fix(es/minifier): Fix top level detection of DCE (#10603)

Author: kdy1

.changeset/soft-pots-roll.md

@@ -0,0 +1,6 @@
+---
+swc_core: patch
+swc_ecma_transforms_optimization: patch
+---
+
+fix(es/minifier): Fix top level detection of DCE

crates/swc_ecma_transforms_optimization/src/simplify/dce/mod.rs

@@ -794,6 +794,13 @@ impl VisitMut for TreeShaker {
         self.in_block_stmt = old_in_block_stmt;
     }
 
+    fn visit_mut_block_stmt_or_expr(&mut self, n: &mut BlockStmtOrExpr) {
+        let old_in_fn = self.in_fn;
+        self.in_fn = true;
+        n.visit_mut_children_with(self);
+        self.in_fn = old_in_fn;
+    }
+
     fn visit_mut_class_members(&mut self, members: &mut Vec<ClassMember>) {
         self.visit_mut_par(cpu_count() * 8, members);
     }