fix `dead_code` on `for` (#2552)

diff --git a/lib/compress.js b/lib/compress.js
index 7d87c4a..914fdd0 100644 (file)
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -3128,9 +3128,6 @@ merge(Compressor.prototype, {
                 if (!cond) {
                     var body = [];
                     extract_declarations_from_unreachable_code(compressor, self.body, body);
-                    body.push(make_node(AST_SimpleStatement, self.condition, {
-                        body: self.condition
-                    }));
                     if (self.init instanceof AST_Statement) {
                         body.push(self.init);
                     } else if (self.init) {
@@ -3138,6 +3135,9 @@ merge(Compressor.prototype, {
                             body: self.init
                         }));
                     }
+                    body.push(make_node(AST_SimpleStatement, self.condition, {
+                        body: self.condition
+                    }));
                     return make_node(AST_BlockStatement, self, { body: body }).optimize(compressor);
                 }
             }

diff --git a/test/compress/loops.js b/test/compress/loops.js
index 44e92c5..3538c22 100644 (file)
--- a/test/compress/loops.js
+++ b/test/compress/loops.js
@@ -468,3 +468,27 @@ init_side_effects: {
     }
     expect_stdout: true
 }
+
+dead_code_condition: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        loops: true,
+        sequences: true,
+    }
+    input: {
+        for (var a = 0, b = 5; (a += 1, 3) - 3 && b > 0; b--) {
+            var c = function() {
+                b--;
+            }(a++);
+        }
+        console.log(a);
+    }
+    expect: {
+        var c;
+        var a = 0, b = 5;
+        a += 1, 0,
+        console.log(a);
+    }
+    expect_stdout: "1"
+}