From f1b3e9df1e4d009a653ae26f1ba51809f3364c95 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Sun, 26 Jun 2022 13:48:14 +0100
Subject: [PATCH] fix corner case in `inline` (#5527)

fixes #5526
---
 lib/compress.js                 |  8 +++++--
 test/compress/arrows.js         |  1 +
 test/compress/awaits.js         |  2 ++
 test/compress/classes.js        |  1 +
 test/compress/collapse_vars.js  |  2 +-
 test/compress/const.js          |  1 +
 test/compress/default-values.js |  1 +
 test/compress/functions.js      | 26 ++++++++++++++++------
 test/compress/nullish.js        |  1 +
 test/compress/spreads.js        |  1 +
 test/compress/yields.js         | 39 ++++++++++++++++++++++++++++++++-
 11 files changed, 72 insertions(+), 11 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index 10ef1f34..d8160222 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -13523,7 +13523,9 @@ Compressor.prototype.compress = function(node) {
             return make_node(AST_If, self, {
                 condition: make_condition(self.left),
                 body: inlined,
-                alternative: no_return ? null : make_node(AST_Return, self, { value: null }),
+                alternative: no_return ? null : make_node(AST_Return, self, {
+                    value: make_node(AST_Undefined, self).transform(compressor),
+                }),
             });
 
             function make_condition(cond) {
@@ -13723,7 +13725,9 @@ Compressor.prototype.compress = function(node) {
                     if (is_undefined(value)) return;
                     node.value = make_node(AST_Await, call, { expression: value });
                 });
-                body.push(make_node(AST_Return, call, { value: null }));
+                body.push(make_node(AST_Return, call, {
+                    value: make_node(AST_Undefined, call).transform(compressor),
+                }));
             }
             return inlined;
 
diff --git a/test/compress/arrows.js b/test/compress/arrows.js
index b0c820b3..a9efd79c 100644
--- a/test/compress/arrows.js
+++ b/test/compress/arrows.js
@@ -1024,6 +1024,7 @@ issue_5414_1: {
         arrows: true,
         if_return: true,
         inline: true,
+        side_effects: true,
         toplevel: true,
     }
     input: {
diff --git a/test/compress/awaits.js b/test/compress/awaits.js
index c05bd5d6..1e1b482b 100644
--- a/test/compress/awaits.js
+++ b/test/compress/awaits.js
@@ -415,6 +415,7 @@ inline_block: {
         awaits: true,
         if_return: true,
         inline: true,
+        side_effects: true,
     }
     input: {
         console.log("foo");
@@ -450,6 +451,7 @@ inline_block_async: {
         awaits: true,
         if_return: true,
         inline: true,
+        side_effects: true,
     }
     input: {
         console.log("foo");
diff --git a/test/compress/classes.js b/test/compress/classes.js
index 2dc7e3b0..3ea7e283 100644
--- a/test/compress/classes.js
+++ b/test/compress/classes.js
@@ -1815,6 +1815,7 @@ issue_4725_2: {
     options = {
         if_return: true,
         inline: true,
+        side_effects: true,
     }
     input: {
         "use strict";
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index b16450d7..d28fe175 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -9611,6 +9611,7 @@ inline_throw: {
         collapse_vars: true,
         inline: true,
         keep_fargs: false,
+        side_effects: true,
         unused: true,
     }
     input: {
@@ -9630,7 +9631,6 @@ inline_throw: {
         try {
             (function(a) {
                 throw a;
-                return;
             })("PASS");
         } catch (e) {
             console.log(e);
diff --git a/test/compress/const.js b/test/compress/const.js
index a8837500..d7d38cc8 100644
--- a/test/compress/const.js
+++ b/test/compress/const.js
@@ -1287,6 +1287,7 @@ issue_4261_2: {
         inline: true,
         reduce_funcs: true,
         reduce_vars: true,
+        side_effects: true,
         toplevel: true,
         unused: true,
     }
diff --git a/test/compress/default-values.js b/test/compress/default-values.js
index 7fdd83cc..5e24120b 100644
--- a/test/compress/default-values.js
+++ b/test/compress/default-values.js
@@ -1930,6 +1930,7 @@ issue_5057_4: {
             var b = "FAIL 2";
             (function(a = console.log("FAIL 1")) {})(b);
             console.log(a);
+            0;
         })("PASS");
     }
     expect_stdout: "PASS"
diff --git a/test/compress/functions.js b/test/compress/functions.js
index 8c2138bb..62b22a52 100644
--- a/test/compress/functions.js
+++ b/test/compress/functions.js
@@ -607,6 +607,7 @@ empty_body: {
 inline_binary_and: {
     options = {
         inline: true,
+        side_effects: true,
     }
     input: {
         console.log(function() {
@@ -626,7 +627,6 @@ inline_binary_and: {
                 return "bar";
             }()) {
                 while (console.log("baz"));
-                return void "moo";
                 return;
             } else
                 return;
@@ -1121,6 +1121,7 @@ inline_return_binary: {
 inline_return_conditional: {
     options = {
         inline: true,
+        side_effects: true,
     }
     input: {
         console.log(function() {
@@ -2295,6 +2296,7 @@ duplicate_argnames_4: {
     options = {
         if_return: true,
         inline: true,
+        side_effects: true,
     }
     input: {
         (function() {
@@ -5545,6 +5547,7 @@ issue_3833_2: {
         inline: true,
         keep_fargs: false,
         reduce_vars: true,
+        side_effects: true,
         toplevel: true,
         unused: true,
     }
@@ -5582,7 +5585,7 @@ issue_3835: {
             return f();
         })();
     }
-    expect_stdout: true
+    expect_stdout: RangeError("Maximum call stack size exceeded")
 }
 
 issue_3836_1: {
@@ -5610,6 +5613,7 @@ issue_3836_2: {
     options = {
         if_return: true,
         inline: true,
+        side_effects: true,
     }
     input: {
         (function() {
@@ -5867,6 +5871,7 @@ statement_var_inline: {
     options = {
         inline: true,
         join_vars: true,
+        side_effects: true,
         unused: true,
     }
     input: {
@@ -6157,6 +6162,7 @@ issue_4261: {
         inline: true,
         reduce_funcs: true,
         reduce_vars: true,
+        side_effects: true,
         toplevel: true,
         unused: true,
     }
@@ -6449,6 +6455,7 @@ issue_4659_1: {
         if_return: true,
         inline: true,
         reduce_vars: true,
+        side_effects: true,
     }
     input: {
         var a = 0;
@@ -6486,6 +6493,7 @@ issue_4659_2: {
         if_return: true,
         inline: true,
         reduce_vars: true,
+        side_effects: true,
     }
     input: {
         var a = 0;
@@ -6510,7 +6518,7 @@ issue_4659_2: {
             function f() {
                 return a++;
             }
-            void (f && a++);
+            f && a++;
             (function() {
                 var a = console && a;
             })();
@@ -6525,6 +6533,7 @@ issue_4659_3: {
         if_return: true,
         inline: true,
         reduce_vars: true,
+        side_effects: true,
         unused: true,
     }
     input: {
@@ -6731,6 +6740,7 @@ issue_4725_2: {
     options = {
         if_return: true,
         inline: true,
+        side_effects: true,
     }
     input: {
         var o = {
@@ -7715,6 +7725,7 @@ issue_5239: {
         functions: true,
         inline: true,
         reduce_vars: true,
+        side_effects: true,
         unused: true,
     }
     input: {
@@ -7730,7 +7741,6 @@ issue_5239: {
             var f = void 0;
             var a = 42, f = function() {};
             while (console.log(f.p || a++));
-            return;
         })();
     }
     expect_stdout: "42"
@@ -7833,9 +7843,9 @@ issue_5249_1: {
                 var a = "FAIL 1";
             else if (a) {
                 while (console.log("FAIL 2"));
-                return;
+                return void 0;
             } else
-                return;
+                return void 0;
             throw "FAIL 3";
         }());
     }
@@ -7996,6 +8006,7 @@ issue_5264_1: {
             (function(arguments) {
                 console.log(arguments);
                 while (console.log("foo"));
+                0;
             })("bar");
             return arguments;
         }("baz")[0]);
@@ -8114,6 +8125,7 @@ issue_5290: {
 issue_5296: {
     options = {
         inline: true,
+        side_effects: true,
     }
     input: {
         var a = "PASS";
@@ -8376,6 +8388,7 @@ issue_5409: {
         inline: true,
         merge_vars: true,
         reduce_vars: true,
+        side_effects: true,
         unused: true,
     }
     input: {
@@ -8393,7 +8406,6 @@ issue_5409: {
             a = void 0;
             console.log(a && a);
             while (!console);
-            return;
         })();
     }
     expect_stdout: "undefined"
diff --git a/test/compress/nullish.js b/test/compress/nullish.js
index b141d10b..2f438d45 100644
--- a/test/compress/nullish.js
+++ b/test/compress/nullish.js
@@ -308,6 +308,7 @@ issue_4679: {
 issue_5266: {
     options = {
         inline: true,
+        side_effects: true,
     }
     input: {
         [
diff --git a/test/compress/spreads.js b/test/compress/spreads.js
index 82658dfe..21d99473 100644
--- a/test/compress/spreads.js
+++ b/test/compress/spreads.js
@@ -188,6 +188,7 @@ do_inline_3: {
     options = {
         if_return: true,
         inline: true,
+        side_effects: true,
     }
     input: {
         (function() {
diff --git a/test/compress/yields.js b/test/compress/yields.js
index fbbe51a5..c2061d40 100644
--- a/test/compress/yields.js
+++ b/test/compress/yields.js
@@ -836,8 +836,10 @@ inline_nested_async: {
 
 inline_nested_block: {
     options = {
+        dead_code: true,
         if_return: true,
         inline: true,
+        side_effects: true,
         yields: true,
     }
     input: {
@@ -857,7 +859,6 @@ inline_nested_block: {
         var a = function*() {
             for (var a of [ "foo", "bar" ])
                 yield a;
-            "FAIL";
         }(), b;
         do {
             b = a.next();
@@ -1562,3 +1563,39 @@ issue_5506: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_5526: {
+    options = {
+        inline: true,
+        side_effects: true,
+    }
+    input: {
+        (async function*() {
+            try {
+                return function() {
+                    while (console.log("foo"));
+                }();
+            } finally {
+                console.log("bar");
+            }
+        })().next();
+        console.log("baz");
+    }
+    expect: {
+        (async function*() {
+            try {
+                while (console.log("foo"));
+                return void 0;
+            } finally {
+                console.log("bar");
+            }
+        })().next();
+        console.log("baz");
+    }
+    expect_stdout: [
+        "foo",
+        "baz",
+        "bar",
+    ]
+    node_version: ">=10"
+}