add new tests from MCP and the tracking issue

rust-lang · bors · Jun 23, 2020 · May 18, 2020 · May 18, 2020 · May 19, 2020
commit be0d10f149579d3ed53507ff8c2f6511b56456f7
diff --git a/src/test/ui/coherence/coherence-fn-implied-bounds.rs b/src/test/ui/coherence/coherence-fn-implied-bounds.rs
@@ -0,0 1,14 @@
 // Example of coherence impls that we accept
 
 #![deny(coherence_leak_check)]
 
 trait Trait {}
 
 impl Trait for for<'a, 'b> fn(&'a &'b u32, &'b &'a u32) -> &'b u32 {}
 
 impl Trait for for<'c> fn(&'c &'c u32, &'c &'c u32) -> &'c u32 {
  //~^ ERROR conflicting implementations
  //~| WARNING this was previously accepted by the compiler
 }
 
 fn main() {}
diff --git a/src/test/ui/coherence/coherence-fn-implied-bounds.stderr b/src/test/ui/coherence/coherence-fn-implied-bounds.stderr
@@ -0,0 1,20 @@
 error: conflicting implementations of trait `Trait` for type `for<'a, 'b> fn(&'a &'b u32, &'b &'a u32) -> &'b u32`:
  --> $DIR/coherence-fn-implied-bounds.rs:9:1
  |
 LL | impl Trait for for<'a, 'b> fn(&'a &'b u32, &'b &'a u32) -> &'b u32 {}
  | ------------------------------------------------------------------ first implementation here
 LL | 
 LL | impl Trait for for<'c> fn(&'c &'c u32, &'c &'c u32) -> &'c u32 {
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a, 'b> fn(&'a &'b u32, &'b &'a u32) -> &'b u32`
  |
 note: the lint level is defined here
  --> $DIR/coherence-fn-implied-bounds.rs:3:9
  |
 LL | #![deny(coherence_leak_check)]
  | ^^^^^^^^^^^^^^^^^^^^
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
  = note: for more information, see issue #56105 <https://github.com/rust-lang/rust/issues/56105>
  = note: this behavior recently changed as a result of a bug fix; see rust-lang/rust#56105 for details
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/coherence/coherence-fn-inputs.rs b/src/test/ui/coherence/coherence-fn-inputs.rs
@@ -0,0 1,27 @@
 // Test that we consider these two types completely equal:
 //
 // * `for<'a, 'b> fn(&'a u32, &'b u32)`
 // * `for<'c> fn(&'c u32, &'c u32)`
 //
 // For a long time we considered these to be distinct types. But in fact they
 // are equivalent, if you work through the implications of subtyping -- this is
 // because:
 //
 // * `'c` can be the intersection of `'a` and `'b` (and there is always an intersection)
 // * `'a` and `'b` can both be equal to `'c`
 
 #![deny(coherence_leak_check)]
 
 trait Trait {}
 impl Trait for for<'a, 'b> fn(&'a u32, &'b u32) {}
 impl Trait for for<'c> fn(&'c u32, &'c u32) {
  //~^ ERROR conflicting implementations
  //
  // Note in particular that we do NOT get a future-compatibility warning
  // here. This is because the new leak-check proposed in [MCP 295] does not
  // "error" when these two types are equated.
  //
  // [MCP 295]: https://github.com/rust-lang/compiler-team/issues/295
 }
 
 fn main() {}
diff --git a/src/test/ui/coherence/coherence-fn-inputs.stderr b/src/test/ui/coherence/coherence-fn-inputs.stderr
@@ -0,0 1,13 @@
 error[E0119]: conflicting implementations of trait `Trait` for type `for<'a, 'b> fn(&'a u32, &'b u32)`:
  --> $DIR/coherence-fn-inputs.rs:17:1
  |
 LL | impl Trait for for<'a, 'b> fn(&'a u32, &'b u32) {}
  | ----------------------------------------------- first implementation here
 LL | impl Trait for for<'c> fn(&'c u32, &'c u32) {
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a, 'b> fn(&'a u32, &'b u32)`
  |
  = note: this behavior recently changed as a result of a bug fix; see rust-lang/rust#56105 for details
 
 error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0119`.
diff --git a/src/test/ui/coherence/coherence-free-vs-bound-region.rs b/src/test/ui/coherence/coherence-free-vs-bound-region.rs
@@ -0,0 1,21 @@
 // Capture a coherence pattern from wasm-bindgen that we discovered as part of
 // future-compatibility warning #56105. This pattern currently receives a lint
 // warning but we probably want to support it long term.
 //
 // Key distinction: we are implementing once for `A` (take ownership) and one
 // for `&A` (borrow).
 //
 // c.f. #56105
 
 #![deny(coherence_leak_check)]
 
 trait TheTrait {}
 
 impl<'a> TheTrait for fn(&'a u8) {}
 
 impl TheTrait for fn(&u8) {
  //~^ ERROR conflicting implementations of trait
  //~| WARNING this was previously accepted by the compiler
 }
 
 fn main() {}
diff --git a/src/test/ui/coherence/coherence-free-vs-bound-region.stderr b/src/test/ui/coherence/coherence-free-vs-bound-region.stderr
@@ -0,0 1,20 @@
 error: conflicting implementations of trait `TheTrait` for type `fn(&u8)`:
  --> $DIR/coherence-free-vs-bound-region.rs:16:1
  |
 LL | impl<'a> TheTrait for fn(&'a u8) {}
  | -------------------------------- first implementation here
 LL | 
 LL | impl TheTrait for fn(&u8) {
  | ^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `fn(&u8)`
  |
 note: the lint level is defined here
  --> $DIR/coherence-free-vs-bound-region.rs:10:9
  |
 LL | #![deny(coherence_leak_check)]
  | ^^^^^^^^^^^^^^^^^^^^
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
  = note: for more information, see issue #56105 <https://github.com/rust-lang/rust/issues/56105>
  = note: this behavior recently changed as a result of a bug fix; see rust-lang/rust#56105 for details
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/coherence/coherence-wasm-bindgen.rs b/src/test/ui/coherence/coherence-wasm-bindgen.rs
@@ -0,0 1,37 @@
 // Capture a coherence pattern from wasm-bindgen that we discovered as part of
 // future-compatibility warning #56105. This pattern currently receives a lint
 // warning but we probably want to support it long term.
 //
 // Key distinction: we are implementing once for `A` (take ownership) and one
 // for `&A` (borrow).
 //
 // c.f. #56105
 
 #![deny(coherence_leak_check)]
 
 trait IntoWasmAbi {
  fn some_method(&self) {}
 }
 
 trait FromWasmAbi {}
 trait RefFromWasmAbi {}
 trait ReturnWasmAbi {}
 
 impl<'a, 'b, A, R> IntoWasmAbi for &'a (dyn Fn(A) -> R 'b)
 where
  A: FromWasmAbi,
  R: ReturnWasmAbi,
 {
 }
 
 // Explicitly writing the bound lifetime.
 impl<'a, 'b, A, R> IntoWasmAbi for &'a (dyn for<'x> Fn(&'x A) -> R 'b)
 where
  A: RefFromWasmAbi,
  R: ReturnWasmAbi,
 {
  //~^^^^^ ERROR conflicting implementation
  //~| WARNING this was previously accepted
 }
 
 fn main() {}
diff --git a/src/test/ui/coherence/coherence-wasm-bindgen.stderr b/src/test/ui/coherence/coherence-wasm-bindgen.stderr
@@ -0,0 1,32 @@
 error: conflicting implementations of trait `IntoWasmAbi` for type `&dyn std::ops::Fn(&_) -> _`:
  --> $DIR/coherence-wasm-bindgen.rs:28:1
  |
 LL | / impl<'a, 'b, A, R> IntoWasmAbi for &'a (dyn Fn(A) -> R 'b)
 LL | | where
 LL | | A: FromWasmAbi,
 LL | | R: ReturnWasmAbi,
 LL | | {
 LL | | }
  | |_- first implementation here
 ...
 LL | / impl<'a, 'b, A, R> IntoWasmAbi for &'a (dyn for<'x> Fn(&'x A) -> R 'b)
 LL | | where
 LL | | A: RefFromWasmAbi,
 LL | | R: ReturnWasmAbi,
 ... |
 LL | |
 LL | | }
  | |_^ conflicting implementation for `&dyn std::ops::Fn(&_) -> _`
  |
 note: the lint level is defined here
  --> $DIR/coherence-wasm-bindgen.rs:10:9
  |
 LL | #![deny(coherence_leak_check)]
  | ^^^^^^^^^^^^^^^^^^^^
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
  = note: for more information, see issue #56105 <https://github.com/rust-lang/rust/issues/56105>
  = note: downstream crates may implement trait `FromWasmAbi` for type `&_`
  = note: this behavior recently changed as a result of a bug fix; see rust-lang/rust#56105 for details
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/hr-subtype/return-static.rs b/src/test/ui/hr-subtype/return-static.rs
@@ -0,0 1,13 @@
 // check-pass
 
 fn make<T>() -> T {
  panic!()
 }
 
 fn take<T>(x: T) {}
 
 fn main() {
  let x: for<'a> fn(&'a u32) -> _ = make();
  let y: &'static u32 = x(&22);
  take::<for<'b> fn(&'b u32) -> &'b u32>(x);
 }