => None,
-                })
-            }
+            Ty::Dyn(predicates) => predicates.iter().find_map(|pred| match pred {
+                GenericPredicate::Implemented(tr) => Some(tr.trait_),
+                _ => None,
+            }),
             _ => None,
         }
     }
diff --git a/crates/ra_hir_ty/src/method_resolution.rs b/crates/ra_hir_ty/src/method_resolution.rs
index 657284fd0..0851e16a8 100644
--- a/crates/ra_hir_ty/src/method_resolution.rs
+++ b/crates/ra_hir_ty/src/method_resolution.rs
@@ -408,8 +408,9 @@ fn iterate_trait_method_candidates<T>(
     receiver_ty: Option<&Canonical<Ty>>,
     mut callback: impl FnMut(&Ty, AssocItemId) -> Option<T>,
 ) -> Option<T> {
-    // if ty is `impl Trait` or `dyn Trait`, the trait doesn't need to be in scope
-    let inherent_trait = self_ty.value.inherent_trait().into_iter();
+    // if ty is `dyn Trait`, the trait doesn't need to be in scope
+    let inherent_trait =
+        self_ty.value.dyn_trait().into_iter().flat_map(|t| all_super_traits(db.upcast(), t));
     let env_traits = if let Ty::Placeholder(_) = self_ty.value {
         // if we have `T: Trait` in the param env, the trait doesn't need to be in scope
         env.trait_predicates_for_self_ty(&self_ty.value)
@@ -601,11 +602,6 @@ pub fn implements_trait(
     krate: CrateId,
     trait_: TraitId,
 ) -> bool {
-    if ty.value.inherent_trait() == Some(trait_) {
-        // FIXME this is a bit of a hack, since Chalk should say the same thing
-        // anyway, but currently Chalk doesn't implement `dyn/impl Trait` yet
-        return true;
-    }
     let goal = generic_implements_goal(db, env, trait_, ty.clone());
     let solution = db.trait_solve(krate, goal);
 
diff --git a/crates/ra_hir_ty/src/tests/method_resolution.rs b/crates/ra_hir_ty/src/tests/method_resolution.rs
index 67f964ab5..9c2c9e1d2 100644
--- a/crates/ra_hir_ty/src/tests/method_resolution.rs
+++ b/crates/ra_hir_ty/src/tests/method_resolution.rs
@@ -1096,3 +1096,34 @@ fn test() { (S {}).method()<|>; }
     );
     assert_eq!(t, "()");
 }
+
+#[test]
+fn dyn_trait_super_trait_not_in_scope() {
+    assert_snapshot!(
+        infer(r#"
+mod m {
+    pub trait SuperTrait {
+        fn foo(&self) -> u32 { 0 }
+    }
+}
+trait Trait: m::SuperTrait {}
+
+struct S;
+impl m::SuperTrait for S {}
+impl Trait for S {}
+
+fn test(d: &dyn Trait) {
+    d.foo();
+}
+"#),
+        @r###"
+    52..56 'self': &Self
+    65..70 '{ 0 }': u32
+    67..68 '0': u32
+    177..178 'd': &dyn Trait
+    192..208 '{     ...o(); }': ()
+    198..199 'd': &dyn Trait
+    198..205 'd.foo()': u32
+    "###
+    );
+}
diff --git a/crates/ra_hir_ty/src/tests/traits.rs b/crates/ra_hir_ty/src/tests/traits.rs
index 9d32cbc7a..c49aacf98 100644
--- a/crates/ra_hir_ty/src/tests/traits.rs
+++ b/crates/ra_hir_ty/src/tests/traits.rs
@@ -1617,6 +1617,138 @@ fn test<F: FnOnce(u32, u64) -> u128>(f: F) {
 }
 
 #[test]
+fn fn_ptr_and_item() {
+    assert_snapshot!(
+        infer(r#"
+#[lang="fn_once"]
+trait FnOnce<Args> {
+    type Output;
+
+    fn call_once(self, args: Args) -> Self::Output;
+}
+
+trait Foo<T> {
+    fn foo(&self) -> T;
+}
+
+struct Bar<T>(T);
+
+impl<A1, R, F: FnOnce(A1) -> R> Foo<(A1, R)> for Bar<F> {
+    fn foo(&self) -> (A1, R) {}
+}
+
+enum Opt<T> { None, Some(T) }
+impl<T> Opt<T> {
+    fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Opt<U> {}
+}
+
+fn test() {
+    let bar: Bar<fn(u8) -> u32>;
+    bar.foo();
+
+    let opt: Opt<u8>;
+    let f: fn(u8) -> u32;
+    opt.map(f);
+}
+"#),
+        @r###"
+75..79 'self': Self
+81..85 'args': Args
+140..144 'self': &Self
+244..248 'self': &Bar<F>
+261..263 '{}': ()
+347..351 'self': Opt<T>
+353..354 'f': F
+369..371 '{}': ()
+385..501 '{     ...(f); }': ()
+395..398 'bar': Bar<fn(u8) -> u32>
+424..427 'bar': Bar<fn(u8) -> u32>
+424..433 'bar.foo()': {unknown}
+444..447 'opt': Opt<u8>
+466..467 'f': fn(u8) -> u32
+488..491 'opt': Opt<u8>
+488..498 'opt.map(f)': Opt<FnOnce::Output<fn(u8) -> u32, (u8,)>>
+496..497 'f': fn(u8) -> u32
+"###
+    );
+}
+
+#[test]
+fn fn_trait_deref_with_ty_default() {
+    assert_snapshot!(
+        infer(r#"
+#[lang = "deref"]
+trait Deref {
+    type Target;
+
+    fn deref(&self) -> &Self::Target;
+}
+
+#[lang="fn_once"]
+trait FnOnce<Args> {
+    type Output;
+
+    fn call_once(self, args: Args) -> Self::Output;
+}
+
+struct Foo;
+
+impl Foo {
+    fn foo(&self) -> usize {}
+}
+
+struct Lazy<T, F = fn() -> T>(F);
+
+impl<T, F> Lazy<T, F> {
+    pub fn new(f: F) -> Lazy<T, F> {}
+}
+
+impl<T, F: FnOnce() -> T> Deref for Lazy<T, F> {
+    type Target = T;
+}
+
+fn test() {
+    let lazy1: Lazy<Foo, _> = Lazy::new(|| Foo);
+    let r1 = lazy1.foo();
+
+    fn make_foo_fn() -> Foo {}
+    let make_foo_fn_ptr: fn() -> Foo = make_foo_fn;
+    let lazy2: Lazy<Foo, _> = Lazy::new(make_foo_fn_ptr);
+    let r2 = lazy2.foo();
+}
+"#),
+        @r###"
+65..69 'self': &Self
+166..170 'self': Self
+172..176 'args': Args
+240..244 'self': &Foo
+255..257 '{}': ()
+335..336 'f': F
+355..357 '{}': ()
+444..690 '{     ...o(); }': ()
+454..459 'lazy1': Lazy<Foo, fn() -> T>
+476..485 'Lazy::new': fn new<Foo, fn() -> T>(fn() -> T) -> Lazy<Foo, fn() -> T>
+476..493 'Lazy::...| Foo)': Lazy<Foo, fn() -> T>
+486..492 '|| Foo': || -> T
+489..492 'Foo': Foo
+503..505 'r1': {unknown}
+508..513 'lazy1': Lazy<Foo, fn() -> T>
+508..519 'lazy1.foo()': {unknown}
+561..576 'make_foo_fn_ptr': fn() -> Foo
+592..603 'make_foo_fn': fn make_foo_fn() -> Foo
+613..618 'lazy2': Lazy<Foo, fn() -> T>
+635..644 'Lazy::new': fn new<Foo, fn() -> T>(fn() -> T) -> Lazy<Foo, fn() -> T>
+635..661 'Lazy::...n_ptr)': Lazy<Foo, fn() -> T>
+645..660 'make_foo_fn_ptr': fn() -> Foo
+671..673 'r2': {unknown}
+676..681 'lazy2': Lazy<Foo, fn() -> T>
+676..687 'lazy2.foo()': {unknown}
+550..552 '{}': ()
+"###
+    );
+}
+
+#[test]
 fn closure_1() {
     assert_snapshot!(
         infer(r#"