diff --git a/lib/compress.js b/lib/compress.js
index 29914940..b94b5040 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -13553,7 +13553,6 @@ Compressor.prototype.compress = function(node) {
             if (fn.body[0] instanceof AST_Directive) return;
             if (fn.contains_this()) return;
             if (!scope) scope = find_scope(compressor);
-            if (in_async_generator(scope)) return;
             var defined = new Dictionary();
             defined.set("NaN", true);
             while (!(scope instanceof AST_Scope)) {
@@ -13624,7 +13623,7 @@ Compressor.prototype.compress = function(node) {
                     }));
                     return !abort;
                 };
-            } else if (in_await && !is_async(fn)) {
+            } else if (in_await && !is_async(fn) || in_async_generator(scope)) {
                 verify_body = function(stat) {
                     var abort = false;
                     var find_return = new TreeWalker(function(node) {
@@ -13735,7 +13734,7 @@ Compressor.prototype.compress = function(node) {
                     node.value = make_node(AST_Await, call, { expression: value });
                 });
                 body.push(make_node(AST_Return, call, {
-                    value: make_node(AST_Undefined, call).transform(compressor),
+                    value: in_async_generator(scope) ? make_node(AST_Undefined, call).transform(compressor) : null,
                 }));
             }
             return inlined;
diff --git a/test/compress/arrows.js b/test/compress/arrows.js
index a9efd79c..b0c820b3 100644
--- a/test/compress/arrows.js
+++ b/test/compress/arrows.js
@@ -1024,7 +1024,6 @@ 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 04016c9c..5fee9e02 100644
--- a/test/compress/awaits.js
+++ b/test/compress/awaits.js
@@ -415,7 +415,6 @@ inline_block: {
         awaits: true,
         if_return: true,
         inline: true,
-        side_effects: true,
     }
     input: {
         console.log("foo");
@@ -451,7 +450,6 @@ 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 860293b3..cc4d0327 100644
--- a/test/compress/classes.js
+++ b/test/compress/classes.js
@@ -1815,7 +1815,6 @@ 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 d28fe175..b16450d7 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -9611,7 +9611,6 @@ inline_throw: {
         collapse_vars: true,
         inline: true,
         keep_fargs: false,
-        side_effects: true,
         unused: true,
     }
     input: {
@@ -9631,6 +9630,7 @@ 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 d7d38cc8..a8837500 100644
--- a/test/compress/const.js
+++ b/test/compress/const.js
@@ -1287,7 +1287,6 @@ 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 5f149d45..50bfd958 100644
--- a/test/compress/default-values.js
+++ b/test/compress/default-values.js
@@ -1930,7 +1930,6 @@ 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 62b22a52..10a4b1f5 100644
--- a/test/compress/functions.js
+++ b/test/compress/functions.js
@@ -607,7 +607,6 @@ empty_body: {
 inline_binary_and: {
     options = {
         inline: true,
-        side_effects: true,
     }
     input: {
         console.log(function() {
@@ -627,9 +626,10 @@ inline_binary_and: {
                 return "bar";
             }()) {
                 while (console.log("baz"));
+                return void "moo";
                 return;
             } else
-                return;
+                return void 0;
         }());
     }
     expect_stdout: [
@@ -1121,7 +1121,6 @@ inline_return_binary: {
 inline_return_conditional: {
     options = {
         inline: true,
-        side_effects: true,
     }
     input: {
         console.log(function() {
@@ -2296,7 +2295,6 @@ duplicate_argnames_4: {
     options = {
         if_return: true,
         inline: true,
-        side_effects: true,
     }
     input: {
         (function() {
@@ -5547,7 +5545,6 @@ issue_3833_2: {
         inline: true,
         keep_fargs: false,
         reduce_vars: true,
-        side_effects: true,
         toplevel: true,
         unused: true,
     }
@@ -5613,7 +5610,6 @@ issue_3836_2: {
     options = {
         if_return: true,
         inline: true,
-        side_effects: true,
     }
     input: {
         (function() {
@@ -5871,7 +5867,6 @@ statement_var_inline: {
     options = {
         inline: true,
         join_vars: true,
-        side_effects: true,
         unused: true,
     }
     input: {
@@ -6162,7 +6157,6 @@ issue_4261: {
         inline: true,
         reduce_funcs: true,
         reduce_vars: true,
-        side_effects: true,
         toplevel: true,
         unused: true,
     }
@@ -6455,7 +6449,6 @@ issue_4659_1: {
         if_return: true,
         inline: true,
         reduce_vars: true,
-        side_effects: true,
     }
     input: {
         var a = 0;
@@ -6493,7 +6486,6 @@ issue_4659_2: {
         if_return: true,
         inline: true,
         reduce_vars: true,
-        side_effects: true,
     }
     input: {
         var a = 0;
@@ -6518,7 +6510,7 @@ issue_4659_2: {
             function f() {
                 return a++;
             }
-            f && a++;
+            void (f && a++);
             (function() {
                 var a = console && a;
             })();
@@ -6533,7 +6525,6 @@ issue_4659_3: {
         if_return: true,
         inline: true,
         reduce_vars: true,
-        side_effects: true,
         unused: true,
     }
     input: {
@@ -6740,7 +6731,6 @@ issue_4725_2: {
     options = {
         if_return: true,
         inline: true,
-        side_effects: true,
     }
     input: {
         var o = {
@@ -7725,7 +7715,6 @@ issue_5239: {
         functions: true,
         inline: true,
         reduce_vars: true,
-        side_effects: true,
         unused: true,
     }
     input: {
@@ -7741,6 +7730,7 @@ issue_5239: {
             var f = void 0;
             var a = 42, f = function() {};
             while (console.log(f.p || a++));
+            return;
         })();
     }
     expect_stdout: "42"
@@ -7843,7 +7833,7 @@ issue_5249_1: {
                 var a = "FAIL 1";
             else if (a) {
                 while (console.log("FAIL 2"));
-                return void 0;
+                return;
             } else
                 return void 0;
             throw "FAIL 3";
@@ -8006,7 +7996,6 @@ issue_5264_1: {
             (function(arguments) {
                 console.log(arguments);
                 while (console.log("foo"));
-                0;
             })("bar");
             return arguments;
         }("baz")[0]);
@@ -8125,7 +8114,6 @@ issue_5290: {
 issue_5296: {
     options = {
         inline: true,
-        side_effects: true,
     }
     input: {
         var a = "PASS";
@@ -8388,7 +8376,6 @@ issue_5409: {
         inline: true,
         merge_vars: true,
         reduce_vars: true,
-        side_effects: true,
         unused: true,
     }
     input: {
@@ -8406,6 +8393,7 @@ issue_5409: {
             a = void 0;
             console.log(a && a);
             while (!console);
+            return;
         })();
     }
     expect_stdout: "undefined"
diff --git a/test/compress/spreads.js b/test/compress/spreads.js
index 21d99473..82658dfe 100644
--- a/test/compress/spreads.js
+++ b/test/compress/spreads.js
@@ -188,7 +188,6 @@ 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 c2061d40..10f76940 100644
--- a/test/compress/yields.js
+++ b/test/compress/yields.js
@@ -836,10 +836,8 @@ inline_nested_async: {
 
 inline_nested_block: {
     options = {
-        dead_code: true,
         if_return: true,
         inline: true,
-        side_effects: true,
         yields: true,
     }
     input: {
@@ -859,6 +857,7 @@ inline_nested_block: {
         var a = function*() {
             for (var a of [ "foo", "bar" ])
                 yield a;
+            "FAIL";
         }(), b;
         do {
             b = a.next();
@@ -1468,6 +1467,80 @@ issue_5385_2: {
     node_version: ">=10"
 }
 
+issue_5385_3: {
+    options = {
+        inline: true,
+    }
+    input: {
+        (async function*() {
+            return function() {
+                try {
+                    throw console.log("foo");
+                } catch (e) {
+                    return console.log("bar");
+                }
+            }();
+        })().next();
+        console.log("moo");
+    }
+    expect: {
+        (async function*() {
+            try {
+                throw console.log("foo");
+            } catch (e) {
+                return console.log("bar");
+            }
+            return void 0;
+        })().next();
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+    ]
+    node_version: ">=10"
+}
+
+issue_5385_4: {
+    options = {
+        awaits: true,
+        inline: true,
+    }
+    input: {
+        (async function*() {
+            return async function() {
+                try {
+                    return {
+                        then(resolve) {
+                            resolve(console.log("FAIL"));
+                        },
+                    };
+                } finally {
+                    return "PASS";
+                }
+            }();
+        })().next().then(o => console.log(o.value, o.done));
+    }
+    expect: {
+        (async function*() {
+            return async function() {
+                try {
+                    return {
+                        then(resolve) {
+                            resolve(console.log("FAIL"));
+                        },
+                    };
+                } finally {
+                    return "PASS";
+                }
+            }();
+        })().next().then(o => console.log(o.value, o.done));
+    }
+    expect_stdout: "PASS true"
+    node_version: ">=10"
+}
+
 issue_5425: {
     options = {
         assignments: true,