fix AST_PropAccess in collapse_vars (take 2) (#2372)

fixes #2364

lib/compress.js

@@ -839,8 +839,7 @@ merge(Compressor.prototype, {
                         if (node instanceof AST_Call
                             || node instanceof AST_Exit
                             || node instanceof AST_PropAccess
-                                && (node.has_side_effects(compressor)
+                                && (side_effects || node.has_side_effects(compressor))
-                                    || get_symbol(node).name in lvalues)
                             || node instanceof AST_SymbolRef
                                && (lvalues[node.name]
                                    || side_effects && !references_in_scope(node.definition()))

test/compress/collapse_vars.js

@@ -2711,3 +2711,75 @@ issue_2364_2: {
         }
     }
 }
+
+issue_2364_3: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+    }
+    input: {
+        function inc(obj) {
+            return obj.count++;
+        }
+        function foo(bar) {
+            var result = inc(bar);
+            return foo.amount = bar.count, result;
+        }
+        var data = {
+            count: 0,
+        };
+        var answer = foo(data);
+        console.log(foo.amount, answer);
+    }
+    expect: {
+        function inc(obj) {
+            return obj.count++;
+        }
+        function foo(bar) {
+            var result = inc(bar);
+            return foo.amount = bar.count, result;
+        }
+        var data = {
+            count: 0,
+        };
+        var answer = foo(data);
+        console.log(foo.amount, answer);
+    }
+    expect_stdout: "1 0"
+}
+
+issue_2364_4: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+    }
+    input: {
+        function inc(obj) {
+            return obj.count++;
+        }
+        function foo(bar, baz) {
+            var result = inc(bar);
+            return foo.amount = baz.count, result;
+        }
+        var data = {
+            count: 0,
+        };
+        var answer = foo(data, data);
+        console.log(foo.amount, answer);
+    }
+    expect: {
+        function inc(obj) {
+            return obj.count++;
+        }
+        function foo(bar, baz) {
+            var result = inc(bar);
+            return foo.amount = baz.count, result;
+        }
+        var data = {
+            count: 0,
+        };
+        var answer = foo(data, data);
+        console.log(foo.amount, answer);
+    }
+    expect_stdout: "1 0"
+}