diff --git a/lib/compress.js b/lib/compress.js
index a4552e85..4f92f289 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -682,7 +682,7 @@ merge(Compressor.prototype, {
                 statements = join_consecutive_vars(statements, compressor);
             }
             if (compressor.option("collapse_vars")) {
-                statements = collapse(statements, compressor);
+                collapse(statements, compressor);
             }
         } while (CHANGED && max_iter-- > 0);
 
@@ -789,7 +789,6 @@ merge(Compressor.prototype, {
                     if (replaced && !remove_candidate(candidate)) statements.splice(stat_index, 1);
                 }
             }
-            return statements;
 
             function extract_candidates(expr) {
                 if (expr instanceof AST_Assign && !expr.left.has_side_effects(compressor)