Fix blocks_in_if_conditions false positive

Author: c410-f3r

clippy_lints/src/blocks_in_if_conditions.rs

@@ -72,9 +72,11 @@ impl<'a, 'tcx> Visitor<'tcx> for ExVisitor<'a, 'tcx> {
 
             let body = self.cx.tcx.hir().body(eid);
             let ex = &body.value;
-            if matches!(ex.kind, ExprKind::Block(_, _)) && !body.value.span.from_expansion() {
-                self.found_block = Some(ex);
-                return;
+            if let ExprKind::Block(block, _) = ex.kind {
+                if !body.value.span.from_expansion() && !block.stmts.is_empty() {
+                    self.found_block = Some(ex);
+                    return;
+                }
             }
         }
         walk_expr(self, expr);

tests/ui/blocks_in_if_conditions_closure.rs

@@ -44,6 +44,14 @@ fn macro_in_closure() {
     }
 }
 
+fn closure(_: impl FnMut()) -> bool {
+    true
+}
+
+fn function_with_empty_closure() {
+    if closure(|| {}) {}
+}
+
 #[rustfmt::skip]
 fn main() {
     let mut range = 0..10;