2 files changed, 123 insertions, 64 deletions

diff --git a/crates/ra_hir_ty/src/tests/coercion.rs b/crates/ra_hir_ty/src/tests/coercion.rs
index 136d28a91..d7fb6a962 100644
--- a/crates/ra_hir_ty/src/tests/coercion.rs
+++ b/crates/ra_hir_ty/src/tests/coercion.rs
@@ -662,7 +662,53 @@ fn test() {
 }
 
 #[test]
-fn coerce_unsize_trait_object() {
+fn coerce_unsize_trait_object_simple() {
+    assert_snapshot!(
+        infer_with_mismatches(r#"
+#[lang = "sized"]
+pub trait Sized {}
+#[lang = "unsize"]
+pub trait Unsize<T> {}
+#[lang = "coerce_unsized"]
+pub trait CoerceUnsized<T> {}
+
+impl<T: Unsize<U>, U> CoerceUnsized<&U> for &T {}
+
+trait Foo<T, U> {}
+trait Bar<U, T, X>: Foo<T, U> {}
+trait Baz<T, X>: Bar<usize, T, X> {}
+
+struct S<T, X>;
+impl<T, X> Foo<T, usize> for S<T, X> {}
+impl<T, X> Bar<usize, T, X> for S<T, X> {}
+impl<T, X> Baz<T, X> for S<T, X> {}
+
+fn test() {
+    let obj: &dyn Baz<i8, i16> = &S;
+    let obj: &dyn Bar<_, i8, i16> = &S;
+    let obj: &dyn Foo<i8, _> = &S;
+}
+"#, true),
+        @r###"
+    424..539 '{     ... &S; }': ()
+    434..437 'obj': &dyn Baz<i8, i16>
+    459..461 '&S': &S<i8, i16>
+    460..461 'S': S<i8, i16>
+    471..474 'obj': &dyn Bar<usize, i8, i16>
+    499..501 '&S': &S<i8, i16>
+    500..501 'S': S<i8, i16>
+    511..514 'obj': &dyn Foo<i8, usize>
+    534..536 '&S': &S<i8, {unknown}>
+    535..536 'S': S<i8, {unknown}>
+    "###
+    );
+}
+
+#[test]
+// The rust reference says this should be possible, but rustc doesn't implement
+// it. We used to support it, but Chalk doesn't.
+#[ignore]
+fn coerce_unsize_trait_object_to_trait_object() {
     assert_snapshot!(
         infer_with_mismatches(r#"
 #[lang = "sized"]
@@ -735,16 +781,17 @@ impl D for S {}
 
 fn test() {
     let obj: &dyn D = &S;
-    let obj: &dyn A = obj;
+    let obj: &dyn A = &S;
 }
 "#, true),
         @r###"
-    328..384 '{     ...obj; }': ()
+    328..383 '{     ... &S; }': ()
     338..341 'obj': &dyn D
     352..354 '&S': &S
     353..354 'S': S
     364..367 'obj': &dyn A
-    378..381 'obj': &dyn D
+    378..380 '&S': &S
+    379..380 'S': S
     "###
     );
 }
diff --git a/crates/ra_hir_ty/src/tests/traits.rs b/crates/ra_hir_ty/src/tests/traits.rs
index 529d9e253..27737fa94 100644
--- a/crates/ra_hir_ty/src/tests/traits.rs
+++ b/crates/ra_hir_ty/src/tests/traits.rs
@@ -1992,6 +1992,28 @@ fn test() {
 }
 
 #[test]
+fn fn_item_fn_trait() {
+    check_types(
+        r#"
+#[lang = "fn_once"]
+trait FnOnce<Args> {
+    type Output;
+}
+
+struct S;
+
+fn foo() -> S {}
+
+fn takes_closure<U, F: FnOnce() -> U>(f: F) -> U { f() }
+
+fn test() {
+    takes_closure(foo);
+} //^^^^^^^^^^^^^^^^^^ S
+"#,
+    );
+}
+
+#[test]
 fn unselected_projection_in_trait_env_1() {
     check_types(
         r#"
@@ -3000,74 +3022,47 @@ fn infer_box_fn_arg() {
 
 #[test]
 fn infer_dyn_fn_output() {
-    assert_snapshot!(
-        infer(
-            r#"
-            //- /lib.rs deps:std
-
-            #[lang = "fn_once"]
-            pub trait FnOnce<Args> {
-                type Output;
-
-                extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-            }
-
-            #[lang = "fn"]
-            pub trait Fn<Args>:FnOnce<Args> {
-                extern "rust-call" fn call(&self, args: Args) -> Self::Output;
-            }
-
-            #[lang = "deref"]
-            pub trait Deref {
-                type Target: ?Sized;
-
-                fn deref(&self) -> &Self::Target;
-            }
+    check_types(
+        r#"
+#[lang = "fn_once"]
+pub trait FnOnce<Args> {
+    type Output;
+    extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
+}
 
-            #[lang = "owned_box"]
-            pub struct Box<T: ?Sized> {
-                inner: *mut T,
-            }
+#[lang = "fn"]
+pub trait Fn<Args>: FnOnce<Args> {
+    extern "rust-call" fn call(&self, args: Args) -> Self::Output;
+}
 
-            impl<T: ?Sized> Deref for Box<T> {
-                type Target = T;
+fn foo() {
+    let f: &dyn Fn() -> i32;
+    f();
+  //^^^ i32
+}"#,
+    );
+}
 
-                fn deref(&self) -> &T {
-                    &self.inner
-                }
-            }
+#[test]
+fn infer_dyn_fn_once_output() {
+    check_types(
+        r#"
+#[lang = "fn_once"]
+pub trait FnOnce<Args> {
+    type Output;
+    extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
+}
 
-            fn foo() {
-                let f: Box<dyn Fn() -> i32> = box(|| 5);
-                let x = f();
-            }
-        "#
-        ),
-        @r###"
-    100..104 'self': Self
-    106..110 'args': Args
-    219..223 'self': &Self
-    225..229 'args': Args
-    333..337 'self': &Self
-    503..507 'self': &Box<T>
-    515..542 '{     ...     }': &T
-    525..536 '&self.inner': &*mut T
-    526..530 'self': &Box<T>
-    526..536 'self.inner': *mut T
-    555..620 '{     ...f(); }': ()
-    565..566 'f': Box<dyn Fn<(), Output = i32>>
-    591..600 'box(|| 5)': Box<|| -> i32>
-    595..599 '|| 5': || -> i32
-    598..599 '5': i32
-    610..611 'x': FnOnce::Output<dyn Fn<(), Output = i32>, ()>
-    614..615 'f': Box<dyn Fn<(), Output = i32>>
-    614..617 'f()': FnOnce::Output<dyn Fn<(), Output = i32>, ()>
-    "###
+fn foo() {
+    let f: dyn FnOnce() -> i32;
+    f();
+  //^^^ i32
+}"#,
     );
 }
 
 #[test]
-fn variable_kinds() {
+fn variable_kinds_1() {
     check_types(
         r#"
 trait Trait<T> { fn get(self, t: T) -> T; }
@@ -3083,3 +3078,20 @@ fn test() {
         "#,
     );
 }
+
+#[test]
+fn variable_kinds_2() {
+    check_types(
+        r#"
+trait Trait { fn get(self) -> Self; }
+impl Trait for u128 {}
+impl Trait for f32 {}
+fn test() {
+    1.get();
+  //^^^^^^^ u128
+    (1.).get();
+  //^^^^^^^^^^ f32
+}
+        "#,
+    );
+}