fix AST_PropAccess in collapse_vars (take 3) (#2375)

Suppress scanning beyond assignment to `a.b`

lib/compress.js

@@ -838,11 +838,12 @@ merge(Compressor.prototype, {
                         if (node instanceof AST_Call
                             || node instanceof AST_Exit
                             || node instanceof AST_PropAccess
-                                && (side_effects || node.has_side_effects(compressor))
+                                && (side_effects || node.expression.may_throw_on_access(compressor))
                             || node instanceof AST_SymbolRef
                                && (lvalues[node.name]
                                    || side_effects && !references_in_scope(node.definition()))
-                            || (sym = lhs_or_def(node)) && get_symbol(sym).name in lvalues
+                            || (sym = lhs_or_def(node))
+                                && (sym instanceof AST_PropAccess || sym.name in lvalues)
                             || parent instanceof AST_Binary && lazy_op(parent.operator)
                             || parent instanceof AST_Case
                             || parent instanceof AST_Conditional
@@ -933,30 +934,15 @@ merge(Compressor.prototype, {
                 }
             }
 
-            function get_symbol(node) {
-                while (node instanceof AST_PropAccess) node = node.expression;
-                return node;
-            }
-
             function get_lvalues(expr) {
                 var lvalues = Object.create(null);
                 if (expr instanceof AST_Unary) return lvalues;
-                var scope;
                 var tw = new TreeWalker(function(node, descend) {
-                    if (node instanceof AST_Scope) {
+                    var sym = node;
-                        var save_scope = scope;
+                    while (sym instanceof AST_PropAccess) sym = sym.expression;
-                        descend();
+                    if (sym instanceof AST_SymbolRef || sym instanceof AST_This) {
-                        scope = save_scope;
-                        return true;
-                    }
-                    if (node instanceof AST_PropAccess
-                        || node instanceof AST_SymbolRef
-                        || node instanceof AST_This) {
-                        var sym = get_symbol(node);
-                        if (sym instanceof AST_SymbolRef || node instanceof AST_This) {
                         lvalues[sym.name] = lvalues[sym.name] || is_lhs(node, tw.parent());
                     }
-                    }
                 });
                 expr[expr instanceof AST_Assign ? "right" : "value"].walk(tw);
                 return lvalues;

test/compress/collapse_vars.js

@@ -2783,3 +2783,171 @@ issue_2364_4: {
     }
     expect_stdout: "1 0"
 }
+
+issue_2364_5: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        pure_getters: true,
+        properties: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f0(o, a, h) {
+            var b = 3 - a;
+            var obj = o;
+            var seven = 7;
+            var prop = 'run';
+            var t = obj[prop](b)[seven] = h;
+            return t;
+        }
+    }
+    expect: {
+        function f0(o, a, h) {
+            return o.run(3 - a)[7] = h;
+        }
+    }
+}
+
+issue_2364_6: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+    }
+    input: {
+        function f(a, b) {
+            var c = a.p;
+            b.p = "FAIL";
+            return c;
+        }
+        var o = {
+            p: "PASS"
+        }
+        console.log(f(o, o));
+    }
+    expect: {
+        function f(a, b) {
+            var c = a.p;
+            b.p = "FAIL";
+            return c;
+        }
+        var o = {
+            p: "PASS"
+        }
+        console.log(f(o, o));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_2364_7: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+    }
+    input: {
+        function f(a, b) {
+            var c = a.p;
+            b.f();
+            return c;
+        }
+        var o = {
+            p: "PASS",
+            f: function() {
+                this.p = "FAIL";
+            }
+        }
+        console.log(f(o, o));
+    }
+    expect: {
+        function f(a, b) {
+            var c = a.p;
+            b.f();
+            return c;
+        }
+        var o = {
+            p: "PASS",
+            f: function() {
+                this.p = "FAIL";
+            }
+        }
+        console.log(f(o, o));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_2364_8: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+    }
+    input: {
+        function f(a, b, c) {
+            var d = a[b.f = function() {
+                return "PASS";
+            }];
+            return c.f(d);
+        }
+        var o = {
+            f: function() {
+                return "FAIL";
+            }
+        };
+        console.log(f({}, o, o));
+    }
+    expect: {
+        function f(a, b, c) {
+            var d = a[b.f = function() {
+                return "PASS";
+            }];
+            return c.f(d);
+        }
+        var o = {
+            f: function() {
+                return "FAIL";
+            }
+        };
+        console.log(f({}, o, o));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_2364_9: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+    }
+    input: {
+        function f(a, b) {
+            var d = a();
+            return b.f(d);
+        }
+        var o = {
+            f: function() {
+                return "FAIL";
+            }
+        };
+        console.log(f(function() {
+            o.f = function() {
+                return "PASS";
+            };
+        }, o));
+    }
+    expect: {
+        function f(a, b) {
+            var d = a();
+            return b.f(d);
+        }
+        var o = {
+            f: function() {
+                return "FAIL";
+            }
+        };
+        console.log(f(function() {
+            o.f = function() {
+                return "PASS";
+            };
+        }, o));
+    }
+    expect_stdout: "PASS"
+}