fix escape analysis for `AST_Conditional` & `AST_Sequence` (#2563)

fixes #2560

2 files changed, 80 insertions, 1 deletions

diff --git a/lib/compress.js b/lib/compress.js
index e59dce63..c80192dc 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -656,7 +656,9 @@ merge(Compressor.prototype, {
                 || parent instanceof AST_VarDef && node === parent.value) {
                 d.escaped = true;
                 return;
-            } else if (parent instanceof AST_Array) {
+            } else if (parent instanceof AST_Array
+                || parent instanceof AST_Conditional && node !== parent.condition
+                || parent instanceof AST_Sequence && node === parent.tail_node()) {
                 mark_escaped(d, scope, parent, parent, level + 1);
             } else if (parent instanceof AST_ObjectKeyVal && node === parent.value) {
                 var obj = tw.parent(level + 1);
diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index 4a098f78..9a66d1cb 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -4544,3 +4544,80 @@ issue_2455: {
         }
     }
 }
+
+issue_2560_1: {
+    options = {
+        reduce_funcs: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function main() {
+            var thing = baz();
+            if (thing !== (thing = baz()))
+                console.log("FAIL");
+            else
+                console.log("PASS");
+        }
+        function baz(s) {
+            return s ? foo : bar;
+        }
+        function foo() {}
+        function bar() {}
+        main();
+    }
+    expect: {
+        function baz(s) {
+            return s ? foo : bar;
+        }
+        function foo() {}
+        function bar() {}
+        (function() {
+            var thing = baz();
+            if (thing !== (thing = baz()))
+                console.log("FAIL");
+            else
+                console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_2560_2: {
+    options = {
+        reduce_funcs: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function main() {
+            var thing = baz();
+            if (thing !== (thing = baz()))
+                console.log("FAIL");
+            else
+                console.log("PASS");
+        }
+        function baz() {
+            return foo, bar;
+        }
+        function foo() {}
+        function bar() {}
+        main();
+    }
+    expect: {
+        function baz() {
+            return function() {}, bar;
+        }
+        function bar() {}
+        (function() {
+            var thing = baz();
+            if (thing !== (thing = baz()))
+                console.log("FAIL");
+            else
+                console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}