Also check if let chains with multiple lets in these two tests

Author: est31

Diff for: tests/ui/pattern/usefulness/conflicting_bindings.rs

@@ -10,6 +10,8 @@ fn main() {
     //~^ ERROR: mutable more than once
     if let Some(ref mut y @ ref mut z) = x && true {}
     //~^ ERROR: mutable more than once
+    if let Some(_) = Some(()) && let Some(ref mut y @ ref mut z) = x && true {}
+    //~^ ERROR: mutable more than once
     while let Some(ref mut y @ ref mut z) = x {}
     //~^ ERROR: mutable more than once
     while let Some(ref mut y @ ref mut z) = x && true {}

Diff for: tests/ui/pattern/usefulness/conflicting_bindings.stderr

@@ -31,36 +31,44 @@ LL |     if let Some(ref mut y @ ref mut z) = x && true {}
    |                 value is mutably borrowed by `y` here
 
 error: cannot borrow value as mutable more than once at a time
-  --> $DIR/conflicting_bindings.rs:13:20
+  --> $DIR/conflicting_bindings.rs:13:43
+   |
+LL |     if let Some(_) = Some(()) && let Some(ref mut y @ ref mut z) = x && true {}
+   |                                           ^^^^^^^^^   --------- value is mutably borrowed by `z` here
+   |                                           |
+   |                                           value is mutably borrowed by `y` here
+
+error: cannot borrow value as mutable more than once at a time
+  --> $DIR/conflicting_bindings.rs:15:20
    |
 LL |     while let Some(ref mut y @ ref mut z) = x {}
    |                    ^^^^^^^^^   --------- value is mutably borrowed by `z` here
    |                    |
    |                    value is mutably borrowed by `y` here
 
 error: cannot borrow value as mutable more than once at a time
-  --> $DIR/conflicting_bindings.rs:15:20
+  --> $DIR/conflicting_bindings.rs:17:20
    |
 LL |     while let Some(ref mut y @ ref mut z) = x && true {}
    |                    ^^^^^^^^^   --------- value is mutably borrowed by `z` here
    |                    |
    |                    value is mutably borrowed by `y` here
 
 error: cannot borrow value as mutable more than once at a time
-  --> $DIR/conflicting_bindings.rs:18:9
+  --> $DIR/conflicting_bindings.rs:20:9
    |
 LL |         ref mut y @ ref mut z => {}
    |         ^^^^^^^^^   --------- value is mutably borrowed by `z` here
    |         |
    |         value is mutably borrowed by `y` here
 
 error: cannot borrow value as mutable more than once at a time
-  --> $DIR/conflicting_bindings.rs:21:24
+  --> $DIR/conflicting_bindings.rs:23:24
    |
 LL |         () if let Some(ref mut y @ ref mut z) = x => {}
    |                        ^^^^^^^^^   --------- value is mutably borrowed by `z` here
    |                        |
    |                        value is mutably borrowed by `y` here
 
-error: aborting due to 8 previous errors
+error: aborting due to 9 previous errors
 

Diff for: tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.rs

@@ -94,4 +94,15 @@ fn use_in_arm_ok(c: bool) {
     };
 }
 
+fn use_in_same_chain(c: bool) {
+    let x: Box<_> = Box::new(1);
+
+    let v = (1, 2);
+
+    match v {
+        (1, 2) if let y = x && c && let z = x => false, //~ ERROR use of moved value: `x`
+        _ => true,
+    };
+}
+
 fn main() {}

Diff for: tests/ui/rfcs/rfc-2294-if-let-guard/move-guard-if-let-chain.stderr

@@ -60,6 +60,22 @@ help: borrow this binding in the pattern to avoid moving the value
 LL |         (1, 2) if let ref y = x && c => false,
    |                       +++
 
-error: aborting due to 4 previous errors
+error[E0382]: use of moved value: `x`
+  --> $DIR/move-guard-if-let-chain.rs:103:41
+   |
+LL |     let x: Box<_> = Box::new(1);
+   |         - move occurs because `x` has type `Box<i32>`, which does not implement the `Copy` trait
+...
+LL |         (1, 2) if let y = x && c && let z = x => false,
+   |                       -                 ^ value used here after move
+   |                       |
+   |                       value moved here
+   |
+help: borrow this binding in the pattern to avoid moving the value
+   |
+LL |         (1, 2) if let ref y = x && c && let z = x => false,
+   |                       +++
+
+error: aborting due to 5 previous errors
 
 For more information about this error, try `rustc --explain E0382`.