fix corner case in side_effects (#5490)

fixes #5489

lib/compress.js

@@ -8638,17 +8638,26 @@ Compressor.prototype.compress = function(node) {
             if (base || self.name || !compressor.has_directive("use strict")) {
                 var node = to_class_expr(self);
                 if (!base) node.extends = null;
-                node.properties = values ? values.length == init ? values : [ make_node(AST_ClassField, self, {
+                node.properties = [];
+                if (values) {
+                    if (values.length == init) {
+                        if (exprs.length) values.unshift(make_node(AST_ClassField, self, {
+                            key: make_sequence(self, exprs),
+                            value: null,
+                        }));
+                        node.properties = values;
+                    } else node.properties.push(make_node(AST_ClassField, self, {
                         static: true,
                         key: exprs.length ? make_sequence(self, exprs) : "c",
                         value: make_value(),
-                }) ] : exprs.length ? [ make_node(AST_ClassMethod, self, {
+                    }));
+                } else if (exprs.length) node.properties.push(make_node(AST_ClassMethod, self, {
                     key: make_sequence(self, exprs),
                     value: make_node(AST_Function, self, {
                         argnames: [],
                         body: [],
                     }).init_vars(node),
-                }) ] : [];
+                }));
                 return node;
             }
             if (values) exprs.push(make_node(AST_Call, self, {

test/compress/classes.js

@@ -3084,3 +3084,62 @@ issue_5481: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_5489: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        (class {
+            [console.log("foo")];
+            static {
+                console.log("bar");
+            }
+            static [console.log("baz")]() {}
+        });
+    }
+    expect: {
+        (class {
+            [(console.log("foo"), console.log("baz"))];
+            static {
+                console.log("bar");
+            }
+        });
+    }
+    expect_stdout: [
+        "foo",
+        "baz",
+        "bar",
+    ]
+    node_version: ">=16"
+}
+
+issue_5489_strict: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        "use strict";
+        (class {
+            [console.log("foo")];
+            static {
+                console.log("bar");
+            }
+            static [console.log("baz")]() {}
+        });
+    }
+    expect: {
+        "use strict";
+        console.log("foo"),
+        console.log("baz"),
+        (() => (() => {
+            console.log("bar");
+        })())();
+    }
+    expect_stdout: [
+        "foo",
+        "baz",
+        "bar",
+    ]
+    node_version: ">=16"
+}