Improve eval_order_dependence output

Author: camsteffen

clippy_lints/src/eval_order_dependence.rs

@@ -305,7 +305,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ReadVisitor<'a, 'tcx> {
                     self.cx,
                     EVAL_ORDER_DEPENDENCE,
                     expr.span,
-                    "unsequenced read of a variable",
+                    &format!("unsequenced read of `{}`", self.cx.tcx.hir().name(self.var)),
                     Some(self.write_expr.span),
                     "whether read occurs before this write depends on evaluation order",
                 );

tests/ui/eval_order_dependence.stderr

@@ -1,4 +1,4 @@
-error: unsequenced read of a variable
+error: unsequenced read of `x`
   --> $DIR/eval_order_dependence.rs:15:9
    |
 LL |     } + x;
@@ -11,7 +11,7 @@ note: whether read occurs before this write depends on evaluation order
 LL |         x = 1;
    |         ^^^^^
 
-error: unsequenced read of a variable
+error: unsequenced read of `x`
   --> $DIR/eval_order_dependence.rs:18:5
    |
 LL |     x += {
@@ -23,7 +23,7 @@ note: whether read occurs before this write depends on evaluation order
 LL |         x = 20;
    |         ^^^^^^
 
-error: unsequenced read of a variable
+error: unsequenced read of `x`
   --> $DIR/eval_order_dependence.rs:31:12
    |
 LL |         a: x,
@@ -35,7 +35,7 @@ note: whether read occurs before this write depends on evaluation order
 LL |             x = 6;
    |             ^^^^^
 
-error: unsequenced read of a variable
+error: unsequenced read of `x`
   --> $DIR/eval_order_dependence.rs:40:9
    |
 LL |         x += {