add back old tail call implementation

test/fixtures/transformation/es6-tail-call/call-apply/actual.js

@@ -0,0 +1,7 @@
+(function f(n) {
+  if (n <= 0) {
+    console.log(this, arguments);
+    return "foo";
+  }
+  return Math.random() > 0.5 ? f.call(this, n - 1) : f.apply(this, [n - 1]);
+})(1e6) === "foo";

test/fixtures/transformation/es6-tail-call/call-apply/expected.js

@@ -0,0 +1,27 @@
+"use strict";
+
+(function f(n) {
+  var _arguments = arguments,
+      _this = this,
+      _shouldContinue,
+      _result;
+  do {
+    _shouldContinue = false;
+    _result = (function (n) {
+      if (n <= 0) {
+        console.log(this, arguments);
+        return "foo";
+      }
+      if (Math.random() > 0.5) {
+        _arguments = [n - 1];
+        _this = this;
+        return _shouldContinue = true;
+      } else {
+        _arguments = [n - 1];
+        _this = this;
+        return _shouldContinue = true;
+      }
+    }).apply(_this, _arguments);
+  } while (_shouldContinue);
+  return _result;
+})(1000000) === "foo";

test/fixtures/transformation/es6-tail-call/expressions/actual.js

@@ -0,0 +1,3 @@
+(function f(n) {
+  return n <= 0 ? "foo" : (doSmth(), getTrueValue() && (getFalseValue() || f(n - 1)));
+})(1e6, true) === "foo";

test/fixtures/transformation/es6-tail-call/expressions/expected.js

@@ -0,0 +1,30 @@
+"use strict";
+
+(function f(n) {
+  var _arguments = arguments,
+      _this = this,
+      _shouldContinue,
+      _result;
+  do {
+    _shouldContinue = false;
+    _result = (function (n) {
+      var _left;
+      if (n <= 0) {
+        return "foo";
+      } else {
+        doSmth();
+
+        if (!(_left = getTrueValue())) {
+          return _left;
+        }
+        if (_left = getFalseValue()) {
+          return _left;
+        }
+        _arguments = [n - 1];
+        _this = undefined;
+        return _shouldContinue = true;
+      }
+    }).apply(_this, _arguments);
+  } while (_shouldContinue);
+  return _result;
+})(1000000, true) === "foo";

test/fixtures/transformation/es6-tail-call/recursion/actual.js

@@ -0,0 +1,8 @@
+(function f(n = getDefaultValue(), /* should be undefined after first pass */ m) {
+  if (n <= 0) {
+    return "foo";
+  }
+  // Should be clean (undefined) on each pass
+  var local;
+  return f(n - 1);
+})(1e6, true) === "foo";

test/fixtures/transformation/es6-tail-call/recursion/expected.js

@@ -0,0 +1,23 @@
+"use strict";
+
+(function f(_x, /* should be undefined after first pass */m) {
+  var _arguments = arguments,
+      _this = this,
+      _shouldContinue,
+      _result;
+  do {
+    _shouldContinue = false;
+    _result = (function (_x, m) {
+      var n = arguments[0] === undefined ? getDefaultValue() : arguments[0];
+      if (n <= 0) {
+        return "foo";
+      }
+      // Should be clean (undefined) on each pass
+      var local;
+      _arguments = [n - 1];
+      _this = undefined;
+      return _shouldContinue = true;
+    }).apply(_this, _arguments);
+  } while (_shouldContinue);
+  return _result;
+})(1000000, true) === "foo";

test/fixtures/transformation/es6-tail-call/try-catch/actual.js

@@ -0,0 +1,39 @@
+(function f(n) {
+  if (n <= 0) {
+    return "foo";
+  }
+  try {
+    return f(n - 1);
+  } catch (e) {}
+})(1e6) === "foo";
+
+(function f(n) {
+  if (n <= 0) {
+    return "foo";
+  }
+  try {
+    throw new Error();
+  } catch (e) {
+    return f(n - 1);
+  }
+})(1e6) === "foo";
+
+(function f(n) {
+  if (n <= 0) {
+    return "foo";
+  }
+  try {
+    throw new Error();
+  } catch (e) {
+    return f(n - 1);
+  } finally {}
+})(1e6) === "foo";
+
+(function f(n) {
+  if (n <= 0) {
+    return "foo";
+  }
+  try {} finally {
+    return f(n - 1);
+  }
+})(1e6) === "foo";

test/fixtures/transformation/es6-tail-call/try-catch/expected.js

@@ -0,0 +1,65 @@
+"use strict";
+
+(function f(n) {
+  if (n <= 0) {
+    return "foo";
+  }
+  try {
+    return f(n - 1);
+  } catch (e) {}
+})(1000000) === "foo";
+
+(function f(n) {
+  var _arguments = arguments,
+      _this = this,
+      _shouldContinue,
+      _result;
+  do {
+    _shouldContinue = false;
+    _result = (function (n) {
+      if (n <= 0) {
+        return "foo";
+      }
+      try {
+        throw new Error();
+      } catch (e) {
+        _arguments = [n - 1];
+        _this = undefined;
+        return _shouldContinue = true;
+      }
+    }).apply(_this, _arguments);
+  } while (_shouldContinue);
+  return _result;
+})(1000000) === "foo";
+
+(function f(n) {
+  if (n <= 0) {
+    return "foo";
+  }
+  try {
+    throw new Error();
+  } catch (e) {
+    return f(n - 1);
+  } finally {}
+})(1000000) === "foo";
+
+(function f(n) {
+  var _arguments = arguments,
+      _this = this,
+      _shouldContinue,
+      _result;
+  do {
+    _shouldContinue = false;
+    _result = (function (n) {
+      if (n <= 0) {
+        return "foo";
+      }
+      try {} finally {
+        _arguments = [n - 1];
+        _this = undefined;
+        return _shouldContinue = true;
+      }
+    }).apply(_this, _arguments);
+  } while (_shouldContinue);
+  return _result;
+})(1000000) === "foo";