Fix src/needless_bool.rs by using ExprBlock(block) = then

clippy_lints/src/let_if_seq.rs

@@ -69,9 +69,9 @@ fn check_block(&mut self, cx: &LateContext<'a, 'tcx>, block: &'tcx hir::Block) {
                 let hir::StmtExpr(ref if_, _) = expr.node,
                 let hir::ExprIf(ref cond, ref then, ref else_) = if_.node,
                 !used_in_expr(cx, def_id, cond),
-                !used_in_expr(cx, def_id, &*then),
                 let hir::ExprBlock(ref then) = then.node,
                 let Some(value) = check_assign(cx, def_id, &*then),
+                !used_in_expr(cx, def_id, value),
             ], {
                 let span = Span { lo: stmt.span.lo, hi: if_.span.hi, ctxt: NO_EXPANSION };
 

clippy_lints/src/needless_bool.rs

@@ -76,7 +76,8 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
                                    "this if-then-else expression returns a bool literal",
                                    |db| { db.span_suggestion(e.span, "you can reduce it to", hint); });
             };
-            match (fetch_bool_expr(&**then_block), fetch_bool_expr(else_expr)) {
+            if let ExprBlock(ref then_block) = then_block.node {
+            match (fetch_bool_block(then_block), fetch_bool_expr(else_expr)) {
                 (RetBool(true), RetBool(true)) |
                 (Bool(true), Bool(true)) => {
                     span_lint(cx,
@@ -97,6 +98,9 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
                 (Bool(false), Bool(true)) => reduce(false, true),
                 _ => (),
             }
+            } else {
+                panic!("IfExpr 'then' node is not an ExprBlock");
+            }
         }
     }
 }