On binding not present in all patterns, suggest potential typo

```
error[E0408]: variable `Ban` is not bound in all patterns
 --> f12.rs:9:9
  |
9 |         (Foo,Bar)|(Ban,Foo) => {}
  |         ^^^^^^^^^  --- variable not in all patterns
  |         |
  |         pattern doesn't bind `Ban`
  |
help: you might have meant to use the similarly named previously used binding `Bar`
  |
9 -         (Foo,Bar)|(Ban,Foo) => {}
9 +         (Foo,Bar)|(Bar,Foo) => {}
  |
```

2 files changed, 33 insertions, 19 deletions

diff --git a/tests/ui/resolve/resolve-inconsistent-names.rs b/tests/ui/resolve/resolve-inconsistent-names.rs
index 9a40b20346c..bf74a4ba0f3 100644
--- a/tests/ui/resolve/resolve-inconsistent-names.rs
+++ b/tests/ui/resolve/resolve-inconsistent-names.rs
@@ -10,8 +10,10 @@ pub mod m {
 fn main() {
     let y = 1;
     match y {
-       a | b => {} //~  ERROR variable `a` is not bound in all patterns
-                   //~| ERROR variable `b` is not bound in all patterns
+        a | b => {} //~  ERROR variable `a` is not bound in all patterns
+        //~| ERROR variable `b` is not bound in all patterns
+        //~| HELP you might have meant to use the similarly named previously used binding `a`
+        //~| HELP you might have meant to use the similarly named previously used binding `b`
     }
 
     let x = (E::A, E::B);
diff --git a/tests/ui/resolve/resolve-inconsistent-names.stderr b/tests/ui/resolve/resolve-inconsistent-names.stderr
index 5fac622eef2..152c16ad404 100644
--- a/tests/ui/resolve/resolve-inconsistent-names.stderr
+++ b/tests/ui/resolve/resolve-inconsistent-names.stderr
@@ -1,21 +1,33 @@
 error[E0408]: variable `b` is not bound in all patterns
-  --> $DIR/resolve-inconsistent-names.rs:13:8
+  --> $DIR/resolve-inconsistent-names.rs:13:9
+   |
+LL |         a | b => {}
+   |         ^   - variable not in all patterns
+   |         |
+   |         pattern doesn't bind `b`
+   |
+help: you might have meant to use the similarly named previously used binding `a`
+   |
+LL -         a | b => {}
+LL +         a | a => {}
    |
-LL |        a | b => {}
-   |        ^   - variable not in all patterns
-   |        |
-   |        pattern doesn't bind `b`
 
 error[E0408]: variable `a` is not bound in all patterns
-  --> $DIR/resolve-inconsistent-names.rs:13:12
+  --> $DIR/resolve-inconsistent-names.rs:13:13
+   |
+LL |         a | b => {}
+   |         -   ^ pattern doesn't bind `a`
+   |         |
+   |         variable not in all patterns
+   |
+help: you might have meant to use the similarly named previously used binding `b`
+   |
+LL -         a | b => {}
+LL +         b | b => {}
    |
-LL |        a | b => {}
-   |        -   ^ pattern doesn't bind `a`
-   |        |
-   |        variable not in all patterns
 
 error[E0408]: variable `c` is not bound in all patterns
-  --> $DIR/resolve-inconsistent-names.rs:19:9
+  --> $DIR/resolve-inconsistent-names.rs:21:9
    |
 LL |         (A, B) | (ref B, c) | (c, A) => ()
    |         ^^^^^^           -     - variable not in all patterns
@@ -24,7 +36,7 @@ LL |         (A, B) | (ref B, c) | (c, A) => ()
    |         pattern doesn't bind `c`
 
 error[E0408]: variable `A` is not bound in all patterns
-  --> $DIR/resolve-inconsistent-names.rs:19:18
+  --> $DIR/resolve-inconsistent-names.rs:21:18
    |
 LL |         (A, B) | (ref B, c) | (c, A) => ()
    |          -       ^^^^^^^^^^       - variable not in all patterns
@@ -38,7 +50,7 @@ LL |         (E::A, B) | (ref B, c) | (c, A) => ()
    |          +++
 
 error[E0408]: variable `B` is not bound in all patterns
-  --> $DIR/resolve-inconsistent-names.rs:19:31
+  --> $DIR/resolve-inconsistent-names.rs:21:31
    |
 LL |         (A, B) | (ref B, c) | (c, A) => ()
    |             -         -       ^^^^^^ pattern doesn't bind `B`
@@ -47,7 +59,7 @@ LL |         (A, B) | (ref B, c) | (c, A) => ()
    |             variable not in all patterns
 
 error[E0409]: variable `B` is bound inconsistently across alternatives separated by `|`
-  --> $DIR/resolve-inconsistent-names.rs:19:23
+  --> $DIR/resolve-inconsistent-names.rs:21:23
    |
 LL |         (A, B) | (ref B, c) | (c, A) => ()
    |             -         ^ bound in different ways
@@ -55,7 +67,7 @@ LL |         (A, B) | (ref B, c) | (c, A) => ()
    |             first binding
 
 error[E0408]: variable `Const2` is not bound in all patterns
-  --> $DIR/resolve-inconsistent-names.rs:31:9
+  --> $DIR/resolve-inconsistent-names.rs:33:9
    |
 LL |         (CONST1, _) | (_, Const2) => ()
    |         ^^^^^^^^^^^       ------ variable not in all patterns
@@ -68,7 +80,7 @@ LL |         (CONST1, _) | (_, m::Const2) => ()
    |                           +++
 
 error[E0408]: variable `CONST1` is not bound in all patterns
-  --> $DIR/resolve-inconsistent-names.rs:31:23
+  --> $DIR/resolve-inconsistent-names.rs:33:23
    |
 LL |         (CONST1, _) | (_, Const2) => ()
    |          ------       ^^^^^^^^^^^ pattern doesn't bind `CONST1`
@@ -82,7 +94,7 @@ LL |     const CONST1: usize = 10;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^ not accessible
 
 error[E0308]: mismatched types
-  --> $DIR/resolve-inconsistent-names.rs:19:19
+  --> $DIR/resolve-inconsistent-names.rs:21:19
    |
 LL |     match x {
    |           - this expression has type `(E, E)`