Change E0369 diagnostic give note information for foreign items.

Make it easy for developers to understand why the binop cannot be applied.

fixes #125631

10 files changed, 143 insertions, 0 deletions

diff --git a/tests/ui/array-slice-vec/vec-res-add.stderr b/tests/ui/array-slice-vec/vec-res-add.stderr
index cf5796f7e4a..34fd69426a8 100644
--- a/tests/ui/array-slice-vec/vec-res-add.stderr
+++ b/tests/ui/array-slice-vec/vec-res-add.stderr
@@ -5,6 +5,11 @@ LL |     let k = i + j;
    |             - ^ - Vec<R>
    |             |
    |             Vec<R>
+   |
+note: the foreign item type `Vec<R>` doesn't implement `Add`
+  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
+   |
+   = note: not implement `Add`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/autoderef-full-lval.stderr b/tests/ui/autoderef-full-lval.stderr
index 9921ce7c154..d90238a7fb2 100644
--- a/tests/ui/autoderef-full-lval.stderr
+++ b/tests/ui/autoderef-full-lval.stderr
@@ -5,6 +5,12 @@ LL |     let z: isize = a.x + b.y;
    |                    --- ^ --- Box<isize>
    |                    |
    |                    Box<isize>
+   |
+note: the foreign item type `Box<isize>` doesn't implement `Add`
+  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
+  ::: $SRC_DIR/alloc/src/boxed.rs:LL:COL
+   |
+   = note: not implement `Add`
 
 error[E0369]: cannot add `Box<isize>` to `Box<isize>`
   --> $DIR/autoderef-full-lval.rs:21:33
@@ -13,6 +19,12 @@ LL |     let answer: isize = forty.a + two.a;
    |                         ------- ^ ----- Box<isize>
    |                         |
    |                         Box<isize>
+   |
+note: the foreign item type `Box<isize>` doesn't implement `Add`
+  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
+  ::: $SRC_DIR/alloc/src/boxed.rs:LL:COL
+   |
+   = note: not implement `Add`
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/binop/binary-op-not-allowed-issue-125631.rs b/tests/ui/binop/binary-op-not-allowed-issue-125631.rs
new file mode 100644
index 00000000000..8827bbb003b
--- /dev/null
+++ b/tests/ui/binop/binary-op-not-allowed-issue-125631.rs
@@ -0,0 +1,16 @@
+use std::io::{Error, ErrorKind};
+use std::thread;
+
+struct T1;
+struct T2;
+
+fn main() {
+    (Error::new(ErrorKind::Other, "1"), T1, 1) == (Error::new(ErrorKind::Other, "1"), T1, 2);
+    //~^ERROR binary operation `==` cannot be applied to type
+    (Error::new(ErrorKind::Other, "2"), thread::current())
+        == (Error::new(ErrorKind::Other, "2"), thread::current());
+    //~^ERROR binary operation `==` cannot be applied to type
+    (Error::new(ErrorKind::Other, "4"), thread::current(), T1, T2)
+        == (Error::new(ErrorKind::Other, "4"), thread::current(), T1, T2);
+    //~^ERROR binary operation `==` cannot be applied to type
+}
diff --git a/tests/ui/binop/binary-op-not-allowed-issue-125631.stderr b/tests/ui/binop/binary-op-not-allowed-issue-125631.stderr
new file mode 100644
index 00000000000..1cf75bbc1a5
--- /dev/null
+++ b/tests/ui/binop/binary-op-not-allowed-issue-125631.stderr
@@ -0,0 +1,75 @@
+error[E0369]: binary operation `==` cannot be applied to type `(std::io::Error, T1, {integer})`
+  --> $DIR/binary-op-not-allowed-issue-125631.rs:8:48
+   |
+LL |     (Error::new(ErrorKind::Other, "1"), T1, 1) == (Error::new(ErrorKind::Other, "1"), T1, 2);
+   |     ------------------------------------------ ^^ ------------------------------------------ (std::io::Error, T1, {integer})
+   |     |
+   |     (std::io::Error, T1, {integer})
+   |
+note: an implementation of `PartialEq` might be missing for `T1`
+  --> $DIR/binary-op-not-allowed-issue-125631.rs:4:1
+   |
+LL | struct T1;
+   | ^^^^^^^^^ must implement `PartialEq`
+note: the foreign item type `std::io::Error` doesn't implement `PartialEq`
+  --> $SRC_DIR/std/src/io/error.rs:LL:COL
+   |
+   = note: not implement `PartialEq`
+help: consider annotating `T1` with `#[derive(PartialEq)]`
+   |
+LL + #[derive(PartialEq)]
+LL | struct T1;
+   |
+
+error[E0369]: binary operation `==` cannot be applied to type `(std::io::Error, Thread)`
+  --> $DIR/binary-op-not-allowed-issue-125631.rs:11:9
+   |
+LL |     (Error::new(ErrorKind::Other, "2"), thread::current())
+   |     ------------------------------------------------------ (std::io::Error, Thread)
+LL |         == (Error::new(ErrorKind::Other, "2"), thread::current());
+   |         ^^ ------------------------------------------------------ (std::io::Error, Thread)
+   |
+note: the foreign item types don't implement required traits for this operation to be valid
+  --> $SRC_DIR/std/src/io/error.rs:LL:COL
+   |
+   = note: not implement `PartialEq`
+  --> $SRC_DIR/std/src/thread/mod.rs:LL:COL
+   |
+   = note: not implement `PartialEq`
+
+error[E0369]: binary operation `==` cannot be applied to type `(std::io::Error, Thread, T1, T2)`
+  --> $DIR/binary-op-not-allowed-issue-125631.rs:14:9
+   |
+LL |     (Error::new(ErrorKind::Other, "4"), thread::current(), T1, T2)
+   |     -------------------------------------------------------------- (std::io::Error, Thread, T1, T2)
+LL |         == (Error::new(ErrorKind::Other, "4"), thread::current(), T1, T2);
+   |         ^^ -------------------------------------------------------------- (std::io::Error, Thread, T1, T2)
+   |
+note: the following types would have to `impl` their required traits for this operation to be valid
+  --> $DIR/binary-op-not-allowed-issue-125631.rs:4:1
+   |
+LL | struct T1;
+   | ^^^^^^^^^ must implement `PartialEq`
+LL | struct T2;
+   | ^^^^^^^^^ must implement `PartialEq`
+note: the foreign item types don't implement required traits for this operation to be valid
+  --> $SRC_DIR/std/src/io/error.rs:LL:COL
+   |
+   = note: not implement `PartialEq`
+  --> $SRC_DIR/std/src/thread/mod.rs:LL:COL
+   |
+   = note: not implement `PartialEq`
+help: consider annotating `T1` with `#[derive(PartialEq)]`
+   |
+LL + #[derive(PartialEq)]
+LL | struct T1;
+   |
+help: consider annotating `T2` with `#[derive(PartialEq)]`
+   |
+LL + #[derive(PartialEq)]
+LL | struct T2;
+   |
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0369`.
diff --git a/tests/ui/binop/binop-bitxor-str.stderr b/tests/ui/binop/binop-bitxor-str.stderr
index 20b1ecc5a93..9d9ec6c5af6 100644
--- a/tests/ui/binop/binop-bitxor-str.stderr
+++ b/tests/ui/binop/binop-bitxor-str.stderr
@@ -5,6 +5,11 @@ LL | fn main() { let x = "a".to_string() ^ "b".to_string(); }
    |                     --------------- ^ --------------- String
    |                     |
    |                     String
+   |
+note: the foreign item type `String` doesn't implement `BitXor`
+  --> $SRC_DIR/alloc/src/string.rs:LL:COL
+   |
+   = note: not implement `BitXor`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/error-codes/E0067.stderr b/tests/ui/error-codes/E0067.stderr
index ec0358cb7df..71b72080544 100644
--- a/tests/ui/error-codes/E0067.stderr
+++ b/tests/ui/error-codes/E0067.stderr
@@ -5,6 +5,12 @@ LL |     LinkedList::new() += 1;
    |     -----------------^^^^^
    |     |
    |     cannot use `+=` on type `LinkedList<_>`
+   |
+note: the foreign item type `LinkedList<_>` doesn't implement `AddAssign<{integer}>`
+  --> $SRC_DIR/alloc/src/collections/linked_list.rs:LL:COL
+  ::: $SRC_DIR/alloc/src/collections/linked_list.rs:LL:COL
+   |
+   = note: not implement `AddAssign<{integer}>`
 
 error[E0067]: invalid left-hand side of assignment
   --> $DIR/E0067.rs:4:23
diff --git a/tests/ui/issues/issue-14915.stderr b/tests/ui/issues/issue-14915.stderr
index 279f5772d21..3558bd651c6 100644
--- a/tests/ui/issues/issue-14915.stderr
+++ b/tests/ui/issues/issue-14915.stderr
@@ -5,6 +5,12 @@ LL |     println!("{}", x + 1);
    |                    - ^ - {integer}
    |                    |
    |                    Box<isize>
+   |
+note: the foreign item type `Box<isize>` doesn't implement `Add<{integer}>`
+  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
+  ::: $SRC_DIR/alloc/src/boxed.rs:LL:COL
+   |
+   = note: not implement `Add<{integer}>`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/minus-string.stderr b/tests/ui/minus-string.stderr
index 105274ee7d0..cf63ec24416 100644
--- a/tests/ui/minus-string.stderr
+++ b/tests/ui/minus-string.stderr
@@ -3,6 +3,11 @@ error[E0600]: cannot apply unary operator `-` to type `String`
    |
 LL | fn main() { -"foo".to_string(); }
    |             ^^^^^^^^^^^^^^^^^^ cannot apply unary operator `-`
+   |
+note: the foreign item type `String` doesn't implement `Neg`
+  --> $SRC_DIR/alloc/src/string.rs:LL:COL
+   |
+   = note: not implement `Neg`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/pattern/pattern-tyvar-2.stderr b/tests/ui/pattern/pattern-tyvar-2.stderr
index c6540e79558..be52fa8b239 100644
--- a/tests/ui/pattern/pattern-tyvar-2.stderr
+++ b/tests/ui/pattern/pattern-tyvar-2.stderr
@@ -5,6 +5,11 @@ LL | fn foo(t: Bar) -> isize { match t { Bar::T1(_, Some(x)) => { return x * 3;
    |                                                                     - ^ - {integer}
    |                                                                     |
    |                                                                     Vec<isize>
+   |
+note: the foreign item type `Vec<isize>` doesn't implement `Mul<{integer}>`
+  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
+   |
+   = note: not implement `Mul<{integer}>`
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/typeck/assign-non-lval-derefmut.stderr b/tests/ui/typeck/assign-non-lval-derefmut.stderr
index b26d16da015..ce0ff1d957b 100644
--- a/tests/ui/typeck/assign-non-lval-derefmut.stderr
+++ b/tests/ui/typeck/assign-non-lval-derefmut.stderr
@@ -19,6 +19,10 @@ LL |     x.lock().unwrap() += 1;
    |     |
    |     cannot use `+=` on type `MutexGuard<'_, usize>`
    |
+note: the foreign item type `MutexGuard<'_, usize>` doesn't implement `AddAssign<{integer}>`
+  --> $SRC_DIR/std/src/sync/mutex.rs:LL:COL
+   |
+   = note: not implement `AddAssign<{integer}>`
 help: `+=` can be used on `usize` if you dereference the left-hand side
    |
 LL |     *x.lock().unwrap() += 1;
@@ -47,6 +51,10 @@ LL |     y += 1;
    |     |
    |     cannot use `+=` on type `MutexGuard<'_, usize>`
    |
+note: the foreign item type `MutexGuard<'_, usize>` doesn't implement `AddAssign<{integer}>`
+  --> $SRC_DIR/std/src/sync/mutex.rs:LL:COL
+   |
+   = note: not implement `AddAssign<{integer}>`
 help: `+=` can be used on `usize` if you dereference the left-hand side
    |
 LL |     *y += 1;