fix corner case in collapse_vars (#5748)

fixes #5747

lib/compress.js

@@ -2474,8 +2474,10 @@ Compressor.prototype.compress = function(node) {
                 if (node instanceof AST_Scope) return node;
                 // Scan computed keys, static fields & initializers in class
                 if (node instanceof AST_Class) {
-                    if (node.name) node.name = node.name.transform(tt);
-                    if (!abort && node.extends) node.extends = node.extends.transform(tt);
+                    var replace = can_replace;
+                    can_replace = false;
+                    if (node.name) node.name.transform(tt);
+                    if (!abort && node.extends) node.extends.transform(tt);
                     var fields = [], stats = [];
                     for (var i = 0; !abort && i < node.properties.length; i++) {
                         var prop = node.properties[i];
@@ -2491,9 +2493,9 @@ Compressor.prototype.compress = function(node) {
                         stats[i].transform(tt);
                     }
                     for (var i = 0; !abort && i < fields.length; i++) {
-                        var prop = fields[i];
-                        prop.value = prop.value.transform(tt);
+                        fields[i].value.transform(tt);
                     }
+                    can_replace = replace;
                     return node;
                 }
                 // Scan object only in a for-in/of statement

test/compress/classes.js

@@ -1165,9 +1165,9 @@ collapse_rhs_static: {
         "use strict";
         var a = "FAIL";
         class A {
-            static p = a = "PASS";
+            static p = "PASS";
         }
-        console.log(a);
+        console.log(a = "PASS");
     }
     expect_stdout: "PASS"
     node_version: ">=12"
@@ -3974,3 +3974,59 @@ issue_5735_2: {
     ]
     node_version: ">=12"
 }
+
+issue_5747_1: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        "use strict";
+        (async function() {
+            var a = await 42;
+            class A {
+                static P = a && console.log(typeof this);
+            }
+        })();
+    }
+    expect: {
+        "use strict";
+        (async function() {
+            var a = await 42;
+            class A {
+                static P = a && console.log(typeof this);
+            }
+        })();
+    }
+    expect_stdout: "function"
+    node_version: ">=12"
+}
+
+issue_5747_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        "use strict";
+        (async function() {
+            var a = await 42;
+            class A {
+                static {
+                    a && console.log(typeof this);
+                }
+            }
+        })();
+    }
+    expect: {
+        "use strict";
+        (async function() {
+            var a = await 42;
+            class A {
+                static {
+                    a && console.log(typeof this);
+                }
+            }
+        })();
+    }
+    expect_stdout: "function"
+    node_version: ">=16"
+}

test/reduce.js

@@ -539,7 +539,9 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
     var before_iterations, diff_error_message, passes = 3, testcase_ast;
     for (var pass = 1; pass <= passes; pass++) {
         if (before_iterations !== testcase) {
-            testcase_ast = U.parse(testcase);
+            testcase_ast = U.parse(testcase, {
+                module: minify_options.module,
+            });
             if (diff_error_message === testcase) {
                 // only difference detected is in error message, so expose that and try again
                 testcase_ast.transform(new U.TreeTransformer(function(node, descend) {
@@ -561,7 +563,9 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                     testcase = code;
                     differs = diff;
                 } else {
-                    testcase_ast = U.parse(testcase);
+                    testcase_ast = U.parse(testcase, {
+                        module: minify_options.module,
+                    });
                 }
             }
             diff_error_message = null;