fix corner case in side_effects (#5315)

fixes #5314

lib/compress.js

@@ -10019,7 +10019,7 @@ Compressor.prototype.compress = function(node) {
                 return make_sequence(self, convert_args(value)).optimize(compressor);
             }
         }
-        if (is_func) {
+        if (is_func && !fn.contains_this()) {
             var def, value, var_assigned = false;
             if (can_inline
                 && !fn.uses_arguments
@@ -10027,8 +10027,7 @@ Compressor.prototype.compress = function(node) {
                 && !(fn.name && fn instanceof AST_LambdaExpression)
                 && (exp === fn || !recursive_ref(compressor, def = exp.definition(), fn)
                     && fn.is_constant_expression(find_scope(compressor)))
-                && (value = can_flatten_body(stat))
+                && (value = can_flatten_body(stat))) {
-                && !fn.contains_this()) {
                 var replacing = exp === fn || def.single_use && def.references.length - def.replaced == 1;
                 if (can_substitute_directly()) {
                     var args = self.args.slice();

test/compress/default-values.js

@@ -2081,3 +2081,43 @@ issue_5256: {
     expect_stdout: "undefined"
     node_version: ">=8"
 }
+
+issue_5314_1: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        A = this;
+        new function() {
+            (function(a = console.log(this === A ? "PASS" : "FAIL")) {})();
+        }();
+    }
+    expect: {
+        A = this;
+        (function() {
+            (function(a = console.log(this === A ? "PASS" : "FAIL")) {})();
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5314_2: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        A = this;
+        new function() {
+            ((a = console.log(this === A ? "FAIL" : "PASS")) => {})();
+        }();
+    }
+    expect: {
+        A = this;
+        new function() {
+            console.log(this === A ? "FAIL" : "PASS");
+        }();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/compress/destructured.js

@@ -3426,3 +3426,51 @@ issue_5288: {
     expect_stdout: "PASS"
     node_version: ">=6"
 }
+
+issue_5314_1: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        A = this;
+        new function() {
+            (function({
+                [console.log(this === A ? "PASS" : "FAIL")]: a,
+            }) {})(42);
+        }();
+    }
+    expect: {
+        A = this;
+        (function() {
+            (function({
+                [console.log(this === A ? "PASS" : "FAIL")]: a,
+            }) {})(42);
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5314_2: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        A = this;
+        new function() {
+            (({
+                [console.log(this === A ? "FAIL" : "PASS")]: a,
+            }) => {})(42);
+        }();
+    }
+    expect: {
+        A = this;
+        new function() {
+            [ {
+                [console.log(this === A ? "FAIL" : "PASS")]: [].e,
+            } ] = [ 42 ];
+        }();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}