From 3a0d7989778b074c53c5c63a395113b356631cec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Wed, 7 Oct 2020 12:19:49 +0200
Subject: [PATCH 01/12] fix issue #365. Fix by yWorks

---
 escodegen.js | 43 +++++++++++++++++++++++++++++++++++++------
 1 file changed, 37 insertions(+), 6 deletions(-)

diff --git a/escodegen.js b/escodegen.js
index 847fc370..5c5eb2fc 100644
--- a/escodegen.js
+++ b/escodegen.js
@@ -1490,9 +1490,23 @@
         },
 
         ThrowStatement: function (stmt, flags) {
+            var shouldParenthesize = false;
+            estraverse.traverse(stmt.argument, {
+                enter: function (node, parent) {
+                    if (node.leadingComments && node.leadingComments.length) {
+                        shouldParenthesize = true;
+                        this.break();
+                    }
+                }
+            });
+            var right = this.generateExpression(stmt.argument, Precedence.Sequence, E_TTT)
+            if (shouldParenthesize) {
+                right = ['(', right, ')']
+            }
+
             return [join(
-                'throw',
-                this.generateExpression(stmt.argument, Precedence.Sequence, E_TTT)
+              'throw',
+              right
             ), this.semicolon(flags)];
         },
 
@@ -1747,10 +1761,27 @@
 
         ReturnStatement: function (stmt, flags) {
             if (stmt.argument) {
-                return [join(
-                    'return',
-                    this.generateExpression(stmt.argument, Precedence.Sequence, E_TTT)
-                ), this.semicolon(flags)];
+                var shouldParenthesize = false;
+                estraverse.traverse(stmt.argument, {
+                    enter: function (node, parent) {
+                        if (node.leadingComments && node.leadingComments.length) {
+                            shouldParenthesize = true;
+                            this.break();
+                        }
+                    }
+                });
+                var result = [];
+                if (shouldParenthesize) {
+                    var that = this;
+                    result.push('(', newline)
+                    withIndent(function () {
+                        result.push(addIndent(that.generateExpression(stmt.argument, Precedence.Sequence, E_TTT)), newline)
+                    });
+                    result.push(addIndent(')'))
+                } else {
+                    result.push(this.generateExpression(stmt.argument, Precedence.Sequence, E_TTT));
+                }
+                return [join('return', result), this.semicolon(flags)];
             }
             return ['return' + this.semicolon(flags)];
         },

From e93336eaca5e30de4e9ce8912eef50ea11efe591 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Wed, 7 Oct 2020 15:25:05 +0200
Subject: [PATCH 02/12] add tests

---
 .../comment-in-return-parenthesis-statement.expected.js    | 6 ++++++
 test/comment/comment-in-return-parenthesis-statement.js    | 7 +++++++
 .../comment-in-throw-parenthesis-statement.expected.js     | 6 ++++++
 test/comment/comment-in-throw-parenthesis-statement.js     | 7 +++++++
 4 files changed, 26 insertions(+)
 create mode 100644 test/comment/comment-in-return-parenthesis-statement.expected.js
 create mode 100644 test/comment/comment-in-return-parenthesis-statement.js
 create mode 100644 test/comment/comment-in-throw-parenthesis-statement.expected.js
 create mode 100644 test/comment/comment-in-throw-parenthesis-statement.js

diff --git a/test/comment/comment-in-return-parenthesis-statement.expected.js b/test/comment/comment-in-return-parenthesis-statement.expected.js
new file mode 100644
index 00000000..16757429
--- /dev/null
+++ b/test/comment/comment-in-return-parenthesis-statement.expected.js
@@ -0,0 +1,6 @@
+function foo(a, b, c) {
+    return (
+        // comment
+        a >= b && a <= c || a === 42 || a === 666
+    );
+}
diff --git a/test/comment/comment-in-return-parenthesis-statement.js b/test/comment/comment-in-return-parenthesis-statement.js
new file mode 100644
index 00000000..824e7510
--- /dev/null
+++ b/test/comment/comment-in-return-parenthesis-statement.js
@@ -0,0 +1,7 @@
+function foo(a, b, c) {
+    return (
+        // comment
+        (a >= b && a <= c)
+        || a === 42 || a === 666
+    );
+}
\ No newline at end of file
diff --git a/test/comment/comment-in-throw-parenthesis-statement.expected.js b/test/comment/comment-in-throw-parenthesis-statement.expected.js
new file mode 100644
index 00000000..ed3aa70f
--- /dev/null
+++ b/test/comment/comment-in-throw-parenthesis-statement.expected.js
@@ -0,0 +1,6 @@
+function foo(a, b, c) {
+    throw (
+        // comment
+        a >= b && a <= c || a === 42 || a === 666
+    );
+}
diff --git a/test/comment/comment-in-throw-parenthesis-statement.js b/test/comment/comment-in-throw-parenthesis-statement.js
new file mode 100644
index 00000000..5703b338
--- /dev/null
+++ b/test/comment/comment-in-throw-parenthesis-statement.js
@@ -0,0 +1,7 @@
+function foo(a, b, c) {
+    throw (
+        // comment
+        (a >= b && a <= c)
+        || a === 42 || a === 666
+    );
+}
\ No newline at end of file

From c1cda7d89a5349fb59f00ce8d4f29b4affab5c91 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Wed, 7 Oct 2020 16:15:17 +0200
Subject: [PATCH 03/12] improve the "throw" fix

---
 escodegen.js | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/escodegen.js b/escodegen.js
index 5c5eb2fc..baea50f1 100644
--- a/escodegen.js
+++ b/escodegen.js
@@ -1499,15 +1499,18 @@
                     }
                 }
             });
-            var right = this.generateExpression(stmt.argument, Precedence.Sequence, E_TTT)
+            var result = [];
             if (shouldParenthesize) {
-                right = ['(', right, ')']
+                var that = this;
+                result.push('(', newline)
+                withIndent(function () {
+                    result.push(addIndent(that.generateExpression(stmt.argument, Precedence.Sequence, E_TTT)), newline)
+                });
+                result.push(addIndent(')'))
+            } else {
+                result.push(this.generateExpression(stmt.argument, Precedence.Sequence, E_TTT));
             }
-
-            return [join(
-              'throw',
-              right
-            ), this.semicolon(flags)];
+            return [join('throw', result), this.semicolon(flags)];
         },
 
         TryStatement: function (stmt, flags) {

From c1e8a4207765f1ca7a0d918888a059393f7ae37e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Tue, 13 Oct 2020 10:21:40 +0200
Subject: [PATCH 04/12] add failing arrow function test

---
 ...ment-in-arrow-function-parenthesis-statement.expected.js | 6 ++++++
 .../comment-in-arrow-function-parenthesis-statement.js      | 6 ++++++
 2 files changed, 12 insertions(+)
 create mode 100644 test/comment/comment-in-arrow-function-parenthesis-statement.expected.js
 create mode 100644 test/comment/comment-in-arrow-function-parenthesis-statement.js

diff --git a/test/comment/comment-in-arrow-function-parenthesis-statement.expected.js b/test/comment/comment-in-arrow-function-parenthesis-statement.expected.js
new file mode 100644
index 00000000..044d5563
--- /dev/null
+++ b/test/comment/comment-in-arrow-function-parenthesis-statement.expected.js
@@ -0,0 +1,6 @@
+let arrowFn = () => (
+    // comment
+    {
+      a: 1, b: 2
+    }
+);
\ No newline at end of file
diff --git a/test/comment/comment-in-arrow-function-parenthesis-statement.js b/test/comment/comment-in-arrow-function-parenthesis-statement.js
new file mode 100644
index 00000000..044d5563
--- /dev/null
+++ b/test/comment/comment-in-arrow-function-parenthesis-statement.js
@@ -0,0 +1,6 @@
+let arrowFn = () => (
+    // comment
+    {
+      a: 1, b: 2
+    }
+);
\ No newline at end of file

From fae05b394dd3db4d8b89485fa145c646cc4c8c60 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Tue, 13 Oct 2020 14:32:30 +0200
Subject: [PATCH 05/12] replace the tests with a single thorough test

---
 ...ment-in-parenthesis-expression.expected.js | 52 ++++++++++++++++++
 ...first-element-in-parenthesis-expression.js | 54 +++++++++++++++++++
 ...function-parenthesis-statement.expected.js |  6 ---
 ...in-arrow-function-parenthesis-statement.js |  6 ---
 ...n-return-parenthesis-statement.expected.js |  6 ---
 ...comment-in-return-parenthesis-statement.js |  7 ---
 ...in-throw-parenthesis-statement.expected.js |  6 ---
 .../comment-in-throw-parenthesis-statement.js |  7 ---
 8 files changed, 106 insertions(+), 38 deletions(-)
 create mode 100644 test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
 create mode 100644 test/comment/comment-as-first-element-in-parenthesis-expression.js
 delete mode 100644 test/comment/comment-in-arrow-function-parenthesis-statement.expected.js
 delete mode 100644 test/comment/comment-in-arrow-function-parenthesis-statement.js
 delete mode 100644 test/comment/comment-in-return-parenthesis-statement.expected.js
 delete mode 100644 test/comment/comment-in-return-parenthesis-statement.js
 delete mode 100644 test/comment/comment-in-throw-parenthesis-statement.expected.js
 delete mode 100644 test/comment/comment-in-throw-parenthesis-statement.js

diff --git a/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js b/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
new file mode 100644
index 00000000..a23c59a4
--- /dev/null
+++ b/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
@@ -0,0 +1,52 @@
+let variable = (
+    // comment
+    3+3
+);
+
+function foo(a, b, c) {
+    return (
+        // comment
+        a >= b && a <= c || a === 42 || a === 666
+    );
+}
+
+function foo(a, b, c) {
+    throw (
+        // comment
+        a >= b && a <= c || a === 42 || a === 666
+    );
+}
+
+let arrowFn = () => (
+    // comment
+    {
+      a: 1, b: 2
+    }
+);
+
+let variable = ( // comment
+    3+3
+);
+
+let variable = ( /* comment */
+    3+3
+);
+
+let variable = ( /* comment
+    comment
+    comment
+    */
+    3+3
+);
+
+let variable = (
+    // comment
+    /* comment */
+    // comment
+    3+3
+);
+
+let variable = /* comment */ (
+    // comment
+    3+3
+);
\ No newline at end of file
diff --git a/test/comment/comment-as-first-element-in-parenthesis-expression.js b/test/comment/comment-as-first-element-in-parenthesis-expression.js
new file mode 100644
index 00000000..2da15762
--- /dev/null
+++ b/test/comment/comment-as-first-element-in-parenthesis-expression.js
@@ -0,0 +1,54 @@
+let variable = (
+    // comment
+    3+3
+);
+
+function foo(a, b, c) {
+    return (
+        // comment
+        (a >= b && a <= c)
+        || a === 42 || a === 666
+    );
+}
+
+function foo(a, b, c) {
+    throw (
+        // comment
+        (a >= b && a <= c)
+        || a === 42 || a === 666
+    );
+}
+
+let arrowFn = () => (
+    // comment
+    {
+      a: 1, b: 2
+    }
+);
+
+let variable = ( // comment
+    3+3
+);
+
+let variable = ( /* comment */
+    3+3
+);
+
+let variable = ( /* comment
+    comment
+    comment
+    */
+    3+3
+);
+
+let variable = (
+    // comment
+    /* comment */
+    // comment
+    3+3
+);
+
+let variable = /* comment */ (
+    // comment
+    3+3
+);
\ No newline at end of file
diff --git a/test/comment/comment-in-arrow-function-parenthesis-statement.expected.js b/test/comment/comment-in-arrow-function-parenthesis-statement.expected.js
deleted file mode 100644
index 044d5563..00000000
--- a/test/comment/comment-in-arrow-function-parenthesis-statement.expected.js
+++ /dev/null
@@ -1,6 +0,0 @@
-let arrowFn = () => (
-    // comment
-    {
-      a: 1, b: 2
-    }
-);
\ No newline at end of file
diff --git a/test/comment/comment-in-arrow-function-parenthesis-statement.js b/test/comment/comment-in-arrow-function-parenthesis-statement.js
deleted file mode 100644
index 044d5563..00000000
--- a/test/comment/comment-in-arrow-function-parenthesis-statement.js
+++ /dev/null
@@ -1,6 +0,0 @@
-let arrowFn = () => (
-    // comment
-    {
-      a: 1, b: 2
-    }
-);
\ No newline at end of file
diff --git a/test/comment/comment-in-return-parenthesis-statement.expected.js b/test/comment/comment-in-return-parenthesis-statement.expected.js
deleted file mode 100644
index 16757429..00000000
--- a/test/comment/comment-in-return-parenthesis-statement.expected.js
+++ /dev/null
@@ -1,6 +0,0 @@
-function foo(a, b, c) {
-    return (
-        // comment
-        a >= b && a <= c || a === 42 || a === 666
-    );
-}
diff --git a/test/comment/comment-in-return-parenthesis-statement.js b/test/comment/comment-in-return-parenthesis-statement.js
deleted file mode 100644
index 824e7510..00000000
--- a/test/comment/comment-in-return-parenthesis-statement.js
+++ /dev/null
@@ -1,7 +0,0 @@
-function foo(a, b, c) {
-    return (
-        // comment
-        (a >= b && a <= c)
-        || a === 42 || a === 666
-    );
-}
\ No newline at end of file
diff --git a/test/comment/comment-in-throw-parenthesis-statement.expected.js b/test/comment/comment-in-throw-parenthesis-statement.expected.js
deleted file mode 100644
index ed3aa70f..00000000
--- a/test/comment/comment-in-throw-parenthesis-statement.expected.js
+++ /dev/null
@@ -1,6 +0,0 @@
-function foo(a, b, c) {
-    throw (
-        // comment
-        a >= b && a <= c || a === 42 || a === 666
-    );
-}
diff --git a/test/comment/comment-in-throw-parenthesis-statement.js b/test/comment/comment-in-throw-parenthesis-statement.js
deleted file mode 100644
index 5703b338..00000000
--- a/test/comment/comment-in-throw-parenthesis-statement.js
+++ /dev/null
@@ -1,7 +0,0 @@
-function foo(a, b, c) {
-    throw (
-        // comment
-        (a >= b && a <= c)
-        || a === 42 || a === 666
-    );
-}
\ No newline at end of file

From d0a7843338b31077e8f7285f78a897ec7ab7c180 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Tue, 13 Oct 2020 15:19:52 +0200
Subject: [PATCH 06/12] add another test - ()expression inside of a return
 expression

---
 ...s-first-element-in-parenthesis-expression.expected.js | 7 +++++++
 ...comment-as-first-element-in-parenthesis-expression.js | 9 +++++++++
 2 files changed, 16 insertions(+)

diff --git a/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js b/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
index a23c59a4..89c4c540 100644
--- a/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
+++ b/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
@@ -10,6 +10,13 @@ function foo(a, b, c) {
     );
 }
 
+function foo(a, b, c) {
+    return (
+        // comment
+        a >= b && a <= c || a === 42 || a === 666
+    );
+}
+
 function foo(a, b, c) {
     throw (
         // comment
diff --git a/test/comment/comment-as-first-element-in-parenthesis-expression.js b/test/comment/comment-as-first-element-in-parenthesis-expression.js
index 2da15762..3c9cc197 100644
--- a/test/comment/comment-as-first-element-in-parenthesis-expression.js
+++ b/test/comment/comment-as-first-element-in-parenthesis-expression.js
@@ -11,6 +11,15 @@ function foo(a, b, c) {
     );
 }
 
+function foo(a, b, c) {
+    return (
+        ( // comment
+            a >= b &&
+            a <= c)
+        || a === 42 || a === 666
+    );
+}
+
 function foo(a, b, c) {
     throw (
         // comment

From 30a90f3356428539c3b840cc20d531872afc5adf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Thu, 15 Oct 2020 21:57:42 +0200
Subject: [PATCH 07/12] more thought out fix; WIP

---
 escodegen.js                                  | 117 ++++++++++--------
 ...ment-in-parenthesis-expression.expected.js |  64 +++++-----
 ...first-element-in-parenthesis-expression.js |  54 ++++----
 3 files changed, 125 insertions(+), 110 deletions(-)

diff --git a/escodegen.js b/escodegen.js
index baea50f1..b8577810 100644
--- a/escodegen.js
+++ b/escodegen.js
@@ -229,6 +229,37 @@
         return len && esutils.code.isLineTerminator(str.charCodeAt(len - 1));
     }
 
+    function removeComments(str) {
+        // https://stackoverflow.com/a/59094308
+        return str.replace(/\/\*[\s\S]*?\*\/|\/\/.*/g, '');
+    }
+
+    function removeTrailingWhiteSpaces(str) {
+        return str.replace(/\S(\s+)$/g, '');
+    }
+
+    function isParenthesized(str) {
+        str = removeComments(str);
+        str = removeTrailingWhiteSpaces(str);
+        var counter = 0;
+        for (var i = 0; i < str.length; ++i) {
+            if (str[i] == '(') {
+                counter++;
+            }
+            else if (str[i] == ')') {
+                if (counter == 0) {
+                    return false;
+                }
+                counter--;
+            }
+        }
+        return counter == 0 && str[str.length-1] == ')';
+    }
+
+    function hasComment(str) {
+        return (/(\/\/|\/\*)/g).test(str);
+    }
+
     function merge(target, override) {
         var key;
         for (key in override) {
@@ -703,10 +734,10 @@
             } else {
                 comment = stmt.leadingComments[0];
                 result = [];
-                if (safeConcatenation && stmt.type === Syntax.Program && stmt.body.length === 0) {
-                    result.push('\n');
-                }
-                result.push(generateComment(comment));
+                result.push('\n');
+                withIndent(function() {
+                    result.push(addIndent(generateComment(comment)));
+                });
                 if (!endsWithLineTerminator(toSourceNodeWhenNeeded(result).toString())) {
                     result.push('\n');
                 }
@@ -717,11 +748,15 @@
                     if (!endsWithLineTerminator(toSourceNodeWhenNeeded(fragment).toString())) {
                         fragment.push('\n');
                     }
-                    result.push(addIndent(fragment));
+                    withIndent(function() {
+                        result.push(addIndent(fragment));
+                    });
                 }
             }
 
-            result.push(addIndent(save));
+            withIndent(function () {
+                result.push(addIndent(save));
+            });
         }
 
         if (stmt.trailingComments) {
@@ -1490,27 +1525,10 @@
         },
 
         ThrowStatement: function (stmt, flags) {
-            var shouldParenthesize = false;
-            estraverse.traverse(stmt.argument, {
-                enter: function (node, parent) {
-                    if (node.leadingComments && node.leadingComments.length) {
-                        shouldParenthesize = true;
-                        this.break();
-                    }
-                }
-            });
-            var result = [];
-            if (shouldParenthesize) {
-                var that = this;
-                result.push('(', newline)
-                withIndent(function () {
-                    result.push(addIndent(that.generateExpression(stmt.argument, Precedence.Sequence, E_TTT)), newline)
-                });
-                result.push(addIndent(')'))
-            } else {
-                result.push(this.generateExpression(stmt.argument, Precedence.Sequence, E_TTT));
-            }
-            return [join('throw', result), this.semicolon(flags)];
+            return [join(
+                'throw',
+                this.generateExpression(stmt.argument, Precedence.Sequence, E_TTT)
+            ), this.semicolon(flags)];
         },
 
         TryStatement: function (stmt, flags) {
@@ -1764,27 +1782,10 @@
 
         ReturnStatement: function (stmt, flags) {
             if (stmt.argument) {
-                var shouldParenthesize = false;
-                estraverse.traverse(stmt.argument, {
-                    enter: function (node, parent) {
-                        if (node.leadingComments && node.leadingComments.length) {
-                            shouldParenthesize = true;
-                            this.break();
-                        }
-                    }
-                });
-                var result = [];
-                if (shouldParenthesize) {
-                    var that = this;
-                    result.push('(', newline)
-                    withIndent(function () {
-                        result.push(addIndent(that.generateExpression(stmt.argument, Precedence.Sequence, E_TTT)), newline)
-                    });
-                    result.push(addIndent(')'))
-                } else {
-                    result.push(this.generateExpression(stmt.argument, Precedence.Sequence, E_TTT));
-                }
-                return [join('return', result), this.semicolon(flags)];
+                return [join(
+                    'return',
+                    this.generateExpression(stmt.argument, Precedence.Sequence, E_TTT)
+                ), this.semicolon(flags)];
             }
             return ['return' + this.semicolon(flags)];
         },
@@ -2531,8 +2532,26 @@
 
 
         if (extra.comment) {
-            result = addComments(expr, result);
+            if (!expr.leadingComments) {
+                // TODO!
+                //addComments(expr, result);
+            }
+            else {
+                result = addComments(expr, result);
+                result = ['(', result, newline, ')'];
+
+                /* this fix is now syntactically correct, but we must (try) to maintain the original formatting... */
+                /* which was not really correctly implemented in my original PR ... */
+                // notice that when the comment is removed, the formatting is correct...
+            }
+        }
+
+        /* TODO: this should be only executed e.g. when returning to the ReturnStatement, ThrowStatement, ArrayFunction .... */
+        var text = toSourceNodeWhenNeeded(result).toString();
+        if (hasLineTerminator(text) && !isParenthesized(text)) {
+            result = ['(', result, ')'];
         }
+
         return toSourceNodeWhenNeeded(result, expr);
     };
 
diff --git a/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js b/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
index 89c4c540..36f27689 100644
--- a/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
+++ b/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
@@ -1,59 +1,55 @@
 let variable = (
     // comment
-    3+3
+    3 + 3
+);
+let variable = (
+    // comment
+    3 + 3
+);
+let variable = (
+    /* comment */
+    3 + 3
+);
+let variable = (
+    /* comment
+    comment
+    comment
+    */
+    3 + 3
+);
+let variable = (
+    // comment
+    /* comment */
+    // comment
+    3 + 3
+);
+let variable = (
+    // comment
+    3 + 3
 );
-
 function foo(a, b, c) {
     return (
         // comment
         a >= b && a <= c || a === 42 || a === 666
     );
 }
-
 function foo(a, b, c) {
     return (
-        // comment
-        a >= b && a <= c || a === 42 || a === 666
+        (
+            // comment
+            a >= b && a <= c
+        ) || a === 42 || a === 666
     );
 }
-
 function foo(a, b, c) {
     throw (
         // comment
         a >= b && a <= c || a === 42 || a === 666
     );
 }
-
 let arrowFn = () => (
     // comment
     {
       a: 1, b: 2
     }
 );
-
-let variable = ( // comment
-    3+3
-);
-
-let variable = ( /* comment */
-    3+3
-);
-
-let variable = ( /* comment
-    comment
-    comment
-    */
-    3+3
-);
-
-let variable = (
-    // comment
-    /* comment */
-    // comment
-    3+3
-);
-
-let variable = /* comment */ (
-    // comment
-    3+3
-);
\ No newline at end of file
diff --git a/test/comment/comment-as-first-element-in-parenthesis-expression.js b/test/comment/comment-as-first-element-in-parenthesis-expression.js
index 3c9cc197..3e95458e 100644
--- a/test/comment/comment-as-first-element-in-parenthesis-expression.js
+++ b/test/comment/comment-as-first-element-in-parenthesis-expression.js
@@ -3,6 +3,33 @@ let variable = (
     3+3
 );
 
+let variable = ( // comment
+    3+3
+);
+
+let variable = ( /* comment */
+    3+3
+);
+
+let variable = ( /* comment
+    comment
+    comment
+    */
+    3+3
+);
+
+let variable = (
+    // comment
+    /* comment */
+    // comment
+    3+3
+);
+
+let variable = /* comment */ (
+    // comment
+    3+3
+);
+
 function foo(a, b, c) {
     return (
         // comment
@@ -34,30 +61,3 @@ let arrowFn = () => (
       a: 1, b: 2
     }
 );
-
-let variable = ( // comment
-    3+3
-);
-
-let variable = ( /* comment */
-    3+3
-);
-
-let variable = ( /* comment
-    comment
-    comment
-    */
-    3+3
-);
-
-let variable = (
-    // comment
-    /* comment */
-    // comment
-    3+3
-);
-
-let variable = /* comment */ (
-    // comment
-    3+3
-);
\ No newline at end of file

From 680ea9788dae8232f2329186d6c3114eb69d734d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Mon, 19 Oct 2020 20:28:08 +0200
Subject: [PATCH 08/12] proper fix

---
 escodegen.js                                  | 127 +++++++++++-------
 gulpfile.js                                   |   2 +
 test/comment.js                               |   2 +
 ...ment-in-parenthesis-expression.expected.js |  30 ++++-
 ...first-element-in-parenthesis-expression.js |  24 ++++
 test/compare-harmony.js                       |   1 +
 6 files changed, 134 insertions(+), 52 deletions(-)

diff --git a/escodegen.js b/escodegen.js
index b8577810..917466af 100644
--- a/escodegen.js
+++ b/escodegen.js
@@ -238,26 +238,49 @@
         return str.replace(/\S(\s+)$/g, '');
     }
 
-    function isParenthesized(str) {
+    function isParenthesized(str, leftPar, rightPar) {
         str = removeComments(str);
         str = removeTrailingWhiteSpaces(str);
         var counter = 0;
         for (var i = 0; i < str.length; ++i) {
-            if (str[i] == '(') {
+            if (str[i] == leftPar) {
                 counter++;
             }
-            else if (str[i] == ')') {
+            else if (str[i] == rightPar) {
                 if (counter == 0) {
                     return false;
                 }
                 counter--;
             }
         }
-        return counter == 0 && str[str.length-1] == ')';
+        return counter == 0 && str[str.length-1] == rightPar;
     }
 
-    function hasComment(str) {
-        return (/(\/\/|\/\*)/g).test(str);
+    function isParenthesizedByAnyBracketKind(str) {
+        return isParenthesized(str, '(', ')') ||
+                isParenthesized(str, '{', '}') ||
+                isParenthesized(str, '[', ']');
+    }
+
+    function shouldParenthesize(str, parentStmt) {
+        if (!hasLineTerminator(str)) {
+            return false;
+        }
+        if (parentStmt !== undefined && (
+            parentStmt.type == Syntax.ObjectExpression ||
+            parentStmt.type == Syntax.ArrayExpression ||
+            parentStmt.type == Syntax.Property
+            )) {
+            return false;
+        }
+        if (!isParenthesizedByAnyBracketKind(str)) {
+            return true;
+        }
+
+        str = removeComments(str);
+        var firstNewlineIdx = str.indexOf(newline);
+        var firstParenthesisIdx = str.match(/[\(\[\{)]/).index;
+        return firstNewlineIdx < firstParenthesisIdx;
     }
 
     function merge(target, override) {
@@ -601,6 +624,18 @@
         return [base, stmt];
     }
 
+    function addMultiLineIndent(stmt) {
+        var str = base + flattenToString(stmt);
+        var split = str.split(/\n/g);
+        var suffix = '';
+        // do not replace the last newline
+        if (split[split.length-1].length == 0) {
+            split = split.slice(0, split.length-1);
+            suffix = newline;
+        }
+        return split.join(newline + base) + suffix;
+    }
+
     function withIndent(fn) {
         var previousBase;
         previousBase = base;
@@ -690,14 +725,14 @@
         return '/*' + comment.value + '*/';
     }
 
-    function addComments(stmt, result) {
+    function addComments(stmt, result, parentStmt) {
         var i, len, comment, save, tailingToStatement, specialBase, fragment,
             extRange, range, prevRange, prefix, infix, suffix, count;
 
         if (stmt.leadingComments && stmt.leadingComments.length > 0) {
             save = result;
 
-            if (preserveBlankLines) {
+            if (preserveBlankLines) { // TODO?
                 comment = stmt.leadingComments[0];
                 result = [];
 
@@ -734,10 +769,12 @@
             } else {
                 comment = stmt.leadingComments[0];
                 result = [];
-                result.push('\n');
-                withIndent(function() {
-                    result.push(addIndent(generateComment(comment)));
-                });
+
+                if (safeConcatenation && stmt.type === Syntax.Program && stmt.body.length === 0) {
+                    result.push('\n');
+                }
+                result.push(generateComment(comment));
+
                 if (!endsWithLineTerminator(toSourceNodeWhenNeeded(result).toString())) {
                     result.push('\n');
                 }
@@ -748,18 +785,33 @@
                     if (!endsWithLineTerminator(toSourceNodeWhenNeeded(fragment).toString())) {
                         fragment.push('\n');
                     }
-                    withIndent(function() {
-                        result.push(addIndent(fragment));
-                    });
+                    result.push(addIndent(fragment));
                 }
             }
 
-            withIndent(function () {
+            if (!isExpression(stmt)) {
                 result.push(addIndent(save));
-            });
+            } else {
+                var text = toSourceNodeWhenNeeded(result).toString();
+                if (shouldParenthesize(text, parentStmt)) {
+                    withIndent(function () {
+                        result = addMultiLineIndent(result);
+                    });
+
+                    result = ['(', newline, result];
+
+                    withIndent(function () {
+                        result.push(addMultiLineIndent(save));
+                    });
+
+                    result.push([newline, base, ')']);
+                } else {
+                    result.push(addIndent(save));
+                }
+            }
         }
 
-        if (stmt.trailingComments) {
+        if (stmt.trailingComments) { // TODO?
 
             if (preserveBlankLines) {
                 comment = stmt.trailingComments[0];
@@ -1012,14 +1064,14 @@
         return result;
     };
 
-    CodeGenerator.prototype.generatePropertyKey = function (expr, computed) {
+    CodeGenerator.prototype.generatePropertyKey = function (expr, computed, parentStmt) {
         var result = [];
 
         if (computed) {
             result.push('[');
         }
 
-        result.push(this.generateExpression(expr, Precedence.Assignment, E_TTT));
+        result.push(this.generateExpression(expr, Precedence.Assignment, E_TTT, parentStmt));
 
         if (computed) {
             result.push(']');
@@ -2130,7 +2182,7 @@
                         }
                     } else {
                         result.push(multiline ? indent : '');
-                        result.push(that.generateExpression(expr.elements[i], Precedence.Assignment, E_TTT));
+                        result.push(that.generateExpression(expr.elements[i], Precedence.Assignment, E_TTT, expr));
                     }
                     if (i + 1 < iz) {
                         result.push(',' + (multiline ? newline : space));
@@ -2190,7 +2242,7 @@
             if (expr.kind === 'get' || expr.kind === 'set') {
                 return [
                     expr.kind, noEmptySpace(),
-                    this.generatePropertyKey(expr.key, expr.computed),
+                    this.generatePropertyKey(expr.key, expr.computed, expr),
                     this.generateFunctionBody(expr.value)
                 ];
             }
@@ -2199,19 +2251,19 @@
                 if (expr.value.type === "AssignmentPattern") {
                     return this.AssignmentPattern(expr.value, Precedence.Sequence, E_TTT);
                 }
-                return this.generatePropertyKey(expr.key, expr.computed);
+                return this.generatePropertyKey(expr.key, expr.computed, expr);
             }
 
             if (expr.method) {
                 return [
                     generateMethodPrefix(expr),
-                    this.generatePropertyKey(expr.key, expr.computed),
+                    this.generatePropertyKey(expr.key, expr.computed, expr),
                     this.generateFunctionBody(expr.value)
                 ];
             }
 
             return [
-                this.generatePropertyKey(expr.key, expr.computed),
+                this.generatePropertyKey(expr.key, expr.computed, expr),
                 ':' + space,
                 this.generateExpression(expr.value, Precedence.Assignment, E_TTT)
             ];
@@ -2226,7 +2278,7 @@
             multiline = expr.properties.length > 1;
 
             withIndent(function () {
-                fragment = that.generateExpression(expr.properties[0], Precedence.Sequence, E_TTT);
+                fragment = that.generateExpression(expr.properties[0], Precedence.Sequence, E_TTT, expr);
             });
 
             if (!multiline) {
@@ -2251,7 +2303,7 @@
                     result.push(',' + newline);
                     for (i = 1, iz = expr.properties.length; i < iz; ++i) {
                         result.push(indent);
-                        result.push(that.generateExpression(expr.properties[i], Precedence.Sequence, E_TTT));
+                        result.push(that.generateExpression(expr.properties[i], Precedence.Sequence, E_TTT, expr));
                         if (i + 1 < iz) {
                             result.push(',' + newline);
                         }
@@ -2519,7 +2571,7 @@
 
     merge(CodeGenerator.prototype, CodeGenerator.Expression);
 
-    CodeGenerator.prototype.generateExpression = function (expr, precedence, flags) {
+    CodeGenerator.prototype.generateExpression = function (expr, precedence, flags, parentStmt) {
         var result, type;
 
         type = expr.type || Syntax.Property;
@@ -2532,24 +2584,7 @@
 
 
         if (extra.comment) {
-            if (!expr.leadingComments) {
-                // TODO!
-                //addComments(expr, result);
-            }
-            else {
-                result = addComments(expr, result);
-                result = ['(', result, newline, ')'];
-
-                /* this fix is now syntactically correct, but we must (try) to maintain the original formatting... */
-                /* which was not really correctly implemented in my original PR ... */
-                // notice that when the comment is removed, the formatting is correct...
-            }
-        }
-
-        /* TODO: this should be only executed e.g. when returning to the ReturnStatement, ThrowStatement, ArrayFunction .... */
-        var text = toSourceNodeWhenNeeded(result).toString();
-        if (hasLineTerminator(text) && !isParenthesized(text)) {
-            result = ['(', result, ')'];
+            result = addComments(expr, result, parentStmt);
         }
 
         return toSourceNodeWhenNeeded(result, expr);
diff --git a/gulpfile.js b/gulpfile.js
index 590e1274..c9ef2e04 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -28,6 +28,8 @@ var gulp = require('gulp');
 var mocha = require('gulp-mocha');
 var eslint = require('gulp-eslint');
 
+//var TEST = [ 'test/comment.js' ];
+//var TEST = [ 'test/compare.js' ];
 var TEST = [ 'test/*.js' ];
 
 var LINT = [
diff --git a/test/comment.js b/test/comment.js
index 57806f39..42bcc36e 100644
--- a/test/comment.js
+++ b/test/comment.js
@@ -62,6 +62,8 @@ function test(code, expected) {
 describe('comment test', function () {
     fs.readdirSync(__dirname + '/comment').sort().forEach(function(file) {
         var code, expected, p;
+        //if (/comment-as-first-element-in-parenthesis-expression\.js$/.test(file) && !/comment-as-first-element-in-parenthesis-expression\.expected\.js$/.test(file)) {
+        //if (/^computed-property-comments-2\.js$/.test(file) && !/^computed-property-comments-2\.expected\.js$/.test(file)) {
         if (/\.js$/.test(file) && !/expected\.js$/.test(file)) {
             it(file, function () {
                 p = file.replace(/\.js$/, '.expected.js');
diff --git a/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js b/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
index 36f27689..f1a36326 100644
--- a/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
+++ b/test/comment/comment-as-first-element-in-parenthesis-expression.expected.js
@@ -27,6 +27,13 @@ let variable = (
     // comment
     3 + 3
 );
+let variable = (
+    // one
+    3 + 3
+) - (
+    // two
+    (1 + 1)
+);
 function foo(a, b, c) {
     return (
         // comment
@@ -35,11 +42,9 @@ function foo(a, b, c) {
 }
 function foo(a, b, c) {
     return (
-        (
-            // comment
-            a >= b && a <= c
-        ) || a === 42 || a === 666
-    );
+        // comment
+        a >= b && a <= c
+    ) || a === 42 || a === 666;
 }
 function foo(a, b, c) {
     throw (
@@ -50,6 +55,19 @@ function foo(a, b, c) {
 let arrowFn = () => (
     // comment
     {
-      a: 1, b: 2
+        a: 1,
+        b: 2
     }
 );
+var test = [
+    /**
+     * Test 2
+     */
+    a,
+    /*
+     * Test 1
+     */
+    2,
+    // Test 3
+    3 + 3
+];
diff --git a/test/comment/comment-as-first-element-in-parenthesis-expression.js b/test/comment/comment-as-first-element-in-parenthesis-expression.js
index 3e95458e..bea0dab4 100644
--- a/test/comment/comment-as-first-element-in-parenthesis-expression.js
+++ b/test/comment/comment-as-first-element-in-parenthesis-expression.js
@@ -30,6 +30,17 @@ let variable = /* comment */ (
     3+3
 );
 
+let variable = (
+    (
+        // one
+        3+3
+    ) -
+    (
+        // two
+        1+1
+    )
+);
+
 function foo(a, b, c) {
     return (
         // comment
@@ -61,3 +72,16 @@ let arrowFn = () => (
       a: 1, b: 2
     }
 );
+
+var test = [
+    /**
+     * Test 2
+     */
+    a,
+    /*
+     * Test 1
+     */
+    2,
+    // Test 3
+    3+3
+];
\ No newline at end of file
diff --git a/test/compare-harmony.js b/test/compare-harmony.js
index 3579da9a..ae314eb3 100644
--- a/test/compare-harmony.js
+++ b/test/compare-harmony.js
@@ -87,6 +87,7 @@ DIR = 'compare-harmony';
 describe('compare harmony test', function () {
     fs.readdirSync(__dirname + '/' + DIR).sort().forEach(function(file) {
         var code, expected, exp, min;
+        //if (/templates-escape\.js$/.test(file) && !/templates-escape\.expected\.js$/.test(file) && !/templates-escape\.expected\.min\.js$/.test(file)) {
         if (/\.js$/.test(file) && !/expected\.js$/.test(file) && !/expected\.min\.js$/.test(file)) {
             it(file, function () {
                 exp = file.replace(/\.js$/, '.expected.js');

From d40ca355e14a6f2946a6d951a98754629af65fa3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Mon, 19 Oct 2020 21:24:28 +0200
Subject: [PATCH 09/12] cleanup

---
 escodegen.js                                                    | 2 +-
 gulpfile.js                                                     | 2 --
 test/comment.js                                                 | 2 --
 .../comment-as-first-element-in-parenthesis-expression.js       | 2 +-
 4 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/escodegen.js b/escodegen.js
index 917466af..00440538 100644
--- a/escodegen.js
+++ b/escodegen.js
@@ -811,7 +811,7 @@
             }
         }
 
-        if (stmt.trailingComments) { // TODO?
+        if (stmt.trailingComments) {
 
             if (preserveBlankLines) {
                 comment = stmt.trailingComments[0];
diff --git a/gulpfile.js b/gulpfile.js
index c9ef2e04..590e1274 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -28,8 +28,6 @@ var gulp = require('gulp');
 var mocha = require('gulp-mocha');
 var eslint = require('gulp-eslint');
 
-//var TEST = [ 'test/comment.js' ];
-//var TEST = [ 'test/compare.js' ];
 var TEST = [ 'test/*.js' ];
 
 var LINT = [
diff --git a/test/comment.js b/test/comment.js
index 42bcc36e..57806f39 100644
--- a/test/comment.js
+++ b/test/comment.js
@@ -62,8 +62,6 @@ function test(code, expected) {
 describe('comment test', function () {
     fs.readdirSync(__dirname + '/comment').sort().forEach(function(file) {
         var code, expected, p;
-        //if (/comment-as-first-element-in-parenthesis-expression\.js$/.test(file) && !/comment-as-first-element-in-parenthesis-expression\.expected\.js$/.test(file)) {
-        //if (/^computed-property-comments-2\.js$/.test(file) && !/^computed-property-comments-2\.expected\.js$/.test(file)) {
         if (/\.js$/.test(file) && !/expected\.js$/.test(file)) {
             it(file, function () {
                 p = file.replace(/\.js$/, '.expected.js');
diff --git a/test/comment/comment-as-first-element-in-parenthesis-expression.js b/test/comment/comment-as-first-element-in-parenthesis-expression.js
index bea0dab4..e87d0528 100644
--- a/test/comment/comment-as-first-element-in-parenthesis-expression.js
+++ b/test/comment/comment-as-first-element-in-parenthesis-expression.js
@@ -84,4 +84,4 @@ var test = [
     2,
     // Test 3
     3+3
-];
\ No newline at end of file
+];

From d9005c90e2d013d2c290b9760840e50b043be1cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Mon, 19 Oct 2020 21:25:06 +0200
Subject: [PATCH 10/12] cleanup

---
 escodegen.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/escodegen.js b/escodegen.js
index 00440538..044b1a8e 100644
--- a/escodegen.js
+++ b/escodegen.js
@@ -732,7 +732,7 @@
         if (stmt.leadingComments && stmt.leadingComments.length > 0) {
             save = result;
 
-            if (preserveBlankLines) { // TODO?
+            if (preserveBlankLines) {
                 comment = stmt.leadingComments[0];
                 result = [];
 

From a5ed1fd33570fa404b415ce084bfa10a10381c45 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Mon, 19 Oct 2020 21:25:34 +0200
Subject: [PATCH 11/12] cleanup

---
 test/compare-harmony.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/compare-harmony.js b/test/compare-harmony.js
index ae314eb3..3579da9a 100644
--- a/test/compare-harmony.js
+++ b/test/compare-harmony.js
@@ -87,7 +87,6 @@ DIR = 'compare-harmony';
 describe('compare harmony test', function () {
     fs.readdirSync(__dirname + '/' + DIR).sort().forEach(function(file) {
         var code, expected, exp, min;
-        //if (/templates-escape\.js$/.test(file) && !/templates-escape\.expected\.js$/.test(file) && !/templates-escape\.expected\.min\.js$/.test(file)) {
         if (/\.js$/.test(file) && !/expected\.js$/.test(file) && !/expected\.min\.js$/.test(file)) {
             it(file, function () {
                 exp = file.replace(/\.js$/, '.expected.js');

From 5f13bfd48db7fb61b781c9df394608d730847cc7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Lu=C4=8Div=C5=88=C3=A1k?= <pavel.lucivnak@gmail.com>
Date: Mon, 19 Oct 2020 21:30:25 +0200
Subject: [PATCH 12/12] prettify

---
 escodegen.js | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/escodegen.js b/escodegen.js
index 044b1a8e..eb06961f 100644
--- a/escodegen.js
+++ b/escodegen.js
@@ -262,14 +262,14 @@
                 isParenthesized(str, '[', ']');
     }
 
-    function shouldParenthesize(str, parentStmt) {
+    function shouldParenthesize(str, parent) {
         if (!hasLineTerminator(str)) {
             return false;
         }
-        if (parentStmt !== undefined && (
-            parentStmt.type == Syntax.ObjectExpression ||
-            parentStmt.type == Syntax.ArrayExpression ||
-            parentStmt.type == Syntax.Property
+        if (parent !== undefined && (
+            parent.type == Syntax.ObjectExpression ||
+            parent.type == Syntax.ArrayExpression ||
+            parent.type == Syntax.Property
             )) {
             return false;
         }
@@ -725,7 +725,7 @@
         return '/*' + comment.value + '*/';
     }
 
-    function addComments(stmt, result, parentStmt) {
+    function addComments(stmt, result, parent) {
         var i, len, comment, save, tailingToStatement, specialBase, fragment,
             extRange, range, prevRange, prefix, infix, suffix, count;
 
@@ -793,7 +793,7 @@
                 result.push(addIndent(save));
             } else {
                 var text = toSourceNodeWhenNeeded(result).toString();
-                if (shouldParenthesize(text, parentStmt)) {
+                if (shouldParenthesize(text, parent)) {
                     withIndent(function () {
                         result = addMultiLineIndent(result);
                     });
@@ -1064,14 +1064,14 @@
         return result;
     };
 
-    CodeGenerator.prototype.generatePropertyKey = function (expr, computed, parentStmt) {
+    CodeGenerator.prototype.generatePropertyKey = function (expr, computed, parent) {
         var result = [];
 
         if (computed) {
             result.push('[');
         }
 
-        result.push(this.generateExpression(expr, Precedence.Assignment, E_TTT, parentStmt));
+        result.push(this.generateExpression(expr, Precedence.Assignment, E_TTT, parent));
 
         if (computed) {
             result.push(']');
@@ -2571,7 +2571,7 @@
 
     merge(CodeGenerator.prototype, CodeGenerator.Expression);
 
-    CodeGenerator.prototype.generateExpression = function (expr, precedence, flags, parentStmt) {
+    CodeGenerator.prototype.generateExpression = function (expr, precedence, flags, parent) {
         var result, type;
 
         type = expr.type || Syntax.Property;
@@ -2584,7 +2584,7 @@
 
 
         if (extra.comment) {
-            result = addComments(expr, result, parentStmt);
+            result = addComments(expr, result, parent);
         }
 
         return toSourceNodeWhenNeeded(result, expr);