Add regression tests for issues

src/test/ui/associated-const/defaults-cyclic-pass.rs

@@ -6,7 +6,8 @@ trait Tr {
     const B: u8 = Self::A;
 }
 
-// This impl is *allowed* unless its assoc. consts are used
+// This impl is *allowed* unless its assoc. consts are used, matching the
+// behavior without defaults.
 impl Tr for () {}
 
 // Overriding either constant breaks the cycle

src/test/ui/associated-types/defaults-cyclic-pass.rs

@@ -2,21 +2,16 @@
 
 #![feature(associated_type_defaults)]
 
+// Having a cycle in assoc. type defaults is okay, as long as there's no impl
+// that retains it.
 trait Tr {
-    type Item = u8;
-    type Container = Vec<Self::Item>;
+    type A = Self::B;
+    type B = Self::A;
 }
 
-impl Tr for () {}
-
-impl Tr for u16 {
-    type Item = u16;
+// An impl has to break the cycle to be accepted.
+impl Tr for u8 {
+    type A = u8;
 }
 
-fn main() {
-    let _container: <() as Tr>::Container = Vec::<u8>::new();
-    let _item: <() as Tr>::Item = 0u8;
-
-    let _container: <u16 as Tr>::Container = Vec::<u16>::new();
-    let _item: <u16 as Tr>::Item = 0u16;
-}
+fn main() {}

src/test/ui/associated-types/defaults-in-other-trait-items-pass.rs

@@ -0,0 +1,22 @@
+// check-pass
+
+#![feature(associated_type_defaults)]
+
+trait Tr {
+    type Item = u8;
+    type Container = Vec<Self::Item>;
+}
+
+impl Tr for () {}
+
+impl Tr for u16 {
+    type Item = u16;
+}
+
+fn main() {
+    let _container: <() as Tr>::Container = Vec::<u8>::new();
+    let _item: <() as Tr>::Item = 0u8;
+
+    let _container: <u16 as Tr>::Container = Vec::<u16>::new();
+    let _item: <u16 as Tr>::Item = 0u16;
+}

src/test/ui/associated-types/defaults-unsound-62211-1.rs

@@ -3,6 +3,9 @@
 //! The old implementation of defaults did not check whether the provided
 //! default actually fulfills all bounds on the assoc. type, leading to
 //! unsoundness, demonstrated here as a use-after-free.
+//!
+//! Note that the underlying cause of this is still not yet fixed.
+//! See: https://github.com/rust-lang/rust/issues/33017
 
 // compile-fail
 

src/test/ui/associated-types/defaults-unsound-62211-1.stderr

@@ -1,18 +1,18 @@
 error[E0277]: the trait bound `Self: std::marker::Copy` is not satisfied
-  --> $DIR/defaults-unsound-62211-1.rs:20:18
+  --> $DIR/defaults-unsound-62211-1.rs:23:18
    |
 LL |     type Output: Copy
    |                  ^^^^ the trait `std::marker::Copy` is not implemented for `Self`
    |
    = help: consider adding a `where Self: std::marker::Copy` bound
 note: required by `UncheckedCopy`
-  --> $DIR/defaults-unsound-62211-1.rs:17:1
+  --> $DIR/defaults-unsound-62211-1.rs:20:1
    |
 LL | trait UncheckedCopy: Sized {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: cannot add-assign `&'static str` to `Self`
-  --> $DIR/defaults-unsound-62211-1.rs:24:7
+  --> $DIR/defaults-unsound-62211-1.rs:27:7
    |
 LL |     + AddAssign<&'static str>
    |       ^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `Self += &'static str`
@@ -20,26 +20,26 @@ LL |     + AddAssign<&'static str>
    = help: the trait `std::ops::AddAssign<&'static str>` is not implemented for `Self`
    = help: consider adding a `where Self: std::ops::AddAssign<&'static str>` bound
 note: required by `UncheckedCopy`
-  --> $DIR/defaults-unsound-62211-1.rs:17:1
+  --> $DIR/defaults-unsound-62211-1.rs:20:1
    |
 LL | trait UncheckedCopy: Sized {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: the trait bound `Self: std::ops::Deref` is not satisfied
-  --> $DIR/defaults-unsound-62211-1.rs:22:7
+  --> $DIR/defaults-unsound-62211-1.rs:25:7
    |
 LL |     + Deref<Target = str>
    |       ^^^^^^^^^^^^^^^^^^^ the trait `std::ops::Deref` is not implemented for `Self`
    |
    = help: consider adding a `where Self: std::ops::Deref` bound
 note: required by `UncheckedCopy`
-  --> $DIR/defaults-unsound-62211-1.rs:17:1
+  --> $DIR/defaults-unsound-62211-1.rs:20:1
    |
 LL | trait UncheckedCopy: Sized {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: `Self` doesn't implement `std::fmt::Display`
-  --> $DIR/defaults-unsound-62211-1.rs:27:7
+  --> $DIR/defaults-unsound-62211-1.rs:30:7
    |
 LL |     + Display = Self;
    |       ^^^^^^^ `Self` cannot be formatted with the default formatter
@@ -48,13 +48,13 @@ LL |     + Display = Self;
    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
    = help: consider adding a `where Self: std::fmt::Display` bound
 note: required by `UncheckedCopy`
-  --> $DIR/defaults-unsound-62211-1.rs:17:1
+  --> $DIR/defaults-unsound-62211-1.rs:20:1
    |
 LL | trait UncheckedCopy: Sized {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: `T` doesn't implement `std::fmt::Display`
-  --> $DIR/defaults-unsound-62211-1.rs:40:9
+  --> $DIR/defaults-unsound-62211-1.rs:43:9
    |
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ `T` cannot be formatted with the default formatter
@@ -64,7 +64,7 @@ LL | impl<T> UncheckedCopy for T {}
    = help: consider adding a `where T: std::fmt::Display` bound
 
 error[E0277]: the trait bound `T: std::ops::Deref` is not satisfied
-  --> $DIR/defaults-unsound-62211-1.rs:40:9
+  --> $DIR/defaults-unsound-62211-1.rs:43:9
    |
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ the trait `std::ops::Deref` is not implemented for `T`
@@ -72,7 +72,7 @@ LL | impl<T> UncheckedCopy for T {}
    = help: consider adding a `where T: std::ops::Deref` bound
 
 error[E0277]: cannot add-assign `&'static str` to `T`
-  --> $DIR/defaults-unsound-62211-1.rs:40:9
+  --> $DIR/defaults-unsound-62211-1.rs:43:9
    |
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ no implementation for `T += &'static str`
@@ -81,7 +81,7 @@ LL | impl<T> UncheckedCopy for T {}
    = help: consider adding a `where T: std::ops::AddAssign<&'static str>` bound
 
 error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
-  --> $DIR/defaults-unsound-62211-1.rs:40:9
+  --> $DIR/defaults-unsound-62211-1.rs:43:9
    |
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`

src/test/ui/associated-types/defaults-unsound-62211-2.rs

@@ -3,6 +3,9 @@
 //! The old implementation of defaults did not check whether the provided
 //! default actually fulfills all bounds on the assoc. type, leading to
 //! unsoundness and ICEs, the latter being demonstrated here.
+//!
+//! Note that the underlying cause of this is still not yet fixed.
+//! See: https://github.com/rust-lang/rust/issues/33017
 
 // compile-fail
 

src/test/ui/associated-types/defaults-unsound-62211-2.stderr

@@ -1,18 +1,18 @@
 error[E0277]: the trait bound `Self: std::marker::Copy` is not satisfied
-  --> $DIR/defaults-unsound-62211-2.rs:20:18
+  --> $DIR/defaults-unsound-62211-2.rs:23:18
    |
 LL |     type Output: Copy
    |                  ^^^^ the trait `std::marker::Copy` is not implemented for `Self`
    |
    = help: consider adding a `where Self: std::marker::Copy` bound
 note: required by `UncheckedCopy`
-  --> $DIR/defaults-unsound-62211-2.rs:17:1
+  --> $DIR/defaults-unsound-62211-2.rs:20:1
    |
 LL | trait UncheckedCopy: Sized {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: cannot add-assign `&'static str` to `Self`
-  --> $DIR/defaults-unsound-62211-2.rs:24:7
+  --> $DIR/defaults-unsound-62211-2.rs:27:7
    |
 LL |     + AddAssign<&'static str>
    |       ^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `Self += &'static str`
@@ -20,26 +20,26 @@ LL |     + AddAssign<&'static str>
    = help: the trait `std::ops::AddAssign<&'static str>` is not implemented for `Self`
    = help: consider adding a `where Self: std::ops::AddAssign<&'static str>` bound
 note: required by `UncheckedCopy`
-  --> $DIR/defaults-unsound-62211-2.rs:17:1
+  --> $DIR/defaults-unsound-62211-2.rs:20:1
    |
 LL | trait UncheckedCopy: Sized {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: the trait bound `Self: std::ops::Deref` is not satisfied
-  --> $DIR/defaults-unsound-62211-2.rs:22:7
+  --> $DIR/defaults-unsound-62211-2.rs:25:7
    |
 LL |     + Deref<Target = str>
    |       ^^^^^^^^^^^^^^^^^^^ the trait `std::ops::Deref` is not implemented for `Self`
    |
    = help: consider adding a `where Self: std::ops::Deref` bound
 note: required by `UncheckedCopy`
-  --> $DIR/defaults-unsound-62211-2.rs:17:1
+  --> $DIR/defaults-unsound-62211-2.rs:20:1
    |
 LL | trait UncheckedCopy: Sized {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: `Self` doesn't implement `std::fmt::Display`
-  --> $DIR/defaults-unsound-62211-2.rs:27:7
+  --> $DIR/defaults-unsound-62211-2.rs:30:7
    |
 LL |     + Display = Self;
    |       ^^^^^^^ `Self` cannot be formatted with the default formatter
@@ -48,13 +48,13 @@ LL |     + Display = Self;
    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
    = help: consider adding a `where Self: std::fmt::Display` bound
 note: required by `UncheckedCopy`
-  --> $DIR/defaults-unsound-62211-2.rs:17:1
+  --> $DIR/defaults-unsound-62211-2.rs:20:1
    |
 LL | trait UncheckedCopy: Sized {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: `T` doesn't implement `std::fmt::Display`
-  --> $DIR/defaults-unsound-62211-2.rs:40:9
+  --> $DIR/defaults-unsound-62211-2.rs:43:9
    |
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ `T` cannot be formatted with the default formatter
@@ -64,7 +64,7 @@ LL | impl<T> UncheckedCopy for T {}
    = help: consider adding a `where T: std::fmt::Display` bound
 
 error[E0277]: the trait bound `T: std::ops::Deref` is not satisfied
-  --> $DIR/defaults-unsound-62211-2.rs:40:9
+  --> $DIR/defaults-unsound-62211-2.rs:43:9
    |
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ the trait `std::ops::Deref` is not implemented for `T`
@@ -72,7 +72,7 @@ LL | impl<T> UncheckedCopy for T {}
    = help: consider adding a `where T: std::ops::Deref` bound
 
 error[E0277]: cannot add-assign `&'static str` to `T`
-  --> $DIR/defaults-unsound-62211-2.rs:40:9
+  --> $DIR/defaults-unsound-62211-2.rs:43:9
    |
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ no implementation for `T += &'static str`
@@ -81,7 +81,7 @@ LL | impl<T> UncheckedCopy for T {}
    = help: consider adding a `where T: std::ops::AddAssign<&'static str>` bound
 
 error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
-  --> $DIR/defaults-unsound-62211-2.rs:40:9
+  --> $DIR/defaults-unsound-62211-2.rs:43:9
    |
 LL | impl<T> UncheckedCopy for T {}
    |         ^^^^^^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T`

src/test/ui/associated-types/issue-32350.rs

@@ -0,0 +1,29 @@
+// check-pass
+
+// This is another instance of the "normalizations don't work" issue with
+// defaulted associated types.
+
+#![feature(associated_type_defaults)]
+
+pub trait Emitter<'a> {
+    type Ctxt: 'a;
+    type CtxtBrw: 'a = &'a Self::Ctxt;
+
+    fn get_cx(&'a self) -> Self::CtxtBrw;
+}
+
+struct MyCtxt;
+
+struct MyEmitter {
+    ctxt: MyCtxt
+}
+
+impl <'a> Emitter<'a> for MyEmitter {
+    type Ctxt = MyCtxt;
+
+    fn get_cx(&'a self) -> &'a MyCtxt {
+        &self.ctxt
+    }
+}
+
+fn main() {}

src/test/ui/associated-types/issue-41868.rs

@@ -0,0 +1,23 @@
+// check-pass
+
+// Defaulted assoc. types should normalize properly in impls that don't
+// override them.
+
+#![feature(associated_type_defaults)]
+
+pub struct Foo;
+
+pub trait CanDecode: Sized {
+    type Output = Self;
+    fn read(rdr: &mut Foo) -> Option<Self::Output>;
+}
+
+impl CanDecode for u8 {
+    fn read(rdr: &mut Foo) -> Option<Self::Output> { Some(42) }
+}
+
+impl CanDecode for u16 {
+    fn read(rdr: &mut Foo) -> Option<u16> { Some(17) }
+}
+
+fn main() {}

src/test/ui/associated-types/issue-43924.rs

@@ -0,0 +1,15 @@
+#![feature(associated_type_defaults)]
+
+// This used to cause an ICE because assoc. type defaults weren't properly
+// type-checked.
+
+trait Foo<T: Default + ToString> {
+    type Out: Default + ToString + ?Sized = dyn ToString;  //~ error: not satisfied
+}
+
+impl Foo<u32> for () {}  //~ error: not satisfied
+impl Foo<u64> for () {}  //~ error: not satisfied
+
+fn main() {
+    assert_eq!(<() as Foo<u32>>::Out::default().to_string(), "false");
+}

src/test/ui/associated-types/issue-43924.stderr

@@ -0,0 +1,27 @@
+error[E0277]: the trait bound `(dyn std::string::ToString + 'static): std::default::Default` is not satisfied
+  --> $DIR/issue-43924.rs:7:15
+   |
+LL |     type Out: Default + ToString + ?Sized = dyn ToString;
+   |               ^^^^^^^ the trait `std::default::Default` is not implemented for `(dyn std::string::ToString + 'static)`
+   |
+note: required by `Foo`
+  --> $DIR/issue-43924.rs:6:1
+   |
+LL | trait Foo<T: Default + ToString> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0277]: the trait bound `(dyn std::string::ToString + 'static): std::default::Default` is not satisfied
+  --> $DIR/issue-43924.rs:10:6
+   |
+LL | impl Foo<u32> for () {}
+   |      ^^^^^^^^ the trait `std::default::Default` is not implemented for `(dyn std::string::ToString + 'static)`
+
+error[E0277]: the trait bound `(dyn std::string::ToString + 'static): std::default::Default` is not satisfied
+  --> $DIR/issue-43924.rs:11:6
+   |
+LL | impl Foo<u64> for () {}
+   |      ^^^^^^^^ the trait `std::default::Default` is not implemented for `(dyn std::string::ToString + 'static)`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0277`.

src/test/ui/associated-types/issue-47385.rs

@@ -0,0 +1,16 @@
+// check-pass
+
+#![feature(associated_type_defaults)]
+
+pub struct Foo;
+
+pub trait Bar: From<<Self as Bar>::Input> {
+    type Input = Self;
+}
+
+impl Bar for Foo {
+    // Will compile with explicit type:
+    // type Input = Self;
+}
+
+fn main() {}

src/test/ui/associated-types/issue-63593.rs

@@ -0,0 +1,11 @@
+#![feature(associated_type_defaults)]
+
+// Tests that `Self` is not assumed to implement `Sized` when used as an
+// associated type default.
+
+trait Inner<S> {}
+
+trait MyTrait {
+    type This = Self;  //~ error: size for values of type `Self` cannot be known
+    fn something<I: Inner<Self::This>>(i: I);
+}

src/test/ui/associated-types/issue-63593.stderr

@@ -0,0 +1,23 @@
+error[E0601]: `main` function not found in crate `issue_63593`
+   |
+   = note: consider adding a `main` function to `$DIR/issue-63593.rs`
+
+error[E0277]: the size for values of type `Self` cannot be known at compilation time
+  --> $DIR/issue-63593.rs:9:5
+   |
+LL |     type This = Self;
+   |     ^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
+   |
+   = help: the trait `std::marker::Sized` is not implemented for `Self`
+   = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
+   = help: consider adding a `where Self: std::marker::Sized` bound
+note: required by `MyTrait`
+  --> $DIR/issue-63593.rs:8:1
+   |
+LL | trait MyTrait {
+   | ^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0277, E0601.
+For more information about an error, try `rustc --explain E0277`.