fix corner case in properties (#5351)

fixes #5350

lib/compress.js

@@ -12746,7 +12746,7 @@ Compressor.prototype.compress = function(node) {
                         if (flatten && value.has_side_effects(compressor)) flatten = false;
                     }
                 }
-                values.unshift(retValue);
+                if (!flatten) values.unshift(retValue);
                 while (--i >= 0) {
                     var value = elements[i].drop_side_effect_free(compressor);
                     if (value) {
@@ -12757,7 +12757,11 @@ Compressor.prototype.compress = function(node) {
                         index--;
                     }
                 }
-                return flatten ? make_sequence(self, values).optimize(compressor) : make_node(AST_Sub, self, {
+                if (flatten) {
+                    values.push(retValue);
+                    return make_sequence(self, values).optimize(compressor);
+                }
+                return make_node(AST_Sub, self, {
                     expression: make_node(AST_Array, expr, { elements: values }),
                     property: make_node(AST_Number, prop, { value: index }),
                 });

test/compress/ie.js

@@ -3444,3 +3444,33 @@ issue_5269_3_ie: {
         "bar",
     ]
 }
+
+issue_5350: {
+    options = {
+        ie: false,
+        properties: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(typeof f, [ 42, function f() {} ][0]);
+    }
+    expect: {
+        console.log(typeof f, 42);
+    }
+    expect_stdout: "undefined 42"
+}
+
+issue_5350_ie: {
+    options = {
+        ie: true,
+        properties: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(typeof f, [ 42, function f() {} ][0]);
+    }
+    expect: {
+        console.log(typeof f, (function f() {}, 42));
+    }
+    expect_stdout: "undefined 42"
+}