Merging upstream version 1.70.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 293 insertions, 95 deletions

diff --git a/tests/ui/ufcs/ufcs-partially-resolved.rs b/tests/ui/ufcs/ufcs-partially-resolved.rs
index e6470aa6d..712668728 100644
--- a/tests/ui/ufcs/ufcs-partially-resolved.rs
+++ b/tests/ui/ufcs/ufcs-partially-resolved.rs
@@ -17,37 +17,37 @@ type A = u32;
 
 fn main() {
     let _: <u8 as Tr>::N; //~ ERROR cannot find associated type `N` in trait `Tr`
-    let _: <u8 as E>::N; //~ ERROR cannot find associated type `N` in enum `E`
-    let _: <u8 as A>::N; //~ ERROR cannot find associated type `N` in `A`
+    let _: <u8 as E>::N; //~ ERROR expected trait, found enum `E`
+    let _: <u8 as A>::N; //~ ERROR expected trait, found type alias `A`
     <u8 as Tr>::N; //~ ERROR cannot find method or associated constant `N` in trait `Tr`
-    <u8 as E>::N; //~ ERROR cannot find method or associated constant `N` in enum `E`
-    <u8 as A>::N; //~ ERROR cannot find method or associated constant `N` in `A`
+    <u8 as E>::N; //~ ERROR expected trait, found enum `E`
+    <u8 as A>::N; //~ ERROR expected trait, found type alias `A`
     let _: <u8 as Tr>::Y; // OK
-    let _: <u8 as E>::Y; //~ ERROR expected associated type, found variant `E::Y`
+    let _: <u8 as E>::Y; //~ ERROR expected trait, found enum `E`
     <u8 as Tr>::Y; // OK
-    <u8 as E>::Y; //~ ERROR expected method or associated constant, found unit variant `E::Y`
+    <u8 as E>::Y; //~ ERROR expected trait, found enum `E`
 
     let _: <u8 as Tr>::N::NN; //~ ERROR cannot find associated type `N` in trait `Tr`
-    let _: <u8 as E>::N::NN; //~ ERROR cannot find associated type `N` in enum `E`
-    let _: <u8 as A>::N::NN; //~ ERROR cannot find associated type `N` in `A`
+    let _: <u8 as E>::N::NN; //~ ERROR expected trait, found enum `E`
+    let _: <u8 as A>::N::NN; //~ ERROR expected trait, found type alias `A`
     <u8 as Tr>::N::NN; //~ ERROR cannot find associated type `N` in trait `Tr`
-    <u8 as E>::N::NN; //~ ERROR cannot find associated type `N` in enum `E`
-    <u8 as A>::N::NN; //~ ERROR cannot find associated type `N` in `A`
+    <u8 as E>::N::NN; //~ ERROR expected trait, found enum `E`
+    <u8 as A>::N::NN; //~ ERROR expected trait, found type alias `A`
     let _: <u8 as Tr>::Y::NN; //~ ERROR ambiguous associated type
-    let _: <u8 as E>::Y::NN; //~ ERROR expected associated type, found variant `E::Y`
+    let _: <u8 as E>::Y::NN; //~ ERROR expected trait, found enum `E`
     <u8 as Tr>::Y::NN; //~ ERROR no associated item named `NN` found for type `u16`
-    <u8 as E>::Y::NN; //~ ERROR expected associated type, found variant `E::Y`
+    <u8 as E>::Y::NN; //~ ERROR expected trait, found enum `E`
 
-    let _: <u8 as Tr::N>::NN; //~ ERROR cannot find associated type `NN` in `Tr::N`
-    let _: <u8 as E::N>::NN; //~ ERROR cannot find associated type `NN` in `E::N`
-    let _: <u8 as A::N>::NN; //~ ERROR cannot find associated type `NN` in `A::N`
-    <u8 as Tr::N>::NN; //~ ERROR cannot find method or associated constant `NN` in `Tr::N`
-    <u8 as E::N>::NN; //~ ERROR cannot find method or associated constant `NN` in `E::N`
-    <u8 as A::N>::NN; //~ ERROR cannot find method or associated constant `NN` in `A::N`
-    let _: <u8 as Tr::Y>::NN; //~ ERROR cannot find associated type `NN` in `Tr::Y`
-    let _: <u8 as E::Y>::NN; //~ ERROR failed to resolve: `Y` is a variant, not a module
-    <u8 as Tr::Y>::NN; //~ ERROR cannot find method or associated constant `NN` in `Tr::Y`
-    <u8 as E::Y>::NN; //~ ERROR failed to resolve: `Y` is a variant, not a module
+    let _: <u8 as Tr::N>::NN; //~ ERROR cannot find trait `N` in trait `Tr`
+    let _: <u8 as E::N>::NN; //~ ERROR cannot find trait `N` in enum `E`
+    let _: <u8 as A::N>::NN; //~ ERROR cannot find trait `N` in `A`
+    <u8 as Tr::N>::NN; //~ ERROR cannot find trait `N` in trait `Tr`
+    <u8 as E::N>::NN; //~ ERROR cannot find trait `N` in enum `E`
+    <u8 as A::N>::NN; //~ ERROR cannot find trait `N` in `A`
+    let _: <u8 as Tr::Y>::NN; //~ ERROR expected trait, found associated type `Tr::Y
+    let _: <u8 as E::Y>::NN; //~ ERROR expected trait, found variant `E::Y`
+    <u8 as Tr::Y>::NN; //~ ERROR expected trait, found associated type `Tr::Y`
+    <u8 as E::Y>::NN; //~ ERROR expected trait, found variant `E::Y`
 
     let _: <u8 as Dr>::Z; //~ ERROR expected associated type, found associated function `Dr::Z`
     <u8 as Dr>::X; //~ ERROR expected method or associated constant, found associated type `Dr::X`
diff --git a/tests/ui/ufcs/ufcs-partially-resolved.stderr b/tests/ui/ufcs/ufcs-partially-resolved.stderr
index 72fccea8a..eef55c8dc 100644
--- a/tests/ui/ufcs/ufcs-partially-resolved.stderr
+++ b/tests/ui/ufcs/ufcs-partially-resolved.stderr
@@ -1,15 +1,3 @@
-error[E0433]: failed to resolve: `Y` is a variant, not a module
-  --> $DIR/ufcs-partially-resolved.rs:48:22
-   |
-LL |     let _: <u8 as E::Y>::NN;
-   |                      ^ `Y` is a variant, not a module
-
-error[E0433]: failed to resolve: `Y` is a variant, not a module
-  --> $DIR/ufcs-partially-resolved.rs:50:15
-   |
-LL |     <u8 as E::Y>::NN;
-   |               ^ `Y` is a variant, not a module
-
 error[E0576]: cannot find associated type `N` in trait `Tr`
   --> $DIR/ufcs-partially-resolved.rs:19:24
    |
@@ -19,17 +7,25 @@ LL |     type Y = u16;
 LL |     let _: <u8 as Tr>::N;
    |                        ^ help: an associated type with a similar name exists: `Y`
 
-error[E0576]: cannot find associated type `N` in enum `E`
-  --> $DIR/ufcs-partially-resolved.rs:20:23
+error[E0404]: expected trait, found enum `E`
+  --> $DIR/ufcs-partially-resolved.rs:20:19
    |
 LL |     let _: <u8 as E>::N;
-   |                       ^ not found in `E`
+   |                   ^ help: a trait with a similar name exists: `Eq`
+  --> $SRC_DIR/core/src/cmp.rs:LL:COL
+   |
+   = note: similarly named trait `Eq` defined here
 
-error[E0576]: cannot find associated type `N` in `A`
-  --> $DIR/ufcs-partially-resolved.rs:21:23
+error[E0404]: expected trait, found type alias `A`
+  --> $DIR/ufcs-partially-resolved.rs:21:19
    |
 LL |     let _: <u8 as A>::N;
-   |                       ^ not found in `A`
+   |                   ^ type aliases cannot be used as traits
+   |
+help: you might have meant to use `#![feature(trait_alias)]` instead of a `type` alias
+   |
+LL | trait A = u32;
+   |
 
 error[E0576]: cannot find method or associated constant `N` in trait `Tr`
   --> $DIR/ufcs-partially-resolved.rs:22:17
@@ -40,29 +36,43 @@ LL |     fn Y() {}
 LL |     <u8 as Tr>::N;
    |                 ^ help: an associated function with a similar name exists: `Y`
 
-error[E0576]: cannot find method or associated constant `N` in enum `E`
-  --> $DIR/ufcs-partially-resolved.rs:23:16
+error[E0404]: expected trait, found enum `E`
+  --> $DIR/ufcs-partially-resolved.rs:23:12
    |
 LL |     <u8 as E>::N;
-   |                ^ not found in `E`
+   |            ^ help: a trait with a similar name exists: `Eq`
+  --> $SRC_DIR/core/src/cmp.rs:LL:COL
+   |
+   = note: similarly named trait `Eq` defined here
 
-error[E0576]: cannot find method or associated constant `N` in `A`
-  --> $DIR/ufcs-partially-resolved.rs:24:16
+error[E0404]: expected trait, found type alias `A`
+  --> $DIR/ufcs-partially-resolved.rs:24:12
    |
 LL |     <u8 as A>::N;
-   |                ^ not found in `A`
+   |            ^ type aliases cannot be used as traits
+   |
+help: you might have meant to use `#![feature(trait_alias)]` instead of a `type` alias
+   |
+LL | trait A = u32;
+   |
 
-error[E0575]: expected associated type, found variant `E::Y`
-  --> $DIR/ufcs-partially-resolved.rs:26:12
+error[E0404]: expected trait, found enum `E`
+  --> $DIR/ufcs-partially-resolved.rs:26:19
    |
 LL |     let _: <u8 as E>::Y;
-   |            ^^^^^^^^^^^^ not a associated type
+   |                   ^ help: a trait with a similar name exists: `Eq`
+  --> $SRC_DIR/core/src/cmp.rs:LL:COL
+   |
+   = note: similarly named trait `Eq` defined here
 
-error[E0575]: expected method or associated constant, found unit variant `E::Y`
-  --> $DIR/ufcs-partially-resolved.rs:28:5
+error[E0404]: expected trait, found enum `E`
+  --> $DIR/ufcs-partially-resolved.rs:28:12
    |
 LL |     <u8 as E>::Y;
-   |     ^^^^^^^^^^^^ not a method or associated constant
+   |            ^ help: a trait with a similar name exists: `Eq`
+  --> $SRC_DIR/core/src/cmp.rs:LL:COL
+   |
+   = note: similarly named trait `Eq` defined here
 
 error[E0576]: cannot find associated type `N` in trait `Tr`
   --> $DIR/ufcs-partially-resolved.rs:30:24
@@ -73,17 +83,25 @@ LL |     type Y = u16;
 LL |     let _: <u8 as Tr>::N::NN;
    |                        ^ help: an associated type with a similar name exists: `Y`
 
-error[E0576]: cannot find associated type `N` in enum `E`
-  --> $DIR/ufcs-partially-resolved.rs:31:23
+error[E0404]: expected trait, found enum `E`
+  --> $DIR/ufcs-partially-resolved.rs:31:19
    |
 LL |     let _: <u8 as E>::N::NN;
-   |                       ^ not found in `E`
+   |                   ^ help: a trait with a similar name exists: `Eq`
+  --> $SRC_DIR/core/src/cmp.rs:LL:COL
+   |
+   = note: similarly named trait `Eq` defined here
 
-error[E0576]: cannot find associated type `N` in `A`
-  --> $DIR/ufcs-partially-resolved.rs:32:23
+error[E0404]: expected trait, found type alias `A`
+  --> $DIR/ufcs-partially-resolved.rs:32:19
    |
 LL |     let _: <u8 as A>::N::NN;
-   |                       ^ not found in `A`
+   |                   ^ type aliases cannot be used as traits
+   |
+help: you might have meant to use `#![feature(trait_alias)]` instead of a `type` alias
+   |
+LL | trait A = u32;
+   |
 
 error[E0576]: cannot find associated type `N` in trait `Tr`
   --> $DIR/ufcs-partially-resolved.rs:33:17
@@ -94,77 +112,103 @@ LL |     type Y = u16;
 LL |     <u8 as Tr>::N::NN;
    |                 ^ help: an associated type with a similar name exists: `Y`
 
-error[E0576]: cannot find associated type `N` in enum `E`
-  --> $DIR/ufcs-partially-resolved.rs:34:16
+error[E0404]: expected trait, found enum `E`
+  --> $DIR/ufcs-partially-resolved.rs:34:12
    |
 LL |     <u8 as E>::N::NN;
-   |                ^ not found in `E`
+   |            ^ help: a trait with a similar name exists: `Eq`
+  --> $SRC_DIR/core/src/cmp.rs:LL:COL
+   |
+   = note: similarly named trait `Eq` defined here
 
-error[E0576]: cannot find associated type `N` in `A`
-  --> $DIR/ufcs-partially-resolved.rs:35:16
+error[E0404]: expected trait, found type alias `A`
+  --> $DIR/ufcs-partially-resolved.rs:35:12
    |
 LL |     <u8 as A>::N::NN;
-   |                ^ not found in `A`
+   |            ^ type aliases cannot be used as traits
+   |
+help: you might have meant to use `#![feature(trait_alias)]` instead of a `type` alias
+   |
+LL | trait A = u32;
+   |
 
-error[E0575]: expected associated type, found variant `E::Y`
-  --> $DIR/ufcs-partially-resolved.rs:37:12
+error[E0404]: expected trait, found enum `E`
+  --> $DIR/ufcs-partially-resolved.rs:37:19
    |
 LL |     let _: <u8 as E>::Y::NN;
-   |            ^^^^^^^^^^^^^^^^ not a associated type
+   |                   ^ help: a trait with a similar name exists: `Eq`
+  --> $SRC_DIR/core/src/cmp.rs:LL:COL
+   |
+   = note: similarly named trait `Eq` defined here
 
-error[E0575]: expected associated type, found variant `E::Y`
-  --> $DIR/ufcs-partially-resolved.rs:39:5
+error[E0404]: expected trait, found enum `E`
+  --> $DIR/ufcs-partially-resolved.rs:39:12
    |
 LL |     <u8 as E>::Y::NN;
-   |     ^^^^^^^^^^^^^^^^ not a associated type
+   |            ^ help: a trait with a similar name exists: `Eq`
+  --> $SRC_DIR/core/src/cmp.rs:LL:COL
+   |
+   = note: similarly named trait `Eq` defined here
 
-error[E0576]: cannot find associated type `NN` in `Tr::N`
-  --> $DIR/ufcs-partially-resolved.rs:41:27
+error[E0405]: cannot find trait `N` in trait `Tr`
+  --> $DIR/ufcs-partially-resolved.rs:41:23
    |
 LL |     let _: <u8 as Tr::N>::NN;
-   |                           ^^ not found in `Tr::N`
+   |                       ^ not found in `Tr`
 
-error[E0576]: cannot find associated type `NN` in `E::N`
-  --> $DIR/ufcs-partially-resolved.rs:42:26
+error[E0405]: cannot find trait `N` in enum `E`
+  --> $DIR/ufcs-partially-resolved.rs:42:22
    |
 LL |     let _: <u8 as E::N>::NN;
-   |                          ^^ not found in `E::N`
+   |                      ^ not found in `E`
 
-error[E0576]: cannot find associated type `NN` in `A::N`
-  --> $DIR/ufcs-partially-resolved.rs:43:26
+error[E0405]: cannot find trait `N` in `A`
+  --> $DIR/ufcs-partially-resolved.rs:43:22
    |
 LL |     let _: <u8 as A::N>::NN;
-   |                          ^^ not found in `A::N`
+   |                      ^ not found in `A`
 
-error[E0576]: cannot find method or associated constant `NN` in `Tr::N`
-  --> $DIR/ufcs-partially-resolved.rs:44:20
+error[E0405]: cannot find trait `N` in trait `Tr`
+  --> $DIR/ufcs-partially-resolved.rs:44:16
    |
 LL |     <u8 as Tr::N>::NN;
-   |                    ^^ not found in `Tr::N`
+   |                ^ not found in `Tr`
 
-error[E0576]: cannot find method or associated constant `NN` in `E::N`
-  --> $DIR/ufcs-partially-resolved.rs:45:19
+error[E0405]: cannot find trait `N` in enum `E`
+  --> $DIR/ufcs-partially-resolved.rs:45:15
    |
 LL |     <u8 as E::N>::NN;
-   |                   ^^ not found in `E::N`
+   |               ^ not found in `E`
 
-error[E0576]: cannot find method or associated constant `NN` in `A::N`
-  --> $DIR/ufcs-partially-resolved.rs:46:19
+error[E0405]: cannot find trait `N` in `A`
+  --> $DIR/ufcs-partially-resolved.rs:46:15
    |
 LL |     <u8 as A::N>::NN;
-   |                   ^^ not found in `A::N`
+   |               ^ not found in `A`
 
-error[E0576]: cannot find associated type `NN` in `Tr::Y`
-  --> $DIR/ufcs-partially-resolved.rs:47:27
+error[E0404]: expected trait, found associated type `Tr::Y`
+  --> $DIR/ufcs-partially-resolved.rs:47:19
    |
 LL |     let _: <u8 as Tr::Y>::NN;
-   |                           ^^ not found in `Tr::Y`
+   |                   ^^^^^ not a trait
+
+error[E0404]: expected trait, found variant `E::Y`
+  --> $DIR/ufcs-partially-resolved.rs:48:19
+   |
+LL |     let _: <u8 as E::Y>::NN;
+   |                   ^^^^ not a trait
 
-error[E0576]: cannot find method or associated constant `NN` in `Tr::Y`
-  --> $DIR/ufcs-partially-resolved.rs:49:20
+error[E0404]: expected trait, found associated type `Tr::Y`
+  --> $DIR/ufcs-partially-resolved.rs:49:12
    |
 LL |     <u8 as Tr::Y>::NN;
-   |                    ^^ not found in `Tr::Y`
+   |            ^^^^^ not a trait
+
+error[E0404]: expected trait, found variant `E::Y`
+  --> $DIR/ufcs-partially-resolved.rs:50:12
+   |
+LL |     <u8 as E::Y>::NN;
+   |            ^^^^ not a trait
 
 error[E0575]: expected associated type, found associated function `Dr::Z`
   --> $DIR/ufcs-partially-resolved.rs:52:12
@@ -226,5 +270,5 @@ LL |     <u8 as Dr>::X::N;
 
 error: aborting due to 32 previous errors
 
-Some errors have detailed explanations: E0223, E0433, E0575, E0576, E0599.
+Some errors have detailed explanations: E0223, E0404, E0405, E0575, E0576, E0599.
 For more information about an error, try `rustc --explain E0223`.
diff --git a/tests/ui/ufcs/ufcs-polymorphic-paths.rs b/tests/ui/ufcs/ufcs-polymorphic-paths.rs
new file mode 100644
index 000000000..a14ebd6a4
--- /dev/null
+++ b/tests/ui/ufcs/ufcs-polymorphic-paths.rs
@@ -0,0 +1,154 @@
+// run-pass
+
+use std::borrow::{Cow, ToOwned};
+use std::default::Default;
+use std::iter::FromIterator;
+use std::ops::Add;
+use std::option::IntoIter as OptionIter;
+
+pub struct XorShiftRng;
+use XorShiftRng as DummyRng;
+impl Rng for XorShiftRng {}
+pub trait Rng {}
+pub trait Rand: Default + Sized {
+    fn rand<R: Rng>(_rng: &mut R) -> Self { Default::default() }
+}
+impl Rand for i32 { }
+
+pub trait IntoCow<'a, B: ?Sized> where B: ToOwned {
+    fn into_cow(self) -> Cow<'a, B>;
+}
+
+impl<'a> IntoCow<'a, str> for String {
+    fn into_cow(self) -> Cow<'a, str> {
+        Cow::Owned(self)
+    }
+}
+
+#[derive(PartialEq, Eq)]
+struct Newt<T>(T);
+
+fn id<T>(x: T) -> T { x }
+fn eq<T: Eq>(a: T, b: T) -> bool { a == b }
+fn u8_as_i8(x: u8) -> i8 { x as i8 }
+fn odd(x: usize) -> bool { x % 2 == 1 }
+fn dummy_rng() -> DummyRng { XorShiftRng }
+
+trait Size: Sized {
+    fn size() -> usize { std::mem::size_of::<Self>() }
+}
+impl<T> Size for T {}
+
+#[derive(PartialEq, Eq)]
+struct BitVec;
+
+impl BitVec {
+    fn from_fn<F>(_: usize, _: F) -> BitVec where F: FnMut(usize) -> bool {
+        BitVec
+    }
+}
+
+#[derive(PartialEq, Eq)]
+struct Foo<T>(T);
+
+impl<T> Foo<T> {
+    fn map_in_place<U, F>(self, mut f: F) -> Foo<U> where F: FnMut(T) -> U {
+        Foo(f(self.0))
+    }
+
+}
+
+macro_rules! tests {
+    ($($expr:expr, $ty:ty, ($($test:expr),*);)+) => (pub fn main() {$({
+        const C: $ty = $expr;
+        static S: $ty = $expr;
+        assert!(eq(C($($test),*), $expr($($test),*)));
+        assert!(eq(S($($test),*), $expr($($test),*)));
+        assert!(eq(C($($test),*), S($($test),*)));
+    })+})
+}
+
+tests! {
+    // Free function.
+    id, fn(i32) -> i32, (5);
+    id::<i32>, fn(i32) -> i32, (5);
+
+    // Enum variant constructor.
+    Some, fn(i32) -> Option<i32>, (5);
+    Some::<i32>, fn(i32) -> Option<i32>, (5);
+
+    // Tuple struct constructor.
+    Newt, fn(i32) -> Newt<i32>, (5);
+    Newt::<i32>, fn(i32) -> Newt<i32>, (5);
+
+    // Inherent static methods.
+    Vec::new, fn() -> Vec<()>, ();
+    Vec::<()>::new, fn() -> Vec<()>, ();
+    <Vec<()>>::new, fn() -> Vec<()>, ();
+    Vec::with_capacity, fn(usize) -> Vec<()>, (5);
+    Vec::<()>::with_capacity, fn(usize) -> Vec<()>, (5);
+    <Vec<()>>::with_capacity, fn(usize) -> Vec<()>, (5);
+    BitVec::from_fn, fn(usize, fn(usize) -> bool) -> BitVec, (5, odd);
+    BitVec::from_fn::<fn(usize) -> bool>, fn(usize, fn(usize) -> bool) -> BitVec, (5, odd);
+
+    // Inherent non-static method.
+    Foo::map_in_place, fn(Foo<u8>, fn(u8) -> i8) -> Foo<i8>, (Foo(b'f'), u8_as_i8);
+    Foo::map_in_place::<i8, fn(u8) -> i8>, fn(Foo<u8>, fn(u8) -> i8) -> Foo<i8>,
+        (Foo(b'f'), u8_as_i8);
+    Foo::<u8>::map_in_place, fn(Foo<u8>, fn(u8) -> i8) -> Foo<i8>
+        , (Foo(b'f'), u8_as_i8);
+    Foo::<u8>::map_in_place::<i8, fn(u8) -> i8>, fn(Foo<u8>, fn(u8) -> i8) -> Foo<i8>
+        , (Foo(b'f'), u8_as_i8);
+
+    // Trait static methods.
+    bool::size, fn() -> usize, ();
+    <bool>::size, fn() -> usize, ();
+    <bool as Size>::size, fn() -> usize, ();
+
+    Default::default, fn() -> i32, ();
+    i32::default, fn() -> i32, ();
+    <i32>::default, fn() -> i32, ();
+    <i32 as Default>::default, fn() -> i32, ();
+
+    Rand::rand, fn(&mut DummyRng) -> i32, (&mut dummy_rng());
+    i32::rand, fn(&mut DummyRng) -> i32, (&mut dummy_rng());
+    <i32>::rand, fn(&mut DummyRng) -> i32, (&mut dummy_rng());
+    <i32 as Rand>::rand, fn(&mut DummyRng) -> i32, (&mut dummy_rng());
+    Rand::rand::<DummyRng>, fn(&mut DummyRng) -> i32, (&mut dummy_rng());
+    i32::rand::<DummyRng>, fn(&mut DummyRng) -> i32, (&mut dummy_rng());
+    <i32>::rand::<DummyRng>, fn(&mut DummyRng) -> i32, (&mut dummy_rng());
+    <i32 as Rand>::rand::<DummyRng>, fn(&mut DummyRng) -> i32, (&mut dummy_rng());
+
+    // Trait non-static methods.
+    Clone::clone, fn(&i32) -> i32, (&5);
+    i32::clone, fn(&i32) -> i32, (&5);
+    <i32>::clone, fn(&i32) -> i32, (&5);
+    <i32 as Clone>::clone, fn(&i32) -> i32, (&5);
+
+    FromIterator::from_iter, fn(OptionIter<i32>) -> Vec<i32>, (Some(5).into_iter());
+    Vec::from_iter, fn(OptionIter<i32>) -> Vec<i32>, (Some(5).into_iter());
+    <Vec<_>>::from_iter, fn(OptionIter<i32>) -> Vec<i32>, (Some(5).into_iter());
+    <Vec<_> as FromIterator<_>>::from_iter, fn(OptionIter<i32>) -> Vec<i32>,
+        (Some(5).into_iter());
+    <Vec<i32> as FromIterator<_>>::from_iter, fn(OptionIter<i32>) -> Vec<i32>,
+        (Some(5).into_iter());
+    FromIterator::from_iter::<OptionIter<i32>>, fn(OptionIter<i32>) -> Vec<i32>,
+        (Some(5).into_iter());
+    <Vec<i32> as FromIterator<_>>::from_iter::<OptionIter<i32>>, fn(OptionIter<i32>) -> Vec<i32>,
+        (Some(5).into_iter());
+
+    Add::add, fn(i32, i32) -> i32, (5, 6);
+    i32::add, fn(i32, i32) -> i32, (5, 6);
+    <i32>::add, fn(i32, i32) -> i32, (5, 6);
+    <i32 as Add<_>>::add, fn(i32, i32) -> i32, (5, 6);
+    <i32 as Add<i32>>::add, fn(i32, i32) -> i32, (5, 6);
+
+    String::into_cow, fn(String) -> Cow<'static, str>,
+        ("foo".to_string());
+    <String>::into_cow, fn(String) -> Cow<'static, str>,
+        ("foo".to_string());
+    <String as IntoCow<_>>::into_cow, fn(String) -> Cow<'static, str>,
+        ("foo".to_string());
+    <String as IntoCow<'static, _>>::into_cow, fn(String) -> Cow<'static, str>,
+        ("foo".to_string());
+}