fix corner case in inline (#5083)

fixes #5082

lib/compress.js

@@ -9522,11 +9522,9 @@ merge(Compressor.prototype, {
                         refs.forEach(function(ref) {
                             ref.scope = exp === fn ? fn.parent_scope : exp.scope;
                             ref.reference();
-                            if (replacing) {
+                            var def = ref.definition();
-                                ref.definition().replaced++;
+                            if (replacing) def.replaced++;
-                            } else {
+                            def.single_use = false;
-                                ref.definition().single_use = false;
-                            }
                         });
                         return node;
                     } else if (!node.has_side_effects(compressor)) {

test/compress/classes.js

@@ -2008,3 +2008,61 @@ issue_5053_4: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_5082_1: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            class B {
+                static P = new A();
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            new A();
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5082_2: {
+    options = {
+        inline: true,
+        passes: 2,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            class B {
+                static P = new A();
+            }
+        })();
+    }
+    expect: {
+        void new class {
+            p = console.log("PASS");
+            q() {}
+        }();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}