Adjust spacing in suggestion, add a test

src/test/ui/generic-associated-types/missing-bounds.stderr

@@ -67,7 +67,7 @@ LL |         Self(self.0 + rhs.0)
 help: consider restricting type parameter `B`
    |
 LL | impl<B: std::ops::Add<Output = B>> Add for D<B> {
-   |       +++++++++++++++++++++++++
+   |       +++++++++++++++++++++++++++
 
 error[E0308]: mismatched types
   --> $DIR/missing-bounds.rs:42:14

src/test/ui/suggestions/issue-97677.stderr

@@ -9,7 +9,7 @@ LL |     n + 10
 help: consider restricting type parameter `N`
    |
 LL | fn add_ten<N: std::ops::Add<i32, Output = N>>(n: N) -> N {
-   |             ++++++++++++++++++++++++++++++
+   |             ++++++++++++++++++++++++++++++++
 
 error: aborting due to previous error
 

src/test/ui/suggestions/restrict-type-not-param.rs

@@ -0,0 +1,12 @@
+use std::ops::Add;
+
+struct Wrapper<T>(T);
+
+trait Foo {}
+
+fn qux<T>(a: Wrapper<T>, b: T) -> T {
+    a + b
+    //~^ ERROR cannot add `T` to `Wrapper<T>`
+}
+
+fn main() {}

src/test/ui/suggestions/restrict-type-not-param.stderr

@@ -0,0 +1,26 @@
+error[E0369]: cannot add `T` to `Wrapper<T>`
+  --> $DIR/restrict-type-not-param.rs:8:7
+   |
+LL |     a + b
+   |     - ^ - T
+   |     |
+   |     Wrapper<T>
+   |
+note: an implementation of `Add<_>` might be missing for `Wrapper<T>`
+  --> $DIR/restrict-type-not-param.rs:3:1
+   |
+LL | struct Wrapper<T>(T);
+   | ^^^^^^^^^^^^^^^^^ must implement `Add<_>`
+note: the following trait must be implemented
+  --> $SRC_DIR/core/src/ops/arith.rs:LL:COL
+   |
+LL | pub trait Add<Rhs = Self> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
+   |
+LL | fn qux<T>(a: Wrapper<T>, b: T) -> T where Wrapper<T>: Add<T, Output = T> {
+   |                                     ++++++++++++++++++++++++++++++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0369`.

src/test/ui/traits/resolution-in-overloaded-op.stderr

@@ -9,7 +9,7 @@ LL |     a * b
 help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
    |
 LL | fn foo<T: MyMul<f64, f64>>(a: &T, b: f64) -> f64 where &T: Mul<f64, Output = f64> {
-   |                                                  ++++++++++++++++++++++++++++++
+   |                                                  ++++++++++++++++++++++++++++++++
 
 error: aborting due to previous error