fix `AST_Node.optimize()` (#1602)

Liberal use of `Compressor.transform()` and `AST_Node.optimize()` presents an issue for look-up operations like `TreeWalker.in_boolean_context()` and `TreeWalker.parent()`.

This is an incremental fix such that `AST_Node.optimize()` would now contain the correct stack information when called correctly.

1 files changed, 129 insertions, 0 deletions

diff --git a/test/compress/transform.js b/test/compress/transform.js
new file mode 100644
index 00000000..7b616e40
--- /dev/null
+++ b/test/compress/transform.js
@@ -0,0 +1,129 @@
+booleans_evaluate: {
+    options = {
+        booleans: true,
+        evaluate: true,
+    }
+    input: {
+        console.log(typeof void 0 != "undefined");
+        console.log(1 == 1, 1 === 1)
+        console.log(1 != 1, 1 !== 1)
+    }
+    expect: {
+        console.log(!1);
+        console.log(!0, !0);
+        console.log(!1, !1);
+    }
+}
+
+booleans_global_defs: {
+    options = {
+        booleans: true,
+        evaluate: true,
+        global_defs: {
+            A: true,
+        },
+    }
+    input: {
+        console.log(A == 1);
+    }
+    expect: {
+        console.log(!0);
+    }
+}
+
+condition_evaluate: {
+    options = {
+        booleans: true,
+        dead_code: false,
+        evaluate: true,
+        loops: false,
+    }
+    input: {
+        while (1 === 2);
+        for (; 1 == true;);
+        if (void 0 == null);
+    }
+    expect: {
+        while (!1);
+        for (; !0;);
+        if (!0);
+    }
+}
+
+if_else_empty: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        if ({} ? a : b); else {}
+    }
+    expect: {
+        !{} ? b : a;
+    }
+}
+
+label_if_break: {
+    options = {
+        conditionals: true,
+        dead_code: true,
+        evaluate: true,
+    }
+    input: {
+        L: if (true) {
+            a;
+            break L;
+        }
+    }
+    expect: {
+        a;
+    }
+}
+
+while_if_break: {
+    options = {
+        conditionals: true,
+        loops: true,
+        sequences: true,
+    }
+    input: {
+        while (a) {
+            if (b) if(c) d;
+            if (e) break;
+        }
+    }
+    expect: {
+        for(; a && (b && c && d, !e););
+    }
+}
+
+if_return: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        if_return: true,
+        sequences: true,
+    }
+    input: {
+        function f(w, x, y, z) {
+            if (x) return;
+            if (w) {
+                if (y) return;
+            } else if (z) return;
+            if (x == y) return true;
+
+            if (x) w();
+            if (y) z();
+            return true;
+        }
+    }
+    expect: {
+        function f(w, x, y, z) {
+            if (!x) {
+                if (w) {
+                    if (y) return;
+                } else if (z) return;
+                return x == y || (x && w(), y && z(), !0);
+            }
+        }
+    }
+}