Rollup merge of rust-lang#73674 - estebank:op-trait-bound-suggestion, r=davidtwco

Tweak binop errors

* Suggest potentially missing binop trait bound (fix rust-lang#73416)
* Use structured suggestion for dereference in binop

Author: Manishearth

src/librustc_typeck/check/method/mod.rs

@@ -295,8 +295,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         opt_input_types: Option<&[Ty<'tcx>]>,
     ) -> Option<InferOk<'tcx, MethodCallee<'tcx>>> {
         debug!(
-            "lookup_in_trait_adjusted(self_ty={:?}, \
-                m_name={}, trait_def_id={:?})",
+            "lookup_in_trait_adjusted(self_ty={:?}, m_name={}, trait_def_id={:?})",
             self_ty, m_name, trait_def_id
         );
 

src/librustc_typeck/check/method/probe.rs

@@ -380,8 +380,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         self.tcx.sess,
                         span,
                         E0699,
-                        "the type of this value must be known \
-                               to call a method on a raw pointer on it"
+                        "the type of this value must be known to call a method on a raw pointer on \
+                         it"
                     )
                     .emit();
                 } else {

src/librustc_typeck/check/op.rs

@@ -0,0 +1,9 @@
+// run-rustfix
+fn main() {
+    let v = vec![1, 2, 3, 4, 5, 6, 7, 8, 9];
+    let vr = v.iter().filter(|x| {
+        *x % 2 == 0
+        //~^ ERROR cannot mod `&&{integer}` by `{integer}`
+    });
+    println!("{:?}", vr);
+}

src/test/ui/binary-op-on-double-ref.fixed

@@ -1,3 +1,4 @@
+// run-rustfix
 fn main() {
     let v = vec![1, 2, 3, 4, 5, 6, 7, 8, 9];
     let vr = v.iter().filter(|x| {

src/test/ui/binary-op-on-double-ref.rs

@@ -1,12 +1,15 @@
 error[E0369]: cannot mod `&&{integer}` by `{integer}`
-  --> $DIR/binary-op-on-double-ref.rs:4:11
+  --> $DIR/binary-op-on-double-ref.rs:5:11
    |
 LL |         x % 2 == 0
    |         - ^ - {integer}
    |         |
    |         &&{integer}
    |
-   = help: `%` can be used on '{integer}', you can dereference `x`: `*x`
+help: `%` can be used on `{integer}`, you can dereference `x`
+   |
+LL |         *x % 2 == 0
+   |         ^
 
 error: aborting due to previous error
 

src/test/ui/binary-op-on-double-ref.stderr

@@ -5,6 +5,11 @@ LL |     a.iter().map(|a| a*a)
    |                      -^- &T
    |                      |
    |                      &T
+   |
+help: consider restricting type parameter `T`
+   |
+LL | fn func<'a, T: std::ops::Mul<Output = &T>>(a: &'a [T]) -> impl Iterator<Item=&'a T> {
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-35668.stderr

@@ -6,10 +6,10 @@ LL |     let x = |ref x: isize| { x += 1; };
    |                              |
    |                              cannot use `+=` on type `&isize`
    |
-help: `+=` can be used on 'isize', you can dereference `x`
+help: `+=` can be used on `isize`, you can dereference `x`
    |
 LL |     let x = |ref x: isize| { *x += 1; };
-   |                              ^^
+   |                              ^
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-5239-1.stderr

@@ -0,0 +1,7 @@
+pub fn foo<T>(s: S<T>, t: S<T>) {
+    let _ = s == t; //~ ERROR binary operation `==` cannot be applied to type `S<T>`
+}
+
+struct S<T>(T);
+
+fn main() {}

src/test/ui/suggestions/invalid-bin-op.rs

@@ -0,0 +1,13 @@
+error[E0369]: binary operation `==` cannot be applied to type `S<T>`
+  --> $DIR/invalid-bin-op.rs:2:15
+   |
+LL |     let _ = s == t;
+   |             - ^^ - S<T>
+   |             |
+   |             S<T>
+   |
+   = note: the trait `std::cmp::PartialEq` is not implemented for `S<T>`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0369`.

src/test/ui/suggestions/invalid-bin-op.stderr

@@ -0,0 +1,7 @@
+// run-rustfix
+
+pub fn foo<T: std::cmp::PartialEq>(s: &[T], t: &[T]) {
+    let _ = s == t; //~ ERROR binary operation `==` cannot be applied to type `&[T]`
+}
+
+fn main() {}

src/test/ui/suggestions/missing-trait-bound-for-op.fixed

@@ -0,0 +1,7 @@
+// run-rustfix
+
+pub fn foo<T>(s: &[T], t: &[T]) {
+    let _ = s == t; //~ ERROR binary operation `==` cannot be applied to type `&[T]`
+}
+
+fn main() {}

src/test/ui/suggestions/missing-trait-bound-for-op.rs

@@ -0,0 +1,16 @@
+error[E0369]: binary operation `==` cannot be applied to type `&[T]`
+  --> $DIR/missing-trait-bound-for-op.rs:4:15
+   |
+LL |     let _ = s == t;
+   |             - ^^ - &[T]
+   |             |
+   |             &[T]
+   |
+help: consider restricting type parameter `T`
+   |
+LL | pub fn foo<T: std::cmp::PartialEq>(s: &[T], t: &[T]) {
+   |             ^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0369`.

src/test/ui/suggestions/missing-trait-bound-for-op.stderr

@@ -5,6 +5,11 @@ LL |     a * b
    |     - ^ - f64
    |     |
    |     &T
+   |
+help: consider further restricting this bound
+   |
+LL | fn foo<T: MyMul<f64, f64> + std::ops::Mul<Output = f64>>(a: &T, b: f64) -> f64 {
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error