Merge pull request #2809 from Aaronepower/if_chain_clean

Refactored nested if lets to if_chain! macro

Author: oli-obk

clippy_lints/src/reference.rs

@@ -38,8 +38,10 @@ fn without_parens(mut e: &Expr) -> &Expr {
 
 impl EarlyLintPass for Pass {
     fn check_expr(&mut self, cx: &EarlyContext, e: &Expr) {
-        if let ExprKind::Unary(UnOp::Deref, ref deref_target) = e.node {
-            if let ExprKind::AddrOf(_, ref addrof_target) = without_parens(deref_target).node {
+        if_chain! {
+            if let ExprKind::Unary(UnOp::Deref, ref deref_target) = e.node;
+            if let ExprKind::AddrOf(_, ref addrof_target) = without_parens(deref_target).node;
+            then {
                 span_lint_and_sugg(
                     cx,
                     DEREF_ADDROF,