fix corner case in collapse_vars (#4946)

lib/compress.js

@@ -1911,7 +1911,8 @@ merge(Compressor.prototype, {
                     if (!--replaced) abort = true;
                     if (is_lhs(node, multi_replacer.parent())) return node;
                     var ref = rvalue.clone();
-                    value_def.references.push(ref);
+                    ref.scope = node.scope;
+                    ref.reference();
                     if (replaced == assign_pos) {
                         abort = true;
                         return make_node(AST_Assign, candidate, {

test/compress/collapse_vars.js

@@ -9245,3 +9245,37 @@ issue_4935: {
     }
     expect_stdout: "1 0"
 }
+
+inline_throw: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        keep_fargs: false,
+        unused: true,
+    }
+    input: {
+        try {
+            (function() {
+                return function(a) {
+                    return function(b) {
+                        throw b;
+                    }(a);
+                };
+            })()("PASS");
+        } catch (e) {
+            console.log(e);
+        }
+    }
+    expect: {
+        try {
+            (function(a) {
+                return function() {
+                    throw a;
+                }();
+            })("PASS");
+        } catch (e) {
+            console.log(e);
+        }
+    }
+    expect_stdout: "PASS"
+}

test/reduce.js

@@ -46,7 +46,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
     if (verbose) {
         log("// Node.js " + process.version + " on " + os.platform() + " " + os.arch());
     }
-    if (differs.error && [ "DefaultsError", "SyntaxError" ].indexOf(differs.error.name) < 0) {
+    if (differs && differs.error && [ "DefaultsError", "SyntaxError" ].indexOf(differs.error.name) < 0) {
         test_for_diff = test_minify;
         differs = test_for_diff(testcase, minify_options, result_cache, max_timeout);
     }