fix reduce_vars on AST_Destructuring (#2672)

fixes #2669
fixes #2670
fixes #2673

test/compress/reduce_vars.js

@@ -5446,3 +5446,44 @@ issue_2598: {
     }
     expect_stdout: "true"
 }
+
+issue_2669: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        let foo;
+        console.log(([ foo ] = [ "PASS" ]) && foo);
+    }
+    expect: {
+        let foo;
+        console.log(([ foo ] = [ "PASS" ]) && foo);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_2670: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        const obj = {};
+        obj.prop = "PASS";
+        const {prop: value} = obj;
+        console.log(value);
+    }
+    expect: {
+        const obj = {};
+        obj.prop = "PASS";
+        const {prop: value} = obj;
+        console.log(value);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}