enhance `inline` (#5105)

4 files changed, 62 insertions, 21 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 2c785251..d5fa5663 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -7300,12 +7300,11 @@ merge(Compressor.prototype, {
                 if (node instanceof AST_Destructured) {
                     if (value === null) {
                         value = make_node(AST_Number, node, { value: 0 });
-                    } else if (value) {
-                        if (value.tail_node().write_only === true || value.may_throw_on_access(compressor, true)) {
-                            value = make_node(AST_Array, node, {
-                                elements: value instanceof AST_Sequence ? value.expressions : [ value ],
-                            });
-                        }
+                    } else if (value && (value.tail_node().write_only === true
+                        || value.may_throw_on_access(compressor, true))) {
+                        value = make_node(AST_Array, node, {
+                            elements: value instanceof AST_Sequence ? value.expressions : [ value ],
+                        });
                     }
                     return make_node(AST_DestructuredObject, node, { properties: [] });
                 }
@@ -7935,9 +7934,10 @@ merge(Compressor.prototype, {
                         exprs = trim(exprs, compressor, first_in_statement, array_spread);
                         return exprs && make_sequence(self, exprs.map(convert_spread));
                     }
-                    if (!fn.contains_this()) return make_node(AST_Call, self, self);
+                    if (!fn.contains_this()) self = make_node(AST_Call, self, self);
                 }
             }
+            self.call_only = true;
             return self;
         });
         function drop_class(self, compressor, first_in_statement) {
@@ -9711,13 +9711,19 @@ merge(Compressor.prototype, {
             return safe;
         }
 
+        function noop_value() {
+            return self.call_only ? make_node(AST_Number, self, { value: 0 }) : make_node(AST_Undefined, self);
+        }
+
         function return_value(stat) {
-            if (!stat) return make_node(AST_Undefined, self);
-            if (stat instanceof AST_Return) return stat.value || make_node(AST_Undefined, self);
-            if (stat instanceof AST_SimpleStatement) return make_node(AST_UnaryPrefix, stat, {
-                operator: "void",
-                expression: stat.body
-            });
+            if (!stat) return noop_value();
+            if (stat instanceof AST_Return) return stat.value || noop_value();
+            if (stat instanceof AST_SimpleStatement) {
+                return self.call_only ? stat.body : make_node(AST_UnaryPrefix, stat, {
+                    operator: "void",
+                    expression: stat.body,
+                });
+            }
         }
 
         function can_flatten_body(stat) {
diff --git a/test/compress/awaits.js b/test/compress/awaits.js
index dc278f7e..0a7ae648 100644
--- a/test/compress/awaits.js
+++ b/test/compress/awaits.js
@@ -227,7 +227,7 @@ inline_await_1_trim: {
         console.log("PASS");
     }
     expect: {
-        void 0;
+        0;
         console.log("PASS");
     }
     expect_stdout: "PASS"
@@ -571,7 +571,7 @@ drop_async_1: {
     }
     expect: {
         console.log(function(a) {
-            void (a *= 7);
+            a *= 7;
             return a;
         }(6));
     }
@@ -1774,7 +1774,7 @@ issue_5001: {
     }
     expect: {
         var a = 0;
-        void a++;
+        a++;
         console.log(a ? "PASS" : "FAIL");
     }
     expect_stdout: "PASS"
diff --git a/test/compress/drop-unused.js b/test/compress/drop-unused.js
index 3d2a4f44..dc934c9b 100644
--- a/test/compress/drop-unused.js
+++ b/test/compress/drop-unused.js
@@ -1557,9 +1557,9 @@ issue_2665: {
     }
     expect: {
         var a = 1;
-        !function g() {
+        (function g() {
             a-- && g();
-        }();
+        })();
         console.log(a);
     }
     expect_stdout: "-1"
@@ -3379,7 +3379,7 @@ issue_4834: {
     }
     expect: {
         try {
-            void b.p;
+            b.p;
         } catch (e) {
             console.log("PASS");
         }
diff --git a/test/compress/functions.js b/test/compress/functions.js
index ccfb3044..05d175c1 100644
--- a/test/compress/functions.js
+++ b/test/compress/functions.js
@@ -1171,11 +1171,11 @@ issue_2620_4: {
     }
     expect: {
         var c = "FAIL";
-        !function() {
+        (function() {
             switch (NaN) {
               case void (c = "PASS"):
             }
-        }();
+        })();
         console.log(c);
     }
     expect_stdout: "PASS"
@@ -6565,3 +6565,38 @@ issue_5098: {
     }
     expect_stdout: "PASS"
 }
+
+shorter_without_void: {
+    options = {
+        inline: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a;
+        function f(b) {
+            a = b;
+        }
+        f("foo");
+        console.log(a) || f("bar");
+        console.log(a, f("baz"));
+        console.log(a);
+    }
+    expect: {
+        var a;
+        function f(b) {
+            a = b;
+        }
+        a = "foo";
+        console.log(a) || (a = "bar");
+        console.log(a, f("baz"));
+        console.log(a);
+    }
+    expect_stdout: [
+        "foo",
+        "bar undefined",
+        "baz",
+    ]
+}